Citation
The Use of indirect tests in the evaluation of malingered or exaggerated memory performance

Material Information

Title:
The Use of indirect tests in the evaluation of malingered or exaggerated memory performance
Creator:
White, Travis Gordon, 1965-
Publication Date:
Language:
English
Physical Description:
vi, 252 leaves : ill. ; 29 cm.

Subjects

Subjects / Keywords:
Amnesia ( jstor )
Clinical psychology ( jstor )
Craniocerebral trauma ( jstor )
Experimentation ( jstor )
Head ( jstor )
Malingering ( jstor )
Memory ( jstor )
Memory interference ( jstor )
Memory retrieval ( jstor )
Symptomatology ( jstor )
Amnesia -- diagnosis ( mesh )
Data Interpretation, Statistical ( mesh )
Head Injuries, Closed ( mesh )
Malingering -- diagnosis ( mesh )
Malingering -- psychology ( mesh )
Memory Disorders -- diagnosis ( mesh )
Neuropsychological Tests ( mesh )
Reproducibility of Results ( mesh )
City of Gainesville ( local )
Genre:
bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )

Notes

Thesis:
Thesis (Ph. D.)--University of Florida, 1992.
Bibliography:
Includes bibliographical references (leaves 230-251).
General Note:
Typescript.
General Note:
Vita.
Statement of Responsibility:
by Travis Gordon White, Jr.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
49614013 ( OCLC )
ocm49614013
0028045134 ( ALEPH )

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Full Text









THE USE OF INDIRECT TESTS IN THE EVALUATION OF MALINGERED
OR EXAGGERATED MEMORY PERFORMANCE












By

TRAVIS G. WHITE, JR.


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA


1992













ACKNOWLEDGEMENTS

I would like to extend my gratitude to those who provided the expertise,

encouragement, and support that enabled the completion of this project. Dr.

Russell Bauer is to be thanked for his multifaceted contributions to my graduate

school training in general and this research project in particular. Dr. Bauer has

been an inspiring example of excellence in clinical practice, academic thought,

and applied research. I hope to always strive to achieve the standards that Dr.

Bauer personifies. My committee members are to be thanked for their

contributions at the inception and culmination of this project. Their attention to

design and methodological issues as well as helpful suggestions at the defense

meeting greatly improved the quality of this project. Dr. Eileen Fennell Is to be

thanked for her donation of equipment and laboratory space. Many people

participated in the arduous task of identifying populations of head injury

patients. Dr. Hugh Brown, Ms. Pat Price, and the special patients of the

Sandybrook Center of Rebound located in Mt. Dora, Florida are to be thanked

for their gracious participation in this project. My family's love, encouragement,

and support were instrumental to the success and completion of this project.

Most importantly, this project could not have been completed without the

unwavering confidence, support, and love of my fiance, Pamela Kennedy.













TABLE OF CONTENTS

ABSTRACT .................................................................................... iv

CHAPTERS

1 INTRODUCTION ............................ ............................... 1

Malingering ............................................................................ 4
Memory Impairment Following Brain Damage ................... 11
Experimental Studies of Malingering .............................. 23
Im plicit Mem ory ................................................................. 53
Hypotheses and Predictions ...................................................... 72

2 M ETHOD ............................................................................. 76

Analysis of Statistical Power ...................................................... 77
Subjects ............................................................................. 78
Design ........................................................................................ 82
Materials ............................................................................. 82
Procedure ............................................................................ 90

3 RESULTS ............................................................................ 104

Descriptive Statistics .............................................................. 105
Experiment 1: Validation of Word Lists .............................. 109
Experim ent 2: Main Study .................................................. 117

4 DISCUSSION ......................................................................... 188

Validity of Group Mem bership ........................................... 188
Experim ental Mem ory Tasks .................................................... 193
Sym ptom Validity Testing ....................................................... 206
Multivariate Detection of Malingering ............................... 213
The "Art" of Detecting Malingering ....................................... 214
Sum m ary ......................................................................... 216








APPENDICES

A PREEXPERIMENTAL MATERIALS ........................................... 218

B EXPERIMENTAL MATERIALS ........................................ 224

C POSTEXPERIMENTAL MATERIALS ........................................ 230

REFERENCES .......................................................................... 233

BIOGRAPHICAL SKETCH .......................................................... 255













Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy

THE USE OF INDIRECT TESTS IN THE EVALUATION OF MALINGERED
OR EXAGGERATED MEMORY PERFORMANCE

By

Travis G. White, Jr.

December, 1992

Chairperson: Russell M. Bauer
Major Department: Clinical and Health Psychology

Claims of amnesia and anterograde memory impairment arise in a variety

of medicolegal contexts. This study examined the performance of normal

subjects given the instructions to malinger or feign memory dysfunction

(Malingerers) on various clinical, two-item forced-choice, and indirect memory

tests. Normal subjects performing to the best of their ability (Genuine subjects)

and patients having sustained a closed head injury with resulting

neuropsychological memory impairment served as the comparison groups.

The results indicated that Malingering subjects lowered their quantitative level of

performance and altered the qualitative aspects of their performance relative to

the Genuine subjects. However, Malingering subjects produced performance

profiles on clinical memory tests which were highly similar to those of the Head







Injured patients with documented neurological damage and bona-fide

neuropsychological memory impairment. In general, no single clinical memory

test or combination of several tests proved useful in diagnosing experimental

malingering.

Word stem completion and perceptual Identification, two commonly used

indirect memory tests, were administered to these subject groups with the

general idea that Malingering subjects might first experience explicit memory for

study items and then engage in postretrieval suppression of correct responses.

This general prediction did not hold up in that Malingering subjects produced

normal strength of priming and levels of processing effects on both indirect

memory tests. However, the results indicated that the Genuine subjects used

explicit memory to increase their strength of priming on word stem completion

but not on perceptual identification.

In contrast to the indirect memory tests, the Symptom Validity Testing

paradigm used in this study was designed as a direct test of short-term

memory. The "art" of SVT lies in the fact that expected performance levels are

not apparent to the typical subject. The main finding concerning the SVT

paradigm was that Malingering subjects, as a group, were impaired relative to

other groups, but scored well above chance levels and demonstrated

surprisingly consistent responding across trials. Several statistical methods

demonstrated that the traditional criterion of chance performance may be

potentially insensitive to malingering response sets.














CHAPTER 1
INTRODUCTION

Claims of amnesia arise in a variety of medicolegal contexts (Wiggins &

Brandt, 1988), especially in cases involving violent crime (Bradford & Smith,

1979). In one review, malingered amnesia was found to be the most frequently

alleged mental defect (Hopwood & Snell, 1933). Hopwood and Snell (1933)

highlight the utility of malingering amnesia for a defendant on trial in a criminal

proceeding. They relate a story of a defendant who, after claiming amnesia for

an alleged murder, has escaped the responsibility for his crime and finds

himself confined to an asylum instead of a prison. He quickly realizes that a

persistence of amnesia for his crime will keep him confined in an asylum and

then suddenly recovers his forgotten memories. This scenario highlights the

volitionality and goal-orientation of malingering. It is also common for claims of

amnesia to arise in civil proceedings (Benton & Spreen, 1961), such as

personal injury suits and disability hearings (Guthkelch, 1980).

The determination of the genuineness of claimed amnesia will often have

a profound impact upon the outcome of legal proceedings. If a claim of

amnesia is judged to be malingered, it can no longer be used to support a

defendant's plea for automatism (i.e., performance of acts without awareness or







2
conscious volition), may result in a partial reduction in, or elimination of,

monetary damages for the plaintiff, and could no doubt discredit other

testimony delivered by the malingerer (Schacter, 1986a). On the other hand, a

successful malingerer reaps highly salient positive reinforcement in a civil

proceeding in the form of monetary compensation and negative reinforcement

in a criminal proceeding in the form of a more desirable disposition.

Memory is a private event and the assessment of its functional integrity is

not always a straightforward process. Given the importance of accurately and

efficiently evaluating neuropsychological function and dysfunction in a forensic

context, the mental health professional is poorly equipped to discriminate

effortful and motivational aspects of a patient's performance (Brandt, 1988).

This state of affairs is readily apparent in the experimental literature involving

malingered amnesia. Taken as a group, the experimental studies attempting to

discriminate between malingered and genuine amnesia have produced mixed

results and are quite difficult to implement in the clinical or medicolegal setting

(Brandt, 1988; Schacter, 1986a, 1986b; Wiggins & Brandt, 1988).

Brandt and his colleagues (Brandt, 1988; Rubinsky & Brandt, 1986) state

that the lay public's perception of normal memory functioning is that it can be

easily faked and that such faking is difficult to detect, in part because of the

belief that it would be easier to withhold behavior (i.e., produce a behavioral

deficit) than it would be to demonstrate a positive symptom. Most researchers

feel that a malingerer will be successful in producing believable deficits to the







3
extent that he has detailed knowledge about the syndrome he is attempting to

simulate and has a refined ability to simultaneously monitor and regulate his

performance throughout a long and anxiety provoking testing situation (see

Binder & Pankratz, 1987, and Goebel, 1983, for more detailed reviews).

It is the aim of this study to examine the performance of normal subjects

given the instructions to malinger memory dysfunction on various clinical and

experimental memory tests, including two perceptual indirect memory tasks

(word stem completion and perceptual identification). These indices may be

sensitive to a malingering response style for several reasons. First, it is unlikely,

even given the recent flurry of academic activity, that a lay person's knowledge

of amnesia would include the knowledge of the dissociation of explicit and

implicit processes. Additionally, the nature of the implicit memory indices (e.g.,

instructions that disguise the memory component; perceptual identification

occurring at or near absolute threshold) may make them somewhat resistant to

volitional control. First, the various theoretical issues related to malingering will

be reviewed. Bona-fide impairment secondary to brain damage will then be

covered. Next, an in-depth review of the literature involving the experimental

portrayal of "mental deficiency," "brain damage," and "amnesia" will be offered.

Implicit memory will be dealt with next. The Introduction section of this paper

will conclude with a statement of the proposed problem and experimental

hypotheses to be tested.







4
Malingerina

Any psychological assessment technique which derives its information

from a person's verbal behavior may be affected by a deceptive response style.

The term "dissimulation" refers to the deliberate distortion or misrepresentation

of symptoms (Rogers, 1988). This category subsumes such concepts as

"defensiveness," "random responding," and "irrelevant responding." This paper

is concerned with another type of dissimulation, malingering. Malingering is

defined by the American Psychiatric Association (APA, 1987) as "the intentional

production of false or grossly exaggerated physical or psychological symptoms,

motivated by external incentives such as avoiding military conscription or duty,

avoiding work, obtaining drugs, or securing better living conditions" (p. 360).

The implicit assumption of this definition is that malingerers are socially deviant

individuals (i.e., those with antisocial personalities) who are likely to fabricate

illness when involved in the legal system and are likely to demonstrate poor

compliance with assessment and treatment procedures (Rogers, 1990a). As

Rogers (1990a) correctly states, the DSM-III-R, in its attempt to remain

theoretical about etiology, nevertheless conceptualizes malingering from a

moralistic and criminological perspective. These issues will be dealt with in

depth in later sections.

Brief History

The concepts and behaviors underlying malingering have been

recognized throughout history (Bash & Alpert, 1980) and have been recorded







5
as early as biblical times (Jones & Uewellyn, 1917, cited in Bash & Alpert,

1980). In military populations, an increase in the prevalence of malingering can

be directly linked to times of war (Anderson, Trethowan, & Kenna, 1959).

Excluding wartime, the emergence of malingering as a diagnostic and legal

entity largely resulted from the Industrial Revolution (Miller & Cartlidge, 1974).

Regler (1879, cited in Miller & Cartlidge, 1974) documented the increased

frequency of malingering as the result of the first accident insurance laws in

Prussia. As technology has progressed, industrial machinery has become

more complex, resulting in more dangerous working conditions and a higher

frequency of both legitimate and malingered injury. Mental health

professionals, including psychologists and neuropsychologists, are testifying as

expert medicolegal witnesses with increasing frequency (Lees-Haley, 1984).

Differential Diagnosis

The concepts of intentionalitv and goal-orientation are central to the

definition of malingering (Cunnien, 1988) and form the basis for differential

diagnosis. Before making the diagnosis of malingering, the clinician must rule

out genuine impairment, factitious disorder, and somatoform disorder.

Factitious disorders are characterized by the "intentional production or feigning

of psychological [or physical] symptoms" due to a "psychological need to

assume the sick role, as evidenced by the absence of external incentives for

the behavior, such as economic gain, better care, or physical well-being." This

disorder must not occur exclusively during the time course of an Axis I mental








6
disorder, such as bipolar disorder (manic phase) (APA, 1987, p. 318). Thus,

the malingerer and the patient with factitious disorder both voluntarily respond

deceptively, with the former being voluntarily motivated to dissimulate by the

prospect of external secondary gain, while the latter reflects an involuntarily

adopted psychological goal to assume the role of sickly patient (Drob & Berger,

1987).

Somatoform disorders refer to a group of psychiatric disorders in which

there are "physical symptoms suggesting physical disorder for which there are

no demonstrable organic findings or known physiologic mechanisms, and for

which there is positive evidence, or a strong presumption, that the symptoms

are linked to psychological factors or conflicts" (APA, 1987, p. 255). Conversion

disorder is subsumed by this category. In somatoform disorders the

mechanisms linking mind and body are presumably not under conscious

control (Reich & Gottfried, 1983). Therefore, a malingerer and an individual with

somatoform disorder both demonstrate physical symptoms that have no known

etiologically significant physical cause, with the former intentionally dissimulating

for an obvious environmental goal, and the latter unintentionally altering his

presentation and no obvious environmental goal.

Classification

One of the most difficult clinical aspects associated with malingering is

classification (Bash & Alpert, 1980). The diagnostic task is made all the more

difficult for the clinician due to the high costs to the medical system from an







7
unrecognized malingerer, as well as the high costs to the patient incorrectly

labeled as a malingerer (Pankratz & Erickson, 1990; Wasyliw & Cavanaugh,

1989). Although debated in the literature, malingering is essentially an act.

performed in specific situations for the purpose of obtaining positive or negative

reinforcement, which exists apart from the actual mental status of the patient

(but see Menninger, 1963 for a discussion of the minority opinion that

malingering is a mental illness). However, malingering can certainly coexist with

mental illness (APA, 1987) and personality disorder (Clark, 1988). The

distinction between an act and a mental status is endorsed by several sources.

First, the American Psychiatric Association (APA, 1987) classifies malingering as

a "V Code," i.e., "a condition not attributable to a mental disorder that is a focus

of treatment" (p. 359). Second, Gorman (1982) states that an act is

differentiated from status in both statute and case law, in the sense that

landmark decisions have established that it is constitutional to punish a person

for performing a wrongful act (e.g., for consuming illegal drugs) but not for his

or her mental status (e.g., for being intoxicated on illegal drugs).

Recent empirical and theoretical work (Rogers, 1987, 1988) has

suggested that the traditional view of malingering as a dichotomous construct

(presence versus absence) is not consistent with clinical observations. Rather,

Rogers states that malingering may in fact be a continuous construct reflecting

gradations of dissimulation. Several authors have advanced classification

schemes for malingering which take this issue into account. Schroeder (1966)







8
divided malingering behavior into four subtypes: (1) pure invention of

symptoms; (2) perseveration. in which formerly genuine, bona-fide symptoms

continue; (3) exaaaeration, in which genuine symptoms are presented as worse

than they actually are; and (4) "transference." in which genuine, bona-fide

symptoms are attributed to an erroneous cause.

Travin and Potter (1984) have suggested three nondiscrete and

overlapping demarcation points on the malingering continuum: (1) other-

deceivers who correspond to the DSM-111-R notion of a fully aware and fully

volitional malingerer; (2) a midrange category of mixed-deceivers, in which the

patient is aware that he making up some aspect of the present symptom but is

not aware that other aspects of the symptom are beyond his control; and (3)

an end-range category of self-deceivers, in which the subject more completely

deceives himself in not realizing the origin of the presented symptoms.

The Development of Malingering

The American Psychiatric Association, faced with a divergence of thought

on the purposes of diagnosis and the underlying theory of psychopathology,

based DSM-III and DSM-III-R on theoretical classification schemes (Rogers,

1990a). Rogers has offered several reviews of the prominent models of

malingering (1990a, 1990b). The pathogenic model of primarily dynamically

oriented analysts (Menninger, 1935; Eissler, 1986) views malingering as an

ineffective defense mechanism which attempts to control psychotic and neurotic

processes by voluntary acceptance and conscious reproduction of the







9
underlying psychopathology. In this view, malingering is an attempt to cope

with underlying psychological and emotional conflicts by accepting and

controlling their expression. While primary mental illness and malingering are

not mutually exclusive, Rogers (1990a) asserts that the pathogenic model offers

little explanatory power for either etiology or motivation.

The DSM-III-R model, discussed previously, can be criticized on several

points (Rogers, 1990a). The emphasis on background and contextual aspects

of the patient's history tends to shift the clinician's focus away from aspects of

the clinical presentation of the suspected malingerer. Specifically, Rogers

states that there is insufficient evidence to support the alleged association of

malingering with antisocial personality disorder. Uncooperativeness with

assessment and treatment procedures is felt to be characteristic of a number of

other bona-fide mental disorders and thus not specific to malingering. The term

"discrepancies with objective findings" is unnecessarily ambiguous. As several

researchers have pointed out, corroborative and naturalistic observational data

rather than "objective data" may prove more useful in the assessment of a

patient's actual impairment (Rogers, 1990a; Rogers & Cunnien, 1986; Pankratz

& Erickson, 1990). For example, informal conversation with the suspected

malingerer after the "evaluation" may reveal detailed and intact memory for the

route taken to the hospital, even though the patient demonstrates severe

impairment on memory tests (Drob & Berger, 1987).







10
The adaptational model shows considerable promise as a conceptual

framework for understanding malingering. This model views malingering as

goal-seeking behavior designed to maximize the chances of success on the

basis of expected utility and likelihood (Rogers, 1990a). This model completely

avoids the overly pathological (malingerers as "mad") and

criminological/moralistic (malingerers as "bad") thinking associated with the

other conceptual models. Rather, malingering behavior is dealt with in terms of

its adaptive value; malingerers are pursuing a course of action that seems to

him or her to be the most effective way of adapting to the difficulties life poses

and of eliciting needed support from others (Pankratz & Erickson, 1990). Most

clinicians would certainly label malingering as "maladaptive" and, to some

extent, "incorrect" (Pankratz & Erickson, 1990; Binder, 1990).

The true value of the adaptational model is that it properly focuses the

clinician on treating the patient, a task which often goes overlooked in the

struggle to accurately diagnose the suspected malingering patient. Viewing

behavior as maladaptive rather than criminalistic also helps the clinician avoid

negative countertransferential reactions to the patient (Rabinowitz, Mark, Modal,

& Margalit, 1990). Pankratz and Erickson (1990) feel that treatment should be

offered to the suspected malingering patient as it would any other; namely,

collaborating with the patient to determine whether psychological treatment

could potentially make the patient's life more fulfilling and satisfying.







11
Memory Impairment Following Brain Damage

Amnesia

Amnesia refers to a condition characterized by the impairment of normal

memory functioning in which a person has an acquired difficulty in learning new

material and in recalling remote events. Amnesia can be classified according to

etiology (organic versus psychogenic) and chronicity (discrete episodes versus

persistent impairment) (Kopelman, 1987). As it is most frequently used,

amnesia refers to a neurological condition that can result from a variety of

etiologic agents and loci of lesions (Butters & Miliotis, 1985). Anoxia,

encephalitis, electroconvulsive therapy (ECT), cerebrovascular accidents, dosed

head injuries, and surgical damage have all produced amnesia in patients

(Drachman & Arbit, 1966; Milner, 1970; Squire, Chace, & Slater, 1976; Levin,

Benton, & Grossman, 1982). Lesions to the medial diencephalic structures,

including the dorsomedial nucleus of the thalamus and the mammillary bodies

(Victor, Adams & Collins, 1971; Butters & Cermak, 1980), the fornix (Heilman &

Sypert, 1977), and the retrosplenial area (e.g., splenium, retrosplenial cortex,

and cingulate bundle) (Valenstein, Bowers, Verfaellie, Heilman, Day & Watson,

1987) have all produced amnesia.

However, amnesia can have a psychogenic etiology as well (Kopelman,

1987). This phenomenon, which has also been referred to as functional

amnesia (Schacter, 1986a), refers to amnesia for a discrete episode of time

occurring in the past. It is produced by severe psychological and emotional







12
trauma. The condition has been well documented and mimics the retrograde

amnesic aspects of organic amnesia (Abeles & Schilder, 1935; Schacter, Wang,

Tuvng, & Friedman, 1982). Amnesia secondary to fugue states (Berrington,

Uddel & Foulds, 1956) and the act of committing a violent crime (see Hopwood

& Snell, 1933) are two examples of temporally discrete amnesias.

Amnesia presents a clinical picture manifesting four distinct

characteristics (Butters & Miliotis, 1985). Al amnesics have anterograde

amnesia, or impairment in the ability to learn new information. Second, all

amnesics have some degree of retrograde amnesia (impairment in retrieving

information learned prior to illness onset). Attentional capacity is spared in

"pure" cases. The above mentioned deficits exist in the presence of intact

intellectual and other higher cortical functions.

Closed Head Iniury

An adequate understanding of malingering in the neuropsychological

context warrants a careful review of the literature involving the etiology and

nature of memory impairment following dosed head injury (CHI), a condition

frequently associated with malingering (Binder, 1990). Impaired memory

functioning is one of the most frequently cited neurobehavioral sequelae of

closed head injury (Brooks, 1972; Levin, Benton, & Grossman, 1982; Schacter

& Crovitz, 1977). Neurotic symptoms are the most common psychiatric

symptoms associated with closed head injury (Ushman, 1973; Miller, 1961) and

include the so-called "accident neurosis" (Miller, 1961), reactive depression in







13
response to a variety of mental and functional losses, and emotional aspects of

postconcussion syndrome (PCS) (Lishman, 1973). While PCS encompasses

many common medical symptoms, it also commonly involves impairment in

attention, concentration, and memory processes. The critical Issue for this

paper is the fact that the etiology of PCS remains a highly controversial issue,

with no clear agreement as to the relative etiological contributions of organic

damage, psychiatric and personality factors, compensation, and litigation

(Binder, 1986). Many investigators have suggested that medicolegal and

related factors may play a significant role in maintaining psychiatric disorder

and memory impairment (Miller, 1961; Levin, Benton, & Grossman, 1982).

Epidemioloav

The magnitude of the problem presented by traumatic brain injury to

modem society is immense (Ushman, 1973). In 1967 three quarters of a million

people sustained a traumatic brain injury in the United States. Of these, 18,000

died, 13,000 sustained permanent disability, and 7,000 sustained temporary

disabilities. In a large sample of severely injured patients, Jennett and

colleagues (Jennett, Snoek, Bond, & Brooks, 1981) found that slightly over half

of their 314 patients remained moderately and severely disabled after six

months. Significant morbidity is associated with even mild injuries (Rimel,

Giordani, Barth, Boll, & Jane, 1981; Binder, 1986).









Neuropatholoa of closed head iniurv

The brain experiences many pathophysiological changes during a

closed head injury. Important determinants of these effects are the direction of

the blow, its force and velocity, and whether the head was free to move at

impact (Nilsson and Ponten, 1977; Ushman, 1973). Regardless of the nature of

the injury, the traumatically injured brain is subject to manifold rotational and

linear stresses which tear and damage nerve fibers (Ushman, 1973). These

changes have been noted after even mild head injury (Strich, 1969). Cortical

lesions are maximal in portions of the frontal and temporal poles (Sekino,

Nakamura, Yuki, Satoh, Kikuchi, & Sanada, 1981). White matter damage is

often found in subcortical tracts, the corpus callosum, and the long tracts of the

brain stem (Lishman, 1987). Adams and colleagues (Adams, Mitchell, Graham,

& Doyle, 1977) have noted that these changes occur immediately after injury

and play an important role in mortality. Concussion and loss of consciousness

are more likely to result from injuries in which the brain is free to move at

impact, producing rotational and shearing forces. Damage to brain stem

centers is usually necessary to produce concussion and loss of consciousness.

In addition to structural damage which occurs following closed head injury,

changes have also been noted in the biochemistry and cerebrovascular

circulation (Ushman, 1973).







15
Memory and learning after PTA termination

Immediate memory. Immediate or short-term memory (STM) refers to

the limited capacity system that holds a limited amount of information over brief

periods of time (less than one minute) (Watkins, 1974). Immediate memory is

usually assessed with the digit span task of the WAIS-R (Wechsler, 1981) or the

Wechsler Memory Scale (Wechsler, 1945).

Immediate memory as reflected by forward digit span is comparatively

resistant to the effects of CHI (Brooks, 1976; Lezak, 1979; Levin, Benton, &

Grossman, 1982). Mildly injured patients generally suffer no reduction in length

of forward digit span, even when tested early after admission (Cronholm &

Jonsson, 1957; Fodor, 1972). Immediate memory as reflected by the more

difficult backward digit span appears more susceptible to the effects of CHI

(Levin, Benton, & Grossman, 1982). Brooks (1976) found the forward digit

span of patients with severe CHI comparable to that of controls, while

backward digit span was significantly impaired relative to controls.

Schacter and Crovitz (1977) state that the findings of normal to near

normal digit span in CHI patients may not provide an adequate test of STM

processes as measured by more demanding tasks. Brooks (1975) used

several experimental methods to investigate STM. He found the short-term

memory abilities of CHI patients lower but not significantly different from those

of controls. Levin, Grossman, and Kelly (1976) have suggested that the format

of information may determine whether deficits are observed in CHI patients.







16
These investigators found CHI patients to have significant difficulty with short-

term recognition of nonverbal designs, even when tested at long intervals after

injury.

To summarize, forward digit span appears relatively insensitive to the

effects of severe CHI, even when tested soon after injury. Backward digit span,

requiring additional information-processing demands, has been shown to be

reduced in the early stages of recovery, but to improve over time. More difficult

tasks, such as varying the format of to-be-remembered information, may

provide a more sensitive index of STM capacities in these patients.

Recent memory. Impaired recent memory functioning (anterograde

amnesia) is one of the most prevalent cognitive impairments following closed

head injury (Brooks, 1972; Levin, Benton, & Grossman, 1982) and is the

primary complaint of most patients and their families (Bond, 1986). Estimates

of the prevalence of persistent memory problems after PTA termination have

varied, from 16% (Udvall, Underoth, & Norlin, 1974) to 23% (Russell & Smith,

1961) to 36% in Russell's (1932) original sample, depending upon the various

methodologies used in the studies (Schacter & Crovitz, 1977).

Brooks (1972) investigated the extent of memory deficit in a group of 27

patients who had sustained severe dosed head injury. The author found that

the CHI patients performed significantly lower than normal controls on all tests

measuring learning and recent memory. These differences were statistically

significant for all indices except the WMS Visual Reproduction subtest







17
(immediate recall). Using the WMS and the Rey Figure, Brooks found that CHI

patients acquired significantly less information initially and they also forgot

proportionately more of this initially acquired information than did controls.

Duration of posttraumatic amnesia had a positive and significant relationship to

immediate memory and forgetting variables.

Brooks (1974) investigated visual recognition memory in a sample of 34

severely head-injured patients using a continuous recognition paradigm. The

results indicated that the CHI patients recognized significantly fewer items,

showed slower learning rates over trials, and committed a significantly higher

proportion of false negative errors than control subjects. Time elapsed

between the injury and the date of testing showed no obvious relationship to

memory performance. Severity of injury, as estimated by duration of PTA,

correlated with the number of correct recognition and false positives. False

negative errors occurred more frequently in the CHI patients regardless of the

severity of the injury, suggesting some kind of threshold effect in that cerebral

trauma produces an all-or-none alteration in the CHI memory abilities. Brooks

interpreted these findings as evidence that the CHI patients adopted a very

strict decision criteria whereby they were unwilling to identify an item as old in

the face of uncertainty.

Brooks (1975) employed a list learning task to assess short- and long-

term memory in a heterogeneous sample of CHI patients. When tested

immediately after presentation, CHI subjects performed similarly to controls for







18
all serial list positions. However, a 20-second interpolated delay interval

between presentation and recall selectively impaired recall in the CHI group.

Brooks then categorized recall words as either STM or LTM, based on Tulving

and Colotla's (1970) criteria. The results indicated that CHI patients scored

lower but not significantly different from controls for STM items. However, the

CHI patients scored significantly lower than did controls for LTM items. Brooks

interpreted his findings as evidence for impaired LTM storage in CHI patients,

with relative sparing of STM processes. Schacter and Crovitz (1977) have been

highly critical of this interpretation, citing methodological flaws in the

experimental memory tasks employed in this study.

Brooks (1976) investigated Wechsler Memory Scale performance in a

sample of 82 severely head-injured patients. With the exception of Mental

Control subtest errors and Digits Forward, CHI patients were inferior to controls

on all other WMS subtests. On Logical Memory, CHI patients were significantly

poorer at an immediate and delayed recall, although their rate of forgetting was

not significantly greater than controls'. CHI patients were significantly lower on

Associate Learning and their rate of learning across trials was lower. In

general, CHI patients demonstrated proportionately more impairment on

delayed memory tasks. Neither focal neurological signs, the presence and site

of skull fracture, nor the elapsed time since injury had appreciable effects on

memory performance. The finding concerning elapsed time since injury is







19
interpreted by Brooks to reflect an early recovery of memory, often in the first

few months after injury, to a permanently deteriorated level.

Lezak (1979) tracked the course of recovery of verbal memory functions

over time in a sample of 24 CHI patients. Estimates of severity of injury were

omitted from her paper. Patients were serially tested at three different points of

recovery. Dependent measures included digit span tests (forward and

backward) and selected variables derived from the Rey Auditory Verbal

Learning Test (RAVLT). The results indicated that on simple measures of

immediate memory, Digits Forward and the first recall trial of the RAVLT, CHI

patients were only mildly impaired at the initial testing and showed consistent

improvement over time. More complex measures of learning were more

significantly impaired and remained so over time. On every measure, the more

severely impaired patients performed more poorly at initial testing than less

severely injured patients. The less severely injured subjects generally

maintained their superiority over more severely injured patients at all three

points of recovery. One interesting finding is that a subset of the CHI patients

showed a deterioration of performance on the complex memory tests at the

final point of testing (three years post injury), suggesting a possible

multifactorial recovery mechanism. Lezak suggested that partial recovery from

a severe injury may occur relatively early on while other pathophysiological

processes may compromise memory efficiency in the later stages of recovery.







20
Gronwall and Wrightson (1981) investigated memory and information

processing capacity following dosed head injury in a heterogeneous sample of

91 patients. Using a variety of cognitive tasks, including the Wechsler Memory

Scale, the Selective Reminding Test, and the Paced Auditory Serial Addition

Task, these investigators isolated three relatively independent cognitive

impairments associated with CHI. Simple and undemanding memory tasks

appear resistant to impairments in information processing capacity, while

memory tasks which involve complex processing demands and time constraints

appear susceptible to this impairment. The ability to store information in LTM

was deficient in CHI patients. This ability was found to be related to either

severity of injury or elapsed time since injury. One quarter of the sample

demonstrated an additional deficit in the ability to retrieve material from LTM

once it has been stored. This impairment bore no relationship between severity

of injury or severity of information processing deficit.

Levin and Goldstein (1986) investigated whether long-term survivors of

severe CHI could gain access to semantic stores and spontaneously use

clustering strategies to guide encoding and retrieval during a list learning task.

The results indicated that controls remembered significantly more words than

CHI patients when tested with free and cued recall paradigms. Both groups

recalled more words when the stimuli were semantically clustered during

learning. Whereas control subjects tended to spontaneously impose their own

clustering to guide encoding and retrieval, CHI patients generally failed to







21
spontaneously use these strategies. Patients with frontotemporal involvement

tended to produce a higher number of intrusion errors. Decreased verbal

intellectual functioning was found to be closely related to impaired verbal

memory functioning. The authors concluded that survivors of severe CHI have

partially preserved semantic memory, although their failure to actively engage In

meta-mnemonic strategies may contribute to reduced memory efficiency.

Crosson and his colleagues (Crosson, Novack, Trenerry, & Craig, 1988)

employed the California Verbal Learning Test (CVLT) to further investigate

qualitative aspects of memory impairment following head injury. The sample

included 33 survivors of severe head injury along with 33 neurologically normal

adult male control subjects. The control group performed at a significantly

higher level than the CHI group on all five individual learning trials. Qualitative

aspects of performance were equated for overall performance level. When

overall level of performance was taken into account, both groups showed

equivalent incremental learning across trials as well as number of

perseverations. CHI patients consistently demonstrated a greater percentage

of intrusions in their response output and a lower level of spontaneous use of

semantic clustering. CHI patients lost a significantly greater amount of

information over delay intervals, as evidenced by impairment on both recall and

recognition probes. The authors interpreted their data as evidence for

disruption in multiple memory processes in survivors of severe CHI, including

problems with encoding, retention, and retrieval of information.







22
Summay. The literature reviewed provides overwhelming evidence for

memory impairment following CHI. While survivors of CHI perform normally on

simple memory tasks, impairment is noted on more complex memory and

learning tasks requiring active and effortful processing of to-be-remembered

information. These patients acquire information at a slower rate than do

normals. They evidence greater forgetting of information after acquisition,

resulting in more marked impairment on delayed memory tests.

The effects of compensation and litigation

Postconcussion syndrome (PCS) refers to a constellation of common

symptoms which include headache, dizziness, irritability, anxiety, blurred vision,

insomnia, easy fatigability, and concentration and memory difficulty (Levin,

Benton, & Grossman, 1982; Ushman, 1973). While PCS as a diagnostic entity

is generally accepted, its etiology remains a hotly contested issue, especially

when symptoms persist for long periods (Binder, 1986). Miller (1961) argued

that PCS is entirely the result of the litigation process. Levin, Benton, and

Grossman (1982) call into question new symptoms that appear after an initial

hospitalization and suggest that the etiology of such symptoms probably is not

organic.

After reviewing the literature concerning the effects of litigation and

compensation on PCS, Binder (1986) concluded that it is not possible to draw

firm conclusions in this area because of a lack of objective evidence.

Specifically, some studies have shown a correlation between claims and







23
disability or persisting subjective symptomatology (Miller, 1961; Cartlidge, 1978).

However, this relationship is not causal; it seems reasonable to assume that a

patient with prolonged symptoms after compensable trauma would be more

likely to make a claim than a patient who recovers quickly (Binder, 1986).

Conversely, research has also shown that prolonged symptoms can persist in

patients with mild head injury who are not seeking compensation (Rimel,

Giordani, Barth, Boll, & Jane, 1981). Binder concludes that the literature does

not support the contention that patients become less symptomatic after a legal

claim is settled.

The point to be made here is that the issue of persisting subjective

symptoms and complaints, in the absence of definitive neuropathological

findings, essentially fulfills one of the DSM-III-R criteria for diagnosing

malingering (Binder, 1990). It is in these cases where there is "discrepancy

between the person's claimed stress or disability and the objective findings"

(APA, 1987, p.360) that malingering becomes a viable yet precarious differential

diagnosis.

Experimental Studies of Malingering

The foregoing discussion emphasizes the importance of thoroughly

evaluating neuropsychological symptomatology in cases of suspected

malingering. Only a few cases have been reported in the literature in which the

patient suspected of malingering either relinquished his symptoms in favor of

genuine responding (Pankratz, 1979) or admitted to having faked impairment







24
(Hartings, 1989). Therefore. clinicians are rarely certain of the true nature of

impairment in cases of questionable motivation. This gives rise to the need for

experimental analog studies which attempt to mimic the clinical situation by

instructing subjects to portray or "simulate" Impairment on testing.

Malingered Mental Deficiency

Pollaczek (1952) investigated the ability of normal college males and

normal Navy recruits to feign feeblemindedness on the "CVS" abbreviated

intelligence scale, a measure which consists of the Comprehension and

Similarities subtests from the Wechsler-Bellevue test and selected vocabulary

items from the Stanford-Binet Intelligence test (Hunt, French, Klebanoff, Mensh,

& Williams, 1948). Fifty male mental retardates were used as the criterion

comparison group. The results indicated that malingering subjects

demonstrated mental impairment equivalent to that of true mental detectives.

Thus, malingerers could not be detected with the use of the CVS total raw

score. An item-by-item analysis revealed significant between-groups differences

on 17 of 37 test items. These critical items were of two types: (1) relatively

easy items occurring at the beginning of each subtest which mental detectives

complete accurately while malingerers failed; and (2) relatively difficult items

occurring at the end of each subtest which mental detectives fail but which

malingerers passed. Cut-off scores were derived and a linear discriminant

function classification produced an 87% sensitivity rate for malingering

subjects, with a 10% false positive rate.







25
Spreen and Benton (1963) instructed subjects to portray the

performance of a "high grade mental defective." Their sample consisted of

three groups composed of genuine mental detectives, medical inpatient

simulators, and normal simulators who were evaluated with Form "C" of the

Visual Retention Test (VRT) (Benton, 1955). The two simulating groups showed

no differences in performance and were subsequently combined into one

group. These investigators found simulators to perform significantly below

mental detectives on measures indicative of overall level of performance (i.e.,

number of correct reproductions and number of circumscribed errors) and to

produce significantly more bizarre or improbable responses than actual mental

detectives. This study has several methodological flaws, however. First, a

normal control group was not employed. Second, and more serious, Spreen

and Benton preexperimentally equated their two simulating groups by their

performances on Form "A" of the VRT. This allowed the simulators to be

exposed to the task in which they would later feign and thus confounded the

results with the effects of preexisting knowledge and practice.

Gudjonsson & Shackleton (1986) looked at the effects of "faking-bad" on

the pattern of scores on the Raven's Matrices test. Subjects included normal

recruited from military settings and a criterion comparison group of 25

neurological patients with bona-fide mental impairment. Several statistical

methods were employed to assess consistency across tests of differing

complexity. The results indicated that malingering subjects failed too many of







26
the easy items at the beginning of the test, resulting in a relatively stable rate of

performance decay as test complexity increased. This pattern of performance

was not characteristic of subjects performing their best or of patients with bona-

fide neurological impairment. Subjects in these conditions scored higher on the

easy portions of the test, resulting in a normal rate of performance decay as

testing complexity increased.

Malingered "Brain Damage"

Anderson, Trewothan, and Kenna (1959) instructed a group of normal

subjects to portray "mental abnormality for some reason best known to

themselves." Various aspects of their behavior were then compared with

groups of patients with documented organic brain damage, pseudodementia

patients (as best can be determined, a mixed group of patients suffering from

mental deficiencies associated with depression and other psychopathology),

and a control group of normal volunteers. Analysis of their data revealed that

the malingering group's level of performance tended to fall between the levels

of the normal group in the unimpaired range and the organic and

pseudodementia group in the impaired range on measures of orientation,

verbal retention and recall, digit span, concentration, mental arithmetic, and

general knowledge. Thus, simulators apparently did not overplay their role. In

the qualitative domain, simulators produced significantly fewer perseverations

than did the organic group.







27
Bruhn and Reed (1975) instructed normal college subjects to simulate

brain damage secondary to concussion and then compared their performance

on the Bender-Gestalt Test with a nonsimulating normal group and a group of

patients with mixed cortical trauma. In their pilot study, Bruhn and Reed found

that both the Pascal-Suttell and Canter scoring methods did poorly in

discriminating organic from simulators. However, a diplomat sorted

malingerers from organic and organic from normals with hit rates of 89% and

92%, respectively. In their main study, two expert raters and one novice used

decision rules derived from the pilot study to obtain similarly accurate

discrimination among the three groups. Thus, nonbrain-damaged subjects

were not successful at malingering brain damage on the Bender-Gestalt test.

Heaton, Smith, Lehman, and Vogt (1978) instructed normal subjects to

"fake the most severe [neuropsychological and psychological] disabilities they

could, without making it obvious to the examiner that they were faking" (p. 894).

Their design included a group of head-injured patients with documented

residual neurologic deficits and a group of normal volunteers given instructions

to malinger. The outcome measures consisted of the WAIS, the Minnesota

Multiphasic Personality Inventory (MMPI), and the Haistead-Reitan

Neuropsychological Test Battery. Their results indicated that the malingerers

exhibited an overall level of performance similar to head-injured patients in that

no group differences were observed on summary measures (three WAIS

intelligence quotients and HRNB impairment indices). Qualitative differences







28
emerged when profile analysis was undertaken. Malingering subjects

significantly underestimated deficits when completing the Category Test, the

Trail Making Test (Part B error component), and all components of the Tactual

Performance Test while they significantly overestimated deficits when

completing the Speech-Sounds Perception Test, the Finger Oscillation Test,

finger agnosia and sensory suppression tasks, grip strength, and digit span.

MMPI profiles of the malingerers revealed clinical elevations on the F scale and

6 clinical scales (1, 3, 6, 7, 8, 0). Therefore, malingering subjects performed

poorly on motor and sensory tasks and produced questionably valid MMPI

profiles, but they performed relatively well on tests sensitive to brain damage.

Heaton et al. (1978) then submitted the test protocols to ten expert judges for

classification. In general, the accuracy of the judges ranged from chance-level

to approximately 20% better than chance. Since the raters were given only test

scores, the poor classification rates may be attributable to the absence of

clinically relevant data, such as interview protocols and behavioral observations.

Finally, results from multivariate discriminant function analyses indicated that

neuropsychological variables accurately predicted group membership in that

100% of the subjects in both malingering and head-injured groups were

correctly classified. Heaton et al. (1978) concluded by stating that the observed

group differences were sufficiently reliable to predict membership in head injury

and malingered head-trauma groups and that MMPI variables may have

improved discriminatory power.







29
Mensch and Woods (1986) examined whether groups of subjects with

normal and above average IQ scores could appear "brain damaged" on the

Luria-Nebraska Neuropsychological Battery if motivated by a small monetary

reward conditional on successful feigning. They employed a double-blind

crossover design. Analysis of their data indicated that 31 of 32 subjects were

able to significantly elevate enough individual scales to suggest brain damage.

However, the malingering subjects' profile of test scores was not qualitatively

consistent with profiles of patients with known neurological pathology. For

example, malingering subjects did not demonstrate significant differences

between the Left and Right hemisphere scales. Malingering subjects

consistently performed quite poorly on sensory motor tests and tests whose

face validity was high and displayed exaggerated response latencies. Mensch

and Woods concluded that the subjects instructed to malinger brain damage in

their study were unsuccessful.

Goebel (1983) investigated the issue of whether naive, neurologically

normal subjects could feign believable deficits on the HRNB, as well as the

more specific question of whether lateralized deficits were more difficult to

simulate than diffuse or nonspecific deficits. Goebel's design consisted of six

groups: mixed neurologic patients, control subjects, and patients told to

simulate either "nonspecific," "diffuse," "left hemisphere," or "right hemisphere"

cortical damage. In a sort of the test protocols, only 2 of 102 malingering

subjects were incorrectly classified (i.e., feigned believable deficits).








30
Goebel implied, but did not provide supporting data, that several

variables (Impairment Index, Category Test, Trails B, and TPT Localization

score) appeared to provide good discriminatory power. Linear discriminant

function analyses revealed that Speech Sounds, TPT Nondominant hand, and

time-to-complete testing were powerful variables in discriminating neurologic

patients from nonpatients. Brain-damaged patients took approximately 1.5

hours longer to complete testing than did non-brain damaged subjects. Grip

Strength Nondominant hand, Finger Tapping Nondominant hand, and WAIS

Performance IQ were powerful variables in discriminating normal controls from

malingering subjects. Goebel also presented data from the debriefing interview

which suggested that individuals were relatively ignorant of brain-behavior

relationships. The most frequently employed strategies of feigning brain

damage included giving wrong answers, slowing of performance, and

displaying motor incoordination.

Hayward, Hall, Hunt, and Zubrick (1987) asked 28 registered nurses with

varying degrees of experience in working with neurological and neurosurgical

patients to simulate performance on a battery of neuropsychological tests in

such a way as to be congruent with a history of trauma to the left

frontotemporal cortex. These data were compared with data obtained from 21

patients with documented cerebral injury and a diagnosis of left frontotemporal

dysfunction. A linear discriminant function analysis resulted in a sensitivity rate

of 86% for both malingering subjects and patients with bona-fide impairment.








31
Specificity rates were 14% for each group. Malingering patients generally

produced lower scores than patients with bona-fide impairment. Malingerers

performed poorly on tests not expected to be affected by left frontotemporal

involvement. Qualitatively, malingering performance was characterized by

elaboration and confabulation (i.e., commission of incorrect behavior), as

opposed to the poverty of content characteristic of the brain-damaged patients.

Malingerers produced types of errors on sensory tests which are not typical of

bona-fide impairment (e.g., confusing digits 1 and 4 on the finger localization

test, instead of the more typical confusion of 2 and 3).

Faust, Hart, & Guilmette (1988) investigated whether a relatively broad

sample of clinicians could identify the malingered protocols of nonsophisticated

subjects. Three children between the ages of 9 and 12 were instructed to "fake

bad" on the HRNB. All three subjects produced impaired performances on this

battery of tests. Information regarding age, sex, handedness, test scores, and

qualitative data from the Aphasia Screening Test was given along with test data

to a random sample of practicing neuropsychologists. Judges rated the results

on normal versus abnormal, etiology, severity of impairment, and confidence in

their diagnosis. The detection rate for malingering was 0%. Moreover,

clinicians rated themselves as moderately to highly confident in their diagnoses.

This study was altered slightly and replicated using adolescent subjects

to produce malingered HRNB profiles (Faust, Hart, Guilmette, & Arkes, 1988).

In Study 1, most clinicians (78%) who received no forewarning of the possibility







32
of malingering classified the cases as neuropsychologically abnormal; 0% of

malingering profiles were detected. In Study 2, clinicians were forewarned

about the malingering protocols and given the base rates. However, their

overall classification accuracy did not surpass chance levels.

Faust and his colleagues (Faust, Hart, & Guilmette, 1988; Faust, Hart,

Guilmette, & Arkes, 1988) have confidently concluded from these two studies

that "adults and adolescents can convincingly portray neuropsychological

deficits." (Faust, Hart, Guilmette, & Arkes, 1988, p. 513). Bigler (1990) has

rightfully taken extreme issue with these methodologically-flawed studies. In

general, the Faust et al. (1988) study fails to approach the reality of clinical

practice. Specifically, the use of questionnaires containing only raw test scores,

the paucity of historical and interview information, and over-reliance on

"objective" indicators biased the results towards the over-interpretation of

"pathology" and provided insufficient information to make accurate clinical

decisions. The true competency and qualifications of the respondent judges

could also be challenged.

Malingered Amnesia

Benton and Spreen (1961) compared brain damaged patients with

neurologically normal subjects instructed to portray moderate memory,

concentration, and motivational deficits secondary to an automobile accident.

They found that the simulators overplayed their role in that they performed at a

level significantly below that of brain damaged patients. Qualitatively, simulating







33
subjects tended to produce very few omission, perseveration, and size errors,

opting instead to produce many more distortion errors than are often seen in

genuinely brain damaged populations.

Williamsen, Johnson, and Eriksen (1965) instructed a group of subjects

to feign hypnosis and post-hypnotic amnesia. The instructions given to this

group were nonspecific and provided no didactic information about

posthypnotic amnesia. No incentive was offered for successful malingering.

This group was compared with groups of nonsimulating/hypnotized subjects

and genuine/nonhypnotized subjects on free recall, word fragment completion,

'"word association", and two-alternative, yes/no recognition measures. The

results obtained indicated that the malingering subjects' level of performance

was significantly lower than the posthypnotic amnesics on all measures. A

critical finding was that the simulators abnormally suppressed their responding

on several measures of implicit memory.

In a brief report, Brandt, Rubinsky, and Lassen (1985) administered a 20

item word list to groups of normals, normals simulating amnesia, patients with

Huntington's disease, and patients with unspecified head trauma. These

subjects were tested first with free recall and then with two-alternative, forced

choice recognition paradigm (cf. Pankratz, 1983). No information was reported

concerning the instructions used for the malingering group, nor was there any

apparent external incentive to malinger. Brandt and his colleagues found that

the malingering group performed the most poorly on free recall, though not







34
significantly different from the other patient groups. The malingering group

produced recognition memory performance that was not above chance levels;

three of the ten had recognition scores below chance.

Schacter (1986) created a laboratory analogue of an episodic event in

order to examine various meta-mnemonic variables in groups of normal

subjects and subjects instructed to "simulate forgetting" of this episode. The

episodes consisted of a passage from a novel and videotaped events and was

constructed in such a way that virtually no subject would be able to accurately

recall it. The instructions given to the simulating group were quite brief and

emphasized the believability of their performance. No reward was offered for

successful simulation. The dependent variables in this study included "feeling

of knowing" ratings, which refer to a person's belief that he could retrieve or

recognize an unrecalled item, event, or fact if he were given more powerful hints

or cues (c.f., Schacter, 1983). In Experiment 1, Schacter found that simulators,

relative to the genuine condition, demonstrated significantly lower cued recall

performance and scored significantly below chance on a two-alternative, forced

choice recognition test. Transcripts of each subject's verbalizations at the time

of recollection were provided to six expert judges, who were subsequently

unable to correctly sort the two groups. Finally, simulating subjects were

significantly more pessimistic that retrieval cues and multiple choices would

improve their remembering of the episode.








35
Experiment 2 replicated and extended these results to show that

simulators displayed the same pattern of inaccurate meta-memorial ratings after

a 90 minute delay period, while Experiment 3 replicated the results after a 24

hour delay period. Expert raters in both Experiments 2 and 3 were still unable

to discriminate between genuine and simulating subjects.

There are several aspects which may limit the generalizability of this

study to situations outside of the laboratory. Most importantly, this experiment

had subjects simulate the forgetting of a specific, temporally-limited episode.

While this situation has direct relevance to certain criminal cases (eg., in the

form of a defendant claiming amnesia at the time of a crime), it neglects the

situation seen in many civil actions in which an individual claims a defect in his

memory process which impairs his ability to learn new information. Additionally,

the simulating subjects may never have initially learned the information under

question, and thus, may never have "forgotten" the information (Wiggins &

Brandt, 1988).

Wiggins and Brandt (1988) used both explicit and implicit memory

measures in their attempt to discriminate experimental malingerers. In

Experiment 1, five groups were evaluated. Three groups of malingerers (one

instructed to simulate amnesia resulting from head injury; one instructed to

simulate amnesia resulting from psychological trauma; and one instructed to

simulate amnesia of an unspecified etiology) were compared with a group of

true amnesics (n=4) and a group of nonsimulating controls. No suggestion







36
was given to the simulators concerning the severity of their feigned amnesia nor

were the simulators offered an incentive or reward for successful malingering.

In Experiment 1, the malingers' performance was characterized by (1)

extremely poor performance on overlearned, autobiographical information

(worse than the performance of even the most impaired patients); (2)

performance on free recall lower than normals but greater than amnesics; (3) a

normal serial position effect, and (4) essentially normal priming effects on

measures of implicit memory. The simulators demonstrated essentially normal

priming effects on an immediate test. However, when retested after a 24 hour

delay the simulators produced significantly fewer target words than the other

groups, thus slightly suppressing their word stem completion performance. On

a word association task, simulators did not differ significantly from normal and

amnesics, with all three groups exhibiting slight priming effects. Of note is the

fact that virtually no differences were detected between the three subgroups of

malingerers, prompting the conclusion that lay people are not generally aware

of symptomatic differences between various types of amnesia.

In Experiment 2, Wiggins and Brandt administered two, 20-item lists of

concrete nouns to the same groups described above, and elicited free recall

and recognition using a two-alternative, forced-choice recognition test (c.f.

Pankratz, 1983). The amnesic group recalled fewer words than the

malingerers, who recalled fewer words than the normal controls. The

malingerers replicated a normal serial position curve. Twenty one percent of







37
the malingerers performed at chance levels on yes/no recognition, though no

malingering subject performed below chance. This performance was

significantly below the recognition levels displayed by the amnesics and normal

controls. The authors concluded that simulators portray amnesia, regardless of

its etiology, as characterized by recall performance better than, and recognition

performance worse than, that of true amnesics, and that the malingerer' serial

position curve resembled that of normals rather than that of amnesics.

Boone (1989) directly examined the effect of coaching on malingering

subjects' neuropsychological memory test performance. Boone randomly

assigned 87 subjects, volunteering for course credit, to one of three conditions:

uninformed-faking, informed-faking, and normal control. The subjects were

instructed to simulate the performance of a person who has recently sustained

a "mild to moderate" head injury in an automobile accident A five dollar reward

was offered for "successful malingering", although in actuality all subjects

received this payment. Boone hypothesized that the performance of

malingerers would be characterized by significant levels of intratest and interest

inconsistency, as operationally defined as significant deviations from the mean

scores on a scale, significant discrepancies between similar scales, improbable

temporal patterning of responses, and improbable performances relative to the

binomial distribution.

The results demonstrated that the performance of the groups of

malingerers was significantly more inconsistent than the control group, with the







38
uninformed-faking group performing more inconsistently than the informed-

faking group. A large proportion of malingerers performed in the severely

impaired range, with uninformed-fakers again demonstrating more significant

levels of impairment than informed-fakers. This study replicated previous

findings that malingerers generally tend to overplay their roles. Two significant

stepwise discriminant function analyses reliably sorted the three groups with an

accuracy rate of 91%. This study would have benefitted from the inclusion of a

group of head injury patients.

Mittenberg, D'Attilio, Gage, and Bass (1990) administered a 30 item

symptom checklist to two large groups of subjects who were instructed to

malinger "symptoms" secondary to a closed head injury they supposedly

sustained six months ago. One group of subjects reported having pre-

experimental knowledge about the symptoms of closed head injury while the

contrast group reported having no special knowledge. No objective criteria of

the subject's knowledge of brain-behavior relationships was used verify group

membership. In both groups, postconcussion syndrome was malingered

significantly more than memory symptoms. Memory complaints were faked at a

level not significantly different than chance. However, post-concussion

syndrome was malingered by 80% of the subjects.

Wylie and Ruff (1990) instructed subjects in post-concussional syndrome.

Multivariate and clinical detection procedures were used to contrast groups of

matched controls, litigating head injury patients, and nonlitigating head injury







39
patients with multivariate and clinical detection procedures. Their results

indicated that clinical and blind raters failed to accurately discriminate

malingerers from other subjects, although multivariate analyses of variance

detected significant group differences between normals and other groups.

Multivariate discriminant function analyses improved classification of malingerers

and head injury patients by 20% over chance.

Bernard (1990) investigated the vulnerability of several widely-used

neuropsychological memory tests to experimental malingering. Three groups of

subjects were used: malingering with no financial incentive, malingering with

financial incentive to the two subjects who produced the most believable

deficits, and normal controls performing genuinely. Overall, there were few

differences between malingerers in the incentive and nonincentive conditions,

whereas both groups of malingerers performed more poorly than the controls.

Two stepwise discriminant function analyses were performed on reduced

variable sets. The first variable set, which included WMS-R Figural Memory and

Immediate Visual Reproduction, produced accuracy rates of 74% on cross-

validation. The second variable set, which included ROCF Delayed

Reproduction, RAVLT Trial 1, and RAVLT Recognition, produced accuracy rates

of 77% on cross-validation. While this study incorporated many methodological

improvements, the failure to employ a group of subjects with bona-fide memory

impairment as the criterion of successful malingering no doubt limits the

generalizability of these results (cf., 8chretien, 1988).








40
Bernard (1991), in a later article, further analyzed the performance of this

same sample of subjects on the Rey Auditory Learning Test. The inclusion of a

group of 18 CHI subjects with relatively severe injuries who were tested early in

their recovery improved the methodology of the study. The results indicated

that the malingering group scored significantly lower than the control group, but

scored significantly higher than the CHI group. Thus, the malingerers portrayed

deficits of insufficient magnitude to resemble patients with bona-fide memory

impairment secondary to severe CHI. Further inspection of the data revealed

that malingering subjects obtained low scores by suppressing their recall of

words from the primacy portion of the list.

Iverson, Franzen, & McCracken (1991) used a verbal list-learning

paradigm to investigate the performance of experimental malingerers, patients

with bona-fide memory impairment of mixed etiology, and normal controls

performing to the best of their ability. Two procedures, free recall of stimuli and

two-item, forced recognition, were employed. The mean free recall score for

the normals was significantly greater than those for malingerers and memory-

disordered patients; the latter two groups did not differ significantly. Main

effects of group on serial position for recall and recognition were nonsignificant.

In the forced-choice task both normals and memory-disordered patients

outperformed malingerers. Sixty percent of malingering subjects scored

significantly below chance levels, while the remaining 40% scored within the

confidence interval constructed around chance performance. No malingering







41
subject scored better than chance. Comparisons with other studies employing

this paradigm should not be made due to the restricted number of trials

employed here (21) as compared with the standard of 100.

Specific Clinical Techniques to Detect Malingerers

Symptom validity testing

Original oaradiam. Theodor and Mandelcorn (1973) first reported the

use of a two-alternative, forced-choice paradigm for evaluating the validity of a

claim of disability or impairment. This procedure is quite simple in nature. The

subject is presented with one of two distinct stimuli and is then, after a brief

delay, asked to determine which of the two had been presented. This is

repeated until a sufficient number of trials have been administered, usually at

least 100 trials. The subject's performance is then compared with what would

be considered chance performance. Nominal chance performance is 50%

correct. A performance significantly different than chance is interpreted as the

subject having a preserved ability to perceive and discriminate between the two

stimuli. If the subject's performance is significantly below chance, then the

subject is suspected of feigning the deficit. For 100 trials, 41% accuracy is

associated with the cumulative binomial probability of 0.04. Alternatively, the

subject is making accurate discrimination if his performance is significantly

above chance. An essentially "normal" subject is expected to score at or near

100% correct. This procedure has been termed "Symptom Validity Testing"

(SVT) by Pankratz, Fausti, and Peed (1975). Symptom Validity Testing can be







42
altered by making the stimuli more complex and giving the subject the

impression that the task is very difficult (c.f., Lezak, 1983).

Theodor and Mandelcorn (1973) used this technique in a case involving

"hysterical blindness." Their patient did in fact demonstrate significantly below-

chance discrimination of a visual stimulus, suggesting that the patient was

processing the stimulus and then volitionally refusing to report it. Pankratz,

Fausti, and Peed (1975) successfully employed the SVT paradigm to

demonstrate that a patient claiming loss of hearing was in fact discriminating

the stimulus on some level. Pankratz (1983) and Binder and Pankratz (1987)

extended these findings, demonstrating the utility of Symptom Validity Testing

to the detection of feigned memory impairment. Binder has reported five

additional case studies in which a below-chance performance on forced-choice

testing was helpful in making the diagnosis of malingering (Binder, 1990b,

1992). Pankratz (1979) demonstrated that Symptom Validity Testing, when

presented to the patient with an expectation for change, allowed the patient to

spontaneously relinquish his symptoms while still maintaining his dignity and the

belief in the physical basis for the symptoms.

Modifications to original paradigm. Following Pankratz's advice (1988),

clinicians have begun to modify and adapt forced-choice testing to meet their

individual clinical needs. Three methods have recently appeared in the

literature. Hiscock and Hiscock (1989) varied the objective task difficulty by

introducing varying retention intervals into the paradigm. Five digit numbers







43
were printed on index cards and presented to subjects to study for five

seconds. Response cards were printed with the target digit string along with a

foil, also a five digit number. Response trials were grouped into three blocks of

24 trials. Presentation of the response card was delayed five seconds in the

first block of 24 trials, ten seconds in the second block, and 15 seconds in the

final block. No intervening distractor activity occurred between presentation of

the study and test cards. Prior to the first block of trials, the patient was told

that the task constituted a "memory test." Following the first and second

blocks, the patient was told that he had performed well and that, consequently,

the retention interval would be increased to make the task more difficult in the

next block of trials. This procedure created the illusion of difficulty for the

suspected malinger. In actuality, correct answers could be produced by simply

recalling the first of the five digits.

Three subjects were then tested with this procedure: a patient suspected

of malingering, a severely demented patient, and a normal five year-old girl.

The results indicated that although the suspected malingerer scored exactly at

the chance level for the first block of trials, his scores showed a progressive

decline across the second and third blocks. His overall accuracy rate of 29%

fell significantly below chance (z=-3.54, p<.0002). The normal child's score of

82% was significantly above chance. Perhaps most important, the demented

patient obtained a score of 51% accuracy, which was not significantly different

from chance. This finding correctly highlights the need to determine the







44
component cognitive processes involved in this task, as well as to validate the

procedure on various neuropsychological patient groups.

Binder's Portland Digit Recognition Test (Binder, 1990b; Binder & Willis,

1991) is similar to that of Hiscock and Hiscock (1989) with two exceptions.

Binder incorporates retention intervals of five, 15, and 30 seconds into the three

blocks of 24 trials. In addition, the interval between study and test is

interpolated by having the subject count backwards. These authors reported

data from testing a series of 64 patients with well-documented brain dysfunction

of varying etiologies who were judged to be motivationally-intact. The mean

performance of these patients was approximately 75% correct; the worst

performance was 54% correct.

Bickart, Meyer, & Connell (1991) devised the Malingered Memory Deficit

Test, a 50-trial test of feigned short-term recognition memory. The basic task

requires subjects to view a sequence of consonants, consisting of a pair of

letters in random sequence (e.g., RTRRT). After a five second latency period,

the subject is shown a second stimulus identical to the first with the exception

of a missing element (e.g., RTRT). The subject is required to supply the name

of the missing letter, selecting one of two presented alternatives. Four

alternatives were devised to assess the difficulty, by varying the number of

elements the subject was required to remember (either three or five letters) and

the effects of interpolated counting. Subjects were 114 male prison inmates

who were instructed to "take the tests as you think a person with severe







45
memory problems would" (p.11). Below-chance performance levels were

observed in only 18.8% of the subjects in the Difficult/Interpolation condition,

21% of the subjects in the Difficult/No Interpolation, 21.5% of the subjects in the

Easy/Interpolation condition, and 19.2% of the subjects in the Easy/No

Interpolation condition. Above-chance performance levels were observed in

49.5% of the subjects in the Difficult/Interpolation condition, 49.5% of the

subjects in the Difficult/No Interpolation, 54.8% of the subjects in the

Easy/Interpolation condition, and 55.8% of the subjects in the Easy/No

Interpolation condition.

Summary of SVT research. In general, the two-item forced-choice testing

paradigm appears to be a highly useful tool to include in a forensic

neuropsychological assessment. This utility may be based on several

concepts. The malingerer probably does not realize his performance should be

no worse than chance. This may result from simple ignorance of the laws of

probability or the malingerer's subjective feeling that producing incorrect

responses on only half the trials underestimates the seriousness of his problem.

Even if the malingerer does recognize the probabilistic nature of the task, it is

difficult to keep track of his responses and to maintain a consistent pattern of

choices. With enough trials, even small errors in judgement would render a

score improbable (Binder & Pankratz, 1987). However, malingering subjects

may be suspicious of transparently simple tasks, and may choose not to feign

impairment on those tasks (Bickart et al., 1991).









Rev's techniques

Fifteen-item test. Lezak (1983) describes several of the French

neuropsychologist Andre Rey's clinical techniques designed to assess

dissimulation. In the Memorization of 15 Items technique (Fifteen Items Test,

FIT), the patient is presented with a three by five item array of symbols, and he

is asked to memorize the "difficult" stimuli. In actuality, only three or four

concepts are needed for accurate recall. According to Lezak, only the most

significantly impaired individuals recall less than three of the five character sets.

Several empirical studies of the FIT have been published recently.

Goldberg & Miller (1986) administered the FIT to psychiatric inpatients and

mentally deficient patients. Their results confirmed the criteria proposed by

Lezak (1983) and suggested that malingering should be considered among

individuals who deny remembering at least six of the 15 items. Bernard and

Fowler (1990) administered the FIT to brain-damaged patients and normal

controls. Their results generally supported the cutoff of nine correct items. A

comparison of the number of sets of items which were correctly recalled was

nonsignificant.

Morgan (1991) validated the FIT on a sample of 60 patients with bona-

fide mild to severe memory impairment. The cutoff of 9 correct items was again

confirmed. However, "failure" on the FIT resulted from bona-fide, severe

memory impairment in some subjects. Qualitative analysis of the protocols

failed to reveal consistent indicators of bona-fide memory impairment. Lee,







47
Loring, and Martin (1992) provided additional validation data for the FIT

administered to temporal-lobe epileptics and consecutive outpatient

neuropsychology clinic referrals. These authors suggested a more conservative

cutoff of seven correct items. In addition, litigating outpatient referrals scored

significantly lower than nonlitigating outpatient referrals.

Dot-counting task. A second task employs seven 3 by 5 Inch index

cards upon which dots are placed in an organized (grouped) or random

(ungrouped) manner. The patient is instructed to count the dots as quickly as

he can, his reaction time for each card is noted, and these times are compared

with normative data from normal adults as well as head injury patients. The

patient's performance for this task is evaluated in terms of the difference

between the reaction times for the grouped and ungrouped dots. Deviations

from the logical temporal pattern may lead the clinician to doubt the patient's

motivation.

Recognition memory Daradiam. Finally, a third task involves

administration of a 15-item word list. Recognition memory is tested

immediately. Later in the session, the subject's level of recognition is compared

with the first trial of free recall on a list learning test (e.g., Rey Auditory Verbal

Learning Test). Given the well established fact that recognition generally

exceeds free recall, a deviation from this pattern suggests a nongenuine

response style.







48
Summary. All three of Rey's tasks attempt to capitalize on the potential

malingerer's lack of requisite knowledge about brain-behavior relationships and

on his inability to simulate behavior that is foreign to him while monitoring the

effectiveness of this behavior in the testing situation. Morgan (1991) cautions

against the use of any of these techniques in isolation.

Summary and Critiaue of Experimental Studies of Malinaerina

The performance of normal subjects instructed to malinger

neuropsychological dysfunction has been shown to vary widely from study to

study. On indices of quantitative performance, some studies have found

malingerers to appear significantly more impaired than the organic populations

they are portraying (Benton & Spreen, 1961; Hayward et al., 1987; and Iverson

et al., 1991; Schacter, 1986; and Spreen & Benton, 1963) while other studies

have found malingerers to appear more impaired than normals but less

impaired than organic patients (Anderson et al., 1959; Bernard, 1991; Brandt et

al., 1985; and Wiggins & Brandt, 1988). Other studies have found malingerers

to exhibit similar levels of impairment as organic patients (Heaton, Smith,

Lehman & Vogt, 1978; and Mensch & Woods, 1983). Many studies have found

malingerers to perform qualitatively differently than either normals or organic

patients (Benton & Spreen, 1961; Boone, 1989; Goebel, 1983; Heaton, Smith,

Lehman & Vogt, 1978; Spreen & Benton, 1963; and Wiggins & Brandt, 1988).

At this point, a call must go out for a more standardized methodology. The

nature of instructional set, the amount of didactic information provided to







49
malingering subjects (i.e, "coaching"), and the saliency of incentive to produce

believable deficits vary widely from study to study.

An informal meta-analysis was conducted on the studies involving

experimental malingering Table 1 presents this data. This sample of studies Is

neither random or representative. Studies were included in the meta-analysis if

they presented means and standard deviations on the outcome measures. A

study had to have directly compared the performance of subjects instructed to

malinger dysfunction with either normals performing their best (control group)

or neuropsychological patients with bona-fide impairment (criterion group). In

general, studies were excluded if they failed to present means and standard

deviations.

The results of the meta-analysis corroborate the conclusions drawn from

the qualitative review of the literature. First, an average effect size of -3.5 is

attributed to '"treating" subjects with instructions to malinger. Following Smith &

Glass' (1974) interpretative framework, this effect size means that a subject

scoring at the mean of the control group would fall to 3.5 standard deviations

below the mean of the control group when given instructions to malinger. This

is an exceptionally large effect size which may be the result of floor and ceiling

effects associated with some dependent measures. For example, Mensch &

Woods (1986) employed the LNNB scales as outcome measures which defined

normality very close to zero, resulting in both mean scores near zero and

artificially constricted variance. On the other hand, normal subjects often obtain









Table 1
Effect Sizes from Selected Experimental Studies of Malinaering


Bonafide Malingerers
Malingerers Impairment vs.
vs. vs. Bonafide
Study Normals Normals Impairment


Pollaczek (1952) -0.1

Heaton et al. (1978) +0.1

Brandt et al. (1985) -2.7 -1.7

Gudjonsson & -0.8
Shackleton (1986)

Mensch & -8.8
Woods (1986)

Hayward et al. (1987) -1.5

Wiggins & -1.9 +0.3
Brandt (1988)

Boone (1989) -5.2

Bernard (1990) -1.9

Bernard (1991) -1.7 -3.2 +1.0

Iverson et al. (1991) -5.2 -2.0 -1.9


-3.5 -1.7


Average Effect Sizes


-0.5







51
near perfect scores on other outcome measures, such as recognition

paradigms, resulting in very high mean scores and artificially constricted

variance. Nevertheless, the effect size computed is no doubt significant and

fulfills Cohen's (1977) criteria for a "large" effect size.

Second, an effect size of -1.7 is attributed to bona-fide organic

impairment. That is, a subject scoring at the mean of the control group would

fall to approximately 1.7 standard deviations below the mean of the control

group if he were to sustain organic impairment. The true litmus test is applied

when malingerers are compared with the criterion group representing bona-fide

impairment or deficiency. An average effect size of -0.5 is associated with the

comparison between organic patients and malingering subjects, which prompts

the conclusion that malingerers are able to successfully suppress the

quantitative level of their performance to levels associated with organic

impairment.

Given that malingering subjects fall to 3.5 standard deviations below the

mean of normals and subjects with bona-fide impairment only fall to 1.7

standard deviations below the mean of normals, it would seem at first glance

that malingering subjects should score approximately 1.8 standard deviations

below organic patients instead of the observed effect size of -0.5. Upon further

inspection, however, it becomes clear that these values cannot be validly

compared because the referent comparison group (i.e., the group whose

standard deviation represents the denominator of the effect size equation) is







52
not the same. The magnitude of the effect size created by the lower means of

malingering subjects is greatly attenuated by the inherent variability of the bona-

fide impairment group. While not mathematically correct, it appears plausible

that malingering groups score significantly lower than organic groups in terms

of normal control group standard deviations, a situation analogous to the

clinical situation of comparing a subject's performance to normal subjects,

rather than organically-impaired patients.

Analysis of the qualitative nature of malingerers performance bears out

Rubinsky and Brandt's (1986) hypothesis that the malingerer is more likely to

alter his performance by withholding behavior (i.e., producing a behavioral

deficit) such as not recalling a word, rather than producing additional behaviors

(i.e, producing a positive symptom) such as perseveratively recalling a word. A

likely explanation for this tendency rests on the malingerer's ignorance of brain-

behavior relationships or on the general idea that "less" is "worse" when it

comes to expressions of cognitive ability. Given this ignorance, it may be that

commission of behavior is too risky a strategy.

Multivariate discriminant function analyses have been used to attempt to

discriminate malingerers from normals from organic patients with some

measure of success. However, these classification equations have yet to be

cross-validated in independent, clinical samples, and are of uncertain value in

the individual case. Highly variable sensitivity and specificity rates have been

produced by clinicians evaluating and sorting test protocols of these three







53
groups. This approach has limited generalizability to the clinical setting due to

the scarcity of qualitative (e.g., verbatim test protocols and interview transcripts)

and observational data that has typically been provided to the clinical judges.

Several indices have emerged which appear promising. Symptom

Validity Testing has been shown to be robust in clinical case studies of relatively

blatant and unsophisticated malingering. Between-groups designs have begun

to validate SVT and Rey's FIT with other neuropsychological patient groups as

well as fine-tune the basic paradigms along task difficulty and retention interval

dimensions. Two studies (Williamsen, Johnson & Eriksen, 1965; and Wiggins &

Brandt, 1988) have provided initial evidence that malingering subjects may tend

to suppress their responses to supraliminal implicit memory indices (word stem

completion and word association). This suppression of priming appears to

intensify after the malingering subject "catches on" to the memorial nature of the

tasks.

Implicit Memory

Modem experimental research involving implicit memory phenomena

includes different areas of concentration (Schacter, 1987). Implicit memory can

be demonstrated with paradigms involving savings during relearning (c.f.,

Slamecka, 1985), the effects of subliminally encoded stimuli (c.f., Cheesman &

Merikle, 1986), and learning and conditioning without awareness (c.f.,

Greenspoon, 1955). However, these three areas of research are outside the

focus of this paper and will not be reviewed. The present paper will concern







54
itself with the phenomena of repetition priming (c.f., Cofer, 1967), which refers

to the facilitative effects of a learning episode on performance of a subsequent

task, such as word stem completion or tachistoscope identification (Graf &

Schacter, 1985).

Definitions

Richardson-Klavehn and Bjork (1988) contrast implicit and explicit forms

of memory with direct and indirect measures of memory. Forms of memory are

definitionally hypothetical and require an assumption to be made concerning

the subject's mental content or mental state at the time of testing. Explicit

memory is commonly assumed to involve the deliberate, directed retrieval of

information about specific episodes. Explicit memory is demonstrated when

performance on a task requires conscious recollection of a previous

experience. Implicit memory does not depend on directed, conscious

demonstrations of memory when performance on a memory task is facilitated

or somehow altered in the absence of conscious recollection (Graf & Schacter,

1985).

Measures of memory can be categorized with respect to task

instructions and measurement criteria (Johnson & Hasher, 1987). This

nomenclature avoids excessive assumptions concerning mental states and

processes involved in performing tasks. Explicit memory is commonly tested

by direct measures of memory such as free recall, cued recall, and recognition.

Implicit memory is tested with indirect memory tasks in which the measures of







55
Interest reflect a change (typically a facilitation) in task performance observed

by comparing performance with relevant prior experience to performance

without such experience (a control condition). The term indirect is particularly

suitable because the relevant tasks do not direct the subject to a target event

(Richardson-Klavehn & Bjork, 1988).

Theories of Imolicit Memory

Two main classes of theories of implicit memory currently occupy the

attention of researchers: multiple memory systems models and processing

models (Roediger, 1990). Experimental manipulations have been shown to

differentially affect direct and indirect memory tests with both normal subjects

and amnesic patients (Shimamura, 1986; Schacter, 1987). Therefore, the task

of any theoretical model is to account for the numerous dissociations between

these forms and measures of memory (Richardson-Klavehn & Bjork, 1988).

Researchers postulating distinct and separate memory systems derive

support from experimental studies of amnesic patients. The central concept is

that certain forms of brain damage selectively affect the memory system for

conscious recollection but leave the system responsible for other forms of

learning relatively intact. Squire and Cohen (Cohen, 1984; Cohen & Squire,

1980; Squire, 1987) have advanced a taxonomy consisting of functionally

separate memory stores for declarative and nondeclarative (formerly

"procedural") memory. Declarative memory (i.e., "knowing that") is available to

consciousness and can be accessed by processes congruent with the







56
contextual and temporal information it contains. Nondeclarative memory (i.e.,

"knowing how") is not directly available to consciousness and is only capable of

being accessed by engaging in processes in which it is embedded. Thus,

amnesia is conceptualized as a preservation of procedural memory as indexed

by indirect memory tasks and a failure of declarative memory as indexed by

direct memory tasks. Much of the experimental evidence for dissociations

between direct and indirect tests can be interpreted within this framework

because the memory systems are though to be largely separate (Roediger,

1990).

Other researchers, primarily cognitive psychologists working with normal

subjects, have proposed various processing models to account for the data.

Processing models de-emphasize the possibilities of different memory stores

and the dissociation of encoding, storage, and retrieval. Instead, Jacoby

(Jacoby, 1983a, 1983b, 1984) as well as Roediger and his colleagues (Roediger

& Blaxton, 1987b; Roediger, Weldon, & Challis, 1989) postulate that implicit and

explicit memory differ in terms of the relationships between processes operating

at both encoding and retrieval. Jacoby (1983b) delineates two dissociable

processes operating on a single, episodic memory store. Processing of

semantic information requires the initiation of conceptually-driven processes by

the subject. Such processes include elaboration, organization, and rehearsal.

Certain tasks that emphasize perceptual or orthographic information invoke

data-driven processing. These researchers feel that implicit memory as







57
measured by indirect tests is primarily indexing data-driven processes and

explicit memory as measured by direct tests is primarily indexing conceptually-

driven processes. It should be emphasized that these concepts represent two

end-points on a single continuum rather than discrete categories.

Roediger (1988) spells out the assumptions which follow from the

processing model. First, performance on memory tests should be facilitated to

the extent that the cognitive operations at test recapitulate those engaged

during the study episode. Second, direct and indirect tests typically, but not

always, require different retrieval operations and consequently benefit from

different types of processing during learning. Most direct memory tests draw

on the encoded meaning of concepts or on semantic or elaborative processing.

Conversely, most indirect tests rely heavily on the match between perceptual

operations between study and test.

The Relationship between Explicit and Implicit Memory

The central concept that this study will attempt to use to "catch"

malingering subjects is the idea that intentional, explicit retrieval (or suppression

of retrieval) can affect performance during nominally indirect memory tests. In

order to fully understand the circumstances under which this can occur, a

discussion concerning the relationship between implicit and explicit forms of

memory is necessary. Three areas of research speak to this issue. First, some

studies have demonstrated stochastic independence between implicit and

explicit memory tasks and have used this data to argue that under some







58
circumstances intentional retrieval does not contribute to repetition priming

(Tulving, Schacter, & Stark, 1982). Second, studies testing implicit memory

after degraded encoding demonstrate that implicit memory can occur in the

absence of explicit memory (Eich, 1984). Third, as levels of processing

manipulations have been shown to robustly affect direct memory tests, LOP

manipulations may increase the likelihood that explicit retrieval may intrude

during indirect memory tests (Schacter, 1987). This review will lay the

groundwork for a careful review of the work of Bowers and Schacter (1990)

which directly investigated implicit memory, LOP, and test awareness.

Stochastic independence

The concept of stochastic (statistical) independence between direct and

indirect memory tests has been taken as evidence for a dissociation between

implicit and explicit forms of memory (Tulving, Schacter, & Stark, 1982).

Stochastic independence is the name given to the relation between two events

in which the probability of their joint occurrence is equal to the product of the

probabilities of the occurrence of each event alone (Tulving, 1985). In a typical

experiment, a subject completes an indirect test of memory, such as word stem

completion. He then completes a yes/no recognition memory test for the study

words. Two scores are then computed. The simple probability of word stem

completion refers to the proportion of study words which were correctly

completed in their target direction. The simple probability of recognition

memory refers to the proportion of target words which were correctly







59
recognized on a direct recognition test, irrespective of word stem completion

status. The conditionalized probability of recognition memory refers to the

proportion of correctly generated target words that were later correctly

recognized on a direct recognition test.

Therefore, stochastic Independence exists when the conditionalized

probability of correct recognition does not exceed the product of the two simple

probabilities. Unlike functional independence, stochastic independence is not

based on comparing the average performance on two tests, but rather on

determining whether performance on a particular item on one test predicts

performance on that same item on another test. If no predictive relationship is

found, then the tests are assumed to be independent (Witherspoon &

Moscovich, 1989).

In the present context, the concept of stochastic independence becomes

relevant because it allows the researcher to examine the relative contribution of

explicit memory processes on indirect memory tests. In general, a number of

studies have firmly demonstrated stochastic independence between direct and

indirect memory tests (Richardson-Klavehn & Bjork, 1988). Jacoby and

Witherspoon (1982) biased the homophone spelling for amnesic patients and

normal control subjects. The spelling of homophones required in the second

phase of the experiment provided an indirect measure of the effect of the prior

presentation of the homophone on its later interpretation. Both groups of

subjects demonstrated intact implicit memory for the biased spelling. Yes/no








60
explicit recognition for the biased spellings was intact for normals and severely

impaired for the amnesic patients. More importantly, the conditionalized

probability of recognition did not differ significantly from the simple probability

of correct recognition for either group. This procedure was repeated using

perceptual identification as the indirect memory test The results were

equivalent; the two tasks were found to be stochastically independent across

12 conditions that differed in overall rate of identification.

Tulving et al. (1982) found that probability of recognition conditionalized

on successful word fragment completion was equivalent to the overall

proportion of words recognized for four conditions that differed in overall

recognition probability. Tulving (1985) reported the extensive results of

Chandler's (1983) work which manipulated the relationship between fragment

completion and direct memory tests in 32 separate conditions. Without

exception, stochastic independence was found in that recognition

conditionalized on correct fragment completion was essentially equivalent to

simple recognition.

Several studies, however, have found stochastic dependence between

performance on an indirect and a direct memory test. Jacoby and Witherspoon

(1982) presented a long list of pronounceable pseudowords for study. A test of

recognition memory for the studied pseudowords was presented in the second

phase of the experiment. A perceptual identification test, given in the final

phase of the experiment, included "new" pseudowords as well as words that







61
had been studied and presented in the test of recognition memory. In line with

previous results, the prior presentation of a pseudoword was found to be

sufficient to enhance its subsequent perceptual identification. Recognition

memory for the pseudowords was also found to be accurate. In contrast to

results obtained for words, however, performance on the two types of test were

dependent on one another. Pseudowords that were later perceptually identified

were more likely to be recognized as having been presented during study (.80)

than were pseudowords that were not later perceptually identified (.70). In

addition, G. Hayman (unpublished observations cited in Schacter, 1985b) found

stochastic dependence in an experiment in which subjects were instructed to

use word fragments to help retrieve study-list words. Several authors have

argued that this data can be explained by assuming that subjects used explicit

memory in both the direct and indirect tests (Richardson-Klavehn & Bjork, 1988;

Schacter, 1985b).

Criticism has been aimed at this procedure on practical as well as

theoretical grounds. Shimamura (1985) argued that stochastic independence

may be an artifact produced by the influence of the first test on the second test.

Performance on the stem completion task represents an additional study trial

for items successfully completed. Therefore, it appears to be a plausible

assumption that the exposures and subject reactions that comprise

performance on the indirect test do not leave the memory system unaltered and

ready to give an uncontaminated picture of the influence of the study episode







62
on a second test (Richardson-Klavehn & Bjork, 1988; Tulving et al., 1982).

Given these two lines of evidence, the methodology offered by stochastic

independence may be one way to evaluate implicit-explicit relationships in the

context of manipulations of motivation and retrieval intentionality.

Restricted or degraded encoding

Studies involving restricted or degraded encoding of stimuli are indirectly

relevant to the present issues of motivation and retrieval intentionality because

they offer the opportunity to observe normal performance on indirect memory

tests with accompanying low levels of performance on direct memory tests

(Bowers & Schacter, 1990). Eich (1984) used a speech-shadowing paradigm

to present target words (homophones) for unattended study. Spelling was

used as an indirect memory test and yes/no recognition served as the direct

memory test. Priming was observed under these degraded study conditions,

even though explicit memory for the words was extremely low. Eich interpreted

his findings as a dissociation between deliberate or intentional remembering

and remembering without awareness. Kunst-Wilson & Zajonc (1980)

tachistoscopically presented irregular geometric shapes to normal subjects for

one millisecond exposure durations. The test phase consisted of an affective

discrimination rating followed by a two-item forced choice recognition memory

judgement. Priming was observed in these subjects despite chance-levels of

recognition memory for the shapes.







63
The study by Jacoby, Woloshyn, and Kelley (1989) warrants a more

detailed review. In Experiment 1, famous and nonfamous names were

presented to be read aloud under conditions of divided or full attention. Gains

in familiarity of names were tracked by changes in performance on a later fame-

judgement task. Explicit memory for the previous presentation of the names

was tested with a standard recognition memory test. Gains in familiarity were

demonstrated even when studied with divided attention, while explicit

recognition memory was lower after divided attention than full attention.

Additional experiments were conducted to preclude the possibility that

the familiarity measure actually reflected some instances of conscious

recollection. Gains in familiarity were placed in opposition to conscious

recollection to further separate the two processes. All names presented in the

study phase were nonfamous and the subjects were told so. Subsequent

conscious recollection of a name during the fame-judgment task would allow

subjects to be certain that the name was nonfamous. Familiarity without

conscious recollection would result in the opposite, calling a name "famous".

Attention was divided again at study and later during the fame-judgement task.

The accurate recognition of old nonfamous names in the full-attention condition

allowed those names to be called "famous" less often. In contrast, dividing

attention radically reduced list recognition. The failure to recognize old

nonfamous names in combination with a gain in their familiarity was revealed by

the finding that old nonfamous names were more likely to be called "famous"







64
than were new nonfamous names in the divided-attention condition. Thus,

Jacoby and his colleagues were successful in demonstrating that unconscious

memory can operate independently from conscious memory.

The foregoing studies demonstrate that implicit memory for target stimuli

can be demonstrated on indirect memory tests in the relative absence of

conscious, explicit memory for the same stimuli. This evidence, however, is

only of indirect interest because most studies of implicit memory have involved

testing normal subjects under unrestricted encoding conditions, making it

possible that normals are typically aware of the study episode during the

performance of an indirect memory test (Bowers & Schacter, 1990).

Additionally, elaborative encoding manipulations would be expected to increase

the strength of the memory trace, thereby increasing the likelihood that a

subject would experience either awareness of remembering or intentional

explicit retrieval (Bowers & Schacter, 1990; Richardson-Klavehn & Bjork, 1988;

Schacter, 1987; Squire, Shimamura, & Graf, 1987).

Level and elaboration of encoding

The levels of processing (LOP) framework was conceived as a model of

memory which focuses on the processes involved in learning and remembering.

It differed from its predecessors in the information-processing tradition which

focused on the structural aspects of the cognitive system (i.e., the successive

stages through which information flows). The LOP framework proposed to

study more directly those processes involved in remembering (e.g., attention,








65
encoding, rehearsal, and retrieval) and to formulate a description of the memory

system in terms of these constituent operations (Craik & Lockhart, 1972; Craik

& Tulving, 1975).

A typical LOP manipulation involves incidental earning in a semantic or

conceptual study condition (e.g., rating the pleasantness; deciding whether a

word fits in a sentence) versus a physical or orthographic study condition (e.g.,

searching for particular letters in the word) (Craik & Lockhart, 1972; Craik &

TuMving, 1975). The relationship between LOP and performance on direct,

explicit measures of retrieval has been shown to be quite robust in normal

subjects: "deeper" semantic processing produces greater explicit retrieval than

does more "shallow" processing (Craik & Tulving, 1975; Bradshaw & Anderson,

1982), which is thought to be due to cognitive elaboration taking place during

the encoding process.

Prior to the popularity of the processing model, most researchers agreed

that LOP had a null effect on indirect memory tests (Graf & Mandler, 1984; Graf,

Mandler, & Haden, 1982; Graf, Squire, & Mandler, 1984; Jacoby & Dallas, 1981;

Richardson-Klavehn & Bjork, 1988). However, the processing model has

allowed for the categorization of indirect memory tests into primarily conceptual

tests versus primarily perceptual tests. Indirect perceptual tests include word

fragment completion, word stem completion, and tachistoscopic perceptual

identification. Research has established that LOP affects priming in indirect

conceptual tests (Hamann, 1990; Srinivas & Roediger, 1990).







66
Challis and Broadbeck (1992) provide an excellent and authoritative

review of research into LOP effects in indirect perceptual tests. Their literature

review uncovered a total of 11 published studies which manipulated LOP and

measured performance on the indirect perceptual memory tests of perceptual

identification (Jacoby & Dallas, 1981; Hashtroudi, Ferguson, Rappold, &

Chrosniak, 1988; Ught & Singh, 1987), word stem completion (Graf, Mandler, &

Haden, 1982; Graf & Mandler, 1984; Graf, Squire, & Mandler, 1984; Squire,

Shimamura, & Graf, 1987; Ught & Singh, 1987; Chiarello & Hoyer, 1988;

Bowers & Schacter, 1990; and Mandler, Hamson, & Dorfman, 1990), and word

fragment completion (Squire et al., 1987; Srinivas & Roediger, 1990).

In 33 of 35 separate experiments conducted in these studies, priming

was numerically greater in the semantic condition than in the physical condition.

While often not statistically significant, the effect sizes of LOP were

characterized as small-to-medium magnitude. Challis and Broadbeck (1992)

provide illuminating evidence which helps explain these contradictory findings.

They found that semantically processed words showed a consistent advantage

over orthographically processed words when tested with a word fragment

completion paradigm. However, when semantic and physical conditions were

presented within-subjects in a mixed list, the LOP effect was negligible and

nonsignificant. The authors interpret this finding as evidence for the

independent contribution of the physical analysis component of the LOP

manipulation.








67
Issues Related to Awareness and Retrieval Intentionality

The initial section discussing the precise definitions of memory forms and

measures highlights a concept which will become central to this study; namely,

the issue of explicit memory occurring during indirect tests of memory

(Richardson-Klavehn & Bjork, 1988). The concept of conscious recollection is

central to the definition of explicit memory. However, Schacter and his

colleagues (Schacter, Bowers, & Booker, 1989) argue that "conscious

recollection" is an ambiguous term. Conscious recollection can refer to the

intentional initiation of retrieval of recently studied information in which the

subject deliberately thinks back to a learning episode and searches for target

information. On the other hand, conscious recollection can simply refer to

awareness of remembering brought on as a consequence of the retrieval

process.

Schacter (Schacter, Bowers, & Booker, 1989) discusses five scenarios

which illustrate the possible contribution of explicit forms of memory during

indirect tests and discusses the methodological difficulty in fractionating forms

of memory in experimental studies. Those scenarios which are most relevant to

the purposes of this paper are discussed below. In the first case, subjects

study words under elaborative study conditions. As instructed, subjects

complete each test stem with the first word that comes to mind, and produce a

large number of study list items. They do not spontaneously become aware

while performing the completion task that any of the items represent a study list








68
target. But when given a yes/no recognition test that requires them to think

back to the study episode, subjects perform quite well, and consciously

remember having studied almost all of the words that were produced as

completions. This scenario represents normal implicit memory performance in

that absence of the spontaneous experience of test awareness, even though

the subjects later demonstrate strong explicit memory for the study episode.

The second represents an example of what Schacter (1987) referred to

as involuntary explicit memory. Subjects could encode target items under

elaborative study conditions, later complete each stem with the first words that

comes to mind, and produce a large number of study list items. For some

stems, all that comes to mind during completion performance is the target word

itself, but for others subjects are reminded by the stem of something that

occurred during the study episode. Nevertheless, the subject continues to

write down the first word that comes to mind. Thus, a cue involuntarily triggers

a recollection of a past event; the awareness of remembering is merely a

consequence of the implicit retrieval process.

The third scenario is more clearly a case of voluntary explicit memory. It

is identical to the preceding case, except that once subjects notice that one or

two of the stems can be completed with the study list items, they surmise that

the experimenter is surreptitiously trying to test their memory, and may decide

that they can improve their performance by thinking back to the study list and

trying to complete each stem with a target item. They have no problem







69
recollecting most of the words that were presented during the study episode.

Thus, the subject "catches on" to the nature of the test and intentionally

recollects the prior episode. The subject is essentially engaging in cued recall.

The relevance of LOP effects also becomes clear at this point. Levels of

processing effects on indirect memory tests should be apparent to the extent

that explicit memory was operating at retrieval. Bowers and Schacter (1990)

provide the only direct evidence concerning these issues. These researchers

conducted a series of experiments using normal control subjects to determine

whether normal priming effects could be observed in subjects who do not

experience test awareness during the performance of an indirect memory test,

in this case word stem completion. Whereas on-line probes could have been

employed, a post-test questionnaire technique was the most direct measure of

awareness which avoided inducing awareness. In Experiment 1, study

instructions (incidental versus intentional) and test instructions (normal implicit

memory instructions versus hints that stems could be completed with target

words) were treated as between-subjects factors. Encoding process (semantic

versus physical processing) was examined within-subjects in that half of the

words were encoded under each encoding condition.

Twenty (50%) of the 40 subjects were categorized as test-aware based

on the post-experimental questionnaire. The results indicated that study

conditions did not induce test awareness in that 11 of the test-aware subjects

were in the study-informed group, and the remaining nine aware subjects were








70
from the study-uninformed condition. The critical finding was that both aware

and unaware subjects showed normal and equivalent priming effects on word

stem completion. Thus, normal priming was observed in the absence of test

awareness. However, the finding that test-aware subjects completed a

statistically significantly higher proportion of semantically encoded words and a

relatively low proportion of structurally encoded words suggests that explicit

memory did impact WSC performance. No LOP effect was noted for test

unaware subjects. Additional evidence of the relationship between test

awareness and explicit retrieval was found on subsequent experiments which

found that only test-aware subjects demonstrated normal implicit memory for

new associations, an indirect test which may be more susceptible to explicit

mediation than other indirect tests.

Conclusions

Several lines of evidence have been reviewed which suggest that implicit

and explicit memory are functionally independent under certain situations.

Implicit memory has been observed when explicit memory was at chance levels

due to restricted or degraded encoding conditions (Eich, 1984; Jacoby,

Woloshyn, & Kelley, 1989; Kunst-Wilson & Zajonc, 1980). Stochastic

independence between performance on direct and indirect memory tests has

been observed in several studies (Chandler, 1983; Jacoby & Witherspoon,

1982; Tulving et al., 1982).







71
However, other studies using designs which leave open the possibility of

explicit memory contamination have found stochastic dependence (G. Hayman,

unpublished observations cited in Schacter, 1985b; Jacoby & Witherspoon,

1982). Moreover, many theorists consider the issue of explicit memory

occurring during performance on a nominally implicit task in need of further

research (Richarson-Klavehn & Bjork, 1988; Schacter, 1987; Squire,

Shimamura, & Graf, 1987). Bowers and Schacter have presented preliminary

data which suggests that normal priming can be observed on word stem

completion without the use of explicit retrieval.

The preceding concepts and data concerning awareness and

intentionality of retrieval all naturally assume that a subject is honest, is

motivated to put forth good effort, and is obeying task instructions by

performing in a straightforward manner. The use of an experimental

manipulation which varied the motivation of a subject would be expected to

influence performance on indirect memory tests to the extent that these tests

were vulnerable to intrusion by explicit retrieval processes. Therefore, the use

of indirect memory tests is important to the present investigation because it

speaks equally to several important clinical and theoretical issues. In the clinical

context, indirect memory tests offer the malingering subjects multiple ways to

"fail" or produce a level or pattern of performance different from that seen in

honest subjects or patients with bona-fide memory impairment. Since the

Symptom Validity Testing paradigm has proven quite beneficial to the clinician








72
due to the indirect nature of its task demands, the indirect memory tests

employed by cognitive psychologists may prove useful in the same regard. In

a more theoretical sense, the effects of different motivational response sets will

extend the domain of knowledge concerning indirect memory tests.

Specifically, this manipulation would allow for subjects to spontaneously

experience test awareness and/or employ explicit retrieval strategies to either

facilitate or suppress their indirect memory performance. The present study

could potentially extend the literature by providing a situation in which

malingering subjects would be motivated to use explicit memory to lower, rather

than raise, their performance on indirect memory tests.

Hypotheses and Predictions

Performance on Clinical Memory Tests

The clinical memory tests will serve two simultaneous functions. First,

performance on these tests provides an easily interpretable benchmark upon

which to later understand performance on laboratory-based experimental

memory tests. Performance profiles can be readily compared with the extant

literature to check the validity of the malingering subjects' participation.

Second, the performance on clinical memory tests is useful in its own right in

that (a) the present battery of tests employed in this study is distinct from

others reported in the literature, and (b) it affords a unique opportunity to

evaluate qualitative aspects of memory behavior which may provide the clinician

with useful interpretive information.









The following specific predictions are made concerning performance on

clinical memory tests.

1. Malingering subjects will lower their overall level of performance relative
to honest subjects. This simulated impairment will be roughly equivalent
to the bona-fide memory impairment produced by closed head injury
patients.

2. Malingering subjects will lower their overall level of memory performance
to the extent that they adopt response strategies which emphasize the
omission of behavior, meaning that these subjects will be unlikely to
commit acts of incorrect behavior (i.e., perseverations, distortions, etc.).

3. While succeeding in lowering their quantitative memory performance to
levels seen in CHI patients, it is predicted that Malingering subjects will
be unable to also mimic the qualitative aspects of bona-fide memory
impairment.

4. Analysis of temporal, material, and process-oriented distinctions of
memory functioning will demonstrate Malingering subjects to be
unsuccessful at accurately portraying memory impairment as it occurs in
the CHI patients.

Performance on Indirect Memory Tests

The overriding hypothesis to be evaluated in the present study is that

explicit memory does affect performance on indirect memory tests. The

likelihood of observing the conflation of explicit and implicit memory on indirect

memory tests would appear highest when the words were encoded under

elaborative study conditions.

1. Given that explicit memory may affect performance on word stem
completion, it is predicted that Malingering subjects will produce
abnormally low performance due to postretrieval suppression.

2. Analysis of recognition memory following WSC and analysis of changes
in accuracy rate as these subjects proceed through the task will further
demonstrate the susceptibility of WSC to postretrieval suppression.









3. De-briefing information concerning test awareness and retrieval
itentionality will demonstrate lowered WSC performance in subjects who
reported postretrieval suppression.

4. Genuine subjects and Head Injury patients will produce null LOP effects
on WSC. Malingering subjects will demonstrate discrepant LOP effects
on WSC relative to the comparison groups due to the impact of
postretrieval suppression.

5. Malingering subjects will produce normal accuracy rates on a perceptual
identification task. However, the extent to which these subjects
experience explicit memory for the stimuli and "think about it" before
responding will be manifest as increased response latencies.

6. Analysis of recognition memory following PI and analysis of changes in
accuracy rate as these subjects proceed through the task will further
demonstrate the immunity of PI to postretrieval suppression.

7. De-briefing information concerning test awareness and retrieval
intentionality will demonstrate equivalent PI performance in subjects who
reported explicitly-mediated suppression.

8. Genuine subjects and Head Injury patients will produce null LOP effects
on PI. Malingering subjects will demonstrate similar null LOP effects on
PI relative to the comparison groups due to the absence of postretrieval
suppression.

Performance on Symptom Validity Testing

As regards Symptom Validity Testing, the main hypothesis to be

evaluated is that robust group differences will be observed between the

malingering subjects and their comparison groups, in line with the results

reported in the literature. The specific predictions are as follows:

1. Malingering subjects will demonstrate significantly lower accuracy rates
and significantly higher response latencies than subjects with bona-fide
memory impairment.

2. Malingering subjects, taken as a group, will demonstrate a level of
performance significantly below that associated with chance
performance.







75
3. Malingering subjects will demonstrate inconsistent responding which can
be demonstrated with alternative data analysis techniques.














CHAPTER 2
METHOD

The present study consists of two generally separate experiments.

Experiment 1 was conducted using Amnesic patients and matched control

subjects. The main purpose of this experiment was to validate the experimental

memory stimuli and procedures (word stem completion, perceptual

identification, free recall, and multiple choice recognition). In so doing, the

quantitative (i.e., strength of priming) and qualitative (i.e., levels of processing

effects, dissociations between indirect and direct tests) characteristics of these

tasks could be established to provide a well-recognized benchmark upon which

to compare the results of Experiment 2. Experiment 2 was conducted using

normal college students given two different roles to play (Genuine and

Malingering performance), while Head Injured patients were used as the

criterion group with bonafide organic memory impairment. By excluding

Amnesic patients and their matched controls from the main analyses of

Experiment 2, the design was more analogous to that seen in the medicolegal

context. Given that malingering is more closely associated with traumatic brain

injury (Binder, 1986) than circumscribed organic amnesia, the most important







77
comparison in this context is that between the suspected malingering patient

and the Head Injured patient.

Analysis of Statistical Power

Statistical power refers to the probability of obtaining a significant result

(i.e., of rejecting the null hypothesis). A heuristic equation exists which can be

computed for a given research design which consists of statistical power,

critical effect size, and sample size. By knowing any two of three values, the

third value may be determined (Kraemer & Thiemann, 1987).

A power analysis was conducted following the suggestions and

dimensions suggested by Kraemer and Thiemann (1987). Effect size estimates

were computed from selected experimental studies on malingering and

presented in the context of an informal meta-analysis presented in Chapter 1.

Several a priori decisions were then necessary. An effect size of (2.0) was

taken as a conservative estimate of the effect size associated with the body of

literature. The proportion of 0.6/0.4 was taken as representative of the relative

number of subjects which could be recruited into the experimental groups and

the patient group, respectively. Using Table 4.3 from Kraemer & Thiemann

(1987, p. 45) a "critical effect size" was extrapolated to be (0.84). The number

of subjects in the malingering and normal healthy control groups was

determined from a master table. Therefore, it was determined that 15 to 20

subjects were needed in the each of the Genuine, Malingering, and Head







78
Injured groups to be 80 percent certain of rejecting the null hypotheses using a

one percent, two tailed significance level.



Subjects were categorized into five experimental groups. Amnesic

patients and age and education matched control subjects participated in

Experiment 1. Two types of subjects comprised the three subject groups of

Experiment 2. Introductory Psychology students at the University of Florida

were randomly assigned to either the Genuine or Malingering groups. Non-

litigating Head Injured patients were recruited from several outpatient clinics and

an inpatient rehabilitation program located in North Central Florida to serve as

the criterion group of bonafide memory impairment.

Amnesic patients were recruited from the standing population of such

patients at the Memory Disorders Research Center at the Veterans Affairs

Medical Center in Boston, Massachusetts. Data were collected from these

patients at the Neuropsychology Laboratory at this hospital. A total of nine

Amnesic patients were tested: four with alcoholic Korsakoffs syndrome, three

with amnesia due to an episode of anoxia or cerebrovascular accident, one

who had a left temporal lobectomy to treat intractable epilepsy, and one who

had suffered from encephalitis. The patients with Korsakoffs syndrome

consisted of four men (mean age=65.5 years; mean education= 11.5 years).

The patients with amnesia from other causes consisted of four men and one

woman (mean age=46 years; mean education=16.4 years). The mean WAIS-R








79
Full Scale IQ for these patients was 103 (mean Verbal IQ= 100; mean

Performance IQ=101). The mean Wechsler Memory Scale-Revised Memory

Quotient for these patients was 81 (mean Verbal MQ=70; mean Delayed

MQ=57). These subjects averaged 27.5 words recalled on trials 1 to 5 of the

California Verbal Learning Test. Neuropsychodogical evaluation and

independent neurological examination indicated that memory impairment was

the only remarkable deficit of higher cortical function. These patients have been

studied as a group for several years, and their memory impairment has been

documented in detail elsewhere (Cermak, Talbot, Chandler, & Wolbarst, 1986).

Control subjects for the Amnesic patients were recruited from various

locations throughout the Health Science Center in Gainesville, Florida and were

paid twenty dollars for their participation. Subjects serving as control subjects

for the alcoholic Korsakoff's patients were recruited from the inpatient

Substance Abuse Treatment Program at the Gainesville Veterans Affairs Medical

Center. These subjects consisted of four men who were matched to the

alcoholic Korsakoff patients on the basis of age and education (mean age=69

years; mean education= 11 years). All four of these subjects had lengthy

histories of alcoholism, but had abstained from alcohol for at least three weeks

prior to testing (average abstinence = 8.3 weeks). Subjects serving as control

subjects for the patients with other forms of amnesic were recruited from

various locations throughout the Gainesville Veterans Affairs Medical Center.

These subjects consisted of five men who were matched to this subgroup of







80
amnesia patients on the basis of age and education (mean age=46 years;

mean education= 14.8 years). Analysis of variance procedures failed to reveal

any significant differences between the subgroups of amnesic patients and the

corresponding subgroup of control subjects or between the pooled amnesic

and control groups (all F's less than 1). The mean WAIS-R Full Scale IQ

estimate for these control subjects was 105. The mean Wechsler Memory

Scale Memory Quotient for these subjects was 114.

Forty Introductory Psychology students from the University of Florida

were randomly assigned to one of two conditions: subjects in the Malingering

group (n=20) were asked to portray "the most severe but believable memory

problems" they could on memory tests. Subjects in the Genuine group (n=20)

were asked to perform to their maximum capabilities on memory tests.

Head Injured subjects (n= 15; nine men and six women) were recruited

from several types of populations. The primary criteria for inclusion in this

group was the absence of any current or future legal actions on the part of the

patient concerning disability or compensation. No Head Injured patient

participated in this study under such legal context. Most of these subjects were

seeking assistance with academic and vocational rehabilitation. Therefore, no

HI patient had readily identifiable incentives to perform poorly and all patients

had readily identifiable incentives to perform to their genuine capabilities. Of

the outpatient clinic referrals (n=7), two agreed to participate in the study after

undergoing a neuropsychological evaluation at the Psychology Clinic at the







81
University of Florida Health Science Center. The remaining five outpatient Head

Injury referrals agreed to participate in the study after undergoing a

neuropsychological evaluation at the Mental Hygiene Clinic at the Veterans

Affairs Medical Center in Gainesville, Florida. Outpatient CHI patients were paid

twenty dollars for their participation. Eight additional Head Injured patients were

recruited from the Sandybrook Center of Rebound, Inc., which is located in ML

Dora, Florida.

Duration of post-traumatic amnesia (PTA) and coma are frequently used

indicators of injury severity in the CHI population (c.f., Levin, Benton, &

Grossman, 1982). Coma was judged to end when the patient was able to

follow verbal commands. Post-traumatic amnesia was judged to end when the

patient regained full temporal and personal orientation. In a few cases, this

information was unavailable from medical records. In these instances, length of

coma and/or PTA was estimated by interview with the patient. Eleven of the 15

patients experienced coma. The median length of coma for these patients was

25 days (range = 1 to 120 days). The median duration of post-traumatic

amnesia was 504 hours or 21 days (range = 0 minutes to 44 days). The

median length of PTA was lower than the median length of coma because

severe and lengthy coma occurred frequently in this sample (11 of 15 patients

sustained coma). All of these patients were judged to be fully oriented after

their coma resolved. Only one patient did not experience either coma or post-

traumatic amnesia, but this patient nevertheless demonstrated significant







82
concentration and memory problems. On average, patients were tested

approximately two years after sustaining their injury (median injury-test Interval

= 26 months; range = 4 to 73 months). By all accounts, most all of these

subjects survived severe head injuries. Those with more minor injuries

nevertheless suffered significant neuropsychological impairment.

Clinical characteristics were analyzed as a function of referral setting

(inpatient rehabilitation versus outpatient clinic). Exploratory analyses of

variance failed to find significant main effects of referral setting on age at time of

testing, injury-test interval, duration of coma, or duration of post-traumatic

amnesia. Because of this, all HI patients were treated as a single group of

patients.

Design

The design of the study consisted of a combination of within-subjects

and between-groups factors. The overriding independent variable of interest

was group membership: the Malingering group served as the experimental

group, the Genuine group served as the normal control group, and the Head

Injured group served as the criterion group with bonafide memory impairment.

The effect of group membership was observed on all dependent measures

deriving from the clinical and experimental memory tasks. Levels of processing

were manipulated in a within-subjects manner.







83
Materials

Preexperimental Materials

An extensive set of materials was necessary for the Genuine and

Malingering subjects. A three-subtest short form of the Wechsler Adult

Intelligence Scale-Revised, consisting of the Information. Vocabulary. and Block

Design subtests (Booker & Cyr, 1986), was employed as an estimate of

intelligence. Sattler (1988) endorses this test for clinical use.

Subjects were then given a sheet of paper printed with information about

the neuropsychological sequelae of closed head injury. Twenty items of

information relating to the memory performance of head injured patients was

presented. This fact sheet is contained in Appendix A. Subjects were given

adequate time to read carefully through this information.

Instructions to subjects (Genuine and Malingering subjects only)

concerning the role they were to play were presented after they had been

randomly assigned to either group. The instructions were presented in the

context of an imaginary scenario which emphasized the playing of a role during

the memory testing phase of the experiment. Appendix A presents the two

scenarios used for each group. Both scenarios included a description of an

automobile accident which occurred recently in which the person sustained a

minor head injury without loss of consciousness; neurological examination

results were negative; the person recently began to experience concentration

and memory problems; and the person contacted his attorney for advice.







84
The two scenarios then diverged. The faking scenario stipulated that if

the subject could portray memory problems then he or she could be entitled to

collect a large sum of money in damages from the other driver; the malingering

role was to play "the most severe but believable memory problems" on the

ensuing tests. The best possible effort scenario stipulated that the patient may

have to resign from his or her lucrative job if he or she was found to have

memory problems; the genuine role was to "put forth the best effort, to try to

perform as best you can" on the ensuing tests.

Subjects were then given a test concerning their retention of (1) the

information concerning memory after closed head injury, and (2) the information

pertaining to their particular scenario and role. Appendix B contains this brief

test.

Experimental Materials

Clinical memory measures

The clinical memory measures used in this study have all been used

extensively to evaluate and describe memory impairment (c.f., Lezak, 1983).

Three main clinical memory tests were employed: the Wechaler Memory Scale

(WMS) (Wechsler, 1945), the California Verbal Learning Test (CVLT) (Delis,

Kramer, Kaplan, Ober, & Fridlund, 1987), and the Rey-Osterrieth Complex

Figure test (ROCF) (c.f., Lezak, 1983).

The Wechsler Memory Scale (WMS) (Wechsler, 1945) consists of seven

subtests. The subtests which contribute to producing the age-corrected







85
Memory Quotient (MQ) are Personal and Current Information, Orientation.

Mental Control. Logical Memory. Digit San. Visual Reproduction, and

Associate Learning. The Loaical Memory and Visual Reoroduction subtests

were tested again after a 30 minute delay (Russell, 1975). Although the WMS

has been frequently criticized (Prigitano, 1978), it continues to enjoy frequent

use in characterizing a patient's memory impairment in both the clinic and

laboratory (Squire & Shimamura, 1986). At the inception of this study, the

original WMS was used instead of the Wechsler Memory Scale-Revised

(Wechsler, 1987) because the latter had not yet gained widespread acceptance

and clinical usage.

The California Verbal Learning Test (CVLT) was employed as a measure

of list learning. This test is composed of repeated presentations of a list of 16

words. The structure of this test provides information about the amount of

information learned, the rate of learning over trials, encoding strategies

employed, error analysis, persistence of memory over retention intervals, and

the use of assisted retrieval. All test protocols were scored with the

accompanying microcomputer software (Fridlund & Delis, 1987).

The Rey-Osterreith Complex Figure Task (ROCF) was employed as an

index of drawing from memory or nonverbal memory. The subject completed

three separate tasks associated with the ROCF. The subject first copied the

figure and then immediately drew the figure from memory. The subject again

drew the figure from memory, this time after a 30 minute delay.







86
Several nonverbal clinical memory tests were employed primarily as

interpolation tasks occurring between the immediate and delayed testing of

verbal memory tasks. Forms C, D, and E of the Benton Visual Retention Test

(Benton, 1974) and the Milner Facial Recognition Test (Milner, 1968) were used

for this purpose. These data were not scored or analyzed.

Experimental memory tasks

A total of 120 low (less than 30 occurrences per million) and high

frequency (between 60 and 200 occurrences per million) words were selected

from Kucera and Francis (1967) according to the following criteria. Each word

had between five and eight letters. The first three letters of each word (i.e.,

stem) uniquely defined each word in the set. However, each word stem was

common to at least 10 different words in Webster's Pocket Dictionary. The total

pool of words was randomly divided into four subsets, with 25 words used for

the study and test of Word Stem Completion (WSC), 45 words used for the

study and test of Perceptual Identification (PI), 25 words used for the study and

test of Free Recall (FR), and 25 words used for the study and test of Multiple

Choice Recognition (MCR). Therefore, each experimental paradigm (WSC, PI,

FR, and MCR) had individual study and test lists which were administered

independently of lists associated with the other tasks in order to prevent

contamination at testing.

The first two and last three words of each study list contained "filler"

words which served as buffer items to control for primacy and recency effects.







87
The remaining words were target words. Within each task, each word was

randomly assigned to a processing condition which either focused subject's

attention on the semantic/conceptual aspects or the physical/orthographic

aspects of the particular word. The processing tasks were adapted from Craik

and Tulving (1975). The semantic encoding condition had subjects verify

whether the word would make sense if inserted in a specified place in a

sentence by responding with "yes" or "no." The physical encoding condition

had subjects verify whether a word contained a specified letter by responding

with "yes" or "no." Within each processing condition, the correct answer ("yes"

versus "no") for the word's processing task was randomly assigned. The

proportion of correct "yes" and "no" responses were equivalent within orienting

conditions and within study lists. Appendix B provides the complete study and

test lists used in the four experimental memory tasks.

Word stem completion (WSC). A pool of 25 words was used for WSC.

The 20 target word were divided into two separate lists of 10 words each, List A

and List B. Each subject studied only one of the two lists. Five words were

encoded with a semantic processing task and five words were encoded with a

physical processing task. WSC study lists (A versus B) were counterbalanced

within group. The five words used as primacy and recency buffers were

invariant across both lists. Study words were printed on four by six inch white

index cards. At test, each subject was given a sheet of paper with 20 word

stems and asked to complete the stems to form the first words that came to his







88
or her mind. Ten of the stems could be completed to form the target words

which were studied. The remaining 10 unexposed words were used as

distractor stimuli. The percentage of these words completed in the target

direction served as baseline performance.

Perceotual identification (PI). A pool of 45 words were used for WSC.

Subjects studied a group of 25 words. Five words were used as primacy and

recency buffers. Of the remaining 20 words on the study list, 10 words were

encoded with a semantic processing task and 10 were encoded with an

physical processing task. Study words were printed on four by six inch white

index cards. The PI test list consisted of 40 words, the 20 target words plus 20

unexposed distractor words. Assignment to serial position in the test list was

random. A yes/no recognition test followed the PI task; it consisted of the

same 40 words.

Free recall. A pool of 25 words were used for FR. The FR study list was

composed of five buffer words, 10 words which were encoded in a semantic

processing task, and 10 words which were encoded in an physical processing

task. Study words were printed on four by six inch white index cards. Subjects

made their FR responses on a sheet of lined paper. Buffer words produced at

test were not counted as correct.

Multiple choice recognition. A pool of 25 words were used for MCR.

The MCR study list was composed of five buffer words, 10 words which were

encoded in a semantic processing task, and 10 words which were encoded in







89
an physical processing task. Study words were printed on four by six inch

white index cards. The testing of MCR involved the subject circling the word,

out of four possible choices, which he or she recognized as studying

previously.

Symptom validity testing

Stimuli for Symptom Validity Testing (SVT) was comprised of a series of

seven digit numbers. Stimuli were presented and subjects made their

responses on an IBM-compatible personal computer. A software program was

written using Micro Experimental Laboratory (M.E.L) (Schneider, 1988,1989).

Appendix B contains the study digit strings, the digit strings serving as the test

foils, and the correct answer for that trial. Fifty complete trials were constructed

and comprised trials one through 50. The same trials were then repeated in

the same order for trials 51 through 100. Correct answers (either "A" or "B")

were randomly assigned. Alternative "A" was correct on 50 trials while "B" was

correct on the remaining 50.

The numbers comprising the digit strings were not randomly generated;

rather, several patterns were built into the stimuli in an attempt to "entice" the

Malingering subject into perceiving the task as more difficult than in actuality.

For all trials, the target and foil digit strings began with different digits. The digit

strings always differed as to odd versus even status. All target digit strings

contained two contiguous digits which were the same number (e.g., 81608W),








90
while the foil string did not contain such a pattern. Thus, correct answers could

be made the basis of remembering several simple ideas.

Procedure

Preexoerimental Procedures

AN subjects completed the informed consent form. Testing in the main

phase of the study was then begun with Amnesic patients, amnesic control

subjects, and Head Injured patients.

An extensive pre-experimental procedure was necessary for the college

normals who participated as Genuine and Malingering subjects. These subjects

were administered the WAIS-R short form. Subjects were then asked several

open-ended questions concerning their medical and neurological history. No

subjects were included with a positive history of neurological illness or learning

disability.

Prior to the subject's receiving his instructions, his or her threshold for

perceiving words was determined in the following manner. Using 35 msecs as

the predicted average perceptual threshold, the method of limits was employed

in both a descending and ascending manner. In the descending method, the

sample word was flashed on the tachistoscope for 60 msecs and the subject

attempted to name the word. Additional trials were repeated, using a different

word each time, by decreasing the duration of exposure by five msecs each

repetition until the subject could no longer read the word. The ascending

method was then employed. This differed only in that the starting exposure







91
duration was well below threshold at 10 msec. Repeated trials were presented

with different words by increasing the duration of exposure by five msecs each

repetition until the subject correctly read the words. An individual subject's

perceptual threshold was computed as the mean of the two thresholds

obtained using the ascending and descending method of limits. The duration

of exposure of PI test words was set approximately 5 msecs below the

individual subject's perceptual threshold.

Subjects were then given a sheet of paper printed with information about

the neuropsychological sequelae of closed head injury. Twenty items of

information relating to the memory performance of head injured patients was

presented. Subjects were given adequate time to read carefully through this

information.

As it was originally planned, Genuine and Malingering subjects were to

attempt to keep the tester (the primary experimenter) from "catching on" to their

particular role. This aspect of the procedure had to be abandoned for several

reasons, however, after eight subjects were run. Most importantly, the idea of

fooling the tester and escaping detection added a layer of complexity to the

situation, making it quite confusing for some Malingering subjects. Another

effect of this procedure was that Malingering subjects interpreted this to mean

that they should emphasize behavioral presentation (i.e., their dramatic or

acting ability) rather than their scorable test-taking behavior. Finally, the

requirement to convince the tester cast a somewhat adversarial atmosphere







92
which tended to obscure the purpose of the study and made some Malingering

subjects anxious. During the de-briefing, one subject stated that she quit

playing her role "somewhere in the middle" due to these issues.

The solution to these problems was as follows. The principal investigator

continued to test subjects due to (1) the potential for anxiety; (2) the need to

thoroughly assess compliance with the role-playing; and (3) the need to

maintain consistency of testers across the Head Injured group. However, the

requirement that subjects were to "fool" or deceive the examiner was de-

emphasized. Emphasis was instead placed on the subject's test-taking

behavior. The subjects were told that, just as they would be playing a role, the

principal investigator would be playing the role of the tester. Subjects were told

that all aspects of the tester's behavior would be strictly according to test

administration instructions and procedures and at no time would the tester

initiate an interruption of the role-playing procedure or portray a "confrontation"

with the "suspected faker." This approach worked quite well in that 100%

compliance with instructional conditions was obtained; no subject refused or

interrupted participation. No subject developed an adverse reaction to

participation. The perfect compliance rate should be contrasted with the results

of Heaton, Smith, Lehman, & Vogt (1978) in which 44% of their subjects

instructed to malinger were rated as investing a "questionable" amount of effort

in their role.







93
The principal investigator remained blind to group assignment. Subjects

drew a number out of an envelope which served as the basis for randomized

group assignment. Subjects were left alone in a small testing room in the

Neuropsychology Laboratory with two folders which separately contained the

materials pertaining to the Genuine and Malingering groups. Subjects indexed

which group they had been assigned to and proceeded to read the materials in

that folder. After reading the pre-experimental material, they completed the

brief true/false test concerning their retention of (1) the information concerning

memory after closed head injury, and (2) the information pertaining to their

particular scenario and role. Incorrect answers to questions about head injury

were corrected and discussed with the subjects; therefore, the subjects learned

this information to 100% accuracy.

The role-playing aspects of this study were then discussed further with

the subjects. As the primary experimenter was blind to group membership,

aspects of the Genuine and Malingering roles were discussed with each

subject, regardless of group assignment. This offered the additional benefit of

putting the role-playing into a clearer perspective for each subject. That is,

Genuine subjects gained a better understanding of how their role-playing

related to the Malingering role-playing and vice versa. All subjects were

forewarned to expect difficulty with playing their role. They were told that only

objective aspects of their behavior was of interest to the experimenter; that is,

they were not being judged on "acting ability" or "dramatic believability." Finally,







94
they were encouraged to not cease playing their role until the experimenter said

"Stop playing your role, the experiment is over." Subjects were given

approximately five to seven minutes of free time to use to plan their role-playing.

They were encouraged to review the fact sheet and to mentally rehearse their

role.

Overview of Experimental Procedures

The main phase of the experiment was grouped into three blocks of

tests. The verbal/nonverbal nature of the memory tasks as well as the requisite

delay intervals for the clinical memory tests were the main considerations in

ordering the test battery. Form E of the Benton VRT was used at any point

where additional nonverbal distractor activity was necessary to maintain correct

delay intervals. The first block of tests consisted of the immediate testing of the

WMS Logical Memory and Visual Reproduction subtests. The SVT paradigm

was administered next. The delayed testing of the WMS Logical Memory and

Visual Reproduction subtests closed out the first block of tests.

The second block of tests began with the administration of the copy and

immediate memory trials of the Rey-Osterreith Complex Figure Test. The four

experimental memory tests (WSC, PI, FR, and MCR) were then administered

next. The order of these four tasks was counterbalanced within groups. Four

to five minute interpolated delay intervals occurred between the study and test

phases of all four experimental memory tasks. The forward portion of the WMS

Diait Span subtest was used at the distractor activity for WSC. The backward




Full Text
17
(immediate recall). Using the WMS and the Rey Figure, Brooks found that CHI
patients acquired significantly less information initially and they also forgot
proportionately more of this initially acquired information than did controls.
Duration of posttraumatic amnesia had a positive and significant relationship to
immediate memory and forgetting variables.
Brooks (1974) investigated visual recognition memory in a sample of 34
severely head-injured patients using a continuous recognition paradigm. The
results indicated that the CHI patients recognized significantly fewer items,
showed slower learning rates over trials, and committed a significantly higher
proportion of false negative errors than control subjects. Time elapsed
between the injury and the date of testing showed no obvious relationship to
memory performance. Severity of injury, as estimated by duration of PTA,
correlated with the number of correct recognitions and false positives. False
negative errors occurred more frequently in the CHI patients regardless of the
severity of the injury, suggesting some kind of threshold effect in that cerebral
trauma produces an all-or-none alteration in the CHI memory abilities. Brooks
interpreted these findings as evidence that the CHI patients adopted a very
strict decision criteria whereby they were unwilling to identify an item as old in
the face of uncertainty.
Brooks (1975) employed a list learning task to assess short- and long
term memory in a heterogeneous sample of CHI patients. When tested
immediately after presentation, CHI subjects performed similarly to controls for


69
recollecting most of the words that were presented during the study episode.
Thus, the subject "catches on" to the nature of the test and intentionally
recollects the prior episode. The subject is essentially engaging in cued recall.
The relevance of LOP effects also becomes clear at this point. Levels of
processing effects on indirect memory tests should be apparent to the extent
that explicit memory was operating at retrieval. Bowers and Schacter (1990)
provide the only direct evidence concerning these issues. These researchers
conducted a series of experiments using normal control subjects to determine
whether normal priming effects could be observed in subjects who do not
experience test awareness during the performance of an indirect memory test,
in this case word stem completion. Whereas on-line probes could have been
employed, a post-test questionnaire technique was the most direct measure of
awareness which avoided inducing awareness. In Experiment 1, study
instructions (incidental versus intentional) and test instructions (normal implicit
memory instructions versus hints that stems could be completed with target
words) were treated as between-subjects factors. Encoding process (semantic
versus physical processing) was examined within-subjects in that half of the
words were encoded under each encoding condition.
Twenty (50%) of the 40 subjects were categorized as test-aware based
on the post-experimental questionnaire. The results indicated that study
conditions did not induce test awareness in that 11 of the test-aware subjects
were in the study-informed group, and the remaining nine aware subjects were


34
significantly different from the other patient groups. The malingering group
produced recognition memory performance that was not above chance levels;
three of the ten had recognition scores below chance.
Schacter (1986) created a laboratory analogue of an episodic event in
order to examine various meta-mnemonic variables in groups of normal
subjects and subjects instructed to "simulate forgetting" of this episode. The
episodes consisted of a passage from a novel and videotaped events and was
constructed in such a way that virtually no subject would be able to accurately
recall it. The instructions given to the simulating group were quite brief and
emphasized the believability of their performance. No reward was offered for
successful simulation. The dependent variables in this study included "feeling
of knowing" ratings, which refer to a persons belief that he could retrieve or
recognize an unrecalled item, event, or fact if he were given more powerful hints
or cues (c.f., Schacter, 1983). In Experiment 1, Schacter found that simulators,
relative to the genuine condition, demonstrated significantly lower cued recall
performance and scored significantly below chance on a two-alternative, forced
choice recognition test. Transcripts of each subjects verbalizations at the time
of recollection were provided to six expert judges, who were subsequently
unable to correctly sort the two groups. Finally, simulating subjects were
significantly more pessimistic that retrieval cues and multiple choices would
improve their remembering of the episode.


176
note that this method fails to detect any other Malingering subject, highlighting
the relative consistency from trial to trial that Malingering subjects are capable
of achieving. This is one additional example of the difficulty in firmly
establishing the presence of malingering or exaggeration.
Multivariate Statistical Detection of Malingering
Whereas previous statistical analyses have focused on establishing
group differences on the various experimental and clinical memory tests, the
current analysis addresses the overall question of whether some multivariate
combination of variables is capable of making a classification between no
memory impairment (Genuine group), malingered memory impairment
(Malingering group), and bona-fide memory impairment (Head Injury group).
Linear discriminant function analyses are routinely used to address questions
related to the clinical utility of tasks in detecting group membership (i.e.,
diagnosis).
Experimental memory tasks
Variables comprising the set of measures of experimental memory tasks
comprised two general types. The indirect memory measures included the
magnitude of priming for stem completion and perceptual identification as well
as the mean reaction time for correctly identified target words during PI.
Measures of explicit memory included the explicit recognition probes associated
with the PI and WSC tasks as well as the free recall and multiple choice
recognition tasks. Two separate questions could be addressed by dividing the


66
Challis and Broadbeck (1992) provide an excellent and authoritative
review of research into LOP effects in indirect perceptual tests. Their literature
review uncovered a total of 11 published studies which manipulated LOP and
measured performance on the indirect perceptual memory tests of perceptual
identification (Jacoby & Dallas, 1981; Hashtroudi, Ferguson, Rappold, &
Chrosniak, 1988; Light & Singh, 1987), word stem completion (Graf, Mandler, &
Haden, 1982; Graf & Mandler, 1984; Graf, Squire, & Mandler, 1984; Squire,
Shimamura, & Graf, 1987; Light & Singh, 1987; Chiarello & Hoyer, 1988;
Bowers & Schacter, 1990; and Mandler, Hamson, & Dorfman, 1990), and word
fragment completion (Squire et al., 1987; Srinivas & Roediger, 1990).
In 33 of 35 separate experiments conducted in these studies, priming
was numerically greater in the semantic condition than in the physical condition.
While often not statistically significant, the effect sizes of LOP were
characterized as small-to-medium magnitude. Challis and Broadbeck (1992)
provide illuminating evidence which helps explain these contradictory findings.
They found that semantically processed words showed a consistent advantage
over orthographically processed words when tested with a word fragment
completion paradigm. However, when semantic and physical conditions were
presented within-subjects in a mixed list, the LOP effect was negligible and
nonsignificant. The authors interpret this finding as evidence for the
independent contribution of the physical analysis component of the LOP
manipulation.


29
Mensch and Woods (1986) examined whether groups of subjects with
normal and above average IQ scores could appear "brain damaged" on the
Luria-Nebraska Neuropsychological Battery if motivated by a small monetary
reward conditional on successful feigning. They employed a double-blind
crossover design. Analysis of their data indicated that 31 of 32 subjects were
able to significantly elevate enough individual scales to suggest brain damage.
However, the malingering subjects profile of test scores was not qualitatively
consistent with profiles of patients with known neurological pathology. For
example, malingering subjects did not demonstrate significant differences
between the Left and Right hemisphere scales. Malingering subjects
consistently performed quite poorly on sensory motor tests and tests whose
face validity was high and displayed exaggerated response latencies. Mensch
and Woods concluded that the subjects instructed to malinger brain damage in
their study were unsuccessful.
Goebel (1983) investigated the issue of whether naive, neurologically
normal subjects could feign believable deficits on the HRNB, as well as the
more specific question of whether lateralized deficits were more difficult to
simulate than diffuse or nonspecific deficits. Goebels design consisted of six
groups: mixed neurologic patients, control subjects, and patients told to
simulate either "nonspecific," "diffuse," "left hemisphere," or "right hemisphere"
cortical damage. In a sort of the test protocols, only 2 of 102 malingering
subjects were incorrectly classified (i.e., feigned believable deficits).


CHAPTER 4
DISCUSSION
Validity of Group Membership
Genuine and Head Iniurv Subjects
The data reviewed in Chapter 3 indicate that subjects in the Genuine
condition adequately invested themselves in their respective scenario and role-
playing to the extent that their performance on clinical memory tests was
normal. In fact, Genuine subjects demonstrated intact and even above average
memory abilities as indexed by the clinical memory tests. Debriefing and
interview data further establish that the participation of these subjects was
adequate. The overall level of performance was relatively high, but consistent
with what would be expected of these subjects based on their age, education
level, and measured intelligence.
Head Injury subjects demonstrated impairment on clinical tasks requiring
complex attentional processes and the learning and retention of new
information. As a group, their level of performance fell in the moderate-to-
significantly impaired range of scores. This group of subjects scored an
average of 2.3 standard deviations below the Genuine group. Relatively
equivalent performance declines were noted on verbal and nonverbal memory
185


191
prediction that Malingering subjects would lower their overall level of
performance on WSC did not occur. Rather, Genuine subjects used explicit
memory to increase their WSC performance. This accounted for the observed
differences between these two groups. No detectable changes in response
strategies or response criteria were evident from analysis of WSC serial
position.
The prediction that the PI task would be relatively immune to the effects
of explicit memory was borne out from two perspectives. Malingering subjects
failed to lower their performance with explicit memory suppression, while
Genuine subjects were unable to raise their performance with explicit memory
mediation. The prediction that Malingering subjects would produce increased
response latencies was not accurate as well. When viewed from a clinical
perspective, the performance of Malingering subjects on the experimental
memory tests was indistinguishable from the memory-disordered Head Injury
patients in terms of quantitative level of performance, response latency, and
LOP effects.
Priming Effects
Study 1 established that the materials and procedure used in this study
were valid indices of direct and indirect memory. Amnesic subjects
demonstrated normal priming on word stem completion and perceptual
identification in spite of severely impaired explicit memory as indexed by free
recall and multiple choice recognition. Amnesic performance on indirect


31
Specificity rates were 14% for each group. Malingering patients generally
produced lower scores than patients with bona-fide impairment. Malingerers
performed poorly on tests not expected to be affected by left frontotemporal
involvement. Qualitatively, malingering performance was characterized by
elaboration and confabulation (i.e., commission of incorrect behavior), as
opposed to the poverty of content characteristic of the brain-damaged patients.
Malingerers produced types of errors on sensory tests which are not typical of
bona-fide impairment (e.g., confusing digits 1 and 4 on the finger localization
test, instead of the more typical confusion of 2 and 3).
Faust, Hart, & Guilmette (1988) investigated whether a relatively broad
sample of clinicians could identify the malingered protocols of nonsophisticated
subjects. Three children between the ages of 9 and 12 were instructed to "fake
bad" on the HRNB. All three subjects produced impaired performances on this
battery of tests. Information regarding age, sex, handedness, test scores, and
qualitative data from the Aphasia Screening Test was given along with test data
to a random sample of practicing neuropsychologists. Judges rated the results
on normal versus abnormal, etiology, severity of impairment, and confidence in
their diagnosis. The detection rate for malingering was 0%. Moreover,
clinicians rated themselves as moderately to highly confident in their diagnoses.
This study was altered slightly and replicated using adolescent subjects
to produce malingered HRNB profiles (Faust, Hart, Guilmette, & Arkes, 1988).
In Study 1, most clinicians (78%) who received no forewarning of the possibility


106
Table 2
Descriptive Information for Experiment 1
Group
Variable
Amnesia
Controls
Number of Subjects
9
9
Age
Mean
SD
F(1,16) = 0.06
54.7*
15.4
56.3a
13.8
Education
Mean
SD
F(1,16) = 0.43
14.2a
3.6
13.1a
3.6
Full Scale IQ
Mean
SD
F(1,16) = 0.12
102.6a
15.3
104.7a
9.4
Mattis DRS Total
Mean
SD
F(1,16) = 1.27
131.5a
4.2
135.3a
6.5
* pc.05 ** pc.01 *** pc.001
Note. Means with different superscripts differ significantly at pc.05.


167
Characteristics of malingering performance
The Malingering subjects performance on SVT is unexpected given what
has previously been reported in the literature. Pankratz and his colleagues
(Pankratz, 1983; Pankratz, Fausti, & Peed, 1975) designed SVT to function as a
clinical tool. One requirement necessary for SVT to be useful in this context is
that the results of SVT can be applied on an individual-subject basis. In order
to fulfill this requirement, the absolute criterion of random or chance
performance is used as the comparison value. Principles of binomial probability
theory are used to determine the probability associated with a particular
subjects performance. The criterion of random or chance performance
provides strong and convincing, though not irrefutable, evidence that a subject
is exaggerating impairment. However, a careful examination of the results
presented here provides a strong indication that the criterion of chance
performance may be too rigorous and may result in insensitivity to malingering
response styles.
Table 18 presents SVT data for all Malingering subjects. A score of 41%
accuracy (out of 100 trials) is associated with the cumulative binomial
probability of .0443. Thus, a subject must obtain a score of 41% accuracy (for
100 trials) or less in order to be classified as performing significantly below
chance, at the .05 alpha level. No Malingering subject scored this low; only one
subject (# 34) scored below nominal chance performance (45/100, binomial
probability=0.184). Only three other Malingering subjects scored near chance


177
variables in this manner. The first issue pertains to the ability of all of the
experimental memory variables, implicit as well as explicit, to detect group
membership. The second issue pertains to the ability of the three implicit
memory variables, taken alone, to predict group membership.
All experimental memory variables. Table 22 presents the classification
rates produced from a linear discriminant function analysis based on the entire
experimental memory variable set. Overall, this variable set produced
surprisingly accurate group predictions. Whereas group differences on the
individual variables failed to separate the three groups, the linear combination of
all tasks would appear to offer a relatively useful clinical tool. Malingering
subjects were classified with the least amount of accuracy. However, the
sensitivity rate of 89.4% and the specificity rate of 11% offer clinically significant
improvements over chance diagnostic rates.
Genuine subjects were identified quite accurately; only one subject was
classified as belonging to the Malingering group. This subjects scores on the
experimental memory tasks were characterized as below average performance
on implicit memory tasks and significantly below average performance on the
explicit memory tasks. Head Injury subjects were identified quite accurately as
well; only one subject was identified as belonging to the Genuine group. This
subjects scores on the experimental memory tasks were characterized as
above average performance on implicit memory tasks but performance on
explicit memory tasks equivalent to that of Genuine subjects.


134
Table 8
Performance on the Copy of the Rev-Osterreith Complex Figure
Unit
Omission Errors
Absent (score=0)
Comission Errors
Distorted (.5/1)
G
M
HI
G
M
HI
1. Cross, UL
0
5
15
60
80
62
2. Lg rectangle
0
10
0
25
35
54
3. Diag. cross
0
15
0
20
25
38
4. Horz. ML of 2
0
15
8
5
10
31
5. Vert. ML of 2
0
15
0
35
30
23
6. Sm. rect. in 2
0
5
8
40
60
62
7. Sm. sg. ab. 6
0
35
15
5
0
8
8. 4 lines in 2
0
10
8
20
30
38
9. Triangle, 2
0
10
0
25
50
31
10. Sm. VL in 2
0
20
8
20
5
15
11. Circle, 3 dots
0
0
8
10
25
15
12. 5 par. lines,
0
5
0
10
50
23
13. Triangle on 2
0
5
0
20
35
39
14. Diamond, 13
0
15
8
5
15
31
15. Vert. In., 13
5
5
15
25
50
38
16. Horz. In., 13
0
10
8
10
15
15
17. Cross, LC
0
10
0
15
45
62
18. Square on 2
0
0
0
25
30
39
Note. Column subheadings are abbreviated as follows: G=Genuine,
M=Malingering, and HI=Head Injury. All data are percentages of each subject
group obtaining the indexed score for the indexed scoring unit.


119
procedures showed significant main effects of group on WMS Digits Backward,
F(2,51)=10.80, pc.0001, but not on WMS Mental Control, F(2,51)=3.97, pc.025
or WMS Digits Forward score, F(2,51)=5.75, pc.006. Follow-up mean
contrasts showed that Genuine subjects produced significantly higher scores
on the Digits Backwards test than either the Malingering or Head Injury groups,
which were not significantly different from each other.
Immediate verbal free recall. A MANOVA performed on the set of
variables representing immediate free recall of verbal material was highly
significant, Wilks Lambda F(8,96)=5.73, pc.0001. Univariate ANOVA
procedures showed significant main effects of group on WMS Logical Memory
score, F(2,51)=13.81, pc.0001, CVLT Trial 1, F(2,51) = 11.76, pc.0001, and
CVLT Trial 5, F(2,51)=10.48, pc.0001. Follow-up mean contrasts showed that
Genuine subjects produced significantly higher scores than either Malingering
or Head Injury groups on all three of these measures. The performance of the
Malingering and Head Injury groups was not significantly different on all three
indices.
Immediate verbal cued recall. A MANOVA performed on the set of
variables representing immediate cued recall of verbal material was highly
significant, Wilks Lambda F(6,98)=6.23, pc.0001. Univariate ANOVA
procedures showed significant main effects for group on WMS "Easy" Paired
Associates, F(2,51)=9.88, pc.0002, WMS "Hard" Paired Associates,
F(2,51)=16.52, pc.0001, and CVLT Short Delay Cued Recall, F(2,51)=17.66,


211
accuracy that the other two groups. An analysis of the incorrect classifications
was suggestive of the fact that the indirect memory tests contributed very little
to the classification process. A subsequent discriminant function performed just
on the variables from the indirect memory tests resulted in very poor
classification rates, suggesting the hypothesis that performance on indirect
memory tests offers little clinical utility in itself in the detection of malingering.
A variable set was then constructed based on selected clinical memory
indices and entered into a linear discriminant function analysis. The
classification rates were extremely high, with a sensitivity rate of 92% and a
specificity rate of 8%, averaged across the three groups. These rates were
slightly more accurate than those produced by the experimental memory tests.
Therefore, it appears that the experimental memory tests in general and the
indirect memory tests in particular do not offer the clinician any additional
information about the potential malingering patient not otherwise afforded by
the routine battery of clinical memory tests. Clearly, cross-validation is needed
for the discriminant equation for the clinical memory tests. It would be useful to
replicate these findings on an unselected groups of litigating and nonlitigating
consecutive clinic admissions with mild CHI.
The "Art11 of Detecting Malingering
Perhaps the most important conclusion to draw from this study is that,
with the notable exception of SVT, a single test or a "snapshot1 of memory
performance is insufficient to catch a Malingerer, even when the domain of such


152
The interaction between group and type of recognition (simple versus
conditionalized) on accuracy rate was nonsignificant, (F < 1). Within-groups
analyses of variance resulted in nonsignificant main effects of type of
recognition (simple versus conditionalized) on accuracy rates for all three
groups (all Fs < 1). These results establish that simple recognition memory
following PI was statistically independent from recognition memory
conditionalized upon correct perceptual identification in all three groups. This
suggests that explicit memory contributed very little to performance on PI.
Trial-bv-trial analysis. A subject could potentially alter his PI performance
to the extent that he or she develops awareness during PI that target words
have been previously encountered in the study phase. On the surface, it would
appear that PI would be much more immune to the effects of explicit memory
than the stem completion task. Similarly, it would appear that deviations in
responding based on explicit memory would be easily detectable by changes in
reaction times. However, PI is much less generative than WSC and therefore
requires only relatively automatic reading from the subject. The withholding or
inhibition of behavior in general would be sufficient for Malingering subjects to
lower their accuracy rate. The change in a subjects response strategy or
response criterion was operationalized as a reduction in percent accuracy that
occurs over several successive groups of target words. The target words were
divided into groups of 4 words, representing partitions of 20% of the overall list.


92
which tended to obscure the purpose of the study and made some Malingering
subjects anxious. During the de-briefing, one subject stated that she quit
playing her role "somewhere in the middle" due to these issues.
The solution to these problems was as follows. The principal investigator
continued to test subjects due to (1) the potential for anxiety; (2) the need to
thoroughly assess compliance with the role-playing; and (3) the need to
maintain consistency of testers across the Head Injured group. However, the
requirement that subjects were to "fool" or deceive the examiner was de-
emphasized. Emphasis was instead placed on the subjects test-taking
behavior. The subjects were told that, just as they would be playing a role, the
principal investigator would be playing the role of the tester. Subjects were told
that all aspects of the testers behavior would be strictly according to test
administration instructions and procedures and at no time would the tester
initiate an interruption of the role-playing procedure or portray a "confrontation"
with the "suspected faker." This approach worked quite well in that 100%
compliance with instructional conditions was obtained; no subject refused or
interrupted participation. No subject developed an adverse reaction to
participation. The perfect compliance rate should be contrasted with the results
of Heaton, Smith, Lehman, & Vogt (1978) in which 44% of their subjects
instructed to malinger were rated as investing a "questionable" amount of effort
in their role.


140
groups showed a slight trend towards higher percent correct stem completion
of target words encoded in the physical orienting condition.
An alternative analytic approach involved computing a binary variable
which reflected whether or not each subject demonstrated priming on stem
completion. For each subject, baseline performance for that subject was
subtracted from target performance, resulting in a variable which reflected the
magnitude of priming. Using a very conservative cutoff of a 25% increase in
performance of targets over distractors, each subject was categorized as to
whether his stem completion performance reflected priming or no priming.
Fourteen of 20 Genuine subjects (70%) demonstrated priming, compared to 9
of 20 Malingering subjects (45%) and 11 of 15 Head Injury subjects (73%).
Nonparametric hypothesis tests for the significance of difference between
proportions failed to reach significance (Z=-.48, p<.32). The Malingering
groups lower frequency of priming approached but barely failed to reach
significance (Z=-1.55, p<.055).
Yes/no recognition following stem completion. One important question
concerns the degree to which subjects employ explicit memory processes while
performing nominally implicit memory tasks. The word stem completion task
would seem especially vulnerable to contamination by explicit memory. After
completing stem completion itself, subjects answered "yes" or "no" beside each
generated word to indicate whether they recognized this word from the study
list. Three aspects of this task were scored. First, the probability of correct


133
recall of verbal material, and delayed cued recall of verbal material. Malingering
subjects scored lower than Head Injury subjects on tasks measuring delayed
recall of verbal and nonverbal material. Only one test, the WMS Delayed Visual
Reproduction subtest, showed sufficient discriminatory power to separate all
three groups. Malingering subjects over-exaggerated their impairment on this
test, producing a grossly impaired score of 3.3, almost half that of the Head
Injury group.
From a qualitative perspective, Malingering subjects demonstrated an
exaggerated amount of forgetting on the WMS Logical Memory and Visual
Reproduction subtests (defined as the loss of originally-learned information over
delay intervals). By and large, however, Malingering subjects successfully
portrayed the qualitative aspects of bona-fide memory impairment. This
includes the Malingering groups ability to accurately balance the omission of
behavior with the commission of incorrect behavior to produce responses
similar to bona-fide memory impairment.
Experimental Memory Tasks
Word stem completion
Main task analysis. Each subject in the present study served as his own
control in that chance or baseline performance on the stem completion task
was determined by the percentage of distractor (new) words completed in the
target direction. Baseline performance for the three groups (Genuine=14%;
Malingering=14%; and Head Injury=8.7%) was not significantly different,


47
Loring, and Martin (1992) provided additional validation data for the FIT
administered to temporal-lobe epileptics and consecutive outpatient
neuropsychology clinic referrals. These authors suggested a more conservative
cutoff of seven correct items. In addition, litigating outpatient referrals scored
significantly lower than nonlitigating outpatient referrals.
Dot-counting task. A second task employs seven 3 by 5 inch index
cards upon which dots are placed in an organized (grouped) or random
(ungrouped) manner. The patient is instructed to count the dots as quickly as
he can, his reaction time for each card is noted, and these times are compared
with normative data from normal adults as well as head injury patients. The
patients performance for this task is evaluated in terms of the difference
between the reaction times for the grouped and ungrouped dots. Deviations
from the logical temporal pattern may lead the clinician to doubt the patients
motivation.
Recognition memory paradigm. Finally, a third task involves
administration of a 15-item word list. Recognition memory is tested
immediately. Later in the session, the subjects level of recognition is compared
with the first trial of free recall on a list learning test (e.g., Rey Auditory Verbal
Learning Test). Given the well established fact that recognition generally
exceeds free recall, a deviation from this pattern suggests a nongenuine
response style.


251
Weissman, H. N. (1990). Distortions and deceptions in self-presentation: Effects
of protracted litigation in personal injury cases. Behavioral Sciences and the
Law. 8, 67-74.
Wiener, D. N. (1948). Subtle and obvious keys for the MMPI. Journal of
Consulting Psychology. 12. 164-170.
Wiggins, E. C., & Brandt, J. (1988). The detection of simulated amnesia. Law
and Human Behavior. 12. 57-78.
Williamsen, J. A., Johnson, H. J., & Eriksen, C. W. (1965). Some characteristics
of posthypnotic amnesia. Journal of Abnormal Psychology. 70. 123-131.
Winnick, W. A., & Daniel, S. A. (1970). Two kinds of response priming in
tachistoscopic recognition. Journal of Experimental Psychology. 84, 74-81.
Witherspoon, D., & Moscovitch, M. (1989). Stochastic independence between
two implicit memory tests. Journal of Experimental Psychology: Learning.
Memory, and Cognition. 15, 22-30.
Wylie, T. F., & Ruff, R. M. (1990, February). Detection of simulated malingering
on neuropsychological tests. Paper presented at the meeting of the
International Neuropsychological Society, Orlando, FL.
Zappala, G., & Trexler, L. A. (1992). Quantitative and qualitative aspects of
memory performance after minor head injury. Archives of Clinical
Neuropsychology. 7, 145-154.


42
altered by making the stimuli more complex and giving the subject the
impression that the task is very difficult (c.f., Lezak, 1983).
Theodor and Mandelcorn (1973) used this technique in a case involving
"hysterical blindness." Their patient did in fact demonstrate significantly below-
chance discrimination of a visual stimulus, suggesting that the patient was
processing the stimulus and then volitionally refusing to report it. Pankratz,
Fausti, and Peed (1975) successfully employed the SVT paradigm to
demonstrate that a patient claiming loss of hearing was in fact discriminating
the stimulus on some level. Pankratz (1983) and Binder and Pankratz (1987)
extended these findings, demonstrating the utility of Symptom Validity Testing
to the detection of feigned memory impairment. Binder has reported five
additional case studies in which a below-chance performance on forced-choice
testing was helpful in making the diagnosis of malingering (Binder, 1990b,
1992). Pankratz (1979) demonstrated that Symptom Validity Testing, when
presented to the patient with an expectation for change, allowed the patient to
spontaneously relinquish his symptoms while still maintaining his dignity and the
belief in the physical basis for the symptoms.
Modifications to original paradigm. Following Pankratzs advice (1988),
clinicians have begun to modify and adapt forced-choice testing to meet their
individual clinical needs. Three methods have recently appeared in the
literature. Hiscock and Hiscock (1989) varied the objective task difficulty by
introducing varying retention intervals into the paradigm. Five digit numbers


218
Best Effort Scenario
The primary experimenter would like for you to play a role as you participate in
this experiment. The role you are to play is based on the following scenario:
Scenario:
You have recently experienced an automobile accident about 1 month
ago. This accident was not your fault; it was the other drivers fault. In
this accident, you sustained a "moderate" Closed Head Injury when you
hit your head on the steering wheel. You were taken to the hospital,
where you received medical care. X-rays and scans were done. The
results of these tests did not turn up any severe damage to your skull or
brain. The doctor told you that you did not have to stay overnight in the
hospital and that the doctor did not need to see you in the future for
further medical treatment.
However, during the last few weeks you have been experiencing
some mental problems which are very much like the problems vou have
just read about. You have contacted your attorney who scheduled
psychological testing in order to determine if in fact your mental ability
and memory have been damaged.
Your attorney tells you that if you have sustained mental injury you
may be unable to continue working at your lucrative job. The less
mental impairment you have, the more work you can do and the more
money you will be able to earn at your job. However, if the psychologist,
based on your test scores, reports that you have mental and memory
problems, you will no longer be able to work at your lucrative job.
At the present time, you have arrived for your appointment for
psychological testing. Your role is to put forth the best effort vou can, to
trv to perform as best as vou can on these memory tests. Your primary
job is to respond to the tests as you think a person with such memory
problems would. Your "acting ability" does not matter. The person who
will be working with you is also playing a role of "tester". While he does
not know what role you will be playing, you should not be concerned
with fooling" or "convincing" him.
Please play this role until the experimenter tells you that the experiment is over.
You are to use vour knowledge about Closed Head Injury which vou iust
learned in order to play this role.
You will now be administered a brief test about your knowledge of CHI to make
sure you are able to use this information when playing your role.
After this test, you will be given 5 minutes in order to play how you will play
your role.


83
Materials
Preexperimental Materials
An extensive set of materials was necessary for the Genuine and
Malingering subjects. A three-subtest short form of the Wechsler Adult
Intelligence Scale-Revised, consisting of the Information. Vocabulary, and Block
Design subtests (Booker & Cyr, 1986), was employed as an estimate of
intelligence. Sattler (1988) endorses this test for clinical use.
Subjects were then given a sheet of paper printed with information about
the neuropsychological sequelae of closed head injury. Twenty items of
information relating to the memory performance of head injured patients was
presented. This fact sheet is contained in Appendix A. Subjects were given
adequate time to read carefully through this information.
Instructions to subjects (Genuine and Malingering subjects only)
concerning the role they were to play were presented after they had been
randomly assigned to either group. The instructions were presented in the
context of an imaginary scenario which emphasized the playing of a role during
the memory testing phase of the experiment. Appendix A presents the two
scenarios used for each group. Both scenarios included a description of an
automobile accident which occurred recently in which the person sustained a
minor head injury without loss of consciousness; neurological examination
results were negative; the person recently began to experience concentration
and memory problems; and the person contacted his attorney for advice.


248
Sierles, F. S. (1984). Correlates of malingering. Behavioral Science and the Law.
2(1), 113-118.
Slamecka, N. J. (1985). Ebbinghaus: Some rejoinders. Journal of Experimental
Psychology: Learning. Memory, and Cognition. 11. 496-500.
Sloman, S. A., Hayman, C. A. G., Ohta, N., Law, J., & Tulving, E. (1986).
Forgetting in primed fragment completion. Journal of Experimental
Psychology: Learning. Memory, and Cognition. 14(2), 223-239.
Smith, E. (1974). Influence of site of impact on cognitive impairment persisting
long after severe closed head injury. Journal of Neurology. Neurosurgery,
and Psychiatry. 37. 719-726.
Smith, M. L, & Glass, G. V. (1977). Meta-analysis of psychotherapy outcome
studies. American Psychologist. 32, 752-761.
Spreen, O., & Benton, A. L. (1963). Simulation of mental deficiency on a visual
memory test. American Journal of Mental Deficiency. 67, 909-913.
Squire, L. R. (1987). Memory and brain. New York: Oxford University Press.
Squire, L. R., Chace, P. M., & Slater, P. C. (1976). Retrograde amnesia following
electroconvulsive therapy. Nature (London). 260. 775-777.
Squire, L. R., & Cohen, N. J. (1984). Human memory and amnesia (pp 3-64). In
J. McGaugh, G. Lynch, and N. Weinberger (Eds.). Proceedings of the
conference on the neurobioloov of learning and memory. New York: Guilford
Press.
Squire, L. R., & Shimamura, A. P. (1986). Characterizing amnesic patients for
neurobehavioral study. Behavioral Neuroscience. 100(6). 866-877.
Squire, L. R., Shimamura, A. P., & Graf, P. (1985). Independence of recognition
memory and priming effects: A neuropsychological analysis. Journal of
Experimental Psychology: Learning. Memory, and Cognition. 11. 37-44.
Stermac, L. (1988). Projective testing and dissimulation (pp 159-168). In R.
Rogers (Ed.). Clinical assessment of deception and malingering. New York:
The Guilford Press.
Stevens, H. (1986). Is it organic or is it functional: Is it hysteria or malingering?
Psychiatric Clinics of North America. 9(2), 241-254.


CHAPTER 2
METHOD
The present study consists of two generally separate experiments.
Experiment 1 was conducted using Amnesic patients and matched control
subjects. The main purpose of this experiment was to validate the experimental
memory stimuli and procedures (word stem completion, perceptual
identification, free recall, and multiple choice recognition). In so doing, the
quantitative (i.e., strength of priming) and qualitative (i.e., levels of processing
effects, dissociations between indirect and direct tests) characteristics of these
tasks could be established to provide a well-recognized benchmark upon which
to compare the results of Experiment 2. Experiment 2 was conducted using
normal college students given two different roles to play (Genuine and
Malingering performance), while Head Injured patients were used as the
criterion group with bonafide organic memory impairment. By excluding
Amnesic patients and their matched controls from the main analyses of
Experiment 2, the design was more analogous to that seen in the medicolegal
context. Given that malingering is more closely associated with traumatic brain
injury (Binder, 1986) than circumscribed organic amnesia, the most important
76


131
reproduction of the ROCF were scored according to criteria put forth by Lezak
(1983). Each of 18 different design elements were scored separately for
absence (score=0), distorted/incomplete and placed poorly (score=0.5),
distorted/incomplete and placed properly (score=1.0), and accurate and proper
placement (score=2). Tables 8, 9, and 10 present data on the percentage of
subjects in each group producing absent or distorted scores for each individual
design element.
For purposes of economy, scoring elements were next divided into two
groups: major configurational elements contributing to the overall gestalt of the
figure and small detail elements. Following Lezaks scoring system, major
configurational elements were the large rectangle (scoring unit number 2), the
diagonal cross (unit 3), the horizontal and vertical midlines of unit 2 (units 4 and
5), and the large triangle connected with 2 (unit 9). The remaining scoring units
were designated as small detail elements. Tables 11, 12, and 13 present mean
percentages of errors committed by subjects in each group as a function of
type of design element.
Hypothesis tests were performed to detect group differences on the
mean percentage of errors for each type of design element for the copy trial of
the ROCF. This was repeated for the immediate and delayed reproductions as
well. Given 36 paired comparisons, a significance level of .001 was used as the
criterion for obtaining a statistically significant difference (alpha of .05/36
comparisons=.0014). No pairwise comparisons reached significance.


93
The principal investigator remained blind to group assignment. Subjects
drew a number out of an envelope which served as the basis for randomized
group assignment. Subjects were left alone in a small testing room in the
Neuropsychology Laboratory with two folders which separately contained the
materials pertaining to the Genuine and Malingering groups. Subjects indexed
which group they had been assigned to and proceeded to read the materials in
that folder. After reading the pre-experimental material, they completed the
brief true/false test concerning their retention of (1) the information concerning
memory after closed head injury, and (2) the information pertaining to their
particular scenario and role. Incorrect answers to questions about head injury
were corrected and discussed with the subjects; therefore, the subjects learned
this information to 100% accuracy.
The role-playing aspects of this study were then discussed further with
the subjects. As the primary experimenter was blind to group membership,
aspects of the Genuine and Malingering roles were discussed with each
subject, regardless of group assignment. This offered the additional benefit of
putting the role-playing into a clearer perspective for each subject. That is,
Genuine subjects gained a better understanding of how their role-playing
related to the Malingering role-playing and vice versa. All subjects were
forewarned to expect difficulty with playing their role. They were told that only
objective aspects of their behavior was of interest to the experimenter; that is,
they were not being judged on "acting ability" or "dramatic believability." Finally,


146
WSC RECOGNITION
Conditional Probabilities
probability
GENUINE
MALINGER
CHI
P(WS*IRec*)
0.88
0.7
0.7
P(WS-IRec+)
0.12
0.28
0.1
p(Dist.lRec+)
0.07
0.27
0.07
WSC SERIAL POSITION
% correctly completed
GROUPS
-a- gen
4- MAL
CHI
Figure 6. WSC Performance: Serial Position and Conditionalized Recognition.


46
Revs techniques
Fifteen-item test. Lezak (1983) describes several of the French
neuropsychologist Andre Reys clinical techniques designed to assess
dissimulation. In the Memorization of 15 Items technique (Fifteen Items Test,
FIT), the patient is presented with a three by five item array of symbols, and he
is asked to memorize the "difficult1 stimuli. In actuality, only three or four
concepts are needed for accurate recall. According to Lezak, only the most
significantly impaired individuals recall less than three of the five character sets.
Several empirical studies of the FIT have been published recently.
Goldberg & Miller (1986) administered the FIT to psychiatric inpatients and
mentally deficient patients. Their results confirmed the criteria proposed by
Lezak (1983) and suggested that malingering should be considered among
individuals who deny remembering at least six of the 15 items. Bernard and
Fowler (1990) administered the FIT to brain-damaged patients and normal
controls. Their results generally supported the cutoff of nine correct items. A
comparison of the number of sets of items which were correctly recalled was
nonsignificant.
Morgan (1991) validated the FIT on a sample of 60 patients with bona-
fide mild to severe memory impairment. The cutoff of 9 correct items was again
confirmed. However, "failure" on the FIT resulted from bona-fide, severe
memory impairment in some subjects. Qualitative analysis of the protocols
failed to reveal consistent indicators of bona-fide memory impairment. Lee,


41
subject scored better than chance. Comparisons with other studies employing
this paradigm should not be made due to the restricted number of trials
employed here (21) as compared with the standard of 100.
Specific Clinical Techniques to Detect Malingerers
Symptom validity testing
Original paradigm. Theodor and Mandelcorn (1973) first reported the
use of a two-alternative, forced-choice paradigm for evaluating the validity of a
claim of disability or impairment. This procedure is quite simple in nature. The
subject is presented with one of two distinct stimuli and is then, after a brief
delay, asked to determine which of the two had been presented. This is
repeated until a sufficient number of trials have been administered, usually at
least 100 trials. The subjects performance is then compared with what would
be considered chance performance. Nominal chance performance is 50%
correct. A performance significantly different than chance is interpreted as the
subject having a preserved ability to perceive and discriminate between the two
stimuli. If the subjects performance is significantly below chance, then the
subject is suspected of feigning the deficit. For 100 trials, 41% accuracy is
associated with the cumulative binomial probability of 0.04. Alternatively, the
subject is making accurate discriminations if his performance is significantly
above chance. An essentially "normal" subject is expected to score at or near
100% correct. This procedure has been termed "Symptom Validity Testing"
(SVT) by Pankratz, Fausti, and Peed (1975). Symptom Validity Testing can be


100
passages. The task for the subject was to recall a number of ideas contained
in the passages. The subject was asked to repeat this recall procedure after a
20-25 minute delay interval. Memory Span consists of recalling verbally
presented digits in the forward and backward directions. For each Digits
Forward and Digits Backward, the score was the maximum number of digits
recalled. Visual Reproduction consists of drawing geometric designs that were
presented visually for a brief period of time. The subject was also asked to
repeat this reproduction procedure after a 20-25 minute delay interval.
Associate Learning consists of the subject learning two word associations and
then recalling the correct target word when given the stimulus word.
On the California Verbal Learning Test, the subjects were read five
presentations of a list of 16 words. After each presentation, the subject was
asked to repeat, in any order, the words on the list. After the fifth presentation,
a second list was presented. After this trial, the first list was tested for a short
delay free recall and short delay cued recall, and followed later by a twenty
minute free recall, twenty minute delay cued recall, and twenty minute delay
recognition.
The Rey-Osterreith Complex Figure Task (c.f., Lezak, 1983) required the
subject to complete three separate tasks. The subject copied the complex
figure, drew the figure from memory immediately after copying it, and drew the
figure from memory after a 30 minute delay period. The drawings were scored
by a neuropsychometrician with extensive experience with this test who was


172
Table 18
SVT and Selected Clinical Data for Malingering Group
Subject
Number
SVT
%Cor
SVT
RT
WMS
MQ
WMS
VR
Delay
CVLT
Total
1-5
ROCF
Delay
34
45
1.85
80
0
35
2.5
36
57
2.10
57
0
31
0.5
20
58
3.87
64
1
31
10.5
12
59
3.58
59
0
44
3.5
24
62
1.70
72
1
24
9.0
28
69
1.69
87
2
60
10.5
16
74
3.77
86
6
61
18.0
9
77
2.45
73
0
36
12.5
15
82
1.50
90
0
36
15.5
33
84
5.07
53
0
14
2.0
39
86
3.87
93
3
27
11.0
23
89
1.85
93
2
39
14.0
14
90
1.48
90
6
47
12.0
27
99
4.30
80
4
44
14.5
2
100
1.73
94
4
38
15.0
5
100
2.11
87
4
36
15.5
8
100
3.52
84
1
57
8.0
18
100
0.67
103
13
40
16.5
31
100
0.59
97
10
57
19.0
38
100
1.34
106
9
51
15.0
Note. All data are raw scores.


TABLE OF CONTENTS
page
ABSTRACT iv
CHAPTERS
1 INTRODUCTION 1
Malingering 4
Memory Impairment Following Brain Damage 11
Experimental Studies of Malingering 23
Implicit Memory 53
Hypotheses and Predictions 72
2 METHOD 76
Analysis of Statistical Power 77
Subjects 78
Design 82
Materials 82
Procedure 90
3 RESULTS 104
Descriptive Statistics 105
Experiment 1: Validation of Word Lists 109
Experiment 2: Main Study 117
4 DISCUSSION 188
Validity of Group Membership 188
Experimental Memory Tasks 193
Symptom Validity Testing 206
Multivariate Detection of Malingering 213
The "Art" of Detecting Malingering 214
Summary 216


113
WORD STEM COMPLETION
Target Advantage
% correct completion
70
60
50
40
30
20
10
0
Targets
Distractors
Encoding Process
% correct completion
70
60
50
40
30
20
10
0
AMNESICS CONTROLS
Sentence 43.6 42.2
Letter 44 48.8
Figure 1. Word Stem Completion Performance for Experiment 1.


194
blend of data-driven and conceptually-driven processing. Thus, subjects
operate on perceptual data provided by the experimenter, but must often
reconstruct the study episode in order to perform accurately (Richardson-
Klavehn & Bjork, 1988).
To sum to this point, only the Amnesic subjects failed to produce LOP
effects on the FR paradigm. The recognition memory of all subject groups
benefitted from semantic processing, although the similarity between study and
test in MCR was such that physical processing did contribute to retrieval. The
defensible conclusion from this data pattern is that consistent LOP effects,
favoring conceptually encoded words, were found on the direct tests of
memory. Therefore, the Malingering subjects produced an equivalent pattern of
performance on the direct tests, in spite of a lowered level of performance.
The LOP data from the indirect memory tests is unequivocal: all subject
groups produced an equivalent proportion of conceptually and physically
encoded words when tested with WSC and PI. This data is highly consistent
with the other reports of null LOP effects in studies involving word stem
completion (Graf & Mandler, 1982; Graf, Squire, & Mandler, 1982) and
perceptual identification (Jacoby & Dallas, 1981). A relatively subtle retrieval
advantage was noted for physically encoded words relative to conceptually
encoded words. This finding is consistent with the predictions of the
processing model (Blaxton, 1989; Roediger & Blaxton, 1987). Additionally, a
similar result was obtained by Challis & Broadbeck (1992) who found null LOP


138
Table 14
Average Observed Effect Sizes
Type of Task
Malingerers
vs.
Normals
Head
Injured
vs.
Normals
Malingerers
vs.
Head
Injured
Clinical Memory Tests
-2.2
-2.3
+0.1
Implicit Memory Tests
Only
-0.5
-0.3
-0.3
All Experimental Memory
Tests
-1.4
-0.9
-0.4
Overall Average
-1.4
-1.2
-0.2


206
portion of experimental malingerers to produce below-chance performance on
forced-choice testing. It could be argued that the case study approach is
superior to the analogue studies on the grounds of ecological validity (see
Schretlen, 1988) and that experimental malingerers are not properly motivated
(i.e., compensated) to lower their SVT performance below chance levels.
However, our clinical experience has encountered a heterogeneous group of
litigating patients which produce accuracy rates somewhere between perfect
and chance levels. To conclude, while below chance SVT performance
provides the clinician with compelling evidence suggestive of malingering, these
data provide equally strong evidence that deviant response sets can produce
accuracy rates well above chance.
The findings concerning the reaction time component of the SVT
paradigm are offered only as heuristic due to the unreliable manner of data
collection. However, the findings do suggest that response latency may prove
sensitive to deviant response styles. Head Injury subjects produced slower
reaction times than Genuine subjects, consistent with past research (MacFlynn,
Montgomery, Fenton, & Rutherford, 1984; Miller, 1970; VanZomeren & Deelman,
1978). Malingering subjects produced significantly slower response latencies
than even the Head Injury patients. This data suggests that Malingering
subjects over-exaggerated impairment in the form of markedly increased
response latencies. Second, the correlation coefficient between SVT response
accuracy and SVT response latency was -0.16. This suggests that these two


38
uninformed-faking group performing more inconsistently than the informed-
faking group. A large proportion of malingerers performed in the severely
impaired range, with uninformed-fakers again demonstrating more significant
levels of impairment than informed-fakers. This study replicated previous
findings that malingerers generally tend to overplay their roles. Two significant
stepwise discriminant function analyses reliably sorted the three groups with an
accuracy rate of 91%. This study would have benefitted from the inclusion of a
group of head injury patients.
Mittenberg, DAttilio, Gage, and Bass (1990) administered a 30 item
symptom checklist to two large groups of subjects who were instructed to
malinger "symptoms" secondary to a closed head injury they supposedly
sustained six months ago. One group of subjects reported having pre-
experimental knowledge about the symptoms of closed head injury while the
contrast group reported having no special knowledge. No objective criteria of
the subjects knowledge of brain-behavior relationships was used verify group
membership. In both groups, postconcussion syndrome was malingered
significantly more than memory symptoms. Memory complaints were faked at a
level not significantly different than chance. However, post-concussion
syndrome was malingered by 80% of the subjects.
Wylie and Ruff (1990) instructed subjects in post-concussional syndrome.
Multivariate and clinical detection procedures were used to contrast groups of
matched controls, litigating head injury patients, and nonlitigating head injury


195
effects when processing conditions were mixed in the same study list for each
subject.
Regardless of the failure to observe statistically significant transfer-
appropriate processing in the indirect memory tests, this study has nevertheless
demonstrated an experimental dissociation between performance on direct and
indirect memory tests. I will return to discuss this matter further after
consideration of possible explanations for this dissociation.
Issues Related to Meta-Memorial Experience
The consideration of the meta-memorial experiences of participating
subjects warrants discussion independent of their possible effects on indirect
memory test performance. In general, the experience of test awareness during
WSC was frequently reported. All but one Malingering subject reported
experiencing test awareness during WSC, although 80% of Genuine subjects
did as well. However, this data pattern was not observed for PI: 65% of the
Genuine subjects and 73% of the Head Injury patients reportedly did not
experience test awareness during PI.
Given that Schacter & Bowers (1990) found that half of their sample
developed test awareness during stem completion, the fact that 80% of
Genuine subjects and 95% of the Malingering subjects reported developing test
awareness strongly suggests that the instructional and motivational sets given
to these subjects induced "meta-memorial vigilance". By this term I mean that
subjects were overly vigilant and attentive for previously presented information,


2
conscious volition), may result in a partial reduction in, or elimination of,
monetary damages for the plaintiff, and could no doubt discredit other
testimony delivered by the malingerer (Schacter, 1986a). On the other hand, a
successful malingerer reaps highly salient positive reinforcement in a civil
proceeding in the form of monetary compensation and negative reinforcement
in a criminal proceeding in the form of a more desirable disposition.
Memory is a private event and the assessment of its functional integrity is
not always a straightforward process. Given the importance of accurately and
efficiently evaluating neuropsychological function and dysfunction in a forensic
context, the mental health professional is poorly equipped to discriminate
effortful and motivational aspects of a patients performance (Brandt, 1988).
This state of affairs is readily apparent in the experimental literature involving
malingered amnesia. Taken as a group, the experimental studies attempting to
discriminate between malingered and genuine amnesia have produced mixed
results and are quite difficult to implement in the clinical or medicolegal setting
(Brandt, 1988; Schacter, 1986a, 1986b; Wiggins & Brandt, 1988).
Brandt and his colleagues (Brandt, 1988; Rubinsky & Brandt, 1986) state
that the lay publics perception of normal memory functioning is that it can be
easily faked and that such faking is difficult to detect, in part because of the
belief that it would be easier to withhold behavior (i.e., produce a behavioral
deficit) than it would be to demonstrate a positive symptom. Most researchers
feel that a malingerer will be successful in producing believable deficits to the


244
Pankratz, L, Fausti, S. A., & Peed, S. (1975). A forced choice technique to
evaluate deafness in a hysterical or malingering patient. Journal of
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158
PERCEP. IDENTIFICATION
Conditional Probabilities
% correct recognition
1
0.9
0.8
L
8
1
0.7
r
m-
0.6
I-
p1
0.5
h
p
W7//
0.4
r I
0.3
h
0.2
h

0.1
r\
r
if
m
m
Conditional
Simple
' ;
1
j
GENUINE
0.87
0.82
I ~r -
MALINGER
0.62
0.61
Recognition
HH Conditional
Simple
0.72
PI Serial Position
100
80 -
% correctly identified
GEN
MAL
CHI
1 to 4 5 to 8 9 to 12 13 to 16 17 to 20
Figure 10. PI Performance: Conditionalized Recognition and Serial Position


236
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184
Responses to open-ended questions
Without exception, subjects in either the Genuine or Malingering
conditions reported how difficult their roles were to play. Genuine subjects
discussed the inherent difficulty of the tasks. Malingering subjects discussed
the necessity to simultaneously attend to both their own bona-fide memory
capabilities and their ongoing calibration of decreased performance levels. The
high demand placed on Malingering subjects attention and concentration led to
an interesting phenomenon. It appeared that most Malingering subjects
information processing capacities became overwhelmed during some tasks,
resulting in bona-fide memory problems for that task. This phenomena would
be analogous to encoding stimuli under degraded or attention-divided
conditions. In several subjects, this led to uncertainty and even anxiety over
their perceptions of their true memory abilities. All malingering subjects
reported their uncertainty over the believability of the impairment they
produced.


79
Full Scale IQ for these patients was 103 (mean Verbal IQ=100; mean
Performance IQ=101). The mean Wechsler Memory Scale-Revised Memory
Quotient for these patients was 81 (mean Verbal MQ=70; mean Delayed
MQ=57). These subjects averaged 27.5 words recalled on trials 1 to 5 of the
California Verbal Learning Test. Neuropsychological evaluation and
independent neurological examination indicated that memory impairment was
the only remarkable deficit of higher cortical function. These patients have been
studied as a group for several years, and their memory impairment has been
documented in detail elsewhere (Cermak, Talbot, Chandler, & Wolbarst, 1986).
Control subjects for the Amnesic patients were recruited from various
locations throughout the Health Science Center in Gainesville, Florida and were
paid twenty dollars for their participation. Subjects serving as control subjects
for the alcoholic Korsakoffs patients were recruited from the inpatient
Substance Abuse Treatment Program at the Gainesville Veterans Affairs Medical
Center. These subjects consisted of four men who were matched to the
alcoholic Korsakoff patients on the basis of age and education (mean age=69
years; mean educations 1 years). All four of these subjects had lengthy
histories of alcoholism, but had abstained from alcohol for at least three weeks
prior to testing (average abstinence = 8.3 weeks). Subjects serving as control
subjects for the patients with other forms of amnesic were recruited from
various locations throughout the Gainesville Veterans Affairs Medical Center.
These subjects consisted of five men who were matched to this subgroup of


216
11. "Long Term Memory" refers to the ability to remember larger amounts of
information for longer periods of time. People with a CHI often have
difficulty with long term memory.
12. In general, the more hints and cues given to a CHI patient about what
they are trying to remember, the easier it is for them to remember.
13. CHI patients usually can remember information that is presented to them
at the beginning and end of an event. They have the most difficulty
remembering information which is presented to them in the middle of the
event.
14. CHI patients usually have the same amount of difficult remembering
verbal information as they do remembering visual information.
15. CHI patients are likely to have a decrease in their intelligence.
16. In general, the more severe the CHI the more the persons intelligence
decreases.
17. Approximately 50% of people having Closed Head Injuries have
moderate to severe impairment in their overall intelligence.
18. Especially difficult tasks for CHI patients involve tasks which require
quick and errorless peformance, paying attention for long periods of
time, and making complex decisions quickly.
19. People with CHI often respond to tasks slower than they did before they
had their injury.
20. CHI patients rarely have difficulty answering simple, yes/no questions
about words and sentences.


32
of malingering classified the cases as neuropsychologically abnormal; 0% of
malingering profiles were detected. In Study 2, clinicians were forewarned
about the malingering protocols and given the base rates. However, their
overall classification accuracy did not surpass chance levels.
Faust and his colleagues (Faust, Hart, & Guilmette, 1988; Faust, Hart,
Guilmette, & Arkes, 1988) have confidently concluded from these two studies
that "adults and adolescents can convincingly portray neuropsychological
deficits." (Faust, Hart, Guilmette, & Arkes, 1988, p. 513). Bigler (1990) has
rightfully taken extreme issue with these methodologically-flawed studies. In
general, the Faust et al. (1988) study fails to approach the reality of clinical
practice. Specifically, the use of questionnaires containing only raw test scores,
the paucity of historical and interview information, and over-reliance on
"objective" indicators biased the results towards the over-interpretation of
"pathology" and provided insufficient information to make accurate clinical
decisions. The true competency and qualifications of the respondent judges
could also be challenged.
Malingered Amnesia
Benton and Spreen (1961) compared brain damaged patients with
neurologically normal subjects instructed to portray moderate memory,
concentration, and motivational deficits secondary to an automobile accident.
They found that the simulators overplayed their role in that they performed at a
level significantly below that of brain damaged patients. Qualitatively, simulating


162
FREE RECALL
Overall Performance
% correctly recalled
70
60
50
40
30
20
10
0
GENUINE MALINGER CHI
Free Recall 35 15.5 10.3
Encoding Process
% correctly recalled
70
60
50
40
30
20
10
0
GENUINE MALINGER CHI
Sentence 49.6 27 16.6
Letter 20.6 4.6 4
Figure 11. Free Recall: Overall Performance and Encoding Effects.


237
Graf, P., & Mandler, G. (1984). Activation makes words more accessible, but
not necessarily more retrievable. Journal of Verbal Learning and Verbal
Behavior. 23, 553-568.
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associations in normal and amnesic subjects. Journal of Experimental
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Graf, P., & Schacter, D. L. (1987). Selective effects of interference on implicit
and explicit memory for new associations. Journal of Experimental
Psychology: Learning. Memory, and Cognition. 12, 45-53.
Graf, P., Shimamura, A. P., & Squire, L. R. (1985). Priming across modalities
and priming across category levels: Extending the domain of preserved
function in amnesia. Journal of Experimental Psychology: Learning. Memory.
and Cognition. 11. 385-395.
Graf, P., Squire, L. R., & Mandler, G. (1984). The information that amnesic
patients do not forget. Journal of Experimental Psychology: Learning.
Memory, and Cognition. IQ, 164-178.
Greene, R. L. (1988). Assessment of malingering and defensiveness by
objective personality inventories (pp. 123-158). In R. Rogers (Ed.), Clinical
assessment of deception and malingering. New York: The Guilford Press.
Greenspoon, J. (1955). The reinforcing effect of two spoken sounds on the
frequency of two responses. American Journal of Psychology. 68. 409-416.
Gronwall, D., & Wrightson, P. (1981). Memory and information processing
capacity after closed head injury. Journal of Neurology. Neurosurgery, and
Psychiatry. 44, 889-895.
Gudjonsson, G. H., & Shackleton, H. (1986). The pattern of scores on Ravens
Matrices during "faking bad" and "non-faking" performance. British Journal of
Clinical Psychology. 25(1), 35-41.
Guthkelch, A. N. (1980). Post-traumatic amnesia, post-concussional syndrome,
and accident neurosis. European Neurology. 19. 91-102.
Hamsher, K. S., & Benton, A. L. (1977). The reliability of reaction time
determinants. Cortex. 13, 306-310.


120
pc.0001. Follow-up mean contrasts showed that Genuine subjects produced
significantly higher scores than either Malingering or Head Injury groups on all
measures of immediate cued recall of verbal material. The performance of the
Malingering and Head Injury groups was not significantly different on any of
these indices.
Delayed verbal free recall. A MANOVA performed on the set of variables
representing delayed and unstructured free recall of verbal material was highly
significant, Wilks Lambda F(4,100) = 14.23, pc.0001. Univariate ANOVA
procedures showed significant main effects for group on WMS Delayed Logical
Memory, F(2,51)=27.14, pc.0001, and CVLT Long Delay Free Recall,
F(2,51)=33.08, pc.0001. Follow-up mean contrasts showed that Genuine
subjects produced significantly higher scores than either Malingering or Head
Injury groups on both measures of this component of memory functioning. The
performance of the Malingering and Head Injury groups was not significantly
different on either index.
Delayed verbal cued recall. A MANOVA performed on the set of
variables representing delayed cued recall of verbal material was highly
significant, Wilks Lambda F(4,100)=11.18, pc.0001. Univariate ANOVA
procedures showed significant main effects for group on CVLT Long Delay
Cued Recall, F(2,51)=19.16, pc.0001. Follow-up mean contrasts showed that
Genuine subjects produced significantly higher scores than either Malingering
or Head Injury groups on this measure of delayed cued recall of verbal material.


135
Table 9
Performance on the Immediate Reprod. of the Rev-Osterreith Complex Figure
Omission Errors
Comission Errors
Absent (score=0)
Distorted (.5/1)
Unit
G M HI
G M HI
1.
Cross, UL
25
20
8
60
75
92
2.
Lg rectangle
0
0
0
35
55
58
3.
Diag. cross
20
55
42
15
5
25
4.
Horz. ML of 2
5
35
33
15
5
25
5.
Vert. ML of 2
5
40
25
20
10
25
6.
Sm. rect. in 2
40
35
42
30
60
50
7.
Sm. sg. ab. 6
60
80
83
5
0
0
8.
4 lines in 2
15
30
58
45
55
34
9.
Triangle, 2
60
75
67
20
20
33
10.
Sm. VL in 2
85
100
92
0
0
8
11.
Circle, 3 dots
10
10
25
25
35
59
12.
5 par. lines, 3
30
55
42
20
30
17
13.
Triangle on 2
15
15
8
25
25
33
14.
Diamond on 13
15
40
33
25
20
17
15.
Vert. In. in 13
75
80
75
15
15
17
16.
Horz. In. in 13
30
40
42
15
0
0
17.
Cross, LC
15
25
33
80
75
67
18.
Square on 2
25
40
33
60
60
67
Note. Column subheadings are abbreviated as follows: G=Genuine,
M=Malingering, and HI=Head Injury. All data are percentages of each subject
group obtaining the indexed score for the indexed scoring unit.


98
Free recall. Subjects studied the FR study list in the same manner as
above. They were told their task was to answer questions about words; no
reference was made to the memorial aspects of the study episode. After the
distractor task, subjects were given a sheet of lined paper and asked to "write
down all the words you can remember from the previous list of words you
studied". Responses were scored as correct only if they were exactly the same
word as was studied. Correct performance was calculated as the proportion of
target words correctly recalled. Correct recall was also calculated within each
processing condition.
Multiple choice recognition. Subjects studied the MCR study list in the
same manner as above. They were told their task was to answer questions
about words; no reference was made to the memorial aspects of the study
episode. After the distractor task, subjects were given a sheet of paper printed
with 20 items consisting of four words and asked to "circle one word from the
four choice that they remember from the previous list of words you studied."
Correct performance was calculated as the proportion of target words correctly
recognized. Correct recognition was also calculated within each processing
condition.
Symptom Validity Testing
The SVT task began with a list of instructions presented to the subject on
the screen. The examiner verbally explained the directions as well, emphasizing
the "extremely difficult" aspects of the test. The subject then pressed the space


4
Malingering
Any psychelggical assessment technique which derives its infcrmation
frcm a perscns verbal behavicr may be affected by a deceptive respcnse style.
The term "dissimulaticn" refers tc the deliberate distorticn cr misrepresentaticn
cf symptcms (Regers, 1988). This categcry subsumes such ccncepts as
"defensiveness," "randem respending," and "irrelevant respending." This paper
is ccncerned with ancther type cf dissimulation, malingering. Malingering is
defined by the American Psychiatric Asscciaticn (APA, 1987) as "the intenticnal
production of false or grossly exaggerated physical or psychological symptoms,
motivated by external incentives such as avoiding military conscription or duty,
avoiding work, obtaining drugs, or securing better living conditions" (p. 360).
The implicit assumption of this definition is that malingerers are socially deviant
individuals (i.e., those with antisocial personalities) who are likely to fabricate
illness when involved in the legal system and are likely to demonstrate poor
compliance with assessment and treatment procedures (Rogers, 1990a). As
Rogers (1990a) correctly states, the DSM-lll-R, in its attempt to remain
atheoretical about etiology, nevertheless conceptualizes malingering from a
moralistic and criminological perspective. These issues will be dealt with in
depth in later sections.
Brief History
The concepts and behaviors underlying malingering have been
recognized throughout history (Bash & Alpert, 1980) and have been recorded


78
Injured groups to be 80 percent certain of rejecting the null hypotheses using a
one percent, two tailed significance level.
Subjects
Subjects were categorized into five experimental groups. Amnesic
patients and age and education matched control subjects participated in
Experiment 1. Two types of subjects comprised the three subject groups of
Experiment 2. Introductory Psychology students at the University of Florida
were randomly assigned to either the Genuine or Malingering groups. Non
litigating Head Injured patients were recruited from several outpatient clinics and
an inpatient rehabilitation program located in North Central Florida to serve as
the criterion group of bonafide memory impairment.
Amnesic patients were recruited from the standing population of such
patients at the Memory Disorders Research Center at the Veterans Affairs
Medical Center in Boston, Massachusetts. Data were collected from these
patients at the Neuropsychology Laboratory at this hospital. A total of nine
Amnesic patients were tested: four with alcoholic Korsakoffs syndrome, three
with amnesia due to an episode of anoxia or cerebrovascular accident, one
who had a left temporal lobectomy to treat intractable epilepsy, and one who
had suffered from encephalitis. The patients with Korsakoffs syndrome
consisted of four men (mean age=65.5 years; mean education=11.5 years).
The patients with amnesia from other causes consisted of four men and one
woman (mean age=46 years; mean educations6.4 years). The mean WAIS-R


247
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129
Table 6
Multivariate Group Differences on Qualitative Clinical Memory Variables
Wilks
Memory Process
Lambda
Variable
Rate of Forgetting
6.28***
WMS LM Percent Forget
WMS VR Percent Forget
ROCF Percent Forget
Recognition Memory
4.92***
CVLT Recognition Hits
CVLT Recognition False Alarms
CVLT D-Prime
CVLT Response Bias
* p<.05 ** p<.01
***
p<.001


173
Table 19
SVT Response Data for Malingering Group
Blocks of 10 Trials
Subject SVT
Number
%Cor
1
2
3
4
5
6
7
8
9
10
34
45
7
4
3
4
5
3
1
5
5
8
36
57
5
8
8
6
4
7
5
5
5
6
20
58
7
7
7
6
5
5
6
6
4
5
12
59
6
6
5
8
6
4
6
6
6
7
24
62
5
6
5
6
6
6
7
7
8
6
28
69
7
7
8
7
7
6
7
6
6
8
16
74
10
9
8
9
7
6
5
6
7
7
9
77
9
8
8
7
10
8
8
5
6
8
15
82
10
9
9
8
8
7
7
8
8
8
33
84
9
8
10
9
9
9
8
8
7
7
39
86
10
10
9
8
8
9
9
9
7
7
23
89
9
8
9
9
9
9
9
8
9
10
14
90
10
10
9
9
10
9
8
8
8
9
27
99
10
10
10
10
9
10
10
10
10
10
2
100
10
10
10
10
10
10
10
10
10
10
5
100
10
10
10
10
10
10
10
10
10
10
8
100
10
10
10
10
10
10
10
10
10
10
18
100
10
10
10
10
10
10
10
10
10
10
31
100
10
10
10
10
10
10
10
10
10
10
38
100
10
10
10
10
10
10
10
10
10
10
Note. All data are raw scores.


243
Mittenberg, W., DAttilio, J., Gage, R., & Bass, A. (1990, February). Malingered
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procedures for the assessment and treatment of functional sensory deficits.
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Neuroosvchologist. 4(4), 379


19
interpreted by Brooks to reflect an early recovery of memory, often in the first
few months after injury, to a permanently deteriorated level.
Lezak (1979) tracked the course of recovery of verbal memory functions
over time in a sample of 24 CHI patients. Estimates of severity of injury were
omitted from her paper. Patients were serially tested at three different points of
recovery. Dependent measures included digit span tests (forward and
backward) and selected variables derived from the Rey Auditory Verbal
Learning Test (RAVLT). The results indicated that on simple measures of
immediate memory, Digits Forward and the first recall trial of the RAVLT, CHI
patients were only mildly impaired at the initial testing and showed consistent
improvement over time. More complex measures of learning were more
significantly impaired and remained so over time. On every measure, the more
severely impaired patients performed more poorly at initial testing than less
severely injured patients. The less severely injured subjects generally
maintained their superiority over more severely injured patients at all three
points of recovery. One interesting finding is that a subset of the CHI patients
showed a deterioration of performance on the complex memory tests at the
final point of testing (three years post injury), suggesting a possible
multifactorial recovery mechanism. Lezak suggested that partial recovery from
a severe injury may occur relatively early on while other pathophysiological
processes may compromise memory efficiency in the later stages of recovery.


199
or test awareness but no explict retrieval. For subjects who reported
experiencing test awareness and explicit mediation, those in the Genuine and
Head Injury groups demonstrated a greater magnitude of priming than those in
the Malingering group. The difference between the Genuine and Malingering
groups was highly significant. The difference between the Head Injury and
Malingering groups approached but failed to reach significance. This suggests
that some Malingering subjects were successful at withholding completion of
target words which were explicitly retrieved. In contrast, PI was more resistant
to the effects of explicit retrieval by virtue of the subliminal nature of testing.
The Relationship Between LOP and Meta-Memory
No consistent statistical relationship was noted between different meta
memorial experiences and levels of processing effects in any of the three
groups for either WSC or PI. It was predicted that Malingering subjects could
lower their level of performance on indirect tests to the extent that they used
explicit retrieval and then used some form of postretrieval suppression.
Malingering subjects did in fact demonstrate a lowered reporting of semantically
encoded words. However, this same data pattern was observed in the other
two groups. Additionally, equivalent LOP effects were observed in Malingering
subjects in all awareness conditions. Given that over half the Genuine subjects
clearly engaged in explicit retrieval during WSC, the fact that these subjects
produced the same slight advantage for physically encoded words is quite
interesting.


56
contextual and temporal information it contains. Nondeclarative memory (i.e.,
"knowing how") is not directly available to consciousness and is only capable of
being accessed by engaging in processes in which it is embedded. Thus,
amnesia is conceptualized as a preservation of procedural memory as indexed
by indirect memory tasks and a failure of declarative memory as indexed by
direct memory tasks. Much of the experimental evidence for dissociations
between direct and indirect tests can be interpreted within this framework
because the memory systems are though to be largely separate (Roediger,
1990).
Other researchers, primarily cognitive psychologists working with normal
subjects, have proposed various processing models to account for the data.
Processing models de-emphasize the possibilities of different memory stores
and the dissociation of encoding, storage, and retrieval. Instead, Jacoby
(Jacoby, 1983a, 1983b, 1984) as well as Roediger and his colleagues (Roediger
& Blaxton, 1987b; Roediger, Weldon, & Challis, 1989) postulate that implicit and
explicit memory differ in terms of the relationships between processes operating
at both encoding and retrieval. Jacoby (1983b) delineates two dissociable
processes operating on a single, episodic memory store. Processing of
semantic information requires the initiation of conceptually-driven processes by
the subject. Such processes include elaboration, organization, and rehearsal.
Certain tasks that emphasize perceptual or orthographic information invoke
data-driven processing. These researchers feel that implicit memory as


205
of trials, an ability which would at least initially appear difficult for the
Malingering subject to master throughout 100 trials. Unexpectedly, Malingering
subjects produced remarkably consistent accuracy rates across the 100 trials.
The method discussed by Miller (1986) breaks contiguous response
trials into discrete blocks. Observed accuracy rates were compared with those
expected based on binomial probability. While this method was able to
document below chance performance in Millers case study, it failed to establish
below chance performance in a very similar subject in this study with an
obviously questionable accuracy rate of 45% (as well as all other Malingering
subjects). The other method presented involves sampling the binomial
distribution using the subjects own accuracy rate as the estimate of the true
population proportion. This method allows for the assignment of cumulative
probabilities associated with all possible accuracy rates within blocks of trials.
This method was useful in establishing that the above Malingering subject
produced an accuracy rate for one block of trials which was probabilistically
below what would be expected given her overall accuracy across 100 trials.
The criterion of chance performance (e.g., 50% in a 2-alternative forced-
choice paradigm) was originally suggested by Pankratz and his colleagues
(Pankratz et al., 1975). Data which support the criterion of chance performance
derive mainly from case studies of suspected malingerers (Binder, 1990b,
1992). The data from this study, however, are consistent with other between-
groups studies (Bickart et al, 1991; Wiggins & Brandt, 1988) which found only a


180
Table 22
Classification Rates for Experimental Memory Tasks
Actual Group
Membership
Classified into Group based on LDF
Genuine
Malingering
Head Injury
Genuine
95.0%
5.0%
0.0%
Malingering
15.0%
80.0%
5.0%
Head Injury
6.7%
0.0%
93.3%
Table 23
Classification Rates for Stem Completion and Perceptual Identification Tasks
Actual Group
Membership
Classified into Group based on LDF
Genuine
Malingering
Head Injury
Genuine
60.0%
30.0%
10.0%
Malingering
25.0%
65.0%
10.0%
Head Injury
53.3%
40.0%
6.7%
Table 24
Classification Rates for Selected Clinical Memory Variables
Actual Group
Membership
Classified into Group based on LDF
Genuine
Malingering
Head Injury
Genuine
100.0%
0.0%
0.0%
Malingering
0.0%
90.0%
10.0%
Head Injury
6.7%
6.7%
86.6%


16
These investigators found CHI patients to have significant difficulty with short
term recognition of nonverbal designs, even when tested at long intervals after
injury.
To summarize, forward digit span appears relatively insensitive to the
effects of severe CHI, even when tested soon after injury. Backward digit span,
requiring additional information-processing demands, has been shown to be
reduced in the early stages of recovery, but to improve over time. More difficult
tasks, such as varying the format of to-be-remembered information, may
provide a more sensitive index of STM capacities in these patients.
Recent memory. Impaired recent memory functioning (anterograde
amnesia) is one of the most prevalent cognitive impairments following closed
head injury (Brooks, 1972; Levin, Benton, & Grossman, 1982) and is the
primary complaint of most patients and their families (Bond, 1986). Estimates
of the prevalence of persistent memory problems after PTA termination have
varied, from 16% (Lidvall, Linderoth, & Norlin, 1974) to 23% (Russell & Smith,
1961) to 36% in Russells (1932) original sample, depending upon the various
methodologies used in the studies (Schacter & Crovitz, 1977).
Brooks (1972) investigated the extent of memory deficit in a group of 27
patients who had sustained severe closed head injury. The author found that
the CHI patients performed significantly lower than normal controls on all tests
measuring learning and recent memory. These differences were statistically
significant for all indices except the WMS Visual Reproduction subtest


94
they were encouraged to not cease playing their role until the experimenter said
"Stop playing your role, the experiment is over." Subjects were given
approximately five to seven minutes of free time to use to plan their role-playing.
They were encouraged to review the fact sheet and to mentally rehearse their
role.
Overview of Experimental Procedures
The main phase of the experiment was grouped into three blocks of
tests. The verbal/nonverbal nature of the memory tasks as well as the requisite
delay intervals for the clinical memory tests were the main considerations in
ordering the test battery. Form E of the Benton VRT was used at any point
where additional nonverbal distractor activity was necessary to maintain correct
delay intervals. The first block of tests consisted of the immediate testing of the
WMS Logical Memory and Visual Reproduction subtests. The SVT paradigm
was administered next. The delayed testing of the WMS Logical Memory and
Visual Reproduction subtests closed out the first block of tests.
The second block of tests began with the administration of the copy and
immediate memory trials of the Rey-Osterreith Complex Figure Test. The four
experimental memory tests (WSC, PI, FR, and MCR) were then administered
next. The order of these four tasks was counterbalanced within groups. Four
to five minute interpolated delay intervals occurred between the study and test
phases of all four experimental memory tasks. The forward portion of the WMS
Digit Span subtest was used at the distractor activity for WSC. The backward


189
Therefore, subjects in the Genuine and Head Injury groups appeared to
be representative of the larger population of subjects. Malingering subjects
performed similar to those in other reported studies of experimental simulation.
In general, clinical memory tests were not overwhelmingly useful in separating
Malingering subjects from Head Injury patients.
As regards the external incentive for the experimental subjects, the
University of Florida Introductory Psychology class required students to earn
eight credits based on participation in experiments. The UF Psychology
Department Subject Pool policies, however, forbade any use of performance-
based incentives. This meant that subjects could not receive additional rewards
beyond their participation, either in the form of extra class credit or money.
However, it should be noted that this study offered subjects the opportunity to
earn all but one of the credits they needed in one testing situation. Only one
study has directly examined this analog factor experimentally. Bernard (1990)
found no significant differences on memory performance between incentive-
based and non-incentive based experimental malingerers. Schretlen (1986)
provided prison inmates instructed to malinger monetary incentive to avoid
detection, but no comparison group was used. Therefore, the fact that
Malingering subjects were not given an additional external incentive does not
appear to be a serious threat to the validity of the findings.
Several studies have provided varying degrees of didactic information
and coaching to experimental malingerers (Boone, 1988; Hayward et al., 1987).


141
recognition was conditionalized upon the probability of correct word
completion. This was operationalized as the percentage of correctly completed
target stems which were correctly recognized as having been studied [denoted
as P(WS+ |REC+)]. Second, the probability of answering "yes" to an
incorrectly completed target stem was computed [denoted as P(WS-|REC+)].
Third, the probability of answering "yes" to a distractor target stem was
computed [denoted as P(DIST|REC+)].
This data is presented in Figure 6. Between-group comparisons were
carried out on these three probability estimates. The results revealed no
significant main effects of group on the conditional probability of correct explicit
recognition, F(2,52)=0.63, p<.59, the probability of responding "yes" to an
incorrect target word, F(2,52)=.63, p<.59, and the probability of responding
"yes" to a distractor word, F(2,52) = 1.85, pc.30.
Trial-bv-trial analysis. Another indirect approach to assess the effect of
explicit memory processes involved evaluating subjects completion accuracy
as they proceeded through the list of stems. A subject could potentially alter
his completion performance to the extent that he develops awareness during an
implicit task that study items were previously encountered during the study
phase of the experiment. In the present context, Genuine subjects could use
explicit memory for the study words in completing the stems (i.e., they could
use stems as recall cues). A Malingering subjects situation is more
complicated, but he could potentially withhold correct completion based on


202
Second, in this study the bias of both implicit and explicit memory was
towards the facilitation of task performance. When experimental effects act in
concert, performance on indirect memory tests might reflect implicit memory or
explicit memory or both (Jacoby, Lindsay, & Toth, 1992). Consider a
hypothetical scenario for a Malingering subject. When performing WSC, the
subject completes two to three words in the target direction and immediately
thereafter explicitly recognizes these words as study words. The Malingering
subject does not perceive that he or she has violated the faking role by simply
reporting relatively automatic behavior. Since no effortful retrieval occurred on
these trials, the Malingering subject feels free to proceed with the same
response criterion without undue fear of exposing their role. On some
subsequent trials the Malingerer also experiences fluent completion on several
stems and responds accordingly. On other trials, however, the subject may
experience explicit retrieval for a target words and engage in postretrieval
response suppression. The interpretive problem is that these instances of
response suppression are indistinguishable for instances of bona-fide incorrect
responses.
Several possible methodological manipulations would address this
problem. One solution to the problem of conflation of implicit and explicit
memory is the method of opposition (Jacoby et al., 1989). In this study,
Jacoby and his colleagues used a fame judgement task to assess unconscious
memory. The essence of this method is that subjects were informed that


136
Table 10
Performance on the Delayed Reprod. of the Rev-Osterreith Complex Figure
Omission Errors
Comission Errors
Absent (score=0)
Distorted (.5/1)
Unit
G M HI
G M HI
1.
Cross, UL
15
40
8
85
60
92
2.
Lg rectangle
0
5
8
45
45
42
3.
Diag. cross
30
50
42
20
15
33
4.
Horz. ML of 2
0
35
25
15
5
17
5.
Vert. ML of 2
5
45
25
20
10
17
6.
Sm. rect. in 2
40
50
42
35
45
50
7.
Sm. sg. ab. 6
60
95
83
0
5
0
8.
4 lines in 2
15
45
75
55
35
25
9.
Triangle, 2
60
90
67
20
5
25
10.
Sm. VL in 2
90
95
92
0
5
0
11.
Circle, 3 dots
10
35
33
35
40
25
12.
5 par. lines, 3
20
65
33
30
30
33
13.
Triangle on 2
15
15
33
15
30
8
14.
Diamond on 13
10
45
33
25
15
17
15.
Vert. In. in 13
60
85
75
25
10
17
16.
Horz. In. in 13
35
50
50
5
10
0
17.
Cross, LC
20
40
33
75
60
67
18.
Square on 2
25
65
42
65
35
58
Note. Column subheadings are abbreviated as follows: G=Genuine,
M=Malingering, and HI=Head Injury. All data are percentages of each subject
group obtaining the indexed score for the indexed scoring unit.


240
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115
FREE RECALL
Overall Performance
40
35
30
25
20
15
10
5
0
Free Recall 1.1 16.7
% correctly recalled
AMNESICS CONTROLS
Variable
Free Recall
Encoding Process
% correctly recalled
40
35
30
25
20
15
10
5
0
AMNESICS CONTROLS
Sentence 1.1 27.8
Letter 1.1 5.6
Figure 3. Free Recall Performance for Experiment 1.


126
Table 5--cont¡nued
Univariate Group Differences on Quantitative Clinical Memory Variables
Group
Variable
Genuine
Malinger
Head Injury
WMS Delayed Log. Mem.
Mean
12.0a
4.9b
5.1B
SD
F(2,52) = 27.14***
3.2
2.7
3.9
CVLT LD Free Recall
Mean
13.6a
5.3s
6.1B
SD
F(2,52) = 33.08***
1.9
3.5
4.6
CVLT LD Cued Recall
Mean
13.9a
7.5b
6.7
SD
F(2,52) = 19.16***
1.7
4.2
4.5
WMS Immed. Vis. Reprod.
Mean
12.2a
7.5B
9.1B
SD
1.7
3.7
3.9
F(2,52) = 11.07***
ROCF Immed. Reprod.
Mean
19.2a
13.7A
14.0a
SD
7.8
6.0
6.0
F(2,52) = 3.61*
* p<.05 ** p<.01 *** p<.001
Note. All data are raw scores. Means with different superscripts differ
significantly at p<.05.


226
Symptom Validity Testing Stimuli (continued)
Trial#
Taraet Strina
Answer Label
Foil Strina
42, 92
2291658
A
7153897
43, 93
4431908
A
1732267
44, 94
4430681
B
9462073
45, 95
1394844
B
6254262
46, 96
3563666
B
4152643
47, 97
9955251
A
4836759
48, 98
6405655
A
7851563
49, 99
3372417
A
8451201
50, 100
3015355
B
8276524


154
during PI, as compared with one each from the Genuine and Head Injury
groups.
Because test awareness was not an independent variable that was
experimentally manipulated in the design, these data were examined with a
nonparametric test for the comparison of two proportions. Main effects of
Group on strength of priming on PI were analyzed within each level of test
awareness. No significant main effects of Group were found for any of the
three levels of test awareness (all Zs < 1). While it appears that Malingering
subjects demonstrated weaker priming than Genuine subjects in the Test
i
Aware/Explicit Mediation condition, the small sample sizes in these cells
mitigated against detecting a significant difference. All three subjects groups
demonstrated priming in all three test awareness conditions. No significant
LOP effects were noted within these groups, although there appeared to be a
relationship between increased awareness and explicit retrieval and greater
completion of physically encoded words in the Genuine and Head Injury
groups.
Free recall
In contrast to the indirect memory tasks, a free recall task was employed
to assess subjects explicit memory. Figure 11 presents this data. A between-
groups ANOVA revealed the main effect of group on free recall performance
was highly significant, F(2,52)=28.08, p<.0001. Follow-up mean contrasts
revealed that Genuine subjects demonstrated significantly higher free recall


64
than were new nonfamous names in the divided-attention condition. Thus,
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memory can operate independently from conscious memory.
The foregoing studies demonstrate that implicit memory for target stimuli
can be demonstrated on indirect memory tests in the relative absence of
conscious, explicit memory for the same stimuli. This evidence, however, is
only of indirect interest because most studies of implicit memory have involved
testing normal subjects under unrestricted encoding conditions, making it
possible that normals are typically aware of the study episode during the
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the strength of the memory trace, thereby increasing the likelihood that a
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Schacter, 1987; Squire, Shimamura, & Graf, 1987).
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memory which focuses on the processes involved in learning and remembering.
It differed from its predecessors in the information-processing tradition which
focused on the structural aspects of the cognitive system (i.e., the successive
stages through which information flows). The LOP framework proposed to
study more directly those processes involved in remembering (e.g., attention,


234
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80
amnesia patients on the basis of age and education (mean age=46 years;
mean education=14.8 years). Analysis of variance procedures failed to reveal
any significant differences between the subgroups of amnesic patients and the
corresponding subgroup of control subjects or between the pooled amnesic
and control groups (all Fs less than 1). The mean WAIS-R Full Scale IQ
estimate for these control subjects was 105. The mean Wechsler Memory
Scale Memory Quotient for these subjects was 114.
Forty introductory Psychology students from the University of Florida
were randomly assigned to one of two conditions: subjects in the Malingering
group (n=20) were asked to portray "the most severe but believable memory
problems" they could on memory tests. Subjects in the Genuine group (n=20)
were asked to perform to their maximum capabilities on memory tests.
Head Injured subjects (n=15; nine men and six women) were recruited
from several types of populations. The primary criteria for inclusion in this
group was the absence of any current or future legal actions on the part of the
patient concerning disability or compensation. No Head Injured patient
participated in this study under such legal context. Most of these subjects were
seeking assistance with academic and vocational rehabilitation. Therefore, no
HI patient had readily identifiable incentives to perform poorly and all patients
had readily identifiable incentives to perform to their genuine capabilities. Of
the outpatient clinic referrals (n=7), two agreed to participate in the study after
undergoing a neuropsychological evaluation at the Psychology Clinic at the


50
Table 1
Effect Sizes from Selected Experimental Studies of Malingering
Study
Malingerers
vs.
Normals
Bonafide
Impairment
vs.
Normals
Malingerers
vs.
Bonafide
Impairment
Pollaczek (1952)
-0.1
Heaton et al. (1978)
+0.1
Brandt et al. (1985)
-2.7
-1.7
Gudjonsson &
Shackleton (1986)
-0.8
Mensch &
Woods (1986)
-8.8
Hayward et al. (1987)
-1.5
Wiggins &
Brandt (1988)
-1.9
+0.3
Boone (1989)
-5.2
Bernard (1990)
-1.9
Bernard (1991)
-1.7
-3.2
+ 1.0
Iverson et al. (1991)
-5.2
-2.0
-1.9
Average Effect Sizes
-3.5
-1.7
-0.5


89
an physical processing task. Study words were printed on four by six inch
white index cards. The testing of MCR involved the subject circling the word,
out of four possible choices, which he or she recognized as studying
previously.
Symptom validity testing
Stimuli for Symptom Validity Testing (SVT) was comprised of a series of
seven digit numbers. Stimuli were presented and subjects made their
responses on an IBM-compatible personal computer. A software program was
written using Micro Experimental Laboratory (M.E.L.) (Schneider, 1988, 1989).
Appendix B contains the study digit strings, the digit strings serving as the test
foils, and the correct answer for that trial. Fifty complete trials were constructed
and comprised trials one through 50. The same trials were then repeated in
the same order for trials 51 through 100. Correct answers (either "A" or "B")
were randomly assigned. Alternative "A" was correct on 50 trials while "B" was
correct on the remaining 50.
The numbers comprising the digit strings were not randomly generated;
rather, several patterns were built into the stimuli in an attempt to "entice" the
Malingering subject into perceiving the task as more difficult than in actuality.
For all trials, the target and foil digit strings began with different digits. The digit
strings always differed as to odd versus even status. All target digit strings
contained two contiguous digits which were the same number (e.g., 81608331.


225
Symptom Validity Testing Stimuli
Trial#
Taraet Strina
Answer Label
Foil Strina
1, 51
8160833
B
6589769
2, 52
2290337
A
5329504
3, 53
3360583
A
8295417
4, 54
6655834
A
1325078
5, 55
1111512
A
6207291
6, 56
8335511
B
3581021
7, 57
7899177
B
2983969
8, 58
9775011
A
4731265
9, 59
1113297
B
4176819
10, 60
7711331
A
8738438
11, 61
4415925
A
3980317
12, 62
5933666
B
4672506
13, 63
9276322
A
6930376
14, 64
7896322
B
2656376
15, 65
5424788
A
8739490
16, 66
2630344
A
1804647
17, 67
8087955
B
3106950
18, 68
9871799
B
4835494
19, 69
5569401
A
4048413
20, 70
1196953
A
2109312
21, 71
6606220
A
9818751
22, 72
8819392
A
7159095
23, 73
1365033
A
4278304
24, 74
5518403
A
6142347
25, 75
1575688
B
4539021
26, 76
2058422
B
7151515
27, 77
2288097
B
5086712
28, 78
3770399
A
4924285
29, 79
5416977
B
2751389
30, 80
4072099
B
7640491
31, 81
7771260
A
6442532
32, 82
3367623
B
2380109
33, 83
2498788
B
5651732
34, 84
4203177
A
3980617
35, 85
7721728
B
6893924
36, 86
9587833
B
8426731
37, 87
6645301
B
9296568
38, 88
8868519
A
1453070
39, 89
7569766
B
8724680
40, 90
5540784
B
8903816
41, 91
4182444
B
5986154


145
WORD STEM COMPLETION
Target Advantage
% correct completion
GENUINE
MALINGER
CHI
Targets
61.5
32.5
47.3
Distractors
14
14
8.7
Word Status
¡Ml Targets
Distractors
Encoding Process
% correct completion
Sentence
MALINGER
31
Process
iHH Sentence
Letter
Figure ^!^¡VSC Performance: Priming and Encoding Effects.


212
tests is expanded to include indirect memory tests that, by their nature, seem
less vulnerable to direct manipulation by subjects. This should come as no
surprise because such an approach is rarely used to characterize the memory
of any type of patient. The "art" of catching Malingerers appears to lie in the
observance of the processes of memory as they change across difficulty levels
and decay across time. While a Malingering subject may accurately portray
impairment on the initial learning trials of the CVLT, he or she may have much
more difficulty titrating performance when the task difficulty changes (say, for
Short Delay Cued Recall). The job of malingering becomes even more
ambiguous and difficult when these free recall and cued recall tasks are again
tested at a 20 minute delay.
The findings concerning the WMS Visual Reproduction subtests provide
an intriguing illustration of these ideas. It is well accepted that the immediate
recall of the WMS figures is not an overly difficult task (Lezak, 1983). The
Malingerers demonstrated a nonsignificant trend towards over-exaggeration of
impairment on the immediate reproduction. However, when tested after the
delay interval their performance was very low, much lower than even the Head
Injury patients. When a forgetting score was computed for this task,
Malingerers again over-exaggerated their impairment. In contrast, Malingerers
were much more successful at calibrating their impairment on the more
complex and demanding ROCF memory trials.


239
Hunt, W. A., French, E. G., Klebanoff, S. G., Mensh, I. N., & Williams, M. (1948).
The cinical possibilities of an abbreviated individual intelligence test. Journal
of Consulting Psychology. 12. 171-173.
Iverson, G. L, Franzen, M. D., & McCracken, L. M. (1991). Evaluation of an
objective assessment technique for the detection of malingered memory
deficits. Law and Human Behavior. 15(6), 1991.
Jacoby, L. L. (1983a). Perceptual enhancement: Persistent effects of an
experience. Journal of Experimental Psychology: Learning. Memory, and
Cognition. 9, 21-38.
Jacoby, L. L. (1983b). Remembering the data: Analyzing interactive processes
in reading. Journal of Verbal Learning and Verbal Behavior. 22, 485-508.
Jacoby, L. L. (1984). Incidental versus intentional retrieval: Remembering and
awareness as separate issues (pp. 145-156). In L. R. Squire & N. Butters
(Eds.), Neuropsychology of memory (pp. 145-156). New York: Guilford
Press.
Jacoby, L. L, & Dallas, M. (1981). On the relationship between autobiographical
memory and perceptual learning. Journal of Experimental Psychology:
General. 110. 306-340.
Jacoby, L. L, Lindsay, D. S., & Toth, J. P. (1992). Unconscious influences
revealed: Attention, awareness, and control. American Psychologist. 47(6),
802-809.
Jacoby, L. L., & Witherspoon, D. (1982). Remembering without awareness.
Canadian Journal of Psychology. 36, 300-324.
Jacoby, L. L., Woloshyn, V., & Kelly, C. (1989). Becoming famous without being
recognized: Unconscious influences of memory produced by divided
attention. Journal of Experimental Psychology: General. 118. 115-125.
Jennett, B., Snoek, J., Bond, M. R., & Brooks, D. N. (1981). Disability after
severe head injury: Observations on the use of the Glasgow Outcome Scale.
Journa of Neurology. Neurosurgery, and Psychiatry. 44. 285-293.
Johnson, M. K., & Hasher, L. (1987). Human learning and memory. Annual
Review of Psychology. 38, 631-668.


Table 21
SVT Analyses based on Miller (1986)
Number of Correct Responses
'
0
1
2
3
4
5
Total
Expected
0.75
3.75
7.5
7.5
3.75
0.75
24
Observed
0
2
12
10
0
0
24
Note. The data represent the frequency of the correct responses per trial block
(out of 5 total). Row data should sum to 24.
Source. Miller (1986).


20
Gronwall and Wrightson (1981) investigated memory and information
processing capacity following closed head injury in a heterogeneous sample of
91 patients. Using a variety of cognitive tasks, including the Wechsler Memory
Scale, the Selective Reminding Test, and the Paced Auditory Serial Addition
Task, these investigators isolated three relatively independent cognitive
impairments associated with CHI. Simple and undemanding memory tasks
appear resistant to impairments in information processing capacity, while
memory tasks which involve complex processing demands and time constraints
appear susceptible to this impairment. The ability to store information in LTM
was deficient in CHI patients. This ability was found to be related to either
severity of injury or elapsed time since injury. One quarter of the sample
demonstrated an additional deficit in the ability to retrieve material from LTM
once it has been stored. This impairment bore no relationship between severity
of injury or severity of information processing deficit.
Levin and Goldstein (1986) investigated whether long-term survivors of
severe CHI could gain access to semantic stores and spontaneously use
clustering strategies to guide encoding and retrieval during a list learning task.
The results indicated that controls remembered significantly more words than
CHI patients when tested with free and cued recall paradigms. Both groups
recalled more words when the stimuli were semantically clustered during
learning. Whereas control subjects tended to spontaneously impose their own
clustering to guide encoding and retrieval, CHI patients generally failed to


52
not the same. The magnitude of the effect size created by the lower means of
malingering subjects is greatly attenuated by the inherent variability of the bona-
fide impairment group. While not mathematically correct, it appears plausible
that malingering groups score significantly lower than organic groups in terms
of normal control group standard deviations, a situation analogous to the
clinical situation of comparing a subjects performance to normal subjects,
rather than organically-impaired patients.
Analysis of the qualitative nature of malingerers performance bears out
Rubinsky and Brandts (1986) hypothesis that the malingerer is more likely to
alter his performance by withholding behavior (i.e., producing a behavioral
deficit) such as not recalling a word, rather than producing additional behaviors
(i.e, producing a positive symptom) such as perseveratively recalling a word. A
likely explanation for this tendency rests on the malingerers ignorance of brain-
behavior relationships or on the general idea that "less" is "worse" when it
comes to expressions of cognitive ability. Given this ignorance, it may be that
"comission" of behavior is too risky a strategy.
Multivariate discriminant function analyses have been used to attempt to
discriminate malingerers from normals from organic patients with some
measure of success. However, these classification equations have yet to be
cross-validated in independent, clinical samples, and are of uncertain value in
the individual case. Highly variable sensitivity and specificity rates have been
produced by clinicians evaluating and sorting test protocols of these three


182
Genuine subjects perceived tasks as significantly more difficult than did
Malingering subjects. Malingering subjects perceived themselves as
significantly less successful in playing their role of producing "severe but
believable impairment' than did Genuine subjects in achieving their best
memory performance.
Both subject groups appeared to hold similar perceptions about the
implicit memory tasks. Word stem completion was perceived as relatively easy
by both groups. Similar effort scores supports the hypothesis that Malingerers
were engaged in effortful processing that involved explicitly-mediated
suppression. Genuine subjects were highly confident in their success in WSC.
One interpretation is that strong explicit memory traces contributed to their self-
knowledge of very high performance levels. Both groups rated PI as more
difficult and effort-demanding than WSC. Similar Success scores for PI suggest
the ambiguous aspects of the task make perceptions of successful and
unsuccessful performance difficult for the naive subject.
Malingering subjects rated themselves as putting forth less effort than
their Genuine counterparts on the SVT paradigm. Interestingly, Malingering
subjects rated SVT as quite easy and undemanding. On the other hand,
Genuine subjects were highly confident in their successful performance on SVT,
with Malingering subjects rating themselves as less confident of the success of
their role-playing.


27
Bruhn and Reed (1975) instructed normal college subjects to simulate
brain damage secondary to concussion and then compared their performance
on the Bender-Gestalt Test with a nonsimulating normal group and a group of
patients with mixed cortical trauma. In their pilot study, Bruhn and Reed found
that both the Pascal-Suttell and Canter scoring methods did poorly in
discriminating organics from simulators. However, a diplmate sorted
malingerers from organics and organics from normals with hit rates of 89% and
92%, respectively. In their main study, two expert raters and one novice used
decision rules derived from the pilot study to obtain similarly accurate
discriminations among the three groups. Thus, nonbrain-damaged subjects
were not successful at malingering brain damage on the Bender-Gestalt test.
Heaton, Smith, Lehman, and Vogt (1978) instructed normal subjects to
"fake the most severe [neuropsychological and psychological] disabilities they
could, without making it obvious to the examiner that they were faking" (p. 894).
Their design included a group of head-injured patients with documented
residual neurologic deficits and a group of normal volunteers given instructions
to malinger. The outcome measures consisted of the WAIS, the Minnesota
Multiphasic Personality Inventory (MMPI), and the Halstead-Reitan
Neuropsychological Test Battery. Their results indicated that the malingerers
exhibited an overall level of performance similar to head-injured patients in that
no group differences were observed on summary measures (three WAIS
intelligence quotients and HRNB impairment indices). Qualitative differences


200
Two conclusions can be drawn from these data. First, implicit memory
as indexed in this study by indirect perceptual memory tests does not totally
exclude explicit memory from intruding upon consciousness and, in some
cases, impacting performance. Although statistically significant findings
supportive of the transfer-appropriate processing framework were not found in
this study, the trend in the data was in the direction of slight superiority of
physically encoded words. The findings that subjects who both maximize
(Genuine) and minimize (Malingering) their level of performance with explicit
memory indicates the strength of the processing model. This means that the
physical, perceptual cues present at testing may partially override the semantic
and conceptual contributions of explicit memory. Given the perceptual testing
context, subjects may be able to intentionally and explicitly access target words
while still retaining the benefit of the perceptual match between study and test
contexts. Second, the contribution of explicit retrieval during nominally indirect
tests appears to be a relatively subtle effect which failed to reach statistically
significance in this study. Explicit retrieval during PI did not appear to affect the
results, and it appears to operate only on a few words for a few subjects during
WSC. It could be argued that limited statistical power may have resulted in a
failure to detect group differences on the indirect memory tests. However, the
preexperimental computation of statistical power combined with the greater
effect sizes associated with the direct experimental tests (FR and MCR) would


156
P.l. REACTION TIME
Word Status
seconds
GENUINE
MALINGER
CHI
Targets
1.776
2.019
1.92
Distractors
1.648
1.868
1.861
VARS
Targets
Distractors
Answer Status for Target Words
seconds
VARS
Correct
Incorrect
GENUINE MALINGER CHI
Correct 1.407 1.702 1.602
Incorrect 2.145 2.335 2.238
Figure 8. PI Reaction Time Data: Word Status and Answer Status.


25
Spreen and Benton (1963) instructed subjects to portray the
performance of a "high grade mental defective." Their sample consisted of
three groups composed of genuine mental defectives, medical inpatient
simulators, and normal simulators who were evaluated with Form "C" of the
Visual Retention Test (VRT) (Benton, 1955). The two simulating groups showed
no differences in performance and were subsequently combined into one
group. These investigators found simulators to perform significantly below
mental defectives on measures indicative of overall level of performance (i.e.,
number of correct reproductions and number of circumscribed errors) and to
produce significantly more bizarre or improbable responses than actual mental
defectives. This study has several methodological flaws, however. First, a
normal control group was not employed. Second, and more serious, Spreen
and Benton preexperimentally equated their two simulating groups by their
performances on Form "A" of the VRT. This allowed the simulators to be
exposed to the task in which they would later feign and thus confounded the
results with the effects of preexisting knowledge and practice.
Gudjonsson & Shackleton (1986) looked at the effects of 'taking-bad" on
the pattern of scores on the Ravens Matrices test. Subjects included normals
recruited from military settings and a criterion comparison group of 25
neurological patients with bona-fide mental impairment. Several statistical
methods were employed to assess consistency across tests of differing
complexity. The results indicated that malingering subjects failed too many of


13
response to a variety of mental and functional losses, and emotional aspects of
postconcussion syndrome (PCS) (Lishman, 1973). While PCS encompasses
many common medical symptoms, it also commonly involves impairment in
attention, concentration, and memory processes. The critical issue for this
paper is the fact that the etiology of PCS remains a highly controversial issue,
with no clear agreement as to the relative etiological contributions of organic
damage, psychiatric and personality factors, compensation, and litigation
(Binder, 1986). Many investigators have suggested that medicolegal and
related factors may play a significant role in maintaining psychiatric disorder
and memory impairment (Miller, 1961; Levin, Benton, & Grossman, 1982).
Epidemiology
The magnitude of the problem presented by traumatic brain injury to
modern society is immense (Lishman, 1973). In 1967 three quarters of a million
people sustained a traumatic brain injury in the United States. Of these, 18,000
died, 13,000 sustained permanent disability, and 7,000 sustained temporary
disabilities. In a large sample of severely injured patients, Jennett and
colleagues (Jennett, Snoek, Bond, & Brooks, 1981) found that slightly over half
of their 314 patients remained moderately and severely disabled after six
months. Significant morbidity is associated with even mild injuries (Rimel,
Giordani, Barth, Boll, & Jane, 1981; Binder, 1986).


142
explicit memory of a target word after "catching on" to the memorial aspects of
the task. The change in a subjects response strategy or criterion was
operationalized as changes in percent accuracy for successive groups of target
stems as serial position increases. Here, serial position refers to position on the
test list rather than the study list. The target stems were divided into groups of
2 words, representing partitions of 20% of the overall list. Figure 6 presents this
data.
Main effects of serial order were analyzed within groups. Within-group
analyses failed to reveal main effects of serial position of blocks of target words
for all three groups (all Fs < 1). Thus, no group demonstrated real evidence
of changing response strategies or criteria as they proceeded through the stem
completion task.
Awareness and intentionalitv. Subjects were asked several open-ended
questions during the debriefing interview concerning their performance on
WSC. Subjects were classified as to whether they experienced test awareness
or not, and whether they consciously employed their explicit memory for test
words to either facilitate or suppress their stem completion performance. Test
awareness was a necessary condition for explicit mediation in all subject
groups. Therefore, subjects could be classified into one of three categories:
(1) those who did not experience test awareness during WSC; (2) those who
did experience test awareness but who did not experience explicit memory
during WSC; and (3) those who both experienced test awareness and judged


26
the easy items at the beginning of the test, resulting in a relatively stable rate of
performance decay as test complexity increased. This pattern of performance
was not characteristic of subjects performing their best or of patients with bona-
fide neurological impairment. Subjects in these conditions scored higher on the
easy portions of the test, resulting in a normal rate of performance decay as
testing complexity increased.
Malingered "Brain Damage"
Anderson, Trewothan, and Kenna (1959) instructed a group of normal
subjects to portray "mental abnormality for some reason best known to
themselves." Various aspects of their behavior were then compared with
groups of patients with documented organic brain damage, pseudodementia
patients (as best can be determined, a mixed group of patients suffering from
mental deficiencies associated with depression and other psychopathology),
and a control group of normal volunteers. Analysis of their data revealed that
the malingering groups level of performance tended to fall between the levels
of the normal group in the unimpaired range and the organic and
pseudodementia group in the impaired range on measures of orientation,
verbal retention and recall, digit span, concentration, mental arithmetic, and
general knowledge. Thus, simulators apparently did not overplay their role. In
the qualitative domain, simulators produced significantly fewer perseverations
than did the organic group.


REFERENCES
Abeles, M., & Schilder, P. (1935). Psychogenic loss of personal identity.
Archives of Neurology and Psychiatry. 34. 587-604.
Adams, J. H., Mitchell, D. E., Graham, D. I., & Doyle, D. (1977). Diffuse brain
damage of the immediate impact type. Brain. 100. 489-502.
Albert, S., Fox, H. M., & Kahn, M. W. (1980). Faking psychosis on a Rorschach:
Can expert judges detect malingering? Journal of Personality Assessment.
44, 115-119.
American Psychiatric Association. (1987). Diagnostic and statistical manual of
mental disorders. (3rd. ed. revised). Washington, DC: Author.
Anderson, E. W., Trethowan, W. H., & Kenna, J. C. (1959). An experimental
investigation of simulation and pseudo-dementia. Acta Psvchiatrica et
Neuroloaica Scandinavica. 132. 5-42.
Anthony, N. (1971). Comparison of patients standard, exaggerated, and
matching MMPI profiles. Journal of Consulting and Clinical Psychology. 36,
100-103.
Baddelly, A. D. (1982). Domains of recollection. Psychological Review. 89, 708-
729.
Barth, J. T., Macciocchi, S. N., Giordani, B.t Rimel, R., Jane, J.A., & Boll, T. J.
(1983). Neuropsychological sequelae of minor head injury. Neurosurgery. 13,
529-533.
Bash, I. Y., & Alpert, M. (1980). The determination of malingering. Annals of
New York Academy of Sciences. 347. 86-99.
Benton, A. L. (1945). Rorschach performances of suspected malingerers.
Journal of Abnormal and Social Psychology. 40. 94-96.
230


Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
THE USE OF INDIRECT TESTS IN THE EVALUATION OF MALINGERED
OR EXAGGERATED MEMORY PERFORMANCE
By
Travis G. White, Jr.
December, 1992
Chairperson: Russell M. Bauer
Major Department: Clinical and Health Psychology
Claims of amnesia and anterograde memory impairment arise in a variety
of medicolegal contexts. This study examined the performance of normal
subjects given the instructions to malinger or feign memory dysfunction
(Malingerers) on various clinical, two-item forced-choice, and indirect memory
tests. Normal subjects performing to the best of their ability (Genuine subjects)
and patients having sustained a closed head injury with resulting
neuropsychological memory impairment served as the comparison groups.
The results indicated that Malingering subjects lowered their quantitative level of
performance and altered the qualitative aspects of their performance relative to
the Genuine subjects. However, Malingering subjects produced performance
profiles on clinical memory tests which were highly similar to those of the Head
v


110
magnitude of priming. Using a conservative cutoff of a 25% increase in
performance of targets over distractors, each subject was scored as to whether
his WSC performance reflected priming or no priming. This criterion reflected
the average strength of priming demonstrated in the relevent literature. Five of
9 amnesic subjects (55.6%) demonstrated priming using this criterion,
compared to 6 of 9 control subjects (66.7%). A nonparametric hypothesis test
for the significance of difference between these two proportions failed to reach
significance (Z=-.48, pc.32).
Perceptual Identification
Baseline performance on Perceptual Identification (PI) for the two groups
(Amnesia=22.2%; Controls=20.6%) was not significantly different (Fs < 1), and
was equivalent to baseline rates reported in the literature (Jacoby & Dallas,
1981). Collapsed across groups, a significant main effect of word status (target
versus distractor) was found, F(1,16)=27.1, pc.0001. Computed within groups,
a significant main effect of word status was found for both the Amnesic group,
F(1,8)=6.33, pc.03, and the control group, F(1,8)=12.27, pc.008, suggesting
that both groups demonstrated priming on the PI task. Follow-up mean
contrasts confirmed that stimulus words were identified significantly more often
when the word was previously exposed compared to the unexposed condition
in both groups. The interaction between group and target status was
nonsignificant (F c 1). Figure 2 presents this data.


ACKNOWLEDGEMENTS
I would like to extend my gratitude to those who provided the expertise,
encouragement, and support that enabled the completion of this project. Dr.
Russell Bauer is to be thanked for his multifaceted contributions to my graduate
school training in general and this research project in particular. Dr. Bauer has
been an inspiring example of excellence in clinical practice, academic thought,
and applied research. I hope to always strive to achieve the standards that Dr.
Bauer personifies. My committee members are to be thanked for their
contributions at the inception and culmination of this project. Their attention to
design and methodological issues as well as helpful suggestions at the defense
meeting greatly improved the quality of this project. Dr. Eileen Fennell is to be
thanked for her donation of equipment and laboratory space. Many people
participated in the arduous task of identifying populations of head injury
patients. Dr. Hugh Brown, Ms. Pat Price, and the special patients of the
Sandybrook Center of Rebound located in Mt. Dora, Florida are to be thanked
for their gracious participation in this project. My familys love, encouragement,
and support were instrumental to the success and completion of this project.
Most importantly, this project could not have been completed without the
unwavering confidence, support, and love of my fiance, Pamela Kennedy.
ii


149
Malingering subjects might be expected to produce increased response
latencies to the extent they were explicitly recognizing target words and then
withholding the correct response. This was evaluated in several ways.
Comparing main effects of word status on response latency relates generally to
the processes underlying perceptual identification. Collapsed across groups,
the main effect of word status on reaction time was nonsignificant,
F(1,52) = 1.93, pc.17. The interaction between group and word status was also
nonsignificant (F < 1). Figure 8 presents this data.
One way Malingering subjects could have lowered their accuracy rate
was by producing incorrect answers. An inhibitory process could be inferred to
the extent that incorrect answers were produced by Malingering subjects at the
expense of exaggerated response latencies. The main effect of answer status
(correct versus incorrect) on reaction time was analyzed within each group.
Figure 8 presents this data. Collapsed across groups, the main effect of
answer status on reaction time was highly significant, F(1,52)=21.28, p<.0001.
The interaction between group and answer status was significant, F(2,52)=4.56,
p<.007. Analyzed within group, the main effect of answer status on reaction
time was significant for the Genuine group, F(1,19)=12.14, p<.001, the
Malingering group, F(1,19) =7.57, pc.009 and the Head Injury group,
F(1,14)=4.40, pc.046. Follow-up mean contrasts demonstrated that all three
groups responded significantly faster when their answer was correct as
compared to incorrect responses, with Genuine subjects demonstrating a


164
MCR SERIAL POSITION
% correctly recognized
GROUPS
-e- GEN
+ MAL
CHI
Figure 13. MC Recognition: Serial Position Effects.


153
Figure 10 presents this data. Main effects of serial order on identification
accuracy were analyzed within groups. Within-group analyses were
nonsignificant for the main effects of serial position of blocks of target words for
the Genuine group, F(4,18)=.75, p<.57, the Malingering group, F(4,18)=.39,
p<.81, and the Head Injury group, F(4,13)=.72, p<.60. Thus, no group
demonstrated real evidence of changing response strategies or criteria as they
proceeded through the PI task.
Awareness and intentionalitv. Aspects of awareness were categorized
for PI performance in the same manner as for PI performance. Test awareness
was a necessary condition for explicit mediation in all subject groups.
Therefore, subjects were classified into one of three categories: (1) those who
did not experience test awareness during PI; (2) those who did experience test
awareness but who did not experience explicit memory during WSC; and (3)
those who both experienced test awareness and judged that their performance
was impacted by explicit memory (for Malingering subjects, this means that
they engaged in postretrieval suppression.
Table 16 presents data concerning the relationship between group
membership, test awareness, magnitude of priming on PI, and LOP effects. A
chi-square analysis detected a significant relationship between group
membership and the awareness variable (X2=13.75, p<.008, df=4). Nine
Malingering subjects reported engaging in explicit mediation (suppression)


155
PERCEPT. IDENTIFICATION
Target Advantage
% correct identification
90
80
GENUINE
MALINGER
CHI
Targets
49.8
38.2
51.2
Distractors
25.5
18.2
23.1
Encoding Process
GENUINE MALINGER CHI
Sentence 47.6 37.4 50
Letter 52 2 39 52.4
Figure 7. PI Performance: Priming and Encoding Effects.


116
MC RECOGNITION
Overall Performance
% correctly recognized
100
90
80
70
60
50
40
30
20
10
0
AMNESICS CONTROLS
MC Recognition 45 78.3
Encoding Process
% correctly recognized
100
90
80
70
60
50
40
30
20
10
0
AMNESICS CONTROLS
Sentence 50 84.4
Letter 40 72.2
Figure 4. Multiple Choice Recognition Performance for Experiment 1.


104
Descriptive Statistics
Characterization of Subject Groups
Table 2 contains descriptive information and demographic variables for
Experiment 1. The Amnesic patients were broken down into two subgroups
based on etiology: alcoholic Korsakoffs syndrome (n=4) and other etiologies
(n=5). A control group consisting of medical outpatients was matched to the
two amnesia subgroups based on age and education. One-way analysis of
variance procedures showed no significant differences between the amnesic
subjects and controls for the demographic variables. Table 3 contains
descriptive information and demographic variables for the main study. Two
groups of normal college students comprised the Genuine (n=20) and Malinger
(n=20) groups. Patients suffering from Closed Head Injury (n=15) were
included as an additional control group. One-way analyses of variance showed
significant differences between the three groups on age at time of testing,
F(2,52)=7.09, pc.01. Follow-up mean contrasts revealed that Head Injury
patients were significantly older than the Genuine and Malinger subjects. As
memory function has been repeatedly shown to decline as a function of age,
the observed age effect in the present study could theoretically pose a threat to
the validity of the results. However, the observed statistical difference in age
between the Head Injury subjects and the other groups is slight (approximately
5 years) and does not represent a practically significant difference.


132
However, certain trends in the data were evident. Malingering subjects tended
to omit more design elements in the copy trial than the other groups.
Malingering and Head Injury subjects tended to produce a similar percentage
of omissions and distortions, higher than Genuine subjects. The omission of
design elements, especially details, rather than distortions lowered the overall
scores in the immediate and delayed memory trials for both the Malingering
and Head Injury subjects.
Summary. Genuine subjects clearly demonstrated intact and above
average memory abilities, as reflected in their scores on composite measures of
general memory functioning. As compared to Genuine subjects, Head Injury
subjects demonstrated clinically significant impairment in attention,
concentration, and recent memory abilities. On average, the performance of
Head Injury subjects fell approximately 2.3 standard deviations below that of the
Genuine subjects. Table 14 presents average effect sizes computed from this
study. From a quantitative perspective, Malingering subjects produced scores
which were remarkably similar to Head Injury subjects. Malingering subjects
typically performed much worse than Genuine subjects, but at a level which
was not significantly different, from the bona-fide memory impairment of the
Head Injury subjects. On average, the performance of Malingering subjects fell
approximately 2.2 standard deviations below that of the Genuine subjects.
Malingering subjects generally scored slightly higher than Head Injury subjects
on tasks measuring attention and concentration, immediate recall and cued


65
encoding, rehearsal, and retrieval) and to formulate a description of the memory
system in terms of these constituent operations (Craik & Lockhart, 1972; Craik
& Tulving, 1975).
A typical LOP manipulation involves incidental learning in a semantic or
conceptual study condition (e.g., rating the pleasantness; deciding whether a
word fits in a sentence) versus a physical or orthographic study condition (e.g.,
searching for particular letters in the word) (Craik & Lockhart, 1972; Craik &
Tulving, 1975). The relationship between LOP and performance on direct,
explicit measures of retrieval has been shown to be quite robust in normal
subjects: "deeper" semantic processing produces greater explicit retrieval than
does more "shallow" processing (Craik & Tulving, 1975; Bradshaw & Anderson,
1982), which is thought to be due to cognitive elaboration taking place during
the encoding process.
Prior to the popularity of the processing model, most researchers agreed
that LOP had a null effect on indirect memory tests (Graf & Mandler, 1984; Graf,
Mandler, & Haden, 1982; Graf, Squire, & Mandler, 1984; Jacoby & Dallas, 1981;
Richardson-Klavehn & Bjork, 1988). However, the processing model has
allowed for the categorization of indirect memory tests into primarily conceptual
tests versus primarily perceptual tests. Indirect perceptual tests include word
fragment completion, word stem completion, and tachistoscopic perceptual
identification. Research has established that LOP affects priming in indirect
conceptual tests (Hamann, 1990; Srinivas & Roediger, 1990).


60
explicit recognition for the biased spellings was intact for normals and severely
impaired for the amnesic patients. More importantly, the conditionalized
probability of recognition did not differ significantly from the simple probability
of correct recognition for either group. This procedure was repeated using
perceptual identification as the indirect memory test. The results were
equivalent; the two tasks were found to be stochastically independent across
12 conditions that differed in overall rate of identification.
Tulving et al. (1982) found that probability of recognition conditionalized
on successful word fragment completion was equivalent to the overall
proportion of words recognized for four conditions that differed in overall
recognition probability. Tulving (1985) reported the extensive results of
Chandlers (1983) work which manipulated the relationship between fragment
completion and direct memory tests in 32 separate conditions. Without
exception, stochastic independence was found in that recognition
conditionalized on correct fragment completion was essentially equivalent to
simple recognition.
Several studies, however, have found stochastic dependence between
performance on an indirect and a direct memory test. Jacoby and Witherspoon
(1982) presented a long list of pronounceable pseudowords for study. A test of
recognition memory for the studied pseudowords was presented in the second
phase of the experiment. A perceptual identification test, given in the final
phase of the experiment, included "new" pseudowords as well as words that


THE USE OF INDIRECT TESTS IN THE EVALUATION OF MALINGERED
OR EXAGGERATED MEMORY PERFORMANCE
By
TRAVIS G. WHITE, JR.
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1992

ACKNOWLEDGEMENTS
I would like to extend my gratitude to those who provided the expertise,
encouragement, and support that enabled the completion of this project. Dr.
Russell Bauer is to be thanked for his multifaceted contributions to my graduate
school training in general and this research project in particular. Dr. Bauer has
been an inspiring example of excellence in clinical practice, academic thought,
and applied research. I hope to always strive to achieve the standards that Dr.
Bauer personifies. My committee members are to be thanked for their
contributions at the inception and culmination of this project. Their attention to
design and methodological issues as well as helpful suggestions at the defense
meeting greatly improved the quality of this project. Dr. Eileen Fennell is to be
thanked for her donation of equipment and laboratory space. Many people
participated in the arduous task of identifying populations of head injury
patients. Dr. Hugh Brown, Ms. Pat Price, and the special patients of the
Sandybrook Center of Rebound located in Mt. Dora, Florida are to be thanked
for their gracious participation in this project. My family’s love, encouragement,
and support were instrumental to the success and completion of this project.
Most importantly, this project could not have been completed without the
unwavering confidence, support, and love of my fiance, Pamela Kennedy.
ii

TABLE OF CONTENTS
page
ABSTRACT iv
CHAPTERS
1 INTRODUCTION 1
Malingering 4
Memory Impairment Following Brain Damage 11
Experimental Studies of Malingering 23
Implicit Memory 53
Hypotheses and Predictions 72
2 METHOD 76
Analysis of Statistical Power 77
Subjects 78
Design 82
Materials 82
Procedure 90
3 RESULTS 104
Descriptive Statistics 105
Experiment 1: Validation of Word Lists 109
Experiment 2: Main Study 117
4 DISCUSSION 188
Validity of Group Membership 188
Experimental Memory Tasks 193
Symptom Validity Testing 206
Multivariate Detection of Malingering 213
The "Art" of Detecting Malingering 214
Summary 216

APPENDICES
A PREEXPERIMENTAL MATERIALS 218
B EXPERIMENTAL MATERIALS 224
C POSTEXPERIMENTAL MATERIALS 230
REFERENCES 233
BIOGRAPHICAL SKETCH 255
IV

Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
THE USE OF INDIRECT TESTS IN THE EVALUATION OF MALINGERED
OR EXAGGERATED MEMORY PERFORMANCE
By
Travis G. White, Jr.
December, 1992
Chairperson: Russell M. Bauer
Major Department: Clinical and Health Psychology
Claims of amnesia and anterograde memory impairment arise in a variety
of medicolegal contexts. This study examined the performance of normal
subjects given the instructions to malinger or feign memory dysfunction
(Malingerers) on various clinical, two-item forced-choice, and indirect memory
tests. Normal subjects performing to the best of their ability (Genuine subjects)
and patients having sustained a closed head injury with resulting
neuropsychological memory impairment served as the comparison groups.
The results indicated that Malingering subjects lowered their quantitative level of
performance and altered the qualitative aspects of their performance relative to
the Genuine subjects. However, Malingering subjects produced performance
profiles on clinical memory tests which were highly similar to those of the Head
v

Injured patients with documented neurological damage and bona-fide
neuropsychological memory impairment. In general, no single clinical memory
test or combination of several tests proved useful in diagnosing experimental
malingering.
Word stem completion and perceptual identification, two commonly used
indirect memory tests, were administered to these subject groups with the
general idea that Malingering subjects might first experience explicit memory for
study items and then engage in postretrieval suppression of correct responses.
This general prediction did not hold up in that Malingering subjects produced
normal strength of priming and levels of processing effects on both indirect
memory tests. However, the results indicated that the Genuine subjects used
explicit memory to increase their strength of priming on word stem completion
but not on perceptual identification.
In contrast to the indirect memory tests, the Symptom Validity Testing
paradigm used in this study was designed as a direct test of short-term
memory. The "art" of SVT lies in the fact that expected performance levels are
not apparent to the typical subject. The main finding concerning the SVT
paradigm was that Malingering subjects, as a group, were impaired relative to
other groups, but scored well above chance levels and demonstrated
surprisingly consistent responding across trials. Several statistical methods
demonstrated that the traditional criterion of chance performance may be
potentially insensitive to malingering response sets.
VI

CHAPTER 1
INTRODUCTION
Claims of amnesia arise in a variety of medicolegal contexts (Wiggins &
Brandt, 1988), especially in cases involving violent crime (Bradford & Smith,
1979). In one review, malingered amnesia was found to be the most frequently
alleged mental defect (Hopwood & Snell, 1933). Hopwood and Snell (1933)
highlight the utility of malingering amnesia for a defendant on trial in a criminal
proceeding. They relate a story of a defendant who, after claiming amnesia for
an alleged murder, has escaped the responsibility for his crime and finds
himself confined to an asylum instead of a prison. He quickly realizes that a
persistence of amnesia for his crime will keep him confined in an asylum and
then suddenly recovers his forgotten memories. This scenario highlights the
volitionalitv and goal-orientation of malingering. It is also common for claims of
amnesia to arise in civil proceedings (Benton & Spreen, 1961), such as
personal injury suits and disability hearings (Guthkelch, 1980).
The determination of the genuineness of claimed amnesia will often have
a profound impact upon the outcome of legal proceedings. If a claim of
amnesia is judged to be malingered, it can no longer be used to support a
defendant’s plea for automatism (i.e., performance of acts without awareness or
1

2
conscious volition), may result in a partial reduction in, or elimination of,
monetary damages for the plaintiff, and could no doubt discredit other
testimony delivered by the malingerer (Schacter, 1986a). On the other hand, a
successful malingerer reaps highly salient positive reinforcement in a civil
proceeding in the form of monetary compensation and negative reinforcement
in a criminal proceeding in the form of a more desirable disposition.
Memory is a private event and the assessment of its functional integrity is
not always a straightforward process. Given the importance of accurately and
efficiently evaluating neuropsychological function and dysfunction in a forensic
context, the mental health professional is poorly equipped to discriminate
effortful and motivational aspects of a patient’s performance (Brandt, 1988).
This state of affairs is readily apparent in the experimental literature involving
malingered amnesia. Taken as a group, the experimental studies attempting to
discriminate between malingered and genuine amnesia have produced mixed
results and are quite difficult to implement in the clinical or medicolegal setting
(Brandt, 1988; Schacter, 1986a, 1986b; Wiggins & Brandt, 1988).
Brandt and his colleagues (Brandt, 1988; Rubinsky & Brandt, 1986) state
that the lay public’s perception of normal memory functioning is that it can be
easily faked and that such faking is difficult to detect, in part because of the
belief that it would be easier to withhold behavior (i.e., produce a behavioral
deficit) than it would be to demonstrate a positive symptom. Most researchers
feel that a malingerer will be successful in producing believable deficits to the

3
extent that he has detailed knowledge about the syndrome he is attempting to
simulate and has a refined ability to simultaneously monitor and regulate his
performance throughout a long and anxiety provoking testing situation (see
Binder & Pankratz, 1987, and Goebel, 1983, for more detailed reviews).
It is the aim of this study to examine the performance of normal subjects
given the instructions to malinger memory dysfunction on various clinical and
experimental memory tests, including two perceptual indirect memory tasks
(word stem completion and perceptual identification). These indices may be
sensitive to a malingering response style for several reasons. First, it is unlikely,
even given the recent flurry of academic activity, that a lay person’s knowledge
of amnesia would include the knowledge of the dissociation of explicit and
implicit processes. Additionally, the nature of the implicit memory indices (e.g.,
instructions that disguise the memory component; perceptual identification
occurring at or near absolute threshold) may make them somewhat resistant to
volitional control. First, the various theoretical issues related to malingering will
be reviewed. Bona-fide impairment secondary to brain damage will then be
covered. Next, an in-depth review of the literature involving the experimental
portrayal of "mental deficiency," "brain damage," and "amnesia" will be offered.
Implicit memory will be dealt with next. The Introduction section of this paper
will conclude with a statement of the proposed problem and experimental
hypotheses to be tested.

4
Malingering
Any psychelggical assessment technique which derives its infcrmation
frcm a perscn’s verbal behavicr may be affected by a deceptive respcnse style.
The term "dissimulaticn" refers tc the deliberate distorticn cr misrepresentaticn
cf symptcms (Regers, 1988). This categcry subsumes such ccncepts as
"defensiveness," "randem respending," and "irrelevant respending." This paper
is ccncerned with ancther type cf dissimulation, malingering. Malingering is
defined by the American Psychiatric Association (APA, 1987) as "the intentional
production of false or grossly exaggerated physical or psychological symptoms,
motivated by external incentives such as avoiding military conscription or duty,
avoiding work, obtaining drugs, or securing better living conditions" (p. 360).
The implicit assumption of this definition is that malingerers are socially deviant
individuals (i.e., those with antisocial personalities) who are likely to fabricate
illness when involved in the legal system and are likely to demonstrate poor
compliance with assessment and treatment procedures (Rogers, 1990a). As
Rogers (1990a) correctly states, the DSM-lll-R, in its attempt to remain
atheoretical about etiology, nevertheless conceptualizes malingering from a
moralistic and criminological perspective. These issues will be dealt with in
depth in later sections.
Brief History
The concepts and behaviors underlying malingering have been
recognized throughout history (Bash & Alpert, 1980) and have been recorded

5
as early as biblical times (Jones & Llewellyn, 1917, cited in Bash & Alpert,
1980). In military populations, an increase in the prevalence of malingering can
be directly linked to times of war (Anderson, Trethowan, & Kenna, 1959).
Excluding wartime, the emergence of malingering as a diagnostic and legal
entity largely resulted from the Industrial Revolution (Miller & Cartlidge, 1974).
Regler (1879, cited in Miller & Cartlidge, 1974) documented the increased
frequency of malingering as the result of the first accident insurance laws in
Prussia. As technology has progressed, industrial machinery has become
more complex, resulting in more dangerous working conditions and a higher
frequency of both legitimate and malingered injury. Mental health
professionals, including psychologists and neuropsychologists, are testifying as
expert medicolegal witnesses with increasing frequency (Lees-Haley, 1984).
Differential Diagnosis
The concepts of intentionalitv and goal-orientation are central to the
definition of malingering (Cunnien, 1988) and form the basis for differential
diagnosis. Before making the diagnosis of malingering, the clinician must rule
out genuine impairment, factitious disorder, and somatoform disorder.
Factitious disorders are characterized by the "intentional production or feigning
of psychological [or physical] symptoms" due to a "psychological need to
assume the sick role, as evidenced by the absence of external incentives for
the behavior, such as economic gain, better care, or physical well-being." This
disorder must not occur exclusively during the time course of an Axis I mental

6
disorder, such as bipolar disorder (manic phase) (APA, 1987, p. 318). Thus,
the malingerer and the patient with factitious disorder both voluntarily respond
deceptively, with the former being voluntarily motivated to dissimulate by the
prospect of external secondary gain, while the latter reflects an involuntarily
adopted psychological goal to assume the role of sickly patient (Drob & Berger,
1987).
Somatoform disorders refer to a group of psychiatric disorders in which
there are "physical symptoms suggesting physical disorder for which there are
no demonstrable organic findings or known physiologic mechanisms, and for
which there is positive evidence, or a strong presumption, that the symptoms
are linked to psychological factors or conflicts" (APA, 1987, p. 255). Conversion
disorder is subsumed by this category. In somatoform disorders the
mechanisms linking mind and body are presumably not under conscious
control (Reich & Gottfried, 1983). Therefore, a malingerer and an individual with
somatoform disorder both demonstrate physical symptoms that have no known
etiologically significant physical cause, with the former intentionally dissimulating
for an obvious environmental goal, and the latter unintentionally altering his
presentation and no obvious environmental goal.
Classification
One of the most difficult clinical aspects associated with malingering is
classification (Bash & Alpert, 1980). The diagnostic task is made all the more
difficult for the clinician due to the high costs to the medical system from an

7
unrecognized malingerer, as well as the high costs to the patient incorrectly
labeled as a malingerer (Pankratz & Erickson, 1990; Wasyliw & Cavanaugh,
1989). Although debated in the literature, malingering is essentially an act,
performed in specific situations for the purpose of obtaining positive or negative
reinforcement, which exists apart from the actual mental status of the patient
(but see Menninger, 1963 for a discussion of the minority opinion that
malingering is a mental illness). However, malingering can certainly coexist with
mental illness (APA, 1987) and personality disorder (Clark, 1988). The
distinction between an act and a mental status is endorsed by several sources.
First, the American Psychiatric Association (APA, 1987) classifies malingering as
a "V Code," i.e., "a condition not attributable to a mental disorder that is a focus
of treatment" (p. 359). Second, Gorman (1982) states that an act is
differentiated from status in both statute and case law, in the sense that
landmark decisions have established that it is constitutional to punish a person
for performing a wrongful act (e.g., for consuming illegal drugs) but not for his
or her mental status (e.g., for being intoxicated on illegal drugs).
Recent empirical and theoretical work (Rogers, 1987, 1988) has
suggested that the traditional view of malingering as a dichotomous construct
(presence versus absence) is not consistent with clinical observations. Rather,
Rogers states that malingering may in fact be a continuous construct reflecting
gradations of dissimulation. Several authors have advanced classification
schemes for malingering which take this issue into account. Schroeder (1966)

8
divided malingering behavior into four subtypes: (1) pure invention of
symptoms; (2) perseveration, in which formerly genuine, bona-fide symptoms
continue; (3) exaggeration, in which genuine symptoms are presented as worse
than they actually are; and (4) "transference.11 in which genuine, bona-fide
symptoms are attributed to an erroneous cause.
Travin and Potter (1984) have suggested three nondiscrete and
overlapping demarcation points on the malingering continuum: (1) other-
deceivers who correspond to the DSM-lll-R notion of a fully aware and fully
volitional malingerer; (2) a midrange category of mixed-deceivers, in which the
patient is aware that he making up some aspect of the present symptom but is
not aware that other aspects of the symptom are beyond his control; and (3)
an end-range category of self-deceivers, in which the subject more completely
deceives himself in not realizing the origin of the presented symptoms.
The Development of Malingering
The American Psychiatric Association, faced with a divergence of thought
on the purposes of diagnosis and the underlying theory of psychopathology,
based DSM-III and DSM-lll-R on atheoretical classification schemes (Rogers,
1990a). Rogers has offered several reviews of the prominent models of
malingering (1990a, 1990b). The pathogenic model of primarily dynamically
oriented analysts (Menninger, 1935; Eissler, 1986) views malingering as an
ineffective defense mechanism which attempts to control psychotic and neurotic
processes by voluntary acceptance and conscious reproduction of the

9
underlying psychopathology. In this view, malingering is an attempt to cope
with underlying psychological and emotional conflicts by accepting and
controlling their expression. While primary mental illness and malingering are
not mutually exclusive, Rogers (1990a) asserts that the pathogenic model offers
little explanatory power for either etiology or motivation.
The DSM-lll-R model, discussed previously, can be criticized on several
points (Rogers, 1990a). The emphasis on background and contextual aspects
of the patient’s history tends to shift the clinician’s focus away from aspects of
the clinical presentation of the suspected malingerer. Specifically, Rogers
states that there is insufficient evidence to support the alleged association of
malingering with antisocial personality disorder. Uncooperativeness with
assessment and treatment procedures is felt to be characteristic of a number of
other bona-fide mental disorders and thus not specific to malingering. The term
"discrepancies with objective findings" is unnecessarily ambiguous. As several
researchers have pointed out, corroborative and naturalistic observational data
rather than "objective data" may prove more useful in the assessment of a
patient’s actual impairment (Rogers, 1990a; Rogers & Cunnien, 1986; Pankratz
& Erickson, 1990). For example, informal conversation with the suspected
malingerer after the "evaluation" may reveal detailed and intact memory for the
route taken to the hospital, even though the patient demonstrates severe
impairment on memory tests (Drob & Berger, 1987).

10
The adaptational model shows considerable promise as a conceptual
framework for understanding malingering. This model views malingering as
goal-seeking behavior designed to maximize the chances of success on the
basis of expected utility and likelihood (Rogers, 1990a). This model completely
avoids the overly pathological (malingerers as "mad") and
criminological/moralistic (malingerers as "bad") thinking associated with the
other conceptual models. Rather, malingering behavior is dealt with in terms of
its adaptive value; malingerers are pursuing a course of action that seems to
him or her to be the most effective way of adapting to the difficulties life poses
and of eliciting needed support from others (Pankratz & Erickson, 1990). Most
clinicians would certainly label malingering as "maladaptive" and, to some
extent, "incorrect" (Pankratz & Erickson, 1990; Binder, 1990).
The true value of the adaptational model is that it properly focuses the
clinician on treating the patient, a task which often goes overlooked in the
struggle to accurately diagnose the suspected malingering patient. Viewing
behavior as maladaptive rather than criminalistic also helps the clinician avoid
negative countertransferential reactions to the patient (Rabinowitz, Mark, Modai,
& Margalit, 1990). Pankratz and Erickson (1990) feel that treatment should be
offered to the suspected malingering patient as it would any other; namely,
collaborating with the patient to determine whether psychological treatment
could potentially make the patient’s life more fulfilling and satisfying.

11
Memory Impairment Following Brain Damage
Amnesia
Amnesia refers to a condition characterized by the impairment of normal
memory functioning in which a person has an acquired difficulty in learning new
material and in recalling remote events. Amnesia can be classified according to
etiology (organic versus psychogenic) and chronicity (discrete episodes versus
persistent impairment) (Kopelman, 1987). As it is most frequently used,
amnesia refers to a neurological condition that can result from a variety of
etiologic agents and loci of lesions (Butters & Miliotis, 1985). Anoxia,
encephalitis, electroconvulsive therapy (ECT), cerebrovascular accidents, closed
head injuries, and surgical damage have all produced amnesia in patients
(Drachman & Arbit, 1966; Milner, 1970; Squire, Chace, & Slater, 1976; Levin,
Benton, & Grossman, 1982). Lesions to the medial diencephalic structures,
including the dorsomedial nucleus of the thalamus and the mammillary bodies
(Victor, Adams & Collins, 1971; Butters & Cermak, 1980), the fornix (Heilman &
Sypert, 1977), and the retrosplenial area (e.g., splenium, retrosplenial cortex,
and cingulate bundle) (Valenstein, Bowers, Verfaellie, Heilman, Day & Watson,
1987) have all produced amnesia.
However, amnesia can have a psychogenic etiology as well (Kopelman,
1987). This phenomenon, which has also been referred to as functional
amnesia (Schacter, 1986a), refers to amnesia for a discrete episode of time
occurring in the past. It is produced by severe psychological and emotional

12
trauma. The condition has been well documented and mimics the retrograde
amnesic aspects of organic amnesia (Abeles & Schilder, 1935; Schacter, Wang,
Tulving, & Friedman, 1982). Amnesia secondary to fugue states (Berrington,
Liddel & Foulds, 1956) and the act of committing a violent crime (see Hopwood
& Snell, 1933) are two examples of temporally discrete amnesias.
Amnesia presents a clinical picture manifesting four distinct
characteristics (Butters & Miliotis, 1985). All amnesics have anterograde
amnesia, or impairment in the ability to learn new information. Second, all
amnesics have some degree of retrograde amnesia (impairment in retrieving
information learned prior to illness onset). Attentional capacity is spared in
"pure" cases. The above mentioned deficits exist in the presence of intact
intellectual and other higher cortical functions.
Closed Head Injury
An adequate understanding of malingering in the neuropsychological
context warrants a careful review of the literature involving the etiology and
nature of memory impairment following closed head injury (CHI), a condition
frequently associated with malingering (Binder, 1990). Impaired memory
functioning is one of the most frequently cited neurobehavioral sequelae of
closed head injury (Brooks, 1972; Levin, Benton, & Grossman, 1982; Schacter
& Crovitz, 1977). Neurotic symptoms are the most common psychiatric
symptoms associated with closed head injury (Lishman, 1973; Miller, 1961) and
include the so-called "accident neurosis" (Miller, 1961), reactive depression in

13
response to a variety of mental and functional losses, and emotional aspects of
postconcussion syndrome (PCS) (Lishman, 1973). While PCS encompasses
many common medical symptoms, it also commonly involves impairment in
attention, concentration, and memory processes. The critical issue for this
paper is the fact that the etiology of PCS remains a highly controversial issue,
with no clear agreement as to the relative etiological contributions of organic
damage, psychiatric and personality factors, compensation, and litigation
(Binder, 1986). Many investigators have suggested that medicolegal and
related factors may play a significant role in maintaining psychiatric disorder
and memory impairment (Miller, 1961; Levin, Benton, & Grossman, 1982).
Epidemiology
The magnitude of the problem presented by traumatic brain injury to
modern society is immense (Lishman, 1973). In 1967 three quarters of a million
people sustained a traumatic brain injury in the United States. Of these, 18,000
died, 13,000 sustained permanent disability, and 7,000 sustained temporary
disabilities. In a large sample of severely injured patients, Jennett and
colleagues (Jennett, Snoek, Bond, & Brooks, 1981) found that slightly over half
of their 314 patients remained moderately and severely disabled after six
months. Significant morbidity is associated with even mild injuries (Rimel,
Giordani, Barth, Boll, & Jane, 1981; Binder, 1986).

14
Neuropathology of closed head iniurv
The brain experiences many pathophysiological changes during a
closed head injury. Important determinants of these effects are the direction of
the blow, its force and velocity, and whether the head was free to move at
impact (Nilsson and Ponten, 1977; Lishman, 1973). Regardless of the nature of
the injury, the traumatically injured brain is subject to manifold rotational and
linear stresses which tear and damage nerve fibers (Lishman, 1973). These
changes have been noted after even mild head injury (Strich, 1969). Cortical
lesions are maximal in portions of the frontal and temporal poles (Sekino,
Nakamura, Yuki, Satoh, Kikuchi, & Sanada, 1981). White matter damage is
often found in subcortical tracts, the corpus callosum, and the long tracts of the
brain stem (Lishman, 1987). Adams and colleagues (Adams, Mitchell, Graham,
& Doyle, 1977) have noted that these changes occur immediately after injury
and play an important role in mortality. Concussion and loss of consciousness
are more likely to result from injuries in which the brain is free to move at
impact, producing rotational and shearing forces. Damage to brain stem
centers is usually necessary to produce concussion and loss of consciousness.
In addition to structural damage which occurs following closed head injury,
changes have also been noted in the biochemistry and cerebrovascular
circulation (Lishman, 1973).

15
Memory and learning after PTA termination
Immediate memory. Immediate or short-term memory (STM) refers to
the limited capacity system that holds a limited amount of information over brief
periods of time (less than one minute) (Watkins, 1974). Immediate memory is
usually assessed with the digit span task of the WAIS-R (Wechsler, 1981) or the
Wechsler Memory Scale (Wechsler, 1945).
Immediate memory as reflected by forward digit span is comparatively
resistant to the effects of CHI (Brooks, 1976; Lezak, 1979; Levin, Benton, &
Grossman, 1982). Mildly injured patients generally suffer no reduction in length
of forward digit span, even when tested early after admission (Cronholm &
Jonsson, 1957; Fodor, 1972). Immediate memory as reflected by the more
difficult backward digit span appears more susceptible to the effects of CHI
(Levin, Benton, & Grossman, 1982). Brooks (1976) found the forward digit
span of patients with severe CHI comparable to that of controls, while
backward digit span was significantly impaired relative to controls.
Schacter and Crovitz (1977) state that the findings of normal to near
normal digit span in CHI patients may not provide an adequate test of STM
processes as measured by more demanding tasks. Brooks (1975) used
several experimental methods to investigate STM. He found the short-term
memory abilities of CHI patients lower but not significantly different from those
of controls. Levin, Grossman, and Kelly (1976) have suggested that the format
of information may determine whether deficits are observed in CHI patients.

16
These investigators found CHI patients to have significant difficulty with short¬
term recognition of nonverbal designs, even when tested at long intervals after
injury.
To summarize, forward digit span appears relatively insensitive to the
effects of severe CHI, even when tested soon after injury. Backward digit span,
requiring additional information-processing demands, has been shown to be
reduced in the early stages of recovery, but to improve over time. More difficult
tasks, such as varying the format of to-be-remembered information, may
provide a more sensitive index of STM capacities in these patients.
Recent memory. Impaired recent memory functioning (anterograde
amnesia) is one of the most prevalent cognitive impairments following closed
head injury (Brooks, 1972; Levin, Benton, & Grossman, 1982) and is the
primary complaint of most patients and their families (Bond, 1986). Estimates
of the prevalence of persistent memory problems after PTA termination have
varied, from 16% (Lidvall, Linderoth, & Norlin, 1974) to 23% (Russell & Smith,
1961) to 36% in Russell’s (1932) original sample, depending upon the various
methodologies used in the studies (Schacter & Crovitz, 1977).
Brooks (1972) investigated the extent of memory deficit in a group of 27
patients who had sustained severe closed head injury. The author found that
the CHI patients performed significantly lower than normal controls on all tests
measuring learning and recent memory. These differences were statistically
significant for all indices except the WMS Visual Reproduction subtest

17
(immediate recall). Using the WMS and the Rey Figure, Brooks found that CHI
patients acquired significantly less information initially and they also forgot
proportionately more of this initially acquired information than did controls.
Duration of posttraumatic amnesia had a positive and significant relationship to
immediate memory and forgetting variables.
Brooks (1974) investigated visual recognition memory in a sample of 34
severely head-injured patients using a continuous recognition paradigm. The
results indicated that the CHI patients recognized significantly fewer items,
showed slower learning rates over trials, and committed a significantly higher
proportion of false negative errors than control subjects. Time elapsed
between the injury and the date of testing showed no obvious relationship to
memory performance. Severity of injury, as estimated by duration of PTA,
correlated with the number of correct recognitions and false positives. False
negative errors occurred more frequently in the CHI patients regardless of the
severity of the injury, suggesting some kind of threshold effect in that cerebral
trauma produces an all-or-none alteration in the CHI memory abilities. Brooks
interpreted these findings as evidence that the CHI patients adopted a very
strict decision criteria whereby they were unwilling to identify an item as old in
the face of uncertainty.
Brooks (1975) employed a list learning task to assess short- and long¬
term memory in a heterogeneous sample of CHI patients. When tested
immediately after presentation, CHI subjects performed similarly to controls for

18
all serial list positions. However, a 20-second interpolated delay interval
between presentation and recall selectively impaired recall in the CHI group.
Brooks then categorized recall words as either STM or LTM, based on Tulving
and Colotla’s (1970) criteria. The results indicated that CHI patients scored
lower but not significantly different from controls for STM items. However, the
CHI patients scored significantly lower than did controls for LTM items. Brooks
interpreted his findings as evidence for impaired LTM storage in CHI patients,
with relative sparing of STM processes. Schacter and Crovitz (1977) have been
highly critical of this interpretation, citing methodological flaws in the
experimental memory tasks employed in this study.
Brooks (1976) investigated Wechsler Memory Scale performance in a
sample of 82 severely head-injured patients. With the exception of Mental
Control subtest errors and Digits Forward, CHI patients were inferior to controls
on all other WMS subtests. On Logical Memory, CHI patients were significantly
poorer at an immediate and delayed recall, although their rate of forgetting was
not significantly greater than controls’. CHI patients were significantly lower on
Associate Learning and their rate of learning across trials was lower. In
general, CHI patients demonstrated proportionately more impairment on
delayed memory tasks. Neither focal neurological signs, the presence and site
of skull fracture, nor the elapsed time since injury had appreciable effects on
memory performance. The finding concerning elapsed time since injury is

19
interpreted by Brooks to reflect an early recovery of memory, often in the first
few months after injury, to a permanently deteriorated level.
Lezak (1979) tracked the course of recovery of verbal memory functions
over time in a sample of 24 CHI patients. Estimates of severity of injury were
omitted from her paper. Patients were serially tested at three different points of
recovery. Dependent measures included digit span tests (forward and
backward) and selected variables derived from the Rey Auditory Verbal
Learning Test (RAVLT). The results indicated that on simple measures of
immediate memory, Digits Forward and the first recall trial of the RAVLT, CHI
patients were only mildly impaired at the initial testing and showed consistent
improvement over time. More complex measures of learning were more
significantly impaired and remained so over time. On every measure, the more
severely impaired patients performed more poorly at initial testing than less
severely injured patients. The less severely injured subjects generally
maintained their superiority over more severely injured patients at all three
points of recovery. One interesting finding is that a subset of the CHI patients
showed a deterioration of performance on the complex memory tests at the
final point of testing (three years post injury), suggesting a possible
multifactorial recovery mechanism. Lezak suggested that partial recovery from
a severe injury may occur relatively early on while other pathophysiological
processes may compromise memory efficiency in the later stages of recovery.

20
Gronwall and Wrightson (1981) investigated memory and information
processing capacity following closed head injury in a heterogeneous sample of
91 patients. Using a variety of cognitive tasks, including the Wechsler Memory
Scale, the Selective Reminding Test, and the Paced Auditory Serial Addition
Task, these investigators isolated three relatively independent cognitive
impairments associated with CHI. Simple and undemanding memory tasks
appear resistant to impairments in information processing capacity, while
memory tasks which involve complex processing demands and time constraints
appear susceptible to this impairment. The ability to store information in LTM
was deficient in CHI patients. This ability was found to be related to either
severity of injury or elapsed time since injury. One quarter of the sample
demonstrated an additional deficit in the ability to retrieve material from LTM
once it has been stored. This impairment bore no relationship between severity
of injury or severity of information processing deficit.
Levin and Goldstein (1986) investigated whether long-term survivors of
severe CHI could gain access to semantic stores and spontaneously use
clustering strategies to guide encoding and retrieval during a list learning task.
The results indicated that controls remembered significantly more words than
CHI patients when tested with free and cued recall paradigms. Both groups
recalled more words when the stimuli were semantically clustered during
learning. Whereas control subjects tended to spontaneously impose their own
clustering to guide encoding and retrieval, CHI patients generally failed to

21
spontaneously use these strategies. Patients with frontotemporal involvement
tended to produce a higher number of intrusion errors. Decreased verbal
intellectual functioning was found to be closely related to impaired verbal
memory functioning. The authors concluded that survivors of severe CHI have
partially preserved semantic memory, although their failure to actively engage in
meta-mnemonic strategies may contribute to reduced memory efficiency.
Crosson and his colleagues (Crosson, Novack, Trenerry, & Craig, 1988)
employed the California Verbal Learning Test (CVLT) to further investigate
qualitative aspects of memory impairment following head injury. The sample
included 33 survivors of severe head injury along with 33 neurologically normal
adult male control subjects. The control group performed at a significantly
higher level than the CHI group on all five individual learning trials. Qualitative
aspects of performance were equated for overall performance level. When
overall level of performance was taken into account, both groups showed
equivalent incremental learning across trials as well as number of
perseverations. CHI patients consistently demonstrated a greater percentage
of intrusions in their response output and a lower level of spontaneous use of
semantic clustering. CHI patients lost a significantly greater amount of
information over delay intervals, as evidenced by impairment on both recall and
recognition probes. The authors interpreted their data as evidence for
disruption in multiple memory processes in survivors of severe CHI, including
problems with encoding, retention, and retrieval of information.

22
Summary. The literature reviewed provides overwhelming evidence for
memory impairment following CHI. While survivors of CHI perform normally on
simple memory tasks, impairment is noted on more complex memory and
learning tasks requiring active and effortful processing of to-be-remembered
information. These patients acquire information at a slower rate than do
normals. They evidence greater forgetting of information after acquisition,
resulting in more marked impairment on delayed memory tests.
The effects of compensation and litigation
Postconcussion syndrome (PCS) refers to a constellation of common
symptoms which include headache, dizziness, irritability, anxiety, blurred vision,
insomnia, easy fatigability, and concentration and memory difficulty (Levin,
Benton, & Grossman, 1982; Lishman, 1973). While PCS as a diagnostic entity
is generally accepted, its etiology remains a hotly contested issue, especially
when symptoms persist for long periods (Binder, 1986). Miller (1961) argued
that PCS is entirely the result of the litigation process. Levin, Benton, and
Grossman (1982) call into question new symptoms that appear after an initial
hospitalization and suggest that the etiology of such symptoms probably is not
organic.
After reviewing the literature concerning the effects of litigation and
compensation on PCS, Binder (1986) concluded that it is not possible to draw
firm conclusions in this area because of a lack of objective evidence.
Specifically, some studies have shown a correlation between claims and

23
disability or persisting subjective symptomatology (Miller, 1961; Cartlidge, 1978).
However, this relationship is not causal; it seems reasonable to assume that a
patient with prolonged symptoms after compensable trauma would be more
likely to make a claim than a patient who recovers quickly (Binder, 1986).
Conversely, research has also shown that prolonged symptoms can persist in
patients with mild head injury who are not seeking compensation (Rimel,
Giordani, Barth, Boll, & Jane, 1981). Binder concludes that the literature does
not support the contention that patients become less symptomatic after a legal
claim is settled.
The point to be made here is that the issue of persisting subjective
symptoms and complaints, in the absence of definitive neuropathological
findings, essentially fulfills one of the DSM-lll-R criteria for diagnosing
malingering (Binder, 1990). It is in these cases where there is "discrepancy
between the person’s claimed stress or disability and the objective findings"
(APA, 1987, p.360) that malingering becomes a viable yet precarious differential
diagnosis.
Experimental Studies of Malingering
The foregoing discussion emphasizes the importance of thoroughly
evaluating neuropsychological symptomatology in cases of suspected
malingering. Only a few cases have been reported in the literature in which the
patient suspected of malingering either relinquished his symptoms in favor of
genuine responding (Pankratz, 1979) or admitted to having faked impairment

24
(Hartings, 1989). Therefore, clinicians are rarely certain of the true nature of
impairment in cases of questionable motivation. This gives rise to the need for
experimental analog studies which attempt to mimic the clinical situation by
instructing subjects to portray or "simulate" impairment on testing.
Malingered Mental Deficiency
Pollaczek (1952) investigated the ability of normal college males and
normal Navy recruits to feign feeblemindedness on the "CVS" abbreviated
intelligence scale, a measure which consists of the Comprehension and
Similarities subtests from the Wechsler-Bellevue test and selected vocabulary
items from the Stanford-Binet Intelligence test (Hunt, French, Klebanoff, Mensh,
& Williams, 1948). Fifty male mental retardates were used as the criterion
comparison group. The results indicated that malingering subjects
demonstrated mental impairment equivalent to that of true mental defectives.
Thus, malingerers could not be detected with the use of the CVS total raw
score. An item-by-item analysis revealed significant between-groups differences
on 17 of 37 test items. These critical items were of two types: (1) relatively
easy items occurring at the beginning of each subtest which mental defectives
complete accurately while malingerers failed; and (2) relatively difficult items
occurring at the end of each subtest which mental defectives fail but which
malingerers passed. Cut-off scores were derived and a linear discriminant
function classification produced an 87% sensitivity rate for malingering
subjects, with a 10% false positive rate.

25
Spreen and Benton (1963) instructed subjects to portray the
performance of a "high grade mental defective." Their sample consisted of
three groups composed of genuine mental defectives, medical inpatient
simulators, and normal simulators who were evaluated with Form "C" of the
Visual Retention Test (VRT) (Benton, 1955). The two simulating groups showed
no differences in performance and were subsequently combined into one
group. These investigators found simulators to perform significantly below
mental defectives on measures indicative of overall level of performance (i.e.,
number of correct reproductions and number of circumscribed errors) and to
produce significantly more bizarre or improbable responses than actual mental
defectives. This study has several methodological flaws, however. First, a
normal control group was not employed. Second, and more serious, Spreen
and Benton preexperimentally equated their two simulating groups by their
performances on Form "A" of the VRT. This allowed the simulators to be
exposed to the task in which they would later feign and thus confounded the
results with the effects of preexisting knowledge and practice.
Gudjonsson & Shackleton (1986) looked at the effects of "faking-bad" on
the pattern of scores on the Raven’s Matrices test. Subjects included normals
recruited from military settings and a criterion comparison group of 25
neurological patients with bona-fide mental impairment. Several statistical
methods were employed to assess consistency across tests of differing
complexity. The results indicated that malingering subjects failed too many of

26
the easy items at the beginning of the test, resulting in a relatively stable rate of
performance decay as test complexity increased. This pattern of performance
was not characteristic of subjects performing their best or of patients with bona-
fide neurological impairment. Subjects in these conditions scored higher on the
easy portions of the test, resulting in a normal rate of performance decay as
testing complexity increased.
Malingered "Brain Damage"
Anderson, Trewothan, and Kenna (1959) instructed a group of normal
subjects to portray "mental abnormality for some reason best known to
themselves." Various aspects of their behavior were then compared with
groups of patients with documented organic brain damage, pseudodementia
patients (as best can be determined, a mixed group of patients suffering from
mental deficiencies associated with depression and other psychopathology),
and a control group of normal volunteers. Analysis of their data revealed that
the malingering group’s level of performance tended to fall between the levels
of the normal group in the unimpaired range and the organic and
pseudodementia group in the impaired range on measures of orientation,
verbal retention and recall, digit span, concentration, mental arithmetic, and
general knowledge. Thus, simulators apparently did not overplay their role. In
the qualitative domain, simulators produced significantly fewer perseverations
than did the organic group.

27
Bruhn and Reed (1975) instructed normal college subjects to simulate
brain damage secondary to concussion and then compared their performance
on the Bender-Gestalt Test with a nonsimulating normal group and a group of
patients with mixed cortical trauma. In their pilot study, Bruhn and Reed found
that both the Pascal-Suttell and Canter scoring methods did poorly in
discriminating organics from simulators. However, a diplómate sorted
malingerers from organics and organics from normals with hit rates of 89% and
92%, respectively. In their main study, two expert raters and one novice used
decision rules derived from the pilot study to obtain similarly accurate
discriminations among the three groups. Thus, nonbrain-damaged subjects
were not successful at malingering brain damage on the Bender-Gestalt test.
Heaton, Smith, Lehman, and Vogt (1978) instructed normal subjects to
"fake the most severe [neuropsychological and psychological] disabilities they
could, without making it obvious to the examiner that they were faking" (p. 894).
Their design included a group of head-injured patients with documented
residual neurologic deficits and a group of normal volunteers given instructions
to malinger. The outcome measures consisted of the WAIS, the Minnesota
Multiphasic Personality Inventory (MMPI), and the Halstead-Reitan
Neuropsychological Test Battery. Their results indicated that the malingerers
exhibited an overall level of performance similar to head-injured patients in that
no group differences were observed on summary measures (three WAIS
intelligence quotients and HRNB impairment indices). Qualitative differences

28
emerged when profile analysis was undertaken. Malingering subjects
significantly underestimated deficits when completing the Category Test, the
Trail Making Test (Part B error component), and all components of the Tactual
Performance Test while they significantly overestimated deficits when
completing the Speech-Sounds Perception Test, the Finger Oscillation Test,
finger agnosia and sensory suppression tasks, grip strength, and digit span.
MMPI profiles of the malingerers revealed clinical elevations on the F scale and
6 clinical scales (1, 3, 6, 7, 8, 0). Therefore, malingering subjects performed
poorly on motor and sensory tasks and produced questionably valid MMPI
profiles, but they performed relatively well on tests sensitive to brain damage.
Heaton et al. (1978) then submitted the test protocols to ten expert judges for
classification. In general, the accuracy of the judges ranged from chance-level
to approximately 20% better than chance. Since the raters were given only test
scores, the poor classification rates may be attributable to the absence of
clinically relevant data, such as interview protocols and behavioral observations.
Finally, results from multivariate discriminant function analyses indicated that
neuropsychological variables accurately predicted group membership in that
100% of the subjects in both malingering and head-injured groups were
correctly classified. Heaton et al. (1978) concluded by stating that the observed
group differences were sufficiently reliable to predict membership in head injury
and malingered head-trauma groups and that MMPI variables may have
improved discriminatory power.

29
Mensch and Woods (1986) examined whether groups of subjects with
normal and above average IQ scores could appear "brain damaged" on the
Luria-Nebraska Neuropsychological Battery if motivated by a small monetary
reward conditional on successful feigning. They employed a double-blind
crossover design. Analysis of their data indicated that 31 of 32 subjects were
able to significantly elevate enough individual scales to suggest brain damage.
However, the malingering subjects’ profile of test scores was not qualitatively
consistent with profiles of patients with known neurological pathology. For
example, malingering subjects did not demonstrate significant differences
between the Left and Right hemisphere scales. Malingering subjects
consistently performed quite poorly on sensory motor tests and tests whose
face validity was high and displayed exaggerated response latencies. Mensch
and Woods concluded that the subjects instructed to malinger brain damage in
their study were unsuccessful.
Goebel (1983) investigated the issue of whether naive, neurologically
normal subjects could feign believable deficits on the HRNB, as well as the
more specific question of whether lateralized deficits were more difficult to
simulate than diffuse or nonspecific deficits. Goebel’s design consisted of six
groups: mixed neurologic patients, control subjects, and patients told to
simulate either "nonspecific," "diffuse," "left hemisphere," or "right hemisphere"
cortical damage. In a sort of the test protocols, only 2 of 102 malingering
subjects were incorrectly classified (i.e., feigned believable deficits).

30
Goebel implied, but did not provide supporting data, that several
variables (Impairment Index, Category Test, Trails B, and TPT Localization
score) appeared to provide good discriminatory power. Linear discriminant
function analyses revealed that Speech Sounds, TPT Nondominant hand, and
time-to-complete testing were powerful variables in discriminating neurologic
patients from nonpatients. Brain-damaged patients took approximately 1.5
hours longer to complete testing than did non-brain damaged subjects. Grip
Strength Nondominant hand, Finger Tapping Nondominant hand, and WAIS
Performance IQ were powerful variables in discriminating normal controls from
malingering subjects. Goebel also presented data from the debriefing interview
which suggested that individuals were relatively ignorant of brain-behavior
relationships. The most frequently employed strategies of feigning brain
damage included giving wrong answers, slowing of performance, and
displaying motor incoordination.
Hayward, Hall, Hunt, and Zubrick (1987) asked 28 registered nurses with
varying degrees of experience in working with neurological and neurosurgical
patients to simulate performance on a battery of neuropsychological tests in
such a way as to be congruent with a history of trauma to the left
frontotemporal cortex. These data were compared with data obtained from 21
patients with documented cerebral injury and a diagnosis of left frontotemporal
dysfunction. A linear discriminant function analysis resulted in a sensitivity rate
of 86% for both malingering subjects and patients with bona-fide impairment.

31
Specificity rates were 14% for each group. Malingering patients generally
produced lower scores than patients with bona-fide impairment. Malingerers
performed poorly on tests not expected to be affected by left frontotemporal
involvement. Qualitatively, malingering performance was characterized by
elaboration and confabulation (i.e., commission of incorrect behavior), as
opposed to the poverty of content characteristic of the brain-damaged patients.
Malingerers produced types of errors on sensory tests which are not typical of
bona-fide impairment (e.g., confusing digits 1 and 4 on the finger localization
test, instead of the more typical confusion of 2 and 3).
Faust, Hart, & Guilmette (1988) investigated whether a relatively broad
sample of clinicians could identify the malingered protocols of nonsophisticated
subjects. Three children between the ages of 9 and 12 were instructed to "fake
bad" on the HRNB. All three subjects produced impaired performances on this
battery of tests. Information regarding age, sex, handedness, test scores, and
qualitative data from the Aphasia Screening Test was given along with test data
to a random sample of practicing neuropsychologists. Judges rated the results
on normal versus abnormal, etiology, severity of impairment, and confidence in
their diagnosis. The detection rate for malingering was 0%. Moreover,
clinicians rated themselves as moderately to highly confident in their diagnoses.
This study was altered slightly and replicated using adolescent subjects
to produce malingered HRNB profiles (Faust, Hart, Guilmette, & Arkes, 1988).
In Study 1, most clinicians (78%) who received no forewarning of the possibility

32
of malingering classified the cases as neuropsychologically abnormal; 0% of
malingering profiles were detected. In Study 2, clinicians were forewarned
about the malingering protocols and given the base rates. However, their
overall classification accuracy did not surpass chance levels.
Faust and his colleagues (Faust, Hart, & Guilmette, 1988; Faust, Hart,
Guilmette, & Arkes, 1988) have confidently concluded from these two studies
that "adults and adolescents can convincingly portray neuropsychological
deficits." (Faust, Hart, Guilmette, & Arkes, 1988, p. 513). Bigler (1990) has
rightfully taken extreme issue with these methodologically-flawed studies. In
general, the Faust et al. (1988) study fails to approach the reality of clinical
practice. Specifically, the use of questionnaires containing only raw test scores,
the paucity of historical and interview information, and over-reliance on
"objective" indicators biased the results towards the over-interpretation of
"pathology" and provided insufficient information to make accurate clinical
decisions. The true competency and qualifications of the respondent judges
could also be challenged.
Malingered Amnesia
Benton and Spreen (1961) compared brain damaged patients with
neurologically normal subjects instructed to portray moderate memory,
concentration, and motivational deficits secondary to an automobile accident.
They found that the simulators overplayed their role in that they performed at a
level significantly below that of brain damaged patients. Qualitatively, simulating

33
subjects tended to produce very few omission, perseveration, and size errors,
opting instead to produce many more distortion errors than are often seen in
genuinely brain damaged populations.
Williamsen, Johnson, and Eriksen (1965) instructed a group of subjects
to feign hypnosis and post-hypnotic amnesia. The instructions given to this
group were nonspecific and provided no didactic information about
posthypnotic amnesia. No incentive was offered for successful malingering.
This group was compared with groups of nonsimulating/hypnotized subjects
and genuine/nonhypnotized subjects on free recall, word fragment completion,
"word association", and two-alternative, yes/no recognition measures. The
results obtained indicated that the malingering subjects’ level of performance
was significantly lower than the posthypnotic amnesics on all measures. A
critical finding was that the simulators abnormally suppressed their responding
on several measures of implicit memory.
In a brief report, Brandt, Rubinsky, and Lassen (1985) administered a 20
item word list to groups of normals, normals simulating amnesia, patients with
Huntington’s disease, and patients with unspecified head trauma. These
subjects were tested first with free recall and then with two-alternative, forced
choice recognition paradigm (cf. Pankratz, 1983). No information was reported
concerning the instructions used for the malingering group, nor was there any
apparent external incentive to malinger. Brandt and his colleagues found that
the malingering group performed the most poorly on free recall, though not

34
significantly different from the other patient groups. The malingering group
produced recognition memory performance that was not above chance levels;
three of the ten had recognition scores below chance.
Schacter (1986) created a laboratory analogue of an episodic event in
order to examine various meta-mnemonic variables in groups of normal
subjects and subjects instructed to "simulate forgetting" of this episode. The
episodes consisted of a passage from a novel and videotaped events and was
constructed in such a way that virtually no subject would be able to accurately
recall it. The instructions given to the simulating group were quite brief and
emphasized the believability of their performance. No reward was offered for
successful simulation. The dependent variables in this study included "feeling
of knowing" ratings, which refer to a person’s belief that he could retrieve or
recognize an unrecalled item, event, or fact if he were given more powerful hints
or cues (c.f., Schacter, 1983). In Experiment 1, Schacter found that simulators,
relative to the genuine condition, demonstrated significantly lower cued recall
performance and scored significantly below chance on a two-alternative, forced
choice recognition test. Transcripts of each subject’s verbalizations at the time
of recollection were provided to six expert judges, who were subsequently
unable to correctly sort the two groups. Finally, simulating subjects were
significantly more pessimistic that retrieval cues and multiple choices would
improve their remembering of the episode.

35
Experiment 2 replicated and extended these results to show that
simulators displayed the same pattern of inaccurate meta-memorial ratings after
a 90 minute delay period, while Experiment 3 replicated the results after a 24
hour delay period. Expert raters in both Experiments 2 and 3 were still unable
to discriminate between genuine and simulating subjects.
There are several aspects which may limit the generalizability of this
study to situations outside of the laboratory. Most importantly, this experiment
had subjects simulate the forgetting of a specific, temporally-limited episode.
While this situation has direct relevance to certain criminal cases (eg., in the
form of a defendant claiming amnesia at the time of a crime), it neglects the
situation seen in many civil actions in which an individual claims a defect in his
memory process which impairs his ability to learn new information. Additionally,
the simulating subjects may never have initially learned the information under
question, and thus, may never have "forgotten" the information (Wiggins &
Brandt, 1988).
Wiggins and Brandt (1988) used both explicit and implicit memory
measures in their attempt to discriminate experimental malingerers. In
Experiment 1, five groups were evaluated. Three groups of malingerers (one
instructed to simulate amnesia resulting from head injury; one instructed to
simulate amnesia resulting from psychological trauma; and one instructed to
simulate amnesia of an unspecified etiology) were compared with a group of
true amnesics (n=4) and a group of nonsimulating controls. No suggestion

36
was given to the simulators concerning the severity of their feigned amnesia nor
were the simulators offered an incentive or reward for successful malingering.
In Experiment 1, the malingers’ performance was characterized by (1)
extremely poor performance on overlearned, autobiographical information
(worse than the performance of even the most impaired patients); (2)
performance on free recall lower than normals but greater than amnesics; (3) a
normal serial position effect, and (4) essentially normal priming effects on
measures of implicit memory. The simulators demonstrated essentially normal
priming effects on an immediate test. However, when retested after a 24 hour
delay the simulators produced significantly fewer target words than the other
groups, thus slightly suppressing their word stem completion performance. On
a word association task, simulators did not differ significantly from normals and
amnesics, with all three groups exhibiting slight priming effects. Of note is the
fact that virtually no differences were detected between the three subgroups of
malingerers, prompting the conclusion that lay people are not generally aware
of symptomatic differences between various types of amnesia.
In Experiment 2, Wiggins and Brandt administered two, 20-item lists of
concrete nouns to the same groups described above, and elicited free recall
and recognition using a two-alternative, forced-choice recognition test (c.f.
Pankratz, 1983). The amnesic group recalled fewer words than the
malingerers, who recalled fewer words than the normal controls. The
malingerers replicated a normal serial position curve. Twenty one percent of

37
the malingerers performed at chance levels on yes/no recognition, though no
malingering subject performed below chance. This performance was
significantly below the recognition levels displayed by the amnesics and normal
controls. The authors concluded that simulators portray amnesia, regardless of
its etiology, as characterized by recall performance better than, and recognition
performance worse than, that of true amnesics, and that the malingerer’ serial
position curve resembled that of normals rather than that of amnesics.
Boone (1989) directly examined the effect of coaching on malingering
subjects’ neuropsychological memory test performance. Boone randomly
assigned 87 subjects, volunteering for course credit, to one of three conditions:
uninformed-faking, informed-faking, and normal control. The subjects were
instructed to simulate the performance of a person who has recently sustained
a "mild to moderate" head injury in an automobile accident. A five dollar reward
was offered for "successful malingering", although in actuality all subjects
received this payment. Boone hypothesized that the performance of
malingerers would be characterized by significant levels of intratest and intertest
inconsistency, as operationally defined as significant deviations from the mean
scores on a scale, significant discrepancies between similar scales, improbable
temporal patterning of responses, and improbable performances relative to the
binomial distribution.
The results demonstrated that the performance of the groups of
malingerers was significantly more inconsistent than the control group, with the

38
uninformed-faking group performing more inconsistently than the informed-
faking group. A large proportion of malingerers performed in the severely
impaired range, with uninformed-fakers again demonstrating more significant
levels of impairment than informed-fakers. This study replicated previous
findings that malingerers generally tend to overplay their roles. Two significant
stepwise discriminant function analyses reliably sorted the three groups with an
accuracy rate of 91%. This study would have benefitted from the inclusion of a
group of head injury patients.
Mittenberg, D’Attilio, Gage, and Bass (1990) administered a 30 item
symptom checklist to two large groups of subjects who were instructed to
malinger "symptoms" secondary to a closed head injury they supposedly
sustained six months ago. One group of subjects reported having pre-
experimental knowledge about the symptoms of closed head injury while the
contrast group reported having no special knowledge. No objective criteria of
the subject’s knowledge of brain-behavior relationships was used verify group
membership. In both groups, postconcussion syndrome was malingered
significantly more than memory symptoms. Memory complaints were faked at a
level not significantly different than chance. However, post-concussion
syndrome was malingered by 80% of the subjects.
Wylie and Ruff (1990) instructed subjects in post-concussional syndrome.
Multivariate and clinical detection procedures were used to contrast groups of
matched controls, litigating head injury patients, and nonlitigating head injury

39
patients with multivariate and clinical detection procedures. Their results
indicated that clinical and blind raters failed to accurately discriminate
malingerers from other subjects, although multivariate analyses of variance
detected significant group differences between normals and other groups.
Multivariate discriminant function analyses improved classification of malingerers
and head injury patients by 20% over chance.
Bernard (1990) investigated the vulnerability of several widely-used
neuropsychological memory tests to experimental malingering. Three groups of
subjects were used: malingering with no financial incentive, malingering with
financial incentive to the two subjects who produced the most believable
deficits, and normal controls performing genuinely. Overall, there were few
differences between malingerers in the incentive and nonincentive conditions,
whereas both groups of malingerers performed more poorly than the controls.
Two stepwise discriminant function analyses were performed on reduced
variable sets. The first variable set, which included WMS-R Figural Memory and
Immediate Visual Reproduction, produced accuracy rates of 74% on cross-
validation. The second variable set, which included ROCF Delayed
Reproduction, RAVLT Trial 1, and RAVLT Recognition, produced accuracy rates
of 77% on cross-validation. While this study incorporated many methodological
improvements, the failure to employ a group of subjects with bona-fide memory
impairment as the criterion of successful malingering no doubt limits the
generalizability of these results (cf., Schretlen, 1988).

40
Bernard (1991), in a later article, further analyzed the performance of this
same sample of subjects on the Rey Auditory Learning Test. The inclusion of a
group of 18 CHI subjects with relatively severe injuries who were tested early in
their recovery improved the methodology of the study. The results indicated
that the malingering group scored significantly lower than the control group, but
scored significantly higher than the CHI group. Thus, the malingerers portrayed
deficits of insufficient magnitude to resemble patients with bona-fide memory
impairment secondary to severe CHI. Further inspection of the data revealed
that malingering subjects obtained low scores by suppressing their recall of
words from the primacy portion of the list.
Iverson, Franzen, & McCracken (1991) used a verbal list-learning
paradigm to investigate the performance of experimental malingerers, patients
with bona-fide memory impairment of mixed etiology, and normal controls
performing to the best of their ability. Two procedures, free recall of stimuli and
two-item, forced recognition, were employed. The mean free recall score for
the normals was significantly greater than those for malingerers and memory-
disordered patients; the latter two groups did not differ significantly. Main
effects of group on serial position for recall and recognition were nonsignificant.
In the forced-choice task both normals and memory-disordered patients
outperformed malingerers. Sixty percent of malingering subjects scored
significantly below chance levels, while the remaining 40% scored within the
confidence interval constructed around chance performance. No malingering

41
subject scored better than chance. Comparisons with other studies employing
this paradigm should not be made due to the restricted number of trials
employed here (21) as compared with the standard of 100.
Specific Clinical Techniques to Detect Malingerers
Symptom validity testing
Original paradigm. Theodor and Mandelcorn (1973) first reported the
use of a two-alternative, forced-choice paradigm for evaluating the validity of a
claim of disability or impairment. This procedure is quite simple in nature. The
subject is presented with one of two distinct stimuli and is then, after a brief
delay, asked to determine which of the two had been presented. This is
repeated until a sufficient number of trials have been administered, usually at
least 100 trials. The subject’s performance is then compared with what would
be considered chance performance. Nominal chance performance is 50%
correct. A performance significantly different than chance is interpreted as the
subject having a preserved ability to perceive and discriminate between the two
stimuli. If the subject’s performance is significantly below chance, then the
subject is suspected of feigning the deficit. For 100 trials, 41% accuracy is
associated with the cumulative binomial probability of 0.04. Alternatively, the
subject is making accurate discriminations if his performance is significantly
above chance. An essentially "normal" subject is expected to score at or near
100% correct. This procedure has been termed "Symptom Validity Testing"
(SVT) by Pankratz, Fausti, and Peed (1975). Symptom Validity Testing can be

42
altered by making the stimuli more complex and giving the subject the
impression that the task is very difficult (c.f., Lezak, 1983).
Theodor and Mandelcorn (1973) used this technique in a case involving
"hysterical blindness." Their patient did in fact demonstrate significantly below-
chance discrimination of a visual stimulus, suggesting that the patient was
processing the stimulus and then volitionally refusing to report it. Pankratz,
Fausti, and Peed (1975) successfully employed the SVT paradigm to
demonstrate that a patient claiming loss of hearing was in fact discriminating
the stimulus on some level. Pankratz (1983) and Binder and Pankratz (1987)
extended these findings, demonstrating the utility of Symptom Validity Testing
to the detection of feigned memory impairment. Binder has reported five
additional case studies in which a below-chance performance on forced-choice
testing was helpful in making the diagnosis of malingering (Binder, 1990b,
1992). Pankratz (1979) demonstrated that Symptom Validity Testing, when
presented to the patient with an expectation for change, allowed the patient to
spontaneously relinquish his symptoms while still maintaining his dignity and the
belief in the physical basis for the symptoms.
Modifications to original paradigm. Following Pankratz’s advice (1988),
clinicians have begun to modify and adapt forced-choice testing to meet their
individual clinical needs. Three methods have recently appeared in the
literature. Hiscock and Hiscock (1989) varied the objective task difficulty by
introducing varying retention intervals into the paradigm. Five digit numbers

43
were printed on index cards and presented to subjects to study for five
seconds. Response cards were printed with the target digit etring along with a
foil, also a five digit number. Response trials were grouped into three blocks of
24 trials. Presentation of the response card was delayed five seconds in the
first block of 24 trials, ten seconds in the second block, and 15 seconds in the
final block. No intervening distractor activity occurred between presentation of
the study and test cards. Prior to the first block of trials, the patient was told
that the task constituted a "memory test." Following the first and second
blocks, the patient was told that he had performed well and that, consequently,
the retention interval would be increased to make the task more difficult in the
next block of trials. This procedure created the illusion of difficulty for the
suspected malinger. In actuality, correct answers could be produced by simply
recalling the first of the five digits.
Three subjects were then tested with this procedure: a patient suspected
of malingering, a severely demented patient, and a normal five year-old girl.
The results indicated that although the suspected malingerer scored exactly at
the chance level for the first block of trials, his scores showed a progressive
decline across the second and third blocks. His overall accuracy rate of 29%
fell significantly below chance (z=-3.54, pc.0002). The normal child’s score of
82% was significantly above chance. Perhaps most important, the demented
patient obtained a score of 51 % accuracy, which was not significantly different
from chance. This finding correctly highlights the need to determine the

44
component cognitive processes involved in this task, as well as to validate the
procedure on various neuropsychological patient groups.
Binder’s Portland Digit Recognition Test (Binder, 1990b; Binder & Willis,
1991) is similar to that of Hiscock and Hiscock (1989) with two exceptions.
Binder incorporates retention intervals of five, 15, and 30 seconds into the three
blocks of 24 trials. In addition, the interval between study and test is
interpolated by having the subject count backwards. These authors reported
data from testing a series of 64 patients with well-documented brain dysfunction
of varying etiologies who were judged to be motivationally-intact. The mean
performance of these patients was approximately 75% correct; the worst
performance was 54% correct.
Bickart, Meyer, & Connell (1991) devised the Malingered Memory Deficit
Test, a 50-trial test of feigned short-term recognition memory. The basic task
requires subjects to view a sequence of consonants, consisting of a pair of
letters in random sequence (e.g., RTRRT). After a five second latency period,
the subject is shown a second stimulus identical to the first with the exception
of a missing element (e.g., RTR_T). The subject is required to supply the name
of the missing letter, selecting one of two presented alternatives. Four
alternatives were devised to assess the difficulty, by varying the number of
elements the subject was required to remember (either three or five letters) and
the effects of interpolated counting. Subjects were 114 male prison inmates
who were instructed to "take the tests as you think a person with severe

45
memory problems would" (p.11). Below-chance performance levels were
observed in only 18.8% of the subjects in the Difficult/Interpolation condition,
21 % of the subjects in the Difficult/No Interpolation, 21.5% of the subjects in the
Easy/Interpolation condition, and 19.2% of the subjects in the Easy/No
Interpolation condition. Above-chance performance levels were observed in
49.5% of the subjects in the Difficult/Interpolation condition, 49.5% of the
subjects in the Difficult/No Interpolation, 54.8% of the subjects in the
Easy/Interpolation condition, and 55.8% of the subjects in the Easy/No
Interpolation condition.
Summary of SVT research. In general, the two-item forced-choice testing
paradigm appears to be a highly useful tool to include in a forensic
neuropsychological assessment. This utility may be based on several
concepts. The malingerer probably does not realize his performance should be
no worse than chance. This may result from simple ignorance of the laws of
probability or the malingerer’s subjective feeling that producing incorrect
responses on only half the trials underestimates the seriousness of his problem.
Even if the malingerer does recognize the probabilistic nature of the task, it is
difficult to keep track of his responses and to maintain a consistent pattern of
choices. With enough trials, even small errors in judgement would render a
score improbable (Binder & Pankratz, 1987). However, malingering subjects
may be suspicious of transparently simple tasks, and may choose not to feign
impairment on those tasks (Bickart et al., 1991).

46
Rev’s techniques
Fifteen-item test. Lezak (1983) describes several of the French
neuropsychologist Andre Rey’s clinical techniques designed to assess
dissimulation. In the Memorization of 15 Items technique (Fifteen Items Test,
FIT), the patient is presented with a three by five item array of symbols, and he
is asked to memorize the "difficult1 stimuli. In actuality, only three or four
concepts are needed for accurate recall. According to Lezak, only the most
significantly impaired individuals recall less than three of the five character sets.
Several empirical studies of the FIT have been published recently.
Goldberg & Miller (1986) administered the FIT to psychiatric inpatients and
mentally deficient patients. Their results confirmed the criteria proposed by
Lezak (1983) and suggested that malingering should be considered among
individuals who deny remembering at least six of the 15 items. Bernard and
Fowler (1990) administered the FIT to brain-damaged patients and normal
controls. Their results generally supported the cutoff of nine correct items. A
comparison of the number of sets of items which were correctly recalled was
nonsignificant.
Morgan (1991) validated the FIT on a sample of 60 patients with bona-
fide mild to severe memory impairment. The cutoff of 9 correct items was again
confirmed. However, "failure" on the FIT resulted from bona-fide, severe
memory impairment in some subjects. Qualitative analysis of the protocols
failed to reveal consistent indicators of bona-fide memory impairment. Lee,

47
Loring, and Martin (1992) provided additional validation data for the FIT
administered to temporal-lobe epileptics and consecutive outpatient
neuropsychology clinic referrals. These authors suggested a more conservative
cutoff of seven correct items. In addition, litigating outpatient referrals scored
significantly lower than nonlitigating outpatient referrals.
Dot-counting task. A second task employs seven 3 by 5 inch index
cards upon which dots are placed in an organized (grouped) or random
(ungrouped) manner. The patient is instructed to count the dots as quickly as
he can, his reaction time for each card is noted, and these times are compared
with normative data from normal adults as well as head injury patients. The
patient’s performance for this task is evaluated in terms of the difference
between the reaction times for the grouped and ungrouped dots. Deviations
from the logical temporal pattern may lead the clinician to doubt the patient’s
motivation.
Recognition memory paradigm. Finally, a third task involves
administration of a 15-item word list. Recognition memory is tested
immediately. Later in the session, the subject’s level of recognition is compared
with the first trial of free recall on a list learning test (e.g., Rey Auditory Verbal
Learning Test). Given the well established fact that recognition generally
exceeds free recall, a deviation from this pattern suggests a nongenuine
response style.

48
Summary. All three of Rey’s tasks attempt to capitalize on the potential
malingerer’s lack of requisite knowledge about brain-behavior relationships and
on his inability to simulate behavior that is foreign to him while monitoring the
effectiveness of this behavior in the testing situation. Morgan (1991) cautions
against the use of any of these techniques in isolation.
Summary and Critique of Experimental Studies of Malingering
The performance of normal subjects instructed to malinger
neuropsychological dysfunction has been shown to vary widely from study to
study. On indices of quantitative performance, some studies have found
malingerers to appear significantly more impaired than the organic populations
they are portraying (Benton & Spreen, 1961; Hayward et al.t 1987; and Iverson
et al., 1991; Schacter, 1986; and Spreen & Benton, 1963) while other studies
have found malingerers to appear more impaired than normals but less
impaired than organic patients (Anderson et al., 1959; Bernard, 1991; Brandt et
al., 1985; and Wiggins & Brandt, 1988). Other studies have found malingerers
to exhibit similar levels of impairment as organic patients (Heaton, Smith,
Lehman & Vogt, 1978; and Mensch & Woods, 1983). Many studies have found
malingerers to perform qualitatively differently than either normals or organic
patients (Benton & Spreen, 1961; Boone, 1989; Goebel, 1983; Heaton, Smith,
Lehman & Vogt, 1978; Spreen & Benton, 1963; and Wiggins & Brandt, 1988).
At this point, a call must go out for a more standardized methodology. The
nature of instructional set, the amount of didactic information provided to

49
malingering subjects (Le, "coaching"), and the saliency of incentive to produce
believable deficits vary widely from study to study.
An informal meta-analysis was conducted on the studies involving
experimental malingering Table 1 presents this data. This sample of studies is
neither random or representative. Studies were included in the meta-analysis if
they presented means and standard deviations on the outcome measures. A
study had to have directly compared the performance of subjects instructed to
malinger dysfunction with either normals performing their best (control group)
or neuropsychological patients with bona-fide impairment (criterion group). In
general, studies were excluded if they failed to present means and standard
deviations.
The results of the meta-analysis corroborate the conclusions drawn from
the qualitative review of the literature. First, an average effect size of -3.5 is
attributed to 'treating" subjects with instructions to malinger. Following Smith &
Glass’ (1974) interpretative framework, this effect size means that a subject
scoring at the mean of the control group would fall to 3.5 standard deviations
below the mean of the control group when given instructions to malinger. This
is an exceptionally large effect size which may be the result of floor and ceiling
effects associated with some dependent measures. For example, Mensch &
Woods (1986) employed the LNNB scales as outcome measures which defined
normality very close to zero, resulting in both mean scores near zero and
artificially constricted variance. On the other hand, normal subjects often obtain

50
Table 1
Effect Sizes from Selected Experimental Studies of Malingering
Study
Malingerers
vs.
Normals
Bonafide
Impairment
vs.
Normals
Malingerers
vs.
Bonafide
Impairment
Pollaczek (1952)
-0.1
Heaton et al. (1978)
+0.1
Brandt et al. (1985)
-2.7
-1.7
Gudjonsson &
Shackleton (1986)
-0.8
Mensch &
Woods (1986)
-8.8
Hayward et al. (1987)
-1.5
Wiggins &
Brandt (1988)
-1.9
+0.3
Boone (1989)
-5.2
Bernard (1990)
-1.9
Bernard (1991)
-1.7
-3.2
+ 1.0
Iverson et al. (1991)
-5.2
-2.0
-1.9
Average Effect Sizes
-3.5
-1.7
-0.5

51
near perfect scores on other outcome measures, such as recognition
paradigms, resulting in very high mean scores and artificially constricted
variance. Nevertheless, the effect size computed is no doubt significant and
fulfills Cohen’s (1977) criteria for a "large" effect size.
Second, an effect size of -1.7 is attributed to bona-fide organic
impairment. That is, a subject scoring at the mean of the control group would
fall to approximately 1.7 standard deviations below the mean of the control
group if he were to sustain organic impairment. The true litmus test is applied
when malingerers are compared with the criterion group representing bona-fide
impairment or deficiency. An average effect size of -0.5 is associated with the
comparison between organic patients and malingering subjects, which prompts
the conclusion that malingerers are able to successfully suppress the
quantitative level of their performance to levels associated with organic
impairment.
Given that malingering subjects fall to 3.5 standard deviations below the
mean of normals and subjects with bona-fide impairment only fall to 1.7
standard deviations below the mean of normals, it would seem at first glance
that malingering subjects should score approximately 1.8 standard deviations
below organic patients instead of the observed effect size of -0.5. Upon further
inspection, however, it becomes clear that these values cannot be validly
compared because the referent comparison group (i.e., the group whose
standard deviation represents the denominator of the effect size equation) is

52
not the same. The magnitude of the effect size created by the lower means of
malingering subjects is greatly attenuated by the inherent variability of the bona-
fide impairment group. While not mathematically correct, it appears plausible
that malingering groups score significantly lower than organic groups in terms
of normal control group standard deviations, a situation analogous to the
clinical situation of comparing a subject’s performance to normal subjects,
rather than organically-impaired patients.
Analysis of the qualitative nature of malingerers performance bears out
Rubinsky and Brandt’s (1986) hypothesis that the malingerer is more likely to
alter his performance by withholding behavior (i.e., producing a behavioral
deficit) such as not recalling a word, rather than producing additional behaviors
(i.e, producing a positive symptom) such as perseveratively recalling a word. A
likely explanation for this tendency rests on the malingerer’s ignorance of brain-
behavior relationships or on the general idea that "less" is "worse" when it
comes to expressions of cognitive ability. Given this ignorance, it may be that
"comission" of behavior is too risky a strategy.
Multivariate discriminant function analyses have been used to attempt to
discriminate malingerers from normals from organic patients with some
measure of success. However, these classification equations have yet to be
cross-validated in independent, clinical samples, and are of uncertain value in
the individual case. Highly variable sensitivity and specificity rates have been
produced by clinicians evaluating and sorting test protocols of these three

53
groups. This approach has limited generalizability to the clinical setting due to
the scarcity of qualitative (e.g., verbatim test protocols and interview transcripts)
and observational data that has typically been provided to the clinical judges.
Several indices have emerged which appear promising. Symptom
Validity Testing has been shown to be robust in clinical case studies of relatively
blatant and unsophisticated malingering. Between-groups designs have begun
to validate SVT and Rey’s FIT with other neuropsychological patient groups as
well as fine-tune the basic paradigms along task difficulty and retention interval
dimensions. Two studies (Williamsen, Johnson & Eriksen, 1965; and Wiggins &
Brandt, 1988) have provided initial evidence that malingering subjects may tend
to suppress their responses to supraliminal implicit memory indices (word stem
completion and word association). This suppression of priming appears to
intensify after the malingering subject "catches on" to the memorial nature of the
tasks.
Implicit Memory
Modern experimental research involving implicit memory phenomena
includes different areas of concentration (Schacter, 1987). Implicit memory can
be demonstrated with paradigms involving savings during relearning (c.f.,
Slamecka, 1985), the effects of subliminally encoded stimuli (c.f., Cheesman &
Merikle, 1986), and learning and conditioning without awareness (c.f.,
Greenspoon, 1955). However, these three areas of research are outside the
focus of this paper and will not be reviewed. The present paper will concern

54
itself with the phenomena of repetition priming (c.f., Cofer, 1967), which refers
to the facilitative effects of a learning episode on performance of a subsequent
task, such as word stem completion or tachistoscope identification (Graf &
Schacter, 1985).
Definitions
Richardson-Klavehn and Bjork (1988) contrast implicit and explicit forms
of memory with direct and indirect measures of memory. Forms of memory are
definitionally hypothetical and require an assumption to be made concerning
the subject’s mental content or mental state at the time of testing. Explicit
memory is commonly assumed to involve the deliberate, directed retrieval of
information about specific episodes. Explicit memory is demonstrated when
performance on a task requires conscious recollection of a previous
experience. Implicit memory does not depend on directed, conscious
demonstrations of memory when performance on a memory task is facilitated
or somehow altered in the absence of conscious recollection (Graf & Schacter,
1985).
Measures of memory can be categorized with respect to task
instructions and measurement criteria (Johnson & Hasher, 1987). This
nomenclature avoids excessive assumptions concerning mental states and
processes involved in performing tasks. Explicit memory is commonly tested
by direct measures of memory such as free recall, cued recall, and recognition.
Implicit memory is tested with indirect memory tasks in which the measures of

55
interest reflect a change (typically a facilitation) in task performance observed
by comparing performance with relevant prior experience to performance
without such experience (a control condition). The term indirect is particularly
suitable because the relevant tasks do not direct the subject to a target event
(Richardson-Klavehn & Bjork, 1988).
Theories of Implicit Memory
Two main classes of theories of implicit memory currently occupy the
attention of researchers: multiple memory systems models and processing
models (Roediger, 1990). Experimental manipulations have been shown to
differentially affect direct and indirect memory tests with both normal subjects
and amnesic patients (Shimamura, 1986; Schacter, 1987). Therefore, the task
of any theoretical model is to account for the numerous dissociations between
these forms and measures of memory (Richardson-Klavehn & Bjork, 1988).
Researchers postulating distinct and separate memory systems derive
support from experimental studies of amnesic patients. The central concept is
that certain forms of brain damage selectively affect the memory system for
conscious recollection but leave the system responsible for other forms of
learning relatively intact. Squire and Cohen (Cohen, 1984; Cohen & Squire,
1980; Squire, 1987) have advanced a taxonomy consisting of functionally
separate memory stores for declarative and nondeclarative (formerly
"procedural") memory. Declarative memory (i.e., "knowing that") is available to
consciousness and can be accessed by processes congruent with the

56
contextual and temporal information it contains. Nondeclarative memory (i.e.,
"knowing how") is not directly available to consciousness and is only capable of
being accessed by engaging in processes in which it is embedded. Thus,
amnesia is conceptualized as a preservation of procedural memory as indexed
by indirect memory tasks and a failure of declarative memory as indexed by
direct memory tasks. Much of the experimental evidence for dissociations
between direct and indirect tests can be interpreted within this framework
because the memory systems are though to be largely separate (Roediger,
1990).
Other researchers, primarily cognitive psychologists working with normal
subjects, have proposed various processing models to account for the data.
Processing models de-emphasize the possibilities of different memory stores
and the dissociation of encoding, storage, and retrieval. Instead, Jacoby
(Jacoby, 1983a, 1983b, 1984) as well as Roediger and his colleagues (Roediger
& Blaxton, 1987b; Roediger, Weldon, & Challis, 1989) postulate that implicit and
explicit memory differ in terms of the relationships between processes operating
at both encoding and retrieval. Jacoby (1983b) delineates two dissociable
processes operating on a single, episodic memory store. Processing of
semantic information requires the initiation of conceptually-driven processes by
the subject. Such processes include elaboration, organization, and rehearsal.
Certain tasks that emphasize perceptual or orthographic information invoke
data-driven processing. These researchers feel that implicit memory as

57
measured by indirect tests is primarily indexing data-driven processes and
explicit memory as measured by direct tests is primarily indexing conceptually-
driven processes. It should be emphasized that these concepts represent two
end-points on a single continuum rather than discrete categories.
Roediger (1988) spells out the assumptions which follow from the
processing model. First, performance on memory tests should be facilitated to
the extent that the cognitive operations at test recapitulate those engaged
during the study episode. Second, direct and indirect tests typically, but not
always, require different retrieval operations and consequently benefit from
different types of processing during learning. Most direct memory tests draw
on the encoded meaning of concepts or on semantic or elaborative processing.
Conversely, most indirect tests rely heavily on the match between perceptual
operations between study and test.
The Relationship between Explicit and Implicit Memory
The central concept that this study will attempt to use to "catch"
malingering subjects is the idea that intentional, explicit retrieval (or suppression
of retrieval) can affect performance during nominally indirect memory tests. In
order to fully understand the circumstances under which this can occur, a
discussion concerning the relationship between implicit and explicit forms of
memory is necessary. Three areas of research speak to this issue. First, some
studies have demonstrated stochastic independence between implicit and
explicit memory tasks and have used this data to argue that under some

58
circumstances intentional retrieval does not contribute to repetition priming
(Tulving, Schacter, & Stark, 1982). Second, studies testing implicit memory
after degraded encoding demonstrate that implicit memory can occur in the
absence of explicit memory (Eich, 1984). Third, as levels of processing
manipulations have been shown to robustly affect direct memory tests, LOP
manipulations may increase the likelihood that explicit retrieval may intrude
during indirect memory tests (Schacter, 1987). This review will lay the
groundwork for a careful review of the work of Bowers and Schacter (1990)
which directly investigated implicit memory, LOP, and test awareness.
Stochastic independence
The concept of stochastic (statistical) independence between direct and
indirect memory tests has been taken as evidence for a dissociation between
implicit and explicit forms of memory (Tulving, Schacter, & Stark, 1982).
Stochastic independence is the name given to the relation between two events
in which the probability of their joint occurrence is equal to the product of the
probabilities of the occurrence of each event alone (Tulving, 1985). In a typical
experiment, a subject completes an indirect test of memory, such as word stem
completion. He then completes a yes/no recognition memory test for the study
words. Two scores are then computed. The simple probability of word stem
completion refers to the proportion of study words which were correctly
completed in their target direction. The simple probability of recognition
memory refers to the proportion of target words which were correctly

59
recognized on a direct recognition test, irrespective of word stem completion
status. The conditionalized probability of recognition memory refers to the
proportion of correctly generated target words that were later correctly
recognized on a direct recognition test.
Therefore, stochastic independence exists when the conditionalized
probability of correct recognition does not exceed the product of the two simple
probabilities. Unlike functional independence, stochastic independence is not
based on comparing the average performance on two tests, but rather on
determining whether performance on a particular item on one test predicts
performance on that same item on another test. If no predictive relationship is
found, then the tests are assumed to be independent (Witherspoon &
Moscovich, 1989).
In the present context, the concept of stochastic independence becomes
relevant because it allows the researcher to examine the relative contribution of
explicit memory processes on indirect memory tests. In general, a number of
studies have firmly demonstrated stochastic independence between direct and
indirect memory tests (Richardson-Klavehn & Bjork, 1988). Jacoby and
Witherspoon (1982) biased the homophone spelling for amnesic patients and
normal control subjects. The spelling of homophones required in the second
phase of the experiment provided an indirect measure of the effect of the prior
presentation of the homophone on its later interpretation. Both groups of
subjects demonstrated intact implicit memory for the biased spelling. Yes/no

60
explicit recognition for the biased spellings was intact for normals and severely
impaired for the amnesic patients. More importantly, the conditionalized
probability of recognition did not differ significantly from the simple probability
of correct recognition for either group. This procedure was repeated using
perceptual identification as the indirect memory test. The results were
equivalent; the two tasks were found to be stochastically independent across
12 conditions that differed in overall rate of identification.
Tulving et al. (1982) found that probability of recognition conditionalized
on successful word fragment completion was equivalent to the overall
proportion of words recognized for four conditions that differed in overall
recognition probability. Tulving (1985) reported the extensive results of
Chandler’s (1983) work which manipulated the relationship between fragment
completion and direct memory tests in 32 separate conditions. Without
exception, stochastic independence was found in that recognition
conditionalized on correct fragment completion was essentially equivalent to
simple recognition.
Several studies, however, have found stochastic dependence between
performance on an indirect and a direct memory test. Jacoby and Witherspoon
(1982) presented a long list of pronounceable pseudowords for study. A test of
recognition memory for the studied pseudowords was presented in the second
phase of the experiment. A perceptual identification test, given in the final
phase of the experiment, included "new" pseudowords as well as words that

61
had been studied and presented in the test of recognition memory. In line with
previous results, the prior presentation of a pseudoword was found to be
sufficient to enhance its subsequent perceptual identification. Recognition
memory for the pseudowords was also found to be accurate. In contrast to
results obtained for words, however, performance on the two types of test were
dependent on one another. Pseudowords that were later perceptually identified
were more likely to be recognized as having been presented during study (.80)
than were pseudowords that were not later perceptually identified (.70). In
addition, G. Hayman (unpublished observations cited in Schacter, 1985b) found
stochastic dependence in an experiment in which subjects were instructed to
use word fragments to help retrieve study-list words. Several authors have
argued that this data can be explained by assuming that subjects used explicit
memory in both the direct and indirect tests (Richardson-Klavehn & Bjork, 1988;
Schacter, 1985b).
Criticism has been aimed at this procedure on practical as well as
theoretical grounds. Shimamura (1985) argued that stochastic independence
may be an artifact produced by the influence of the first test on the second test.
Performance on the stem completion task represents an additional study trial
for items successfully completed. Therefore, it appears to be a plausible
assumption that the exposures and subject reactions that comprise
performance on the indirect test do not leave the memory system unaltered and
ready to give an uncontaminated picture of the influence of the study episode

62
on a second test (Richardson-Klavehn & Bjork, 1988; Tulving et al.t 1982).
Given these two lines of evidence, the methodology offered by stochastic
independence may be one way to evaluate implicit-explicit relationships in the
context of manipulations of motivation and retrieval intentionally.
Restricted or degraded encoding
Studies involving restricted or degraded encoding of stimuli are indirectly
relevant to the present issues of motivation and retrieval intentionality because
they offer the opportunity to observe normal performance on indirect memory
tests with accompanying low levels of performance on direct memory tests
(Bowers & Schacter, 1990). Eich (1984) used a speech-shadowing paradigm
to present target words (homophones) for unattended study. Spelling was
used as an indirect memory test and yes/no recognition served as the direct
memory test. Priming was observed under these degraded study conditions,
even though explicit memory for the words was extremely low. Eich interpreted
his findings as a dissociation between deliberate or intentional remembering
and remembering without awareness. Kunst-Wilson & Zajonc (1980)
tachistoscopically presented irregular geometric shapes to normal subjects for
one millisecond exposure durations. The test phase consisted of an affective
discrimination rating followed by a two-item forced choice recognition memory
judgement. Priming was observed in these subjects despite chance-levels of
recognition memory for the shapes.

63
The study by Jacoby, Woloshyn, and Kelley (1989) warrants a more
detailed review. In Experiment 1, famous and nonfamous names were
presented to be read aloud under conditions of divided or full attention. Gains
in familiarity of names were tracked by changes in performance on a later fame-
judgement task. Explicit memory for the previous presentation of the names
was tested with a standard recognition memory test. Gains in familiarity were
demonstrated even when studied with divided attention, while explicit
recognition memory was lower after divided attention than full attention.
Additional experiments were conducted to preclude the possibility that
the familiarity measure actually reflected some instances of conscious
recollection. Gains in familiarity were placed in opposition to conscious
recollection to further separate the two processes. All names presented in the
study phase were nonfamous and the subjects were told so. Subsequent
conscious recollection of a name during the fame-judgment task would allow
subjects to be certain that the name was nonfamous. Familiarity without
conscious recollection would result in the opposite, calling a name "famous".
Attention was divided again at study and later during the fame-judgement task.
The accurate recognition of old nonfamous names in the full-attention condition
allowed those names to be called "famous" less often. In contrast, dividing
attention radically reduced list recognition. The failure to recognize old
nonfamous names in combination with a gain in their familiarity was revealed by
the finding that old nonfamous names were more likely to be called "famous"

64
than were new nonfamous names in the divided-attention condition. Thus,
Jacoby and his colleagues were successful in demonstrating that unconscious
memory can operate independently from conscious memory.
The foregoing studies demonstrate that implicit memory for target stimuli
can be demonstrated on indirect memory tests in the relative absence of
conscious, explicit memory for the same stimuli. This evidence, however, is
only of indirect interest because most studies of implicit memory have involved
testing normal subjects under unrestricted encoding conditions, making it
possible that normals are typically aware of the study episode during the
performance of an indirect memory test (Bowers & Schacter, 1990).
Additionally, elaborative encoding manipulations would be expected to increase
the strength of the memory trace, thereby increasing the likelihood that a
subject would experience either awareness of remembering or intentional
explicit retrieval (Bowers & Schacter, 1990; Richardson-Klavehn & Bjork, 1988;
Schacter, 1987; Squire, Shimamura, & Graf, 1987).
Level and elaboration of encoding
The levels of processing (LOP) framework was conceived as a model of
memory which focuses on the processes involved in learning and remembering.
It differed from its predecessors in the information-processing tradition which
focused on the structural aspects of the cognitive system (i.e., the successive
stages through which information flows). The LOP framework proposed to
study more directly those processes involved in remembering (e.g., attention,

65
encoding, rehearsal, and retrieval) and to formulate a description of the memory
system in terms of these constituent operations (Craik & Lockhart, 1972; Craik
& Tulving, 1975).
A typical LOP manipulation involves incidental learning in a semantic or
conceptual study condition (e.g., rating the pleasantness; deciding whether a
word fits in a sentence) versus a physical or orthographic study condition (e.g.,
searching for particular letters in the word) (Craik & Lockhart, 1972; Craik &
Tulving, 1975). The relationship between LOP and performance on direct,
explicit measures of retrieval has been shown to be quite robust in normal
subjects: "deeper" semantic processing produces greater explicit retrieval than
does more "shallow" processing (Craik & Tulving, 1975; Bradshaw & Anderson,
1982), which is thought to be due to cognitive elaboration taking place during
the encoding process.
Prior to the popularity of the processing model, most researchers agreed
that LOP had a null effect on indirect memory tests (Graf & Mandler, 1984; Graf,
Mandler, & Haden, 1982; Graf, Squire, & Mandler, 1984; Jacoby & Dallas, 1981;
Richardson-Klavehn & Bjork, 1988). However, the processing model has
allowed for the categorization of indirect memory tests into primarily conceptual
tests versus primarily perceptual tests. Indirect perceptual tests include word
fragment completion, word stem completion, and tachistoscopic perceptual
identification. Research has established that LOP affects priming in indirect
conceptual tests (Hamann, 1990; Srinivas & Roediger, 1990).

66
Challis and Broadbeck (1992) provide an excellent and authoritative
review of research Into LOP effects in indirect perceptual tests. Their literature
review uncovered a total of 11 published studies which manipulated LOP and
measured performance on the indirect perceptual memory tests of perceptual
identification (Jacoby & Dallas, 1981; Hashtroudi, Ferguson, Rappold, &
Chrosniak, 1988; Light & Singh, 1987), word stem completion (Graf, Mandler, &
Haden, 1982; Graf & Mandler, 1984; Graf, Squire, & Mandler, 1984; Squire,
Shimamura, & Graf, 1987; Light & Singh, 1987; Chiarello & Hoyer, 1988;
Bowers & Schacter, 1990; and Mandler, Hamson, & Dorfman, 1990), and word
fragment completion (Squire et al., 1987; Srinivas & Roediger, 1990).
In 33 of 35 separate experiments conducted in these studies, priming
was numerically greater in the semantic condition than in the physical condition.
While often not statistically significant, the effect sizes of LOP were
characterized as small-to-medium magnitude. Challis and Broadbeck (1992)
provide illuminating evidence which helps explain these contradictory findings.
They found that semantically processed words showed a consistent advantage
over orthographically processed words when tested with a word fragment
completion paradigm. However, when semantic and physical conditions were
presented within-subjects in a mixed list, the LOP effect was negligible and
nonsignificant. The authors interpret this finding as evidence for the
independent contribution of the physical analysis component of the LOP
manipulation.

67
Issues Related to Awareness and Retrieval Intentionalitv
The initial section discussing the precise definitions of memory forms and
measures highlights a concept which will become central to this study; namely,
the issue of explicit memory occurring during indirect tests of memory
(Richardson-Klavehn & Bjork, 1988). The concept of conscious recollection is
central to the definition of explicit memory. However, Schacter and his
colleagues (Schacter, Bowers, & Booker, 1989) argue that "conscious
recollection" is an ambiguous term. Conscious recollection can refer to the
intentional initiation of retrieval of recently studied information in which the
subject deliberately thinks back to a learning episode and searches for target
information. On the other hand, conscious recollection can simply refer to
awareness of remembering brought on as a consequence of the retrieval
process.
Schacter (Schacter, Bowers, & Booker, 1989) discusses five scenarios
which illustrate the possible contribution of explicit forms of memory during
indirect tests and discusses the methodological difficulty in fractionating forms
of memory in experimental studies. Those scenarios which are most relevant to
the purposes of this paper are discussed below. In the first case, subjects
study words under elaborative study conditions. As instructed, subjects
complete each test stem with the first word that comes to mind, and produce a
large number of study list items. They do not spontaneously become aware
while performing the completion task that any of the items represent a study list

68
target. But when given a yes/no recognition test that requires them to think
back to the study episode, subjects perform quite well, and consciously
remember having studied almost all of the words that were produced as
completions. This scenario represents normal implicit memory performance in
that absence of the spontaneous experience of test awareness, even though
the subjects later demonstrate strong explicit memory for the study episode.
The second represents an example of what Schacter (1987) referred to
as involuntary explicit memory. Subjects could encode target items under
elaborative study conditions, later complete each stem with the first words that
comes to mind, and produce a large number of study list items. For some
stems, all that comes to mind during completion performance is the target word
itself, but for others subjects are reminded by the stem of something that
occurred during the study episode. Nevertheless, the subject continues to
write down the first word that comes to mind. Thus, a cue involuntarily triggers
a recollection of a past event; the awareness of remembering is merely a
consequence of the implicit retrieval process.
The third scenario is more clearly a case of voluntary explicit memory. It
is identical to the preceding case, except that once subjects notice that one or
two of the stems can be completed with the study list items, they surmise that
the experimenter is surreptitiously trying to test their memory, and may decide
that they can improve their performance by thinking back to the study list and
trying to complete each stem with a target item. They have no problem

69
recollecting most of the words that were presented during the study episode.
Thus, the subject "catches on" to the nature of the test and intentionally
recollects the prior episode. The subject is essentially engaging in cued recall.
The relevance of LOP effects also becomes clear at this point. Levels of
processing effects on indirect memory tests should be apparent to the extent
that explicit memory was operating at retrieval. Bowers and Schacter (1990)
provide the only direct evidence concerning these issues. These researchers
conducted a series of experiments using normal control subjects to determine
whether normal priming effects could be observed in subjects who do not
experience test awareness during the performance of an indirect memory test,
in this case word stem completion. Whereas on-line probes could have been
employed, a post-test questionnaire technique was the most direct measure of
awareness which avoided inducing awareness. In Experiment 1, study
instructions (incidental versus intentional) and test instructions (normal implicit
memory instructions versus hints that stems could be completed with target
words) were treated as between-subjects factors. Encoding process (semantic
versus physical processing) was examined within-subjects in that half of the
words were encoded under each encoding condition.
Twenty (50%) of the 40 subjects were categorized as test-aware based
on the post-experimental questionnaire. The results indicated that study
conditions did not induce test awareness in that 11 of the test-aware subjects
were in the study-informed group, and the remaining nine aware subjects were

70
from the study-uninformed condition. The critical finding was that both aware
and unaware subjects showed normal and equivalent priming effects on word
stem completion. Thus, normal priming was observed in the absence of test
awareness. However, the finding that test-aware subjects completed a
statistically significantly higher proportion of semantically encoded words and a
relatively low proportion of structurally encoded words suggests that explicit
memory did impact WSC performance. No LOP effect was noted for test
unaware subjects. Additional evidence of the relationship between test
awareness and explicit retrieval was found on subsequent experiments which
found that only test-aware subjects demonstrated normal implicit memory for
new associations, an indirect test which may be more susceptible to explicit
mediation than other indirect tests.
Conclusions
Several lines of evidence have been reviewed which suggest that implicit
and explicit memory are functionally independent under certain situations.
Implicit memory has been observed when explicit memory was at chance levels
due to restricted or degraded encoding conditions (Eich, 1984; Jacoby,
Woloshyn, & Kelley, 1989; Kunst-Wilson & Zajonc, 1980). Stochastic
independence between performance on direct and indirect memory tests has
been observed in several studies (Chandler, 1983; Jacoby & Witherspoon,
1982; Tulving et al., 1982).

71
However, other studies using designs which leave open the possibility of
explicit memory contamination have found stochastic dependence (G. Hayman,
unpublished observations cited in Schacter, 1985b; Jacoby & Witherspoon,
1982). Moreover, many theorists consider the issue of explicit memory
occurring during performance on a nominally implicit task in need of further
research (Richarson-Klavehn & Bjork, 1988; Schacter, 1987; Squire,
Shimamura, & Graf, 1987). Bowers and Schacter have presented preliminary
data which suggests that normal priming can be observed on word stem
completion without the use of explicit retrieval.
The preceding concepts and data concerning awareness and
intentionally of retrieval all naturally assume that a subject is honest, is
motivated to put forth good effort, and is obeying task instructions by
performing in a straightforward manner. The use of an experimental
manipulation which varied the motivation of a subject would be expected to
influence performance on indirect memory tests to the extent that these tests
were vulnerable to intrusion by explicit retrieval processes. Therefore, the use
of indirect memory tests is important to the present investigation because it
speaks equally to several important clinical and theoretical issues. In the clinical
context, indirect memory tests offer the malingering subjects multiple ways to
"fail" or produce a level or pattern of performance different from that seen in
honest subjects or patients with bona-fide memory impairment. Since the
Symptom Validity Testing paradigm has proven quite beneficial to the clinician

72
due to the indirect nature of its task demands, the indirect memory tests
employed by cognitive psychologists may prove useful in the same regard. In
a more theoretical sense, the effects of different motivational response sets will
extend the domain of knowledge concerning indirect memory tests.
Specifically, this manipulation would allow for subjects to spontaneously
experience test awareness and/or employ explicit retrieval strategies to either
facilitate or suppress their indirect memory performance. The present study
could potentially extend the literature by providing a situation in which
malingering subjects would be motivated to use explicit memory to lower, rather
than raise, their performance on indirect memory tests.
Hypotheses and Predictions
Performance on Clinical Memory Tests
The clinical memory tests will serve two simultaneous functions. First,
performance on these tests provides an easily interpretable benchmark upon
which to later understand performance on laboratory-based experimental
memory tests. Performance profiles can be readily compared with the extant
literature to check the validity of the malingering subjects’ participation.
Second, the performance on clinical memory tests is useful in its own right in
that (a) the present battery of tests employed in this study is distinct from
others reported in the literature, and (b) it affords a unique opportunity to
evaluate qualitative aspects of memory behavior which may provide the clinician
with useful interpretive information.

73
The following specific predictions are made concerning performance on
clinical memory tests.
1. Malingering subjects will lower their overall level of performance relative
to honest subjects. This simulated impairment will be roughly equivalent
to the bona-fide memory impairment produced by closed head injury
patients.
2. Malingering subjects will lower their overall level of memory performance
to the extent that they adopt response strategies which emphasize the
omission of behavior, meaning that these subjects will be unlikely to
commit acts of incorrect behavior (i.e., perseverations, distortions, etc.).
3. While succeeding in lowering their quantitative memory performance to
levels seen in CHI patients, it is predicted that Malingering subjects will
be unable to also mimic the qualitative aspects of bona-fide memory
impairment.
4. Analysis of temporal, material, and process-oriented distinctions of
memory functioning will demonstrate Malingering subjects to be
unsuccessful at accurately portraying memory impairment as it occurs in
the CHI patients.
Performance on Indirect Memory Tests
The overriding hypothesis to be evaluated in the present study is that
explicit memory does affect performance on indirect memory tests. The
likelihood of observing the conflation of explicit and implicit memory on indirect
memory tests would appear highest when the words were encoded under
elaborative study conditions.
1. Given that explicit memory may affect performance on word stem
completion, it is predicted that Malingering subjects will produce
abnormally low performance due to postretrieval suppression.
2. Analysis of recognition memory following WSC and analysis of changes
in accuracy rate as these subjects proceed through the task will further
demonstrate the susceptibility of WSC to postretrieval suppression.

74
3. De-briefing information concerning test awareness and retrieval
intentionality will demonstrate lowered WSC performance in subjects who
reported postretrieval suppression.
4. Genuine subjects and Head Injury patients will produce null LOP effects
on WSC. Malingering subjects will demonstrate discrepant LOP effects
on WSC relative to the comparison groups due to the impact of
postretrieval suppression.
5. Malingering subjects will produce normal accuracy rates on a perceptual
identification task. However, the extent to which these subjects
experience explicit memory for the stimuli and "think about if' before
responding will be manifest as increased response latencies.
6. Analysis of recognition memory following PI and analysis of changes in
accuracy rate as these subjects proceed through the task will further
demonstrate the immunity of PI to postretrieval suppression.
7. De-briefing information concerning test awareness and retrieval
intentionality will demonstrate equivalent PI performance in subjects who
reported explicitly-mediated suppression.
8. Genuine subjects and Head Injury patients will produce null LOP effects
on PI. Malingering subjects will demonstrate similar null LOP effects on
PI relative to the comparison groups due to the absence of postretrieval
suppression.
Performance on Symptom Validity Testing
As regards Symptom Validity Testing, the main hypothesis to be
evaluated is that robust group differences will be observed between the
malingering subjects and their comparison groups, in line with the results
reported in the literature. The specific predictions are as follows:
1. Malingering subjects will demonstrate significantly lower accuracy rates
and significantly higher response latencies than subjects with bona-fide
memory impairment.
2. Malingering subjects, taken as a group, will demonstrate a level of
performance significantly below that associated with chance
performance.

75
3. Malingering subjects will demonstrate inconsistent responding which can
be demonstrated with alternative data analysis techniques.

CHAPTER 2
METHOD
The present study consists of two generally separate experiments.
Experiment 1 was conducted using Amnesic patients and matched control
subjects. The main purpose of this experiment was to validate the experimental
memory stimuli and procedures (word stem completion, perceptual
identification, free recall, and multiple choice recognition). In so doing, the
quantitative (i.e., strength of priming) and qualitative (i.e., levels of processing
effects, dissociations between indirect and direct tests) characteristics of these
tasks could be established to provide a well-recognized benchmark upon which
to compare the results of Experiment 2. Experiment 2 was conducted using
normal college students given two different roles to play (Genuine and
Malingering performance), while Head Injured patients were used as the
criterion group with bonafide organic memory impairment. By excluding
Amnesic patients and their matched controls from the main analyses of
Experiment 2, the design was more analogous to that seen in the medicolegal
context. Given that malingering is more closely associated with traumatic brain
injury (Binder, 1986) than circumscribed organic amnesia, the most important
76

77
comparison in this context is that between the suspected malingering patient
and the Head Injured patient.
Analysis of Statistical Power
Statistical power refers to the probability of obtaining a significant result
(i.e., of rejecting the null hypothesis). A heuristic equation exists which can be
computed for a given research design which consists of statistical power,
critical effect size, and sample size. By knowing any two of three values, the
third value may be determined (Kraemer & Thiemann, 1987).
A power analysis was conducted following the suggestions and
dimensions suggested by Kraemer and Thiemann (1987). Effect size estimates
were computed from selected experimental studies on malingering and
presented in the context of an informal meta-analysis presented in Chapter 1.
Several a priori decisions were then necessary. An effect size of (2.0) was
taken as a conservative estimate of the effect size associated with the body of
literature. The proportion of 0.6/0.4 was taken as representative of the relative
number of subjects which could be recruited into the experimental groups and
the patient group, respectively. Using Table 4.3 from Kraemer & Thiemann
(1987, p. 45) a "critical effect size" was extrapolated to be (0.84). The number
of subjects in the malingering and normal healthy control groups was
determined from a master table. Therefore, it was determined that 15 to 20
subjects were needed in the each of the Genuine, Malingering, and Head

78
Injured groups to be 80 percent certain of rejecting the null hypotheses using a
one percent, two tailed significance level.
Subjects
Subjects were categorized into five experimental groups. Amnesic
patients and age and education matched control subjects participated in
Experiment 1. Two types of subjects comprised the three subject groups of
Experiment 2. Introductory Psychology students at the University of Florida
were randomly assigned to either the Genuine or Malingering groups. Non¬
litigating Head Injured patients were recruited from several outpatient clinics and
an inpatient rehabilitation program located in North Central Florida to serve as
the criterion group of bonafide memory impairment.
Amnesic patients were recruited from the standing population of such
patients at the Memory Disorders Research Center at the Veterans Affairs
Medical Center in Boston, Massachusetts. Data were collected from these
patients at the Neuropsychology Laboratory at this hospital. A total of nine
Amnesic patients were tested: four with alcoholic Korsakoff’s syndrome, three
with amnesia due to an episode of anoxia or cerebrovascular accident, one
who had a left temporal lobectomy to treat intractable epilepsy, and one who
had suffered from encephalitis. The patients with Korsakoff’s syndrome
consisted of four men (mean age=65.5 years; mean education=11.5 years).
The patients with amnesia from other causes consisted of four men and one
woman (mean age=46 years; mean educations6.4 years). The mean WAIS-R

79
Full Scale IQ for these patients was 103 (mean Verbal IQ=100; mean
Performance IQ=101). The mean Wechsler Memory Scale-Revised Memory
Quotient for these patients was 81 (mean Verbal MQ=70; mean Delayed
MQ=57). These subjects averaged 27.5 words recalled on trials 1 to 5 of the
California Verbal Learning Test. Neuropsychological evaluation and
independent neurological examination indicated that memory impairment was
the only remarkable deficit of higher cortical function. These patients have been
studied as a group for several years, and their memory impairment has been
documented in detail elsewhere (Cermak, Talbot, Chandler, & Wolbarst, 1986).
Control subjects for the Amnesic patients were recruited from various
locations throughout the Health Science Center in Gainesville, Florida and were
paid twenty dollars for their participation. Subjects serving as control subjects
for the alcoholic Korsakoff’s patients were recruited from the inpatient
Substance Abuse Treatment Program at the Gainesville Veterans Affairs Medical
Center. These subjects consisted of four men who were matched to the
alcoholic Korsakoff patients on the basis of age and education (mean age=69
years; mean educations 1 years). All four of these subjects had lengthy
histories of alcoholism, but had abstained from alcohol for at least three weeks
prior to testing (average abstinence = 8.3 weeks). Subjects serving as control
subjects for the patients with other forms of amnesic were recruited from
various locations throughout the Gainesville Veterans Affairs Medical Center.
These subjects consisted of five men who were matched to this subgroup of

80
amnesia patients on the basis of age and education (mean age=46 years;
mean education=14.8 years). Analysis of variance procedures failed to reveal
any significant differences between the subgroups of amnesic patients and the
corresponding subgroup of control subjects or between the pooled amnesic
and control groups (all F’s less than 1). The mean WAIS-R Full Scale IQ
estimate for these control subjects was 105. The mean Wechsler Memory
Scale Memory Quotient for these subjects was 114.
Forty introductory Psychology students from the University of Florida
were randomly assigned to one of two conditions: subjects in the Malingering
group (n=20) were asked to portray "the most severe but believable memory
problems" they could on memory tests. Subjects in the Genuine group (n=20)
were asked to perform to their maximum capabilities on memory tests.
Head Injured subjects (n=15; nine men and six women) were recruited
from several types of populations. The primary criteria for inclusion in this
group was the absence of any current or future legal actions on the part of the
patient concerning disability or compensation. No Head Injured patient
participated in this study under such legal context. Most of these subjects were
seeking assistance with academic and vocational rehabilitation. Therefore, no
HI patient had readily identifiable incentives to perform poorly and all patients
had readily identifiable incentives to perform to their genuine capabilities. Of
the outpatient clinic referrals (n=7), two agreed to participate in the study after
undergoing a neuropsychological evaluation at the Psychology Clinic at the

81
University of Florida Health Science Center. The remaining five outpatient Head
Injury referrals agreed to participate in the study after undergoing a
neuropsychological evaluation at the Mental Hygiene Clinic at the Veterans
Affairs Medical Center in Gainesville, Florida. Outpatient CHI patients were paid
twenty dollars for their participation. Eight additional Head Injured patients were
recruited from the Sandybrook Center of Rebound, Inc., which is located in Mt.
Dora, Florida.
Duration of post-traumatic amnesia (PTA) and coma are frequently used
indicators of injury severity in the CHI population (c.f., Levin, Benton, &
Grossman, 1982). Coma was judged to end when the patient was able to
follow verbal commands. Post-traumatic amnesia was judged to end when the
patient regained full temporal and personal orientation. In a few cases, this
information was unavailable from medical records. In these instances, length of
coma and/or PTA was estimated by interview with the patient. Eleven of the 15
patients experienced coma. The median length of coma for these patients was
25 days (range = 1 to 120 days). The median duration of post-traumatic
amnesia was 504 hours or 21 days (range = 0 minutes to 44 days). The
median length of PTA was lower than the median length of coma because
severe and lengthy coma occurred frequently in this sample (11 of 15 patients
sustained coma). All of these patients were judged to be fully oriented after
their coma resolved. Only one patient did not experience either coma or post-
traumatic amnesia, but this patient nevertheless demonstrated significant

82
concentration and memory problems. On average, patients were tested
approximately two years after sustaining their injury (median injury-test interval
= 26 months; range = 4 to 73 months). By all accounts, most all of these
subjects survived severe head injuries. Those with more minor injuries
nevertheless suffered significant neuropsychological impairment.
Clinical characteristics were analyzed as a function of referral setting
(inpatient rehabilitation versus outpatient clinic). Exploratory analyses of
variance failed to find significant main effects of referral setting on age at time of
testing, injury-test interval, duration of coma, or duration of post-traumatic
amnesia. Because of this, all HI patients were treated as a single group of
patients.
Design
The design of the study consisted of a combination of within-subjects
and between-groups factors. The overriding independent variable of interest
was group membership: the Malingering group served as the experimental
group, the Genuine group served as the normal control group, and the Head
Injured group served as the criterion group with bonafide memory impairment.
The effect of group membership was observed on all dependent measures
deriving from the clinical and experimental memory tasks. Levels of processing
were manipulated in a within-subjects manner.

83
Materials
Preexperimental Materials
An extensive set of materials was necessary for the Genuine and
Malingering subjects. A three-subtest short form of the Wechsler Adult
Intelligence Scale-Revised, consisting of the Information. Vocabulary, and Block
Design subtests (Booker & Cyr, 1986), was employed as an estimate of
intelligence. Sattler (1988) endorses this test for clinical use.
Subjects were then given a sheet of paper printed with information about
the neuropsychological sequelae of closed head injury. Twenty items of
information relating to the memory performance of head injured patients was
presented. This fact sheet is contained in Appendix A. Subjects were given
adequate time to read carefully through this information.
Instructions to subjects (Genuine and Malingering subjects only)
concerning the role they were to play were presented after they had been
randomly assigned to either group. The instructions were presented in the
context of an imaginary scenario which emphasized the playing of a role during
the memory testing phase of the experiment. Appendix A presents the two
scenarios used for each group. Both scenarios included a description of an
automobile accident which occurred recently in which the person sustained a
minor head injury without loss of consciousness; neurological examination
results were negative; the person recently began to experience concentration
and memory problems; and the person contacted his attorney for advice.

84
The two scenarios then diverged. The faking scenario stipulated that if
the subject could portray memory problems then he or she could be entitled to
collect a large sum of money in damages from the other driver; the malingering
role was to play 'the most severe but believable memory problems" on the
ensuing tests. The best possible effort scenario stipulated that the patient may
have to resign from his or her lucrative job if he or she was found to have
memory problems; the genuine role was to "put forth the best effort, to try to
perform as best you can" on the ensuing tests.
Subjects were then given a test concerning their retention of (1) the
information concerning memory after closed head injury, and (2) the information
pertaining to their particular scenario and role. Appendix B contains this brief
test.
Experimental Materials
Clinical memory measures
The clinical memory measures used in this study have all been used
extensively to evaluate and describe memory impairment (c.f., Lezak, 1983).
Three main clinical memory tests were employed: the Wechsler Memory Scale
(WMS) (Wechsler, 1945), the California Verbal Learning Test (CVLT) (Delis,
Kramer, Kaplan, Ober, & Fridlund, 1987), and the Rey-Osterrieth Complex
Figure test (ROCF) (c.f., Lezak, 1983).
The Wechsler Memory Scale (WMS) (Wechsler, 1945) consists of seven
subtests. The subtests which contribute to producing the age-corrected

85
Memory Quotient (MQ) are Personal and Current Information. Orientation.
Mental Control. Logical Memory. Digit Span. Visual Reproduction, and
Associate Learning. The Logical Memory and Visual Reproduction subtests
were tested again after a 30 minute delay (Russell, 1975). Although the WMS
has been frequently criticized (Prigitano, 1978), it continues to enjoy frequent
use in characterizing a patient’s memory impairment in both the clinic and
laboratory (Squire & Shimamura, 1986). At the inception of this study, the
original WMS was used instead of the Wechsler Memory Scale-Revised
(Wechsler, 1987) because the latter had not yet gained widespread acceptance
and clinical usage.
The California Verbal Learning Test (CVLT) was employed as a measure
of list learning. This test is composed of repeated presentations of a list of 16
words. The structure of this test provides information about the amount of
information learned, the rate of learning over trials, encoding strategies
employed, error analysis, persistence of memory over retention intervals, and
the use of assisted retrieval. All test protocols were scored with the
accompanying microcomputer software (Fridlund & Delis, 1987).
The Rey-Osterreith Complex Figure Task (ROCF) was employed as an
index of drawing from memory or nonverbal memory. The subject completed
three separate tasks associated with the ROCF. The subject first copied the
figure and then immediately drew the figure from memory. The subject again
drew the figure from memory, this time after a 30 minute delay.

86
Several nonverbal clinical memory tests were employed primarily as
interpolation tasks occurring between the immediate and delayed testing of
verbal memory tasks. Forms C, D, and E of the Benton Visual Retention Test
(Benton, 1974) and the Milner Facial Recognition Test (Milner, 1968) were used
for this purpose. These data were not scored or analyzed.
Experimental memory tasks
A total of 120 low (less than 30 occurrences per million) and high
frequency (between 60 and 200 occurrences per million) words were selected
from Kucera and Francis (1967) according to the following criteria. Each word
had between five and eight letters. The first three letters of each word (i.e.,
stem) uniquely defined each word in the set. However, each word stem was
common to at least 10 different words in Webster’s Pocket Dictionary. The total
pool of words was randomly divided into four subsets, with 25 words used for
the study and test of Word Stem Completion (WSC), 45 words used for the
study and test of Perceptual Identification (PI), 25 words used for the study and
test of Free Recall (FR), and 25 words used for the study and test of Multiple
Choice Recognition (MCR). Therefore, each experimental paradigm (WSC, PI,
FR, and MCR) had individual study and test lists which were administered
independently of lists associated with the other tasks in order to prevent
contamination at testing.
The first two and last three words of each study list contained "filler"
words which served as buffer items to control for primacy and recency effects.

87
The remaining words were target words. Within each task, each word was
randomly assigned to a processing condition which either focused subject’s
attention on the semantic/conceptual aspects or the physical/orthographic
aspects of the particular word. The processing tasks were adapted from Craik
and Tulving (1975). The semantic encoding condition had subjects verify
whether the word would make sense if inserted in a specified place in a
sentence by responding with "yes" or "no." The physical encoding condition
had subjects verify whether a word contained a specified letter by responding
with "yes" or "no." Within each processing condition, the correct answer ("yes"
versus "no") for the word’s processing task was randomly assigned. The
proportion of correct "yes" and "no" responses were equivalent within orienting
conditions and within study lists. Appendix B provides the complete study and
test lists used in the four experimental memory tasks.
Word stem completion (WSC). A pool of 25 words was used for WSC.
The 20 target word were divided into two separate lists of 10 words each, List A
and List B. Each subject studied only one of the two lists. Five words were
encoded with a semantic processing task and five words were encoded with a
physical processing task. WSC study lists (A versus B) were counterbalanced
within group. The five words used as primacy and recency buffers were
invariant across both lists. Study words were printed on four by six inch white
index cards. At test, each subject was given a sheet of paper with 20 word
stems and asked to complete the stems to form the first words that came to his

88
or her mind. Ten of the stems could be completed to form the target words
which were studied. The remaining 10 unexposed words were used as
distractor stimuli. The percentage of these words completed in the target
direction served as baseline performance.
Perceptual identification (PIT A pool of 45 words were used for WSC.
Subjects studied a group of 25 words. Five words were used as primacy and
recency buffers. Of the remaining 20 words on the study list, 10 words were
encoded with a semantic processing task and 10 were encoded with an
physical processing task. Study words were printed on four by six inch white
index cards. The PI test list consisted of 40 words, the 20 target words plus 20
unexposed distractor words. Assignment to serial position in the test list was
random. A yes/no recognition test followed the PI task; it consisted of the
same 40 words.
Free recall. A pool of 25 words were used for FR. The FR study list was
composed of five buffer words, 10 words which were encoded in a semantic
processing task, and 10 words which were encoded in an physical processing
task. Study words were printed on four by six inch white index cards. Subjects
made their FR responses on a sheet of lined paper. Buffer words produced at
test were not counted as correct.
Multiple choice recognition. A pool of 25 words were used for MCR.
The MCR study list was composed of five buffer words, 10 words which were
encoded in a semantic processing task, and 10 words which were encoded in

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an physical processing task. Study words were printed on four by six inch
white index cards. The testing of MCR involved the subject circling the word,
out of four possible choices, which he or she recognized as studying
previously.
Symptom validity testing
Stimuli for Symptom Validity Testing (SVT) was comprised of a series of
seven digit numbers. Stimuli were presented and subjects made their
responses on an IBM-compatible personal computer. A software program was
written using Micro Experimental Laboratory (M.E.L.) (Schneider, 1988, 1989).
Appendix B contains the study digit strings, the digit strings serving as the test
foils, and the correct answer for that trial. Fifty complete trials were constructed
and comprised trials one through 50. The same trials were then repeated in
the same order for trials 51 through 100. Correct answers (either "A" or "B")
were randomly assigned. Alternative "A" was correct on 50 trials while "B" was
correct on the remaining 50.
The numbers comprising the digit strings were not randomly generated;
rather, several patterns were built into the stimuli in an attempt to "entice" the
Malingering subject into perceiving the task as more difficult than in actuality.
For all trials, the target and foil digit strings began with different digits. The digit
strings always differed as to odd versus even status. All target digit strings
contained two contiguous digits which were the same number (e.g., 81608331.

90
while the foil string did not contain such a pattern. Thus, correct answers could
be made the basis of remembering several simple ideas.
Procedure
Preexperimental Procedures
All subjects completed the informed consent form. Testing in the main
phase of the study was then begun with Amnesic patients, amnesic control
subjects, and Head Injured patients.
An extensive pre-experimental procedure was necessary for the college
normals who participated as Genuine and Malingering subjects. These subjects
were administered the WAIS-R short form. Subjects were then asked several
open-ended questions concerning their medical and neurological history. No
subjects were included with a positive history of neurological illness or learning
disability.
Prior to the subject’s receiving his instructions, his or her threshold for
perceiving words was determined in the following manner. Using 35 msecs as
the predicted average perceptual threshold, the method of limits was employed
in both a descending and ascending manner. In the descending method, the
sample word was flashed on the tachistoscope for 60 msecs and the subject
attempted to name the word. Additional trials were repeated, using a different
word each time, by decreasing the duration of exposure by five msecs each
repetition until the subject could no longer read the word. The ascending
method was then employed. This differed only in that the starting exposure

91
duration was well below threshold at 10 msec. Repeated trials were presented
with different words by increasing the duration of exposure by five msecs each
repetition until the subject correctly read the words. An individual subject’s
perceptual threshold was computed as the mean of the two thresholds
obtained using the ascending and descending method of limits. The duration
of exposure of PI test words was set approximately 5 msecs below the
individual subject’s perceptual threshold.
Subjects were then given a sheet of paper printed with information about
the neuropsychological sequelae of closed head injury. Twenty items of
information relating to the memory performance of head injured patients was
presented. Subjects were given adequate time to read carefully through this
information.
As it was originally planned, Genuine and Malingering subjects were to
attempt to keep the tester (the primary experimenter) from "catching on" to their
particular role. This aspect of the procedure had to be abandoned for several
reasons, however, after eight subjects were run. Most importantly, the idea of
fooling the tester and escaping detection added a layer of complexity to the
situation, making it quite confusing for some Malingering subjects. Another
effect of this procedure was that Malingering subjects interpreted this to mean
that they should emphasize behavioral presentation (i.e., their dramatic or
acting ability) rather than their scorable test-taking behavior. Finally, the
requirement to convince the tester cast a somewhat adversarial atmosphere

92
which tended to obscure the purpose of the study and made some Malingering
subjects anxious. During the de-briefing, one subject stated that she quit
playing her role "somewhere in the middle" due to these issues.
The solution to these problems was as follows. The principal investigator
continued to test subjects due to (1) the potential for anxiety; (2) the need to
thoroughly assess compliance with the role-playing; and (3) the need to
maintain consistency of testers across the Head Injured group. However, the
requirement that subjects were to "fool" or deceive the examiner was de-
emphasized. Emphasis was instead placed on the subject’s test-taking
behavior. The subjects were told that, just as they would be playing a role, the
principal investigator would be playing the role of the tester. Subjects were told
that all aspects of the tester’s behavior would be strictly according to test
administration instructions and procedures and at no time would the tester
initiate an interruption of the role-playing procedure or portray a "confrontation"
with the "suspected faker." This approach worked quite well in that 100%
compliance with instructional conditions was obtained; no subject refused or
interrupted participation. No subject developed an adverse reaction to
participation. The perfect compliance rate should be contrasted with the results
of Heaton, Smith, Lehman, & Vogt (1978) in which 44% of their subjects
instructed to malinger were rated as investing a "questionable" amount of effort
in their role.

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The principal investigator remained blind to group assignment. Subjects
drew a number out of an envelope which served as the basis for randomized
group assignment. Subjects were left alone in a small testing room in the
Neuropsychology Laboratory with two folders which separately contained the
materials pertaining to the Genuine and Malingering groups. Subjects indexed
which group they had been assigned to and proceeded to read the materials in
that folder. After reading the pre-experimental material, they completed the
brief true/false test concerning their retention of (1) the information concerning
memory after closed head injury, and (2) the information pertaining to their
particular scenario and role. Incorrect answers to questions about head injury
were corrected and discussed with the subjects; therefore, the subjects learned
this information to 100% accuracy.
The role-playing aspects of this study were then discussed further with
the subjects. As the primary experimenter was blind to group membership,
aspects of the Genuine and Malingering roles were discussed with each
subject, regardless of group assignment. This offered the additional benefit of
putting the role-playing into a clearer perspective for each subject. That is,
Genuine subjects gained a better understanding of how their role-playing
related to the Malingering role-playing and vice versa. All subjects were
forewarned to expect difficulty with playing their role. They were told that only
objective aspects of their behavior was of interest to the experimenter; that is,
they were not being judged on "acting ability" or "dramatic believability." Finally,

94
they were encouraged to not cease playing their role until the experimenter said
"Stop playing your role, the experiment is over." Subjects were given
approximately five to seven minutes of free time to use to plan their role-playing.
They were encouraged to review the fact sheet and to mentally rehearse their
role.
Overview of Experimental Procedures
The main phase of the experiment was grouped into three blocks of
tests. The verbal/nonverbal nature of the memory tasks as well as the requisite
delay intervals for the clinical memory tests were the main considerations in
ordering the test battery. Form E of the Benton VRT was used at any point
where additional nonverbal distractor activity was necessary to maintain correct
delay intervals. The first block of tests consisted of the immediate testing of the
WMS Logical Memory and Visual Reproduction subtests. The SVT paradigm
was administered next. The delayed testing of the WMS Logical Memory and
Visual Reproduction subtests closed out the first block of tests.
The second block of tests began with the administration of the copy and
immediate memory trials of the Rey-Osterreith Complex Figure Test. The four
experimental memory tests (WSC, PI, FR, and MCR) were then administered
next. The order of these four tasks was counterbalanced within groups. Four
to five minute interpolated delay intervals occurred between the study and test
phases of all four experimental memory tasks. The forward portion of the WMS
Digit Span subtest was used at the distractor activity for WSC. The backward

95
portion of the WMS Digit Span subtest was used as the distractor activity for PI.
The WMS Orientation and Personal and Current Information subtests were used
as the distractor activity for FR. The WMS Mental Control subtest was used as
the distractor activity for MCR. The second blocks of tests concluded with the
delayed memory trial of the ROCF. The third block of tests began with the
study and immediate testing trials of the CVLT. Forms C and D (and E if
necessary) of the Benton VRT were then administered, followed by the Milner
Facial Recognition Test. The 20 minute delayed testing of the CVLT followed.
Testing culminated with administration of the WMS Associate Learning subtest.
Experimental memory procedures
For Study 1, a computer software program was written which presented
study words and corresponding orienting questions to the Amnesic patients
and the control subjects. Several factors necessitated a change in presentation
of stimuli in Study 2. The computerized version required too much
administration time. Additionally, some Malingering subjects portrayed
problems in interacting with the computer, causing it to become inoperable on
several occasions. Therefore, the following modifications were made for all
subjects participating in Study 2.
Word stem completion. Each subject studied either WSC List A or List
B. Words were printed on four by six inch white index cards. Subjects held
the deck of cards. They were told their task was to answer questions about
words; no reference was made to the memorial aspects of the study episode.

96
The experimenter read aloud the corresponding processing question. The
subject made his response verbally. After responding, the subject proceeded
to the next word. Following the distractor task, the subject was then given a
sheet of paper with 20 word stems and asked to complete the stems to form
the first words that came to mind. No reference was made to the study list.
Subjects were encouraged to complete the stems in the order listed. After
completing all 20 word stems to form words, each subject then was asked to
mark "Y" by each words which he or she explicitly remembered from the study
list. This is a variant of the traditional paradigm used to analyze stochastic
independence (e.g., Jacoby & Witherspoon, 1983). In these studies, subjects
are given the original study words with which to make yes/no recognition
judgements. In the current study, subjects made recognition judgements
based on the words which they produced.
Words were scored as correct only if they were exactly the same word
as was studied. Correct performance was calculated as the proportion of
words correctly completed in the target direction. Correct completion was also
calculated within each processing condition. Baseline performance was
calculated as the proportion of unexposed distractor words completed in their
target direction. Thus, each subject served as his or her own control by
producing words to distractor stems.
Perceptual identification. Subjects studied the PI study list in the same
manner as above. They were told their task was to answer questions about

97
words; no reference was made to the memorial aspects of the study episode.
A four-channel Gerbrands tachistoscope equipped with a voice-activated
response timer was used to present the stimuli. At PI testing, target words
were tachistoscopically presented one after another at a fixed exposure
duration in the following manner. After a subject signaled his readiness to
proceed, an orienting stimulus was exposed on the screen for 500 msec
indicating to the subject where the word was to be presented. The word was
then exposed for the appropriate duration, followed immediately by a mask
which remained for 2 seconds. The subject attempted to read the word as
quickly as he could. The subject’s verbal answer and response latency were
recorded for each trial. This was repeated for every word in the test list. After
the PI test, subjects were given a list of the same 40 words and asked to circle
'T or "N" based on whether they recognized the word from the study list.
(Note: this procedure conforms directly with the traditional procedure used to
compute stochastic independence.). Responses were scored as correct only if
they were exactly the same word as was studied. Correct performance was
calculated as the proportion of target words correctly identified. Correct
identification rate was also calculated within each processing condition.
Baseline performance was calculated as the proportion of distractor words
correctly identified. Thus, each subject served as his or her own control by
attempting to identify distractor words.

98
Free recall. Subjects studied the FR study list in the same manner as
above. They were told their task was to answer questions about words; no
reference was made to the memorial aspects of the study episode. After the
distractor task, subjects were given a sheet of lined paper and asked to "write
down all the words you can remember from the previous list of words you
studied". Responses were scored as correct only if they were exactly the same
word as was studied. Correct performance was calculated as the proportion of
target words correctly recalled. Correct recall was also calculated within each
processing condition.
Multiple choice recognition. Subjects studied the MCR study list in the
same manner as above. They were told their task was to answer questions
about words; no reference was made to the memorial aspects of the study
episode. After the distractor task, subjects were given a sheet of paper printed
with 20 items consisting of four words and asked to "circle one word from the
four choice that they remember from the previous list of words you studied."
Correct performance was calculated as the proportion of target words correctly
recognized. Correct recognition was also calculated within each processing
condition.
Symptom Validity Testing
The SVT task began with a list of instructions presented to the subject on
the screen. The examiner verbally explained the directions as well, emphasizing
the "extremely difficult" aspects of the test. The subject then pressed the space

99
bar to begin the testing. The first target string was presented in the middle of
the screen for a total of two seconds, after which it was briefly covered with a
mask for one second. The screen immediately cleared, presenting the subject
with two different digit strings, the correct target string and an incorrect foil
string. The string presented on the left side of the screen was labeled as "A"
and the string presented on the right side of the screen was labeled as "B".
Labels marked "A" and "B" were placed on the F and J keys on the keyboard,
respectively. Subjects held both index fingers on these keys throughout
testing. Subjects made their responses by first hitting the corresponding key
and then calling out their answer. Unfortunately, the computer software failed
to properly record the reaction times for the subjects. As a contingency to this
problem, the examiner unobtrusively sat behind the subjects and manually
recorded response latencies with a stopwatch. Reaction time data derived from
the SVT paradigm was subsequently analyzed but interpreted with the inherent
unreliability of the data collection method taken into account.
Clinical Memory Procedures
The WMS consists of seven subtests. Personal and Current Information
consists of six questions which tap recall of long established verbal information.
Orientation consists of five questions which tap immediate temporal orientation.
Mental Control consists of three subtasks, all of which are completed under
time pressure: counting backwards from 20; repeating the alphabet; and
counting in increments of three’s. Logical Memory consists of two literary

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passages. The task for the subject was to recall a number of ideas contained
in the passages. The subject was asked to repeat this recall procedure after a
20-25 minute delay interval. Memory Span consists of recalling verbally
presented digits in the forward and backward directions. For each Digits
Forward and Digits Backward, the score was the maximum number of digits
recalled. Visual Reproduction consists of drawing geometric designs that were
presented visually for a brief period of time. The subject was also asked to
repeat this reproduction procedure after a 20-25 minute delay interval.
Associate Learning consists of the subject learning two word associations and
then recalling the correct target word when given the stimulus word.
On the California Verbal Learning Test, the subjects were read five
presentations of a list of 16 words. After each presentation, the subject was
asked to repeat, in any order, the words on the list. After the fifth presentation,
a second list was presented. After this trial, the first list was tested for a short
delay free recall and short delay cued recall, and followed later by a twenty
minute free recall, twenty minute delay cued recall, and twenty minute delay
recognition.
The Rey-Osterreith Complex Figure Task (c.f., Lezak, 1983) required the
subject to complete three separate tasks. The subject copied the complex
figure, drew the figure from memory immediately after copying it, and drew the
figure from memory after a 30 minute delay period. The drawings were scored
by a neuropsychometrician with extensive experience with this test who was

101
blind to group membership. The drawings were scored separately for each of
eighteen units. Each unit was scored for presence or absence, placement,
distortion, and recognizability according to the criteria specified by Lezak
(1983). Each trial yielded one overall score derived from the summation of the
points earned for each of the eighteen units.
Twenty five percent of the subjects of each group were randomly
sampled and re-scored by the primary experimenter who was also blind to
group membership. Reliability coefficients demonstrated very high inter-rater
agreement for the copy (r=0.99), the immediate reproduction (r=0.99), and the
delayed reproduction (r=0.99). In 32 of 39 cases, summary scores from the
two raters did not differ by more than one point.
Debriefing
Given the nature of this study, subjects in the Genuine and Malingering
conditions were interviewed at length about their experiences and perceptions
while playing their respective roles during the experiment. Immediately after the
role-playing phase of their participation, subjects in the Genuine and
Malingering groups were given verbal descriptions of many of the memory
tasks they completed and asked to make Likert ratings concerning their (1)
effort put forth while completing that particular test; (2) perceptions of the
difficulty of the task (for a "normal" person with genuine motivation); and (3)
perceived success at portraying their role on that task. Twenty two tasks were
described; each subject rated the three characteristics for each task on a

102
seven-point scale. The three scales were anchored in the following manner. A
rating of one indicated the least amount of effort, task difficulty, and perceived
success. A rating of seven indicated the most amount of effort, task difficulty,
and perceived success. A rating of four represented the midpoint of each
scale. The form used for obtaining these ratings is presented in Appendix C.
Next, subjects were presented with their responses on the experimental
memory tasks and SVT in order to probe for several specific questions.
Subjects were asked several open-ended questions during the debriefing
interview concerning their performance on these tasks. As regards the indirect
memory tests, subjects were asked (1) "During WSC (and PI), did you
recognize that some of the words you generated were actually studied on a
previous deck of words?"; and (2) "During WSC (and PI) did you ever use your
conscious memory to deliberately think back to the study episode try to
respond with target words you remembered studying?". Based on their
answers to these questions, subjects were classified as to whether they
experienced test awareness, and whether they consciously employed their
explicit memory for test words to either facilitate or suppress their performance
on the indirect memory tests.
The subject’s de-briefing ratings were scanned by the principal
investigator for any notable responses, which were then discussed with the
subject. Subjects were then given a chance to discuss their perceptions and
feelings about their role playing and to ask any further questions.

CHAPTER 3
RESULTS
The first part of the results section will provide descriptive and
demographic information in order to fully characterize the composition of the
five experimental groups. Results from Experiment 1 involving the amnesic
patients and controls will be presented with the goal of establishing the
concurrent validity of the experimental memory tasks as representative of those
found in the literature. Extensive results from Experiment 2 involving the
Genuine, Malingering, and Head Injury subjects will then be presented.
A note concerning the use of various statistical procedures is warranted.
The use of multivariate analysis of variance procedures (MANOVA) will be
employed only when analyzing multiple response variables which represent
theoretically dissociable constructs of memory functioning (e.g., free recall of
verbal material, cued recall of verbal material, etc.). This will protect against an
inflated experiment-wise error rate. Inflated comparison-wise error rates will be
controlled by employing additive (Bonferroni) error splitting. In this case, alpha
levels will be divided by the number of comparisons made on related variables.
103

104
Descriptive Statistics
Characterization of Subject Groups
Table 2 contains descriptive information and demographic variables for
Experiment 1. The Amnesic patients were broken down into two subgroups
based on etiology: alcoholic Korsakoff’s syndrome (n=4) and other etiologies
(n=5). A control group consisting of medical outpatients was matched to the
two amnesia subgroups based on age and education. One-way analysis of
variance procedures showed no significant differences between the amnesic
subjects and controls for the demographic variables. Table 3 contains
descriptive information and demographic variables for the main study. Two
groups of normal college students comprised the Genuine (n=20) and Malinger
(n=20) groups. Patients suffering from Closed Head Injury (n=15) were
included as an additional control group. One-way analyses of variance showed
significant differences between the three groups on age at time of testing,
F(2,52)=7.09, pc.01. Follow-up mean contrasts revealed that Head Injury
patients were significantly older than the Genuine and Malinger subjects. As
memory function has been repeatedly shown to decline as a function of age,
the observed age effect in the present study could theoretically pose a threat to
the validity of the results. However, the observed statistical difference in age
between the Head Injury subjects and the other groups is slight (approximately
5 years) and does not represent a practically significant difference.

105
Correlations and covariances were computed between age and the
response variables for (1) the overall sample, and (2) by each subject group
separately. The results indicated that age was not statistically related to any
response variable, both for the overall sample and within each subject group.
Nevertheless, age was used as a covariate in all between-group analyses for
the main experiment.
A similar pattern of results was noted for Full Scale IQ, F(2,52)=9.88,
pc.001, with Head Injury subjects showing significantly lower FSIQ estimates
than the Genuine or Malingering subjects, which were not significantly different
from the other. A one-way analysis of variance showed no significant
differences between the three groups on level of education at time of testing,
F(2,52)=2.03, pc.14. Lowered FSIQ is one manifestation of the
neuropsychological sequelae of head injury. Because differences between
Genuine and Malingering subjects cannot be explained by FSIQ differences,
FSIQ was not treated as a covariate. It could be argued that the difference in
education level between the college groups and the head injured patients was
clinically significant, even though this difference failed to reach statistical
significance. However, eleven of the head injury patients had completed their
high school diploma. Three had completed at least one year of college and six
other were reportedly enrolled in college prepatory classes prior to their injury.

106
Table 2
Descriptive Information for Experiment 1
Group
Variable
Amnesia
Controls
Number of Subjects
9
9
Age
Mean
SD
F(1,16) = 0.06
54.7*
15.4
56.3a
13.8
Education
Mean
SD
F(1,16) = 0.43
14.2a
3.6
13.1a
3.6
Full Scale IQ
Mean
SD
F(1,16) = 0.12
102.6a
15.3
104.7a
9.4
Mattis DRS Total
Mean
SD
F(1,16) = 1.27
131.5a
4.2
135.3a
6.5
* pc.05 ** pc.01 *** pc.001
Note. Means with different superscripts differ significantly at pc.05.

107
Table 3
Descriptive Information for Experiment 2
Group
Variable
Genuine
Malinger
Head Injury
Number of Subjects
20
20
15
Age
Mean
21.1A
21.6a
26.9B
SD
F(2,52) = 7.09**
3.6
5.1
6.1
Education
Mean
12.9a
12.8a
12.3a
SD
F(2,52) = 2.03
1.0
0.8
1.1
Full Scale IQ
108.3a
110.3a
92.4b
Mean
SD
F(2,52) = 9.88**
11.5
14.0
12.1
* p<.05 ** p<.01 *** p<.001
Note. Means with different superscripts differ significantly at p<.05.

108
Normality of Data
All response variables were examined for skewness, kurtosis, and
normality of distribution to determine the need for transformation of the raw
scores. The response variables included those derived from percentage of
correctly produced targets from WSC, PI, FR, and MCR as well as reaction
times for PI and SVT. In all cases, the raw data adequately conformed to the
parameters necessary to satisfy the analysis of variance procedure assumption
of approximate normality.
Experiment 1: Validation of Word Lists
The results of statistical tests will be reported in the following order.
First, main effects (target status, orienting task, answer status, etc.) collapsed
across groups will be reported. Next, statistical interactions between group and
these other variables will be reported. Regardless of the statistical significance
of these interaction terms, these main effects (target status, orienting task,
answer status) will be analyzed separately within each group in order to
document whether each group produced the hypothesized pattern of
performance.
Word Stem Completion
Each subject in the present study served as his own control subject in
that chance or baseline performance on the stem completion task was
determined by the percentage of distractor (new) words completed in the target
direction. Baseline performance for the two groups (Amnesia=7.7%;

109
Controls=10%) was not significantly different, F(1,16)=.30, p<.59, and was
equivalent to baseline rates reported in the literature (Graf & Williams, 1987).
Collapsed across groups, a significant main effect of word status (target versus
distractor) was found, F(1,16)=30.9, pc.0001. Computed within groups, a
significant main effect of target status was found for both the Amnesic group,
F(1,8)=16.96, pc.003, and the control group, £(1,8)=21.56, pc.002. These
findings suggest that both Amnesic and control groups demonstrated priming
on the WSC task. Follow-up mean comparisons confirmed that word stems
were completed in the target direction significantly more often when the word
was previously exposed compared to the unexposed condition. The interaction
between group and target status was nonsignificant, F(2,16)=0.00, pc.97,
suggesting that the strength of priming was similar in Amnesics and controls.
Figure 1 presents this data. Collapsed across groups, the main effect of
orienting task was nonsignificant. Additionally, the interaction between group
and orienting task was nonsignificant (F’s c 1). Control subjects showed a
slight trend towards higher percent correct stem completion when the target
words were encoded in the physical orienting condition, while Amnesic subjects
showed virtually identical performance in both orienting conditions.
An alternative analytic approach involved computing a binary variable
which reflected whether or not each subject demonstrated priming on stem
completion. For each subject, baseline performance for that subject was
subtracted from target performance, resulting in a variable which reflected the

110
magnitude of priming. Using a conservative cutoff of a 25% increase in
performance of targets over distractors, each subject was scored as to whether
his WSC performance reflected priming or no priming. This criterion reflected
the average strength of priming demonstrated in the relevent literature. Five of
9 amnesic subjects (55.6%) demonstrated priming using this criterion,
compared to 6 of 9 control subjects (66.7%). A nonparametric hypothesis test
for the significance of difference between these two proportions failed to reach
significance (Z=-.48, pc.32).
Perceptual Identification
Baseline performance on Perceptual Identification (PI) for the two groups
(Amnesia=22.2%; Controls=20.6%) was not significantly different (F’s < 1), and
was equivalent to baseline rates reported in the literature (Jacoby & Dallas,
1981). Collapsed across groups, a significant main effect of word status (target
versus distractor) was found, F(1,16)=27.1, pc.0001. Computed within groups,
a significant main effect of word status was found for both the Amnesic group,
F(1,8)=6.33, pc.03, and the control group, F(1,8)=12.27, pc.008, suggesting
that both groups demonstrated priming on the PI task. Follow-up mean
contrasts confirmed that stimulus words were identified significantly more often
when the word was previously exposed compared to the unexposed condition
in both groups. The interaction between group and target status was
nonsignificant (F c 1). Figure 2 presents this data.

111
Collapsed across groups, the main effect of orienting task was
nonsignificant. The interaction between group and orienting task was also
nonsignificant (all F’s < 1). Both groups showed virtually identical performance
in the sentence and letter orienting conditions.
A binary variable reflecting whether a subject demonstrated priming on
perceptual identification was computed in the same manner as discussed
above, using a 25% increase in performance of targets over distractors as the
marker for priming. Four of 9 amnesic subjects (44.4%) demonstrated priming,
compared to 3 of 9 control subjects (33.3%). A nonparametric hypothesis test
for the significance of difference between these two proportions failed to reach
significance (Z=-.48, p<.32).
Free Recall
The main effect of group on free recall performance was highly
significant, F(1,16)=25.29, pc.0001. Amnesic subjects demonstrated grossly
impaired explicit memory as measured by free recall of previously presented
words. Within-group analyses of variance showed that the main effect of
orienting task was nonsignificant for the Amnesic group, F(1,8)=.00, pc.1.0, but
was highly significant for the control group, F(1,8) = 14.81, pc.005. A follow-up
mean contrast test established that control subjects recalled significantly more
words which were encoded in the conceptual orienting condition
(mean=27.8%) than words encoded in the physical orienting condition
(mean=5.6%). A floor effect likely prevented amnesic subjects from showing

112
the expected free recall advantage afforded by the conceptual orienting
condition. Their grossly impaired explicit memory likely prevented them from
learning any new information. The interaction between group and orienting task
was also highly significant, F(1,16)=12.90, pc.002, with control subjects
showing a significantly greater levels of processing effect than Amnesic
subjects. Figure 3 presents this data.
Multiple Choice Recognition
The main effect of group on multiple choice recognition performance was
highly significant, F(1,16)=47.06, pc.0001. Amnesic subjects demonstrated
grossly impaired explicit memory (mean=45%) as measured by multiple choice
recognition of previously presented words when compared with control
subjects (mean=78.3%). The MCR performance of Amnesics subjects was not
significantly greater than chance performance (Z=1.39, pc.08). The interaction
between group and orienting task was nonsignificant, F(1,16)=.05, pc.82, with
Amnesic and control subjects showing equivalent orienting task effects. Figure
4 presents this data.
Experiment 2: Main Study
Validity of Group Membership: Clinical Memory Performance
The data generated from the clinical memory tests were used as a
validity check to establish that each subject group produced a pattern of
performance similar to that reported in the literature. Performance on clinical
memory tests provides an easily interpretable benchmark upon which to later

113
WORD STEM COMPLETION
Target Advantage
% correct completion
70
60
50
40
30
20
10
0
Targets
Distractors
Encoding Process
% correct completion
70
60
50
40
30
20
10
0
AMNESICS CONTROLS
Sentence 43.6 42.2
Letter 44 48.8
Figure 1. Word Stem Completion Performance for Experiment 1.

114
PERCEPT. IDENTIFICATION
Target Advantage
% correct identification
70 i
AMNESICS CONTROLS
Targets 43.3 44.4
Distractors 22.2 20.6
Encoding Process
% correct identification
Sentence
Lette
Process
iHH Sentence
Letter
Letter 42.2 44.4
Figure 2. Perceptual Identification Performance for Experiment 1.

115
FREE RECALL
Overall Performance
40
35
30
25
20
15
10
5
0
Free Recall 1.1 16.7
% correctly recalled
AMNESICS CONTROLS
Variable
Free Recall
Encoding Process
% correctly recalled
40
35
30
25
20
15
10
5
0
AMNESICS CONTROLS
Sentence 1.1 27.8
Letter 1.1 5.6
Figure 3. Free Recall Performance for Experiment 1.

116
MC RECOGNITION
Overall Performance
% correctly recognized
100
90
80
70
60
50
40
30
20
10
0
AMNESICS CONTROLS
MC Recognition 45 78.3
Encoding Process
% correctly recognized
100
90
80
70
60
50
40
30
20
10
0
AMNESICS CONTROLS
Sentence 50 84.4
Letter 40 72.2
Figure 4. Multiple Choice Recognition Performance for Experiment 1.

117
understand performance on laboratory-based experimental memory tests.
Specifically, performance on clinical memory tests will be used to demonstrate
that (1) subjects in the Genuine condition demonstrate intact if not above
average memory abilities, and (2) Head Injury subjects manifest impaired
attention, concentration, and recent memory abilities. The performance of
Malingering subjects on clinical memory tests will allow a thorough
characterization of their memory behavior.
Selected clinical memory variables were identified from a larger dataset
based on common clinical usage and a priori knowledge of their construct
validity. Next, memory processes were classified along two dimensions which
have been shown to be sensitive to clinical memory disorders. Distinctions
about the quantitative aspects of memory performance, which refers to the
extent or capacity of memory functioning, were made on the basis of temporal.
material, and retrieval-process divisions. Eighteen variables comprised the
variable set representing quantitative memory functioning. Qualitative aspects
of memory performance, which refers to those characteristics of memory
behavior not directly related to capacity of memory, were also analyzed. For
example, the number of false positive errors provides useful data concerning a
subject’s response tendencies. Ten variables comprised the variable set
representing qualitative aspects of memory functioning. For each memory
process, a multivariate analysis of variance was first computed. Significant

118
MANOVAs were followed with multiple univariate analyses of variance of the
constituent variables.
Quantitative variables
Eighteen variables comprised the variable set representing quantitative
memory functioning. Table 4 presents the specific memory processes, the
constituent clinical variables which tap the processes, and MANOVA results.
Univariate ANOVA alpha levels for these comparisons were corrected to provide
Type I error protection, yielding an alpha level of .003 as the criterion necessary
to obtain statistical significance (alpha of .05/18 comparisons=.0027). Table 5
presents this data.
Composite, general memory functions. A MANOVA performed on the set
of variables representing composite, general memory functions was highly
significant, Wilk’s Lambda F(4,100) = 12.26, pc.0001. Univariate ANOVA
procedures showed significant main effects of group on WMS Memory
Quotient, F(2,51)=17.13, pc.0001, and CVLT Total of Trials 1 to 5,
F(2,51)=17.13, p<.0001. Follow-up mean contrasts showed that Genuine
subjects produced significantly higher scores on these two indices than either
Malingering or Head Injury groups, which were not significantly different from
each other.
Attention and concentration. A MANOVA performed on the set of
variables representing attention and concentration functions was highly
significant, Wilk’s Lambda F(6,98)=3.51, pc.004. Univariate ANOVA

119
procedures showed significant main effects of group on WMS Digits Backward,
F(2,51)=10.80, pc.0001, but not on WMS Mental Control, F(2,51)=3.97, pc.025
or WMS Digits Forward score, F(2,51)=5.75, pc.006. Follow-up mean
contrasts showed that Genuine subjects produced significantly higher scores
on the Digits Backwards test than either the Malingering or Head Injury groups,
which were not significantly different from each other.
Immediate verbal free recall. A MANOVA performed on the set of
variables representing immediate free recall of verbal material was highly
significant, Wilk’s Lambda F(8,96)=5.73, pc.0001. Univariate ANOVA
procedures showed significant main effects of group on WMS Logical Memory
score, F(2,51)=13.81, pc.0001, CVLT Trial 1, F(2,51)=11.76, pc.0001, and
CVLT Trial 5, F(2,51)=10.48, pc.0001. Follow-up mean contrasts showed that
Genuine subjects produced significantly higher scores than either Malingering
or Head Injury groups on all three of these measures. The performance of the
Malingering and Head Injury groups was not significantly different on all three
indices.
Immediate verbal cued recall. A MANOVA performed on the set of
variables representing immediate cued recall of verbal material was highly
significant, Wilk’s Lambda F(6,98)=6.23, pc.0001. Univariate ANOVA
procedures showed significant main effects for group on WMS "Easy" Paired
Associates, F(2,51)=9.88, pc.0002, WMS "Hard" Paired Associates,
F(2,51)=16.52, pc.0001, and CVLT Short Delay Cued Recall, F(2,51)=17.66,

120
pc.0001. Follow-up mean contrasts showed that Genuine subjects produced
significantly higher scores than either Malingering or Head Injury groups on all
measures of immediate cued recall of verbal material. The performance of the
Malingering and Head Injury groups was not significantly different on any of
these indices.
Delayed verbal free recall. A MANOVA performed on the set of variables
representing delayed and unstructured free recall of verbal material was highly
significant, Wilk’s Lambda F(4,100) = 14.23, pc.0001. Univariate ANOVA
procedures showed significant main effects for group on WMS Delayed Logical
Memory, F(2,51)=27.14, pc.0001, and CVLT Long Delay Free Recall,
F(2,51)=33.08, pc.0001. Follow-up mean contrasts showed that Genuine
subjects produced significantly higher scores than either Malingering or Head
Injury groups on both measures of this component of memory functioning. The
performance of the Malingering and Head Injury groups was not significantly
different on either index.
Delayed verbal cued recall. A MANOVA performed on the set of
variables representing delayed cued recall of verbal material was highly
significant, Wilk’s Lambda F(4,100)=11.18, pc.0001. Univariate ANOVA
procedures showed significant main effects for group on CVLT Long Delay
Cued Recall, F(2,51)=19.16, pc.0001. Follow-up mean contrasts showed that
Genuine subjects produced significantly higher scores than either Malingering
or Head Injury groups on this measure of delayed cued recall of verbal material.

121
The performance of the Malingering and Head Injury groups was not
significantly different on this index.
Immediate nonverbal free reproduction. A MANOVA performed on the
set of variables representing the immediate reproduction of nonverbal material,
Wilk’s Lambda F(4,100)=5.09, pc.0009. Univariate ANOVA procedures
showed significant main effects for group on WMS Visual Reproduction,
F(2,51)=11.07, pc.0001, but not for the ROCF immediate memory trial,
F(2,51)=3.61, pc.03. Follow-up mean contrasts showed that Genuine subjects
produced significantly higher scores than either Malingering or Head Injury
groups on more simple Visual Reproduction subtest. The performance of the
Malingering and Head Injury groups was not significantly different on this index.
Delayed nonverbal free reproduction. A MANOVA performed on the set
of variables representing the delayed reproduction of nonverbal material was
highly significant, Wilk’s Lambda F(4,100)=7.47, pc.0001. Univariate ANOVA
procedures showed significant main effects for group on WMS Delayed Visual
Reproduction subtest, F(2,51)=16.49, pc.0001, and ROCF delayed memory
trial, F(2,51)=7.07, pc.002. Follow-up mean contrasts showed that all three
groups differed significantly from each other with respect to performance on
Delayed Visual Reproduction. Genuine subjects performed higher than Head
Injury subjects, while Malingering subjects performed significantly lower than
both comparison groups. The performance of Genuine and Head Injury groups
on the ROCF delayed reproduction trial was not significantly different.

122
Malingering subjects demonstrated significantly lower performance than the
Genuine group but not the Head Injury group.
Qualitative variables
Whereas some variables represent the quantitative output of a subject’s
memory capacity, other indices have been developed which describe more
qualitative aspects of memory behavior. Ten variables comprised the variable
set representing qualitative aspects of memory functioning. Univariate ANOVA
alpha levels for these comparisons were corrected to provide Type I error
protection, yielding an alpha level of .005 as the criterion necessary to obtain
statistical significance (alpha of .05/10 comparisons=.005). Table 6 presents
several qualitative memory constructs, the clinical memory variables which
measure them, and MANOVA results. Table 7 presents the results of univariate
ANOVAs and follow-up mean contrasts.
Forgetting. Scores representing the amount of information which was
forgotten over delay intervals were computed for WMS Logical Memory and
Visual Reproduction subjects as well as the ROCF memory trials. These scores
were computed as the delayed memory score divided by the immediate
memory score, multiplied by 100, and therefore take into account the amount of
information that was originally learned. A MANOVA performed on this variable
set was highly significant, Wilk’s Lambda F(6,98)=6.28, p<.0001. Univariate
ANOVA procedures showed significant main effects for group on the WMS
Logical Memory Percent Forget score, F(2,52)=8.40, pc.0007, and the

123
Table 4
Multivariate Group Differences on Quantitative Clinical Memory Variables
Memory Process
Wilk’s
Lambda
Variable
Composite, Overall Memory
Functions
12.26***
WMS Memory Quotient
CVLT Total from Trials 1-5
Attention and
Concentration
3.50**
WMS Mental Control subtest
WMS Digits Forward
WMS Digits Backward
Immediate Free Recall
of Verbal Material
5.73***
WMS Immed. Logical Memory
CVLT Trial 1
CVLT Trial 5
Immediate Cued Recall
of Verbal Material
6.23***
WMS "Easy" Paired Associates
WMS "Hard" Paired Associates
CVLT Short Delay Cued Recall
Delayed Free Recall
of Verbal Material
14.23***
WMS Delayed Logical Memory
CVLT Long Delay Free Recall
Delayed Cued Recall
of Verbal Material
11.18***
CVLT Long Delay Cued Recall
CVLT Recognition Hits
Immediate Reproduction
of Nonverbal Material
5.09**
WMS Immed. Visual Reprod.
ROCF Immed. Reproduction.
Delayed Reproduciton
of Nonverbal Material
7.47***
WMS Delayed Visual Reprod.
ROCF Delayed Reproduction
* pc.05 ** pc.01 *** pc.001

124
Table 5
Univariate Group Differences on Quantitative Clinical Memory Variables
Group
Variable
Genuine
Malinger
Head Injury
WMS Memory Quotient
Mean
116.1A
82.4B
85.8b
SD
F(2,52) = 26.89***
13.2
15.1
17.4
CVLT Total Trials 1-5
Mean
59.2a
40.4B
35.7®
SD
F(2,52) = 17.13***
7.5
12.5
15.0
WMS Mental Control
Mean
7.3A
6.5KB
5.3B
SD
F(2,52) = 3.97*
1.8
2.8
1.9
WMS Digits Forward
Mean
7.3a
6.1B
5.8B
SD
F(2,52) = 5.75**
0.7
2.0
1.2
WMS Digits Backward
Mean
5.8a
4.3B
3.9B
SD
F(2,52) = 10.80***
1.2
1.5
1.0
WMS Immed. Log. Mem.
Mean
12.5a
7.1B
7.0B
SD
F(2,52) = 13.82***
3.5
2.4
4.4
* pc.05 ** pc.01 *** pc.001
Note. All data are raw scores. Means with different superscripts differ
significantly at pc.05.

125
Table 5--continued
Univariate Group Differences on Quantitative Clinical Memory Variables
Group
Variable
Genuine
Malinger
Head Injury
CVLT Trial 1
Mean
8.4*
5.1B
5.0B
SD
F(2,52) = 11.76***
2.2
1.8
2.9
CVLT Trial 5
Mean
13.6*
9.9B
8.7B
SD
F(2,52) = 10.48**
1.9
3.5
3.8
WMS "Easy" Assoc.
Mean
17.7*
15.78
15.3B
SD
F(2,52) = 9.88**
0.5
2.2
1.7
WMS "Hard" Assoc.
Mean
9.7*
5.7®
4.3B
SD
F(2,52) = 16.52***
1.9
3.2
3.1
CVLT SD Cued Recall
Mean
13.6*
8.6B
7.3B
SD
F(2,52) = 17.66***
1.7
3.7
3.6
* p<.05 ** p<.01 *** pc.001
Note. All data are raw scores. Means with different superscripts differ
significantly at pc.05.

126
Table 5--cont¡nued
Univariate Group Differences on Quantitative Clinical Memory Variables
Group
Variable
Genuine
Malinger
Head Injury
WMS Delayed Log. Mem.
Mean
12.0a
4.9b
5.1B
SD
F(2,52) = 27.14***
3.2
2.7
3.9
CVLT LD Free Recall
Mean
13.6a
5.3s
6.1B
SD
F(2,52) = 33.08***
1.9
3.5
4.6
CVLT LD Cued Recall
Mean
13.9a
7.5b
6.7®
SD
F(2,52) = 19.16***
1.7
4.2
4.5
WMS Immed. Vis. Reprod.
Mean
12.2a
7.5B
9.1B
SD
1.7
3.7
3.9
F(2,52) = 11.07***
ROCF Immed. Reprod.
Mean
19.2a
13.7A
14.0a
SD
7.8
6.0
6.0
F(2,52) = 3.61*
* p<.05 ** p<.01 *** p<.001
Note. All data are raw scores. Means with different superscripts differ
significantly at p<.05.

127
Table 5-continued
Univariate Group Differences on Quantitative Clinical Memory Variables
Group
Variable Genuine
Malinger
Head Injury
WMS Delayed Vis. Reprod.
Mean 9.9a
3.3C
6.4B
SD 3.0
F(2,52) = 16.49***
2.7
4.1
ROCF Delayed Reprod.
Mean 19.0a
11.3B
13.6a8
SD 7.3
F(2,52) = 7.07**
5.5
6.3
* p<.05 ** p<.01 *** pc.001
Note. Means with different superscripts differ significantly at pc.05.

128
WMS Visual Reproduction Percent Forget score, F(2,52)=12.16, pc.0001, but
not the ROCF Percent Forget score, F(2,52)=4.30, pc.02.
Follow-up mean contrasts showed that Malingering subjects produced
significantly higher forgetting scores on the WMS Logical Memory and Visual
Reproduction subtests than either Genuine or Head Injury groups. The
performance of the Genuine and Head Injury groups was not significantly
different on these two indices.
Recognition memory. Variables derived from the CVLT Recognition list
provided a good opportunity to evaluate group differences in variables
generated from a signal detection framework. A MANOVA performed on this
variable set was highly significant, Wilk’s lambda F(8,96)=4.92, pc.0001.
Univariate ANOVA procedures showed significant main effects of Group on d-
Prime, F(2,52) = 13.64, pc.0001, and False Alarms, F(2,52)=7.16, pc.002, but
not on Response Bias, F(2,52)=0.25, pc.78. Follow-up mean contrasts
revealed that the Genuine group demonstrated superior discriminability and
fewer false positive errors than either the Malingering or Head Injury group.
The Malingering and Head Injury groups did not differ significantly with respect
to these recognition indices. The groups did not differ significantly on their
tendency to favor "yes" or "no" responses irrespective of the stimulus type.
ROCF qualitative scoring. Performance on the Rey-Osterrieth Complex
Figure provided an excellent opportunity to analyze qualitative aspects of
memory performance. The copy, immediate reproduction, and delayed

129
Table 6
Multivariate Group Differences on Qualitative Clinical Memory Variables
Wilk’s
Memory Process
Lambda
Variable
Rate of Forgetting
6.28***
WMS LM Percent Forget
WMS VR Percent Forget
ROCF Percent Forget
Recognition Memory
4.92***
CVLT Recognition Hits
CVLT Recognition False Alarms
CVLT D-Prime
CVLT Response Bias
* p<.05 ** p<.01
***
p<.001

130
Table 7
Univariate Group Differences on Qualitative Clinical Memory Variables
Group
Variable
Genuine
Malinger
Head Injury
LM Percent Forget
Mean
3.38
34.4a
31.3B
SD
F(2,52) = 8.40***
10.4
22.4
40.9
VR Percent Forget
Mean
18.70
63.8A
35.4B
SD
F(2,52) = 12.16***
22.5
31.6
33.4
ROCF Percent Forget
Mean
-2.6B
19.6a
5.0a8
SD
F(2,52) = 4.30*
27.5
24.2
24.8
CVLT D-Prime
Mean
96.1A
78.9b
83.8B
SD
F(2,52) = 13.64***
3.7
13.2
12.2
CVLT Response Bias
Mean
-0.1
-0.1
0.00
SD
F(2,52) = 0.25
0.2
0.5
0.4
CVLT Recog. False Alarms
Mean
0.5B
4.6a
4.2a
SD
F(2,52) = 7.16**
1.0
4.7
4.2
* p<.05 ** p<.01 *** pc.001
Note. All data are raw scores. Means with different superscripts differ
significantly at pc.05.

131
reproduction of the ROCF were scored according to criteria put forth by Lezak
(1983). Each of 18 different design elements were scored separately for
absence (score=0), distorted/incomplete and placed poorly (score=0.5),
distorted/incomplete and placed properly (score=1.0), and accurate and proper
placement (score=2). Tables 8, 9, and 10 present data on the percentage of
subjects in each group producing absent or distorted scores for each individual
design element.
For purposes of economy, scoring elements were next divided into two
groups: major configurational elements contributing to the overall gestalt of the
figure and small detail elements. Following Lezak’s scoring system, major
configurational elements were the large rectangle (scoring unit number 2), the
diagonal cross (unit 3), the horizontal and vertical midlines of unit 2 (units 4 and
5), and the large triangle connected with 2 (unit 9). The remaining scoring units
were designated as small detail elements. Tables 11, 12, and 13 present mean
percentages of errors committed by subjects in each group as a function of
type of design element.
Hypothesis tests were performed to detect group differences on the
mean percentage of errors for each type of design element for the copy trial of
the ROCF. This was repeated for the immediate and delayed reproductions as
well. Given 36 paired comparisons, a significance level of .001 was used as the
criterion for obtaining a statistically significant difference (alpha of .05/36
comparisons=.0014). No pairwise comparisons reached significance.

132
However, certain trends in the data were evident. Malingering subjects tended
to omit more design elements in the copy trial than the other groups.
Malingering and Head Injury subjects tended to produce a similar percentage
of omissions and distortions, higher than Genuine subjects. The omission of
design elements, especially details, rather than distortions lowered the overall
scores in the immediate and delayed memory trials for both the Malingering
and Head Injury subjects.
Summary. Genuine subjects clearly demonstrated intact and above
average memory abilities, as reflected in their scores on composite measures of
general memory functioning. As compared to Genuine subjects, Head Injury
subjects demonstrated clinically significant impairment in attention,
concentration, and recent memory abilities. On average, the performance of
Head Injury subjects fell approximately 2.3 standard deviations below that of the
Genuine subjects. Table 14 presents average effect sizes computed from this
study. From a quantitative perspective, Malingering subjects produced scores
which were remarkably similar to Head Injury subjects. Malingering subjects
typically performed much worse than Genuine subjects, but at a level which
was not significantly different, from the bona-fide memory impairment of the
Head Injury subjects. On average, the performance of Malingering subjects fell
approximately 2.2 standard deviations below that of the Genuine subjects.
Malingering subjects generally scored slightly higher than Head Injury subjects
on tasks measuring attention and concentration, immediate recall and cued

133
recall of verbal material, and delayed cued recall of verbal material. Malingering
subjects scored lower than Head Injury subjects on tasks measuring delayed
recall of verbal and nonverbal material. Only one test, the WMS Delayed Visual
Reproduction subtest, showed sufficient discriminatory power to separate all
three groups. Malingering subjects over-exaggerated their impairment on this
test, producing a grossly impaired score of 3.3, almost half that of the Head
Injury group.
From a qualitative perspective, Malingering subjects demonstrated an
exaggerated amount of forgetting on the WMS Logical Memory and Visual
Reproduction subtests (defined as the loss of originally-learned information over
delay intervals). By and large, however, Malingering subjects successfully
portrayed the qualitative aspects of bona-fide memory impairment. This
includes the Malingering group’s ability to accurately balance the omission of
behavior with the commission of incorrect behavior to produce responses
similar to bona-fide memory impairment.
Experimental Memory Tasks
Word stem completion
Main task analysis. Each subject in the present study served as his own
control in that chance or baseline performance on the stem completion task
was determined by the percentage of distractor (new) words completed in the
target direction. Baseline performance for the three groups (Genuine=14%;
Malingering=14%; and Head Injury=8.7%) was not significantly different,

134
Table 8
Performance on the Copy of the Rev-Osterreith Complex Figure
Unit
Omission Errors
Absent (score=0)
Comission Errors
Distorted (.5/1)
G
M
HI
G
M
HI
1. Cross, UL
0
5
15
60
80
62
2. Lg rectangle
0
10
0
25
35
54
3. Diag. cross
0
15
0
20
25
38
4. Horz. ML of 2
0
15
8
5
10
31
5. Vert. ML of 2
0
15
0
35
30
23
6. Sm. rect. in 2
0
5
8
40
60
62
7. Sm. sg. ab. 6
0
35
15
5
0
8
8. 4 lines in 2
0
10
8
20
30
38
9. Triangle, 2
0
10
0
25
50
31
10. Sm. VL in 2
0
20
8
20
5
15
11. Circle, 3 dots
0
0
8
10
25
15
12. 5 par. lines,
0
5
0
10
50
23
13. Triangle on 2
0
5
0
20
35
39
14. Diamond, 13
0
15
8
5
15
31
15. Vert. In., 13
5
5
15
25
50
38
16. Horz. In., 13
0
10
8
10
15
15
17. Cross, LC
0
10
0
15
45
62
18. Square on 2
0
0
0
25
30
39
Note. Column subheadings are abbreviated as follows: G=Genuine,
M=Malingering, and HI=Head Injury. All data are percentages of each subject
group obtaining the indexed score for the indexed scoring unit.

135
Table 9
Performance on the Immediate Reprod. of the Rev-Osterreith Complex Figure
Omission Errors
Comission Errors
Absent (score=0)
Distorted (.5/1)
Unit
G M HI
G M HI
1.
Cross, UL
25
20
8
60
75
92
2.
Lg rectangle
0
0
0
35
55
58
3.
Diag. cross
20
55
42
15
5
25
4.
Horz. ML of 2
5
35
33
15
5
25
5.
Vert. ML of 2
5
40
25
20
10
25
6.
Sm. rect. in 2
40
35
42
30
60
50
7.
Sm. sg. ab. 6
60
80
83
5
0
0
8.
4 lines in 2
15
30
58
45
55
34
9.
Triangle, 2
60
75
67
20
20
33
10.
Sm. VL in 2
85
100
92
0
0
8
11.
Circle, 3 dots
10
10
25
25
35
59
12.
5 par. lines, 3
30
55
42
20
30
17
13.
Triangle on 2
15
15
8
25
25
33
14.
Diamond on 13
15
40
33
25
20
17
15.
Vert. In. in 13
75
80
75
15
15
17
16.
Horz. In. in 13
30
40
42
15
0
0
17.
Cross, LC
15
25
33
80
75
67
18.
Square on 2
25
40
33
60
60
67
Note. Column subheadings are abbreviated as follows: G=Genuine,
M=Malingering, and HI=Head Injury. All data are percentages of each subject
group obtaining the indexed score for the indexed scoring unit.

136
Table 10
Performance on the Delayed Reprod. of the Rev-Osterreith Complex Figure
Omission Errors
Comission Errors
Absent (score=0)
Distorted (.5/1)
Unit
G M HI
G M HI
1.
Cross, UL
15
40
8
85
60
92
2.
Lg rectangle
0
5
8
45
45
42
3.
Diag. cross
30
50
42
20
15
33
4.
Horz. ML of 2
0
35
25
15
5
17
5.
Vert. ML of 2
5
45
25
20
10
17
6.
Sm. rect. in 2
40
50
42
35
45
50
7.
Sm. sg. ab. 6
60
95
83
0
5
0
8.
4 lines in 2
15
45
75
55
35
25
9.
Triangle, 2
60
90
67
20
5
25
10.
Sm. VL in 2
90
95
92
0
5
0
11.
Circle, 3 dots
10
35
33
35
40
25
12.
5 par. lines, 3
20
65
33
30
30
33
13.
Triangle on 2
15
15
33
15
30
8
14.
Diamond on 13
10
45
33
25
15
17
15.
Vert. In. in 13
60
85
75
25
10
17
16.
Horz. In. in 13
35
50
50
5
10
0
17.
Cross, LC
20
40
33
75
60
67
18.
Square on 2
25
65
42
65
35
58
Note. Column subheadings are abbreviated as follows: G=Genuine,
M=Malingering, and HI=Head Injury. All data are percentages of each subject
group obtaining the indexed score for the indexed scoring unit.

137
Table 11
Performance on the Copy of the Rev-Osterreith Complex Figure
Absent (score=0)
Distorted (.5/1)
Unit G
M
HI
G
M
HI
Configurational Elements 0*
12a
3a
19b
25b
33B
Detail Elements 0C
10°
T
22°
37°
35°
Table 12
Performance on the Immed. Reorod. of the Rev-Osterreith ComDlex Fiaure
Absent (score=0)
Distorted (.5/1)
Unit G
M
HI
G
M
HI
Configurational Elements 12E
31E
25e
21*
17*
28*
Detail Elements 38G
49s
49s
32H
37H
38H
Table 13
Performance on the Delayed. Reprod. of the Rev-Osterreith Complex Figure
Absent (score=0)
Distorted (.5/1)
Unit G M HI
G M HI
Configurational Elements 14' 33' 31'
Detail Elements 35K 63K 51K
2a1
38L 29L 34L
Note. Column subheadings are abbreviated as follows: G=Genuine,
M=Malingering, and HI=Head Injury. All data are percentages of each subject
group obtaining the indexed score for the indexed scoring unit. Means within
each scoring category and element type with different superscripts differ
significantly at p<.05.

138
Table 14
Average Observed Effect Sizes
Type of Task
Malingerers
vs.
Normals
Head
Injured
vs.
Normals
Malingerers
vs.
Head
Injured
Clinical Memory Tests
-2.2
-2.3
+0.1
Implicit Memory Tests
Only
-0.5
-0.3
-0.3
All Experimental Memory
Tests
-1.4
-0.9
-0.4
Overall Average
-1.4
-1.2
-0.2

139
F(2,52)=1.27, p<.29, and was equivalent to baseline rates reported in the
literature (Graf, Squire, & Mandler, 1984) which average approximately 11
percent. Collapsed across groups, the main effect of word status (target
versus distractor) was highly significant, F(1,52)=80.49, pc.0001.
Within-group analyses of variance revealed that all three experimental
groups demonstrated priming on the word stem completion task. Figure 5
presents this data. The main effect of word status (target versus distractor)
was significant for the Genuine group, F(1,19)=67.29, pc.0001, the Malingering
group, F(1,19)=22.79, pc.0002, and the Head Injury group, F(1,14)=39.88,
pc.0001. Follow-up mean comparisons confirmed that word stems were
completed in the target direction significantly more often when the word was
previously exposed compared to the unexposed condition for all three groups.
The interaction between group and target status was significant, F(2,52)=9.00,
pc.0004. Follow-up analyses indicated that Genuine subjects demonstrated
significantly more priming on WSC than either the Malingering or Head Injury
groups.
Collapsed across groups, the main effect of orienting task was
nonsignificant, F(1,52) = 1.75, pc.19. The interaction between group and
orienting task was also nonsignificant, F(2,52)=.03, pc.97. Computed within
group, the main effect of orienting task was nonsignificant for the Genuine
group, F(1,19)=.17, pc.69, the Malingering group, F(1,19)=.17, pc.69, and the
Head Injury group, F(1,14)=.26, pc.62. Figure 5 presents this data. All three

140
groups showed a slight trend towards higher percent correct stem completion
of target words encoded in the physical orienting condition.
An alternative analytic approach involved computing a binary variable
which reflected whether or not each subject demonstrated priming on stem
completion. For each subject, baseline performance for that subject was
subtracted from target performance, resulting in a variable which reflected the
magnitude of priming. Using a very conservative cutoff of a 25% increase in
performance of targets over distractors, each subject was categorized as to
whether his stem completion performance reflected priming or no priming.
Fourteen of 20 Genuine subjects (70%) demonstrated priming, compared to 9
of 20 Malingering subjects (45%) and 11 of 15 Head Injury subjects (73%).
Nonparametric hypothesis tests for the significance of difference between
proportions failed to reach significance (Z=-.48, p<.32). The Malingering
group’s lower frequency of priming approached but barely failed to reach
significance (Z=-1.55, p<.055).
Yes/no recognition following stem completion. One important question
concerns the degree to which subjects employ explicit memory processes while
performing nominally implicit memory tasks. The word stem completion task
would seem especially vulnerable to contamination by explicit memory. After
completing stem completion itself, subjects answered "yes" or "no" beside each
generated word to indicate whether they recognized this word from the study
list. Three aspects of this task were scored. First, the probability of correct

141
recognition was conditionalized upon the probability of correct word
completion. This was operationalized as the percentage of correctly completed
target stems which were correctly recognized as having been studied [denoted
as P(WS+ |REC+)]. Second, the probability of answering "yes" to an
incorrectly completed target stem was computed [denoted as P(WS-|REC+)].
Third, the probability of answering "yes" to a distractor target stem was
computed [denoted as P(DIST|REC+)].
This data is presented in Figure 6. Between-group comparisons were
carried out on these three probability estimates. The results revealed no
significant main effects of group on the conditional probability of correct explicit
recognition, F(2,52)=0.63, p<.59, the probability of responding "yes" to an
incorrect target word, F(2,52)=.63, p<.59, and the probability of responding
"yes" to a distractor word, F(2,52) = 1.85, pc.30.
Trial-bv-trial analysis. Another indirect approach to assess the effect of
explicit memory processes involved evaluating subject’s completion accuracy
as they proceeded through the list of stems. A subject could potentially alter
his completion performance to the extent that he develops awareness during an
implicit task that study items were previously encountered during the study
phase of the experiment. In the present context, Genuine subjects could use
explicit memory for the study words in completing the stems (i.e., they could
use stems as recall cues). A Malingering subject’s situation is more
complicated, but he could potentially withhold correct completion based on

142
explicit memory of a target word after "catching on" to the memorial aspects of
the task. The change in a subject’s response strategy or criterion was
operationalized as changes in percent accuracy for successive groups of target
stems as serial position increases. Here, serial position refers to position on the
test list rather than the study list. The target stems were divided into groups of
2 words, representing partitions of 20% of the overall list. Figure 6 presents this
data.
Main effects of serial order were analyzed within groups. Within-group
analyses failed to reveal main effects of serial position of blocks of target words
for all three groups (all F’s < 1). Thus, no group demonstrated real evidence
of changing response strategies or criteria as they proceeded through the stem
completion task.
Awareness and intentionalitv. Subjects were asked several open-ended
questions during the debriefing interview concerning their performance on
WSC. Subjects were classified as to whether they experienced test awareness
or not, and whether they consciously employed their explicit memory for test
words to either facilitate or suppress their stem completion performance. Test
awareness was a necessary condition for explicit mediation in all subject
groups. Therefore, subjects could be classified into one of three categories:
(1) those who did not experience test awareness during WSC; (2) those who
did experience test awareness but who did not experience explicit memory
during WSC; and (3) those who both experienced test awareness and judged

143
that their performance was impacted by explicit memory (for Malingering
subjects, this means that they engaged in postretrieval suppression. For
notational purposes, this score will be referred to as test awareness.
Table 15 presents data concerning the relationship between group
membership, test awareness, magnitude of priming on WSC, and LOP effects.
A chi-square analysis failed to detect a relationship between group membership
and test awareness (X*=4.91, df=4). However, only one Malingering subject
failed to develop awareness during WSC, compared with 4 of the Genuine
subjects and 5 of the Head Injury subjects.
Because test awareness was not an independent variable that was
experimentally manipulated in the design, these data were examined with a
nonparametric test for the comparison of two proportions. Main effects of
Group on strength of priming on WSC were analyzed within level of test
awareness. No significant main effects of Group were found for the Not Aware
condition or the Test Aware/No Explicit Mediation condition (all Z’s < 1). A
different data pattern was noted in the Test Aware/Explicit Mediation condition.
In this condition, Genuine subjects demonstrated a significantly greater strength
of priming on WSC (mean target advantage=68%) than Malingering subjects
(mean target advantages8%), Z=-2.43, p<.007. The difference between the
Malingering subjects and the Head Injury subjects approached but failed to
reach significance, Z=-1.34, p<.09. The Genuine and Head Injury groups did
not differ significantly, Z < 1.

144
No significant LOP effects were noted within these conditions, although
there appeared to be a relationship between increased awareness and the use
of explicit retrieval and greater completion of physically encoded words in all
three groups, a highly unexpected trend.
Perceptual identification
Main task analysis. Each subject in the present study served as his own
control in that chance or baseline performance on the perceptual identification
task was determined by the percentage of distractor (new) words correctly
identified. Baseline performance for the three groups (Genuine=25.5%;
Malinger=18.2%; and Head Injury=23.1%) was not significantly different,
F(2,52)=1.16, p<.32, and was equivalent to baseline rates reported in the
literature (Jacoby & Dallas, 1981). Collapsed across groups, the main effect of
word status (target versus distractor) was significant, F(1,52)=94.1, pc.0001.
Computed within groups, the main effect of word status was significant for the
Genuine group, F(1,19)=14.44, pc.001, the Malingering group, F(1,19)=8.71,
pc.008, and the Head Injury group, F(1,14)=10.69, pc.006, suggesting that all
three groups demonstrated priming on PI. Follow-up mean comparisons
confirmed that word stems were completed in the target direction significantly
more often when the word was previously exposed compared to the
unexposed condition for all three groups. Figure 7 presents this data. The
interaction between group and target status was nonsignificant, F(2,52)=.31,

145
WORD STEM COMPLETION
Target Advantage
% correct completion
GENUINE
MALINGER
CHI
Targets
61.5
32.5
47.3
Distractors
14
14
8.7
Word Status
HH Targets
Distractors
Encoding Process
% correct completion
Sentence
MALINGER
31
Process
I® Sentence
Letter
Figure ^!^¡VSC Performance: Priming and Encoding Effects.

146
WSC RECOGNITION
Conditional Probabilities
probability
GENUINE
MALINGER
CHI
P(WS+IRec*)
0.88
0.7
0.7
P(WS-IRec+)
0.12
0.28
0.1
p(Dist.lRec+)
0.07
0.27
0.07
VARS
â–¡
P(WS*IRec+)
P(WS-IRec*)
p(Dist.lRec+)
WSC SERIAL POSITION
% correctly completed
GROUPS
-a- GEN
4- MAL
CHI
Figure 6. WSC Performance: Serial Position and Conditionalized Recognition.

147
Table 15
Test Awareness and Retrieval Intentionalitv in Word Stem Completion
%of
Group
Priming
Levels of
Processing
Sen. Let.
Not Aware
Genuine
20
+23*
50
30
Malinger
5
+10*
0
40
Head Injury
33
+34*
36
48
Aware but No Explicit Mediation
Genuine
25
+22*
36
40
Malinger
35
+20*
37
31
Head Injury
27
+30*
45
45
Aware and Explicit Mediation
Genuine
55
+68*
72
87
Malinger
60
+ 18B
30
35
Head Injury
40
+48*b
50
57
Note. Within level of test awareness, means with different superscripts differ
significantly at pc.05.

148
pc.74, indicating that all three groups demonstrated an equivalent perceptual
identification advantage for previously exposed words.
Collapsed across groups, the main effect of orienting task was
nonsignificant, F(1,52)=1.05, pc.31. The interaction between group and
orienting task was also nonsignificant, F(2,52)=.03, pc.97. All three groups
showed a slight trend towards higher percent correct identification of target
words encoded in the physical orienting condition.
An alternative analytic approach involved computing a binary variable
which reflected whether or not each subject demonstrated priming on stem
completion. For each subject, baseline performance for that subject was
subtracted from target performance, resulting in a variable which reflected the
magnitude of priming. Using a very conservative cutoff of a 25% increase in
performance of targets over distractors, each subject was scored as to whether
his stem completion performance reflected priming or no priming. Nine of 20
Genuine subjects (45%) demonstrated priming, compared to 8 of 20
Malingering subjects (40%) and 8 of 15 Head Injury subjects (53.3%).
Nonparametric hypothesis tests for the significance of difference between
proportions failed to reach significance, indicating equivalent numbers of
subjects demonstrated priming in each group.
Reaction time. The reaction time component of the perceptual
identification paradigm served as one indicator of possible response strategies
and criteria employed by subjects in each of the three groups. Specifically,

149
Malingering subjects might be expected to produce increased response
latencies to the extent they were explicitly recognizing target words and then
withholding the correct response. This was evaluated in several ways.
Comparing main effects of word status on response latency relates generally to
the processes underlying perceptual identification. Collapsed across groups,
the main effect of word status on reaction time was nonsignificant,
F(1,52) = 1.93, pc.17. The interaction between group and word status was also
nonsignificant (F < 1). Figure 8 presents this data.
One way Malingering subjects could have lowered their accuracy rate
was by producing incorrect answers. An inhibitory process could be inferred to
the extent that incorrect answers were produced by Malingering subjects at the
expense of exaggerated response latencies. The main effect of answer status
(correct versus incorrect) on reaction time was analyzed within each group.
Figure 8 presents this data. Collapsed across groups, the main effect of
answer status on reaction time was highly significant, F(1,52)=21.28, p<.0001.
The interaction between group and answer status was significant, F(2,52)=4.56,
p<.007. Analyzed within group, the main effect of answer status on reaction
time was significant for the Genuine group, F(1,19)=12.14, pc.001, the
Malingering group, F(1,19) =7.57, pc.009 and the Head Injury group,
F(1,14)=4.40, pc.046. Follow-up mean contrasts demonstrated that all three
groups responded significantly faster when their answer was correct as
compared to incorrect responses, with Genuine subjects demonstrating a

150
greater difference in response latency between correct versus incorrect
answers.
The previous results have shown that perceptual identification of
physically encoded words shows slight but nonsignificant superiority to
identification of conceptually encoded words. While Malingering subjects failed
to significantly lower their accuracy rate by responding with fewer physically
encoded words, trends towards explicitly driven suppression (i.e., "thinking
about it") may be evident in reaction time differences between words encoded
semantically versus physically in the Malingering group. Figure 9 presents this
data. Collapsed across groups, the main effect of orienting task on reaction
time was nonsignificant (F < 1). The interaction between group and orienting
task was also nonsignificant (F < 1). All three groups showed a trend towards
increased response latencies for target words relative to distractor words. A
very subtle but interesting trend was evident in the data. Genuine and Head
Injury subjects showed slightly faster response latencies for physically encoded
words relative to conceptually encoded words, in line with the increased ability
to accurately identify these words. In contrast, the Malingering subjects
showed the opposite pattern of slightly higher response latencies for physically
encoded words. One possible explanation for this would be that Malingering
subjects experienced normal facilitation of identification of physically encoded
words but then engaged in an explicitly driven suppression before responding.

151
Yes/no recognition following identification. The degree to which subjects
employ explicit memory processes while performing nominally implicit memory
tasks could also potentially affect PI performance. However, this particular task
would seem much more immune to contamination from explicit memory due to
the task demands of rapid reporting of near-threshold stimuli. Subjects were
given a list of the same 40 words used in the PI test phase (20 targets, 20
distractors) and instructed to answer "yes" or "no" beside each stimulus word to
indicate whether they recognized this word from the study portion. The task
demands placed on subjects were different than those of the recognition test
following WSC in that subjects did not have visual access to their responses
during the test phase of PI. Two aspects of this task were scored. First, the
probability of correct recognition was conditionalized upon the probability of
correct identification in the test phase of PI. This was operationalized as the
percentage of correctly identified target words which were correctly explicitly
recognized as having been studied [denoted as P(PI+|REC+)]. Second, the
probability of answering "yes" to an incorrectly identified target word was
computed [denoted as P(WS-|REC+)].
Between-group comparisons were carried out on these two probability
estimates. Figure 10 presents this data. The results were nonsignificant for
main effects of group on the conditional probability of correct explicit
recognition and the probability of responding "yes" to a non-identified target
word (F’s < 1).

152
The interaction between group and type of recognition (simple versus
conditionalized) on accuracy rate was nonsignificant, (F < 1). Within-groups
analyses of variance resulted in nonsignificant main effects of type of
recognition (simple versus conditionalized) on accuracy rates for all three
groups (all F’s < 1). These results establish that simple recognition memory
following PI was statistically independent from recognition memory
conditionalized upon correct perceptual identification in all three groups. This
suggests that explicit memory contributed very little to performance on PI.
Trial-bv-trial analysis. A subject could potentially alter his PI performance
to the extent that he or she develops awareness during PI that target words
have been previously encountered in the study phase. On the surface, it would
appear that PI would be much more immune to the effects of explicit memory
than the stem completion task. Similarly, it would appear that deviations in
responding based on explicit memory would be easily detectable by changes in
reaction times. However, PI is much less generative than WSC and therefore
requires only relatively automatic reading from the subject. The withholding or
inhibition of behavior in general would be sufficient for Malingering subjects to
lower their accuracy rate. The change in a subject’s response strategy or
response criterion was operationalized as a reduction in percent accuracy that
occurs over several successive groups of target words. The target words were
divided into groups of 4 words, representing partitions of 20% of the overall list.

153
Figure 10 presents this data. Main effects of serial order on identification
accuracy were analyzed within groups. Within-group analyses were
nonsignificant for the main effects of serial position of blocks of target words for
the Genuine group, F(4,18)=.75, p<.57, the Malingering group, F(4,18)=.39,
p<.81, and the Head Injury group, F(4,13)=.72, p<.60. Thus, no group
demonstrated real evidence of changing response strategies or criteria as they
proceeded through the PI task.
Awareness and intentionalitv. Aspects of awareness were categorized
for PI performance in the same manner as for PI performance. Test awareness
was a necessary condition for explicit mediation in all subject groups.
Therefore, subjects were classified into one of three categories: (1) those who
did not experience test awareness during PI; (2) those who did experience test
awareness but who did not experience explicit memory during WSC; and (3)
those who both experienced test awareness and judged that their performance
was impacted by explicit memory (for Malingering subjects, this means that
they engaged in postretrieval suppression.
Table 16 presents data concerning the relationship between group
membership, test awareness, magnitude of priming on PI, and LOP effects. A
chi-square analysis detected a significant relationship between group
membership and the awareness variable (X*=13.75, p<.008, df=4). Nine
Malingering subjects reported engaging in explicit mediation (suppression)

154
during PI, as compared with one each from the Genuine and Head Injury
groups.
Because test awareness was not an independent variable that was
experimentally manipulated in the design, these data were examined with a
nonparametric test for the comparison of two proportions. Main effects of
Group on strength of priming on PI were analyzed within each level of test
awareness. No significant main effects of Group were found for any of the
three levels of test awareness (all Z’s < 1). While it appears that Malingering
subjects demonstrated weaker priming than Genuine subjects in the Test
Aware/Explicit Mediation condition, the small sample sizes in these cells
mitigated against detecting a significant difference. All three subjects groups
demonstrated priming in all three test awareness conditions. No significant
LOP effects were noted within these groups, although there appeared to be a
relationship between increased awareness and explicit retrieval and greater
completion of physically encoded words in the Genuine and Head Injury
groups.
Free recall
In contrast to the indirect memory tasks, a free recall task was employed
to assess subject’s explicit memory. Figure 11 presents this data. A between-
groups ANOVA revealed the main effect of group on free recall performance
was highly significant, F(2,52)=28.08, p<.0001. Follow-up mean contrasts
revealed that Genuine subjects demonstrated significantly higher free recall

155
PERCEPT. IDENTIFICATION
Target Advantage
% correct identification
Word Status
ÜÜ Targets
1MS3 Distractors
GENUINE MALINGER CHI
Targets 49.8 38.2 51.2
Distractors 25.5 18.2 23.1
Encoding Process
GENUINE
MALINGER
CHI
Sentence
47.6
37.4
50
Letter
52.2
39
52.4
Figure 7. PI Performance: Priming and Encoding Effects.

156
P.l. REACTION TIME
Word Status
seconds
GENUINE
MALINGER
CHI
Targets
1.776
2.019
1.92
Distractors
1.648
1.868
1.861
VARS
Targets
Distractors
Answer Status for Target Words
seconds
3.5
3
2.5
2
1.5
1
0.5
0
GENUINE MALINGER CHI
Correct 1.407 1.702 1.602
Incorrect 2.145 2.335 2.238
Figure 8. PI Reaction Time Data: Word Status and Answer Status.

157
P.l. REACTION TIME
Encoding Process
seconds
3.5
3
2.5
2
1.5
1
0.5
0
GENUINE
MALINGER
CHI
Sentence
1.765
1.88
1.938
Letter
1.686
1.956
1.847
Processing by Answer Interaction
seconds
Groups
~^ Genuine
— Malinger
CHI
Cor. Letter Cor. Sent. Incor. Letter Incor. Sent.
Genuine 1.327 1.397 2.043 2.131
Malinger 1.588 1.421 2.232 2.338
CHI 1.578 1.612
Figure 9. PI Reaction Time Data:
2.116 2.236
Encoding Process Effects.

158
PERCEP. IDENTIFICATION
Conditional Probabilities
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Conditional 0.87 0.62 0.79
Simple 0.82 0.61 0.72
Recognition
Conditional
Simple
PI Serial Position
% correctly identified
20 -
GROUPS
-S- GEN
+ MAL
CHI
1 to 4 5 to 8 9 to 12 13 to 16 17 to 20
Figure 10. PI Performance: Conditionalized Recognition and Serial Position

159
Table 16
Test Awareness and Retrieval Intentionalitv in Perceptual Identification
%of
Group
Priming
Levels of
Processing
Sen. Let.
Not Aware
Genuine
65
+21*
46
48
Malinger
30
+ 13*
36
33
Head Injury
73
+28*
51
51
Aware but No Explicit Mediation
Genuine
30
+30*
50
62
Malinger
25
+33*
56
54
Head Injury
20
+32*
53
67
Aware and Explicit Mediation
Genuine
5
+40*
50
50
Malinger
45
+ 18*
28
34
Head Injury
7
+20*
30
20
Note. Within level of test awareness, means with different superscripts differ
significantly at p<.05.

160
(mean=35%) than either the Malingering (mean=15.5%) or Head Injury groups
(mean=10.3%), which were not significantly different from each other.
Within-group analyses of variance showed the main effect of orienting
task was highly significant for the Genuine group, F(1,19)=24.21, pc.0001, the
Malingering group, F(1,19)=33.62, pc.0001, and the Head Injury group,
F(1,19)=8.65, pc.01. Figure 11 presents this data. Follow-up mean contrast
tests established that all experimental groups recalled significantly more words
encoded in the conceptual orienting condition than words encoded in the
physical orienting condition. The interaction between group and orienting task
approached but failed to reach significance, F(2,52)=2.70, pc.08.
Multiple choice recognition
Main task analysis. Multiple choice recognition was employed as another
indirect memory test. Figure 12 presents this data. A between-groups ANOVA
revealed the main effect of group on multiple choice recognition was highly
significant, F(2,52) = 18.39, pc.0001. Follow-up mean contrasts revealed that
genuine subjects demonstrated significantly higher explicit memory
(mean=93.8%) as measured by recognition of previously presented words than
either the Malingering (mean=62.5%) or Head Injury groups (mean=70.7%),
which were not significantly different from the other.
Within-group analyses of variance showed the main effect of orienting
task was nonsignificant for the Genuine group, F(1,19)=1.43, pc.25, the
Malingering group, F(1,19)2.70, pc. 12, and the Head Injury group,

161
F(1,19)=4.28, pc.06. The interaction between group and orienting task failed
to reach significance, F (2,52)=.82, pc.44. Figure 12 presents this data. The
failure of subjects in each group to demonstrate the expected advantage for
conceptually encoded words is consistent with other reports in the literature of
an absence of orienting task effects in recognition paradigms (see Bradshaw &
Anderson, 1982). The task demands of this task were not difficult, permitting
subjects to accurately recognize words encoded in the physical condition.
Trial-bv-trial analysis. A Malingering subject could potentially suppress
his multiple choice recognition performance to the extent that he perceived that
he is "over-responding" or portraying memory ability of insufficient impairment,
not understanding the undemanding task requirements of MCR. The change in
a subject’s response strategy or criterion was operationalized as changes in
percent correct recognition for successive blocks of test words. The stimuli
were divided into groups of 4 words, representing partitions of 20% of the
overall list.
Figure 13 presents this data. Main effects of serial order were analyzed
within groups. Within-group analyses were nonsignificant for main effects of
serial position of blocks of target words for the Genuine group, F(4,18)=1.68,
pc.16, or the Malingering group, F(4,18)=2.66, pc.039. A significant main
effect of serial order was found for the Head Injury group, F(4,13)=4.72,
pc.002. Follow-up mean contrasts revealed that Head Injury subjects
recognized significantly fewer words on the last 20% of the test list than from

162
FREE RECALL
Overall Performance
% correctly recalled
70
60
50
40
30
20
10
0
GENUINE MALINGER CHI
Free Recall 35 15.5 10.3
Encoding Process
% correctly recalled
70
60
50
40
30
20
10
0
GENUINE MALINGER CHI
Sentence 49.6 27 16.6
Letter 20.6 4.6 4
Figure 11. Free Recall: Overall Performance and Encoding Effects.

163
MC RECOGNITION
Overall Performance
% correctly recognized
100
90
80
70
60
50
40
30
20
10
0
GENUINE MALINGER CHI
MC Recognition 93.8 62.5 70.7
Encoding Process
% correctly recognized
100
90
80
70
60
50
40
30
20
10
0
GENUINE
MALINGER
CHI
Sentence
96
71.4
78.6
Letter
91.6
54
62.6
Figure 12. MC Recognition: Overall Performance and Encoding Effects

164
MCR SERIAL POSITION
% correctly recognized
GROUPS
-e- GEN
+ MAL
CHI
Figure 13. MC Recognition: Serial Position Effects.

165
the second 20%. No other blocks of words were significantly different. This
finding may reflect the vulnerability of the Head Injury patients to increasing
levels of interference as the task proceeds.
Symptom Validity Testing
Two components of the Symptom Validity Testing paradigm were
analyzed. First, the subject’s number of correct responses over the 100 trials
(expressed as percent correct) were subjected to between-groups analyses of
variance. Second, reaction time data was analyzed between-groups.
Characteristics of the performance of the Malingering group were analyzed in
more fine detail.
Between-groups analyses
Response accuracy. A between-groups analysis of variance resulted in
a highly significant main effect of group upon SVT accuracy rate,
F(3,60)=17.23, pc.0001. Follow-up mean contrasts revealed that the
Malingering group scored significantly lower (mean=81.6% correct) than either
the Genuine (mean=100% correct), the Head Injury group (mean=98.7%
correct), or the Amnesic group (mean=99.8%), which were not significantly
different from one another. Table 16 presents the response accuracy data.
Response latency. The response latency to forced choice testing could
potentially be sensitive to a malingering response style in that Malingering
subjects may generally produce slowed or exaggerated behavior while playing
their role. A between-groups analysis of variance demonstrated a highly

166
significant main effect of group on SVT response latencies, F(2,52)=24.42,
pc.0001. Follow-up mean contrasts revealed that Malingering subjects
(mean=2.46 seconds) produced significantly longer response latencies to
respond to items, irrespective of correctness of response, than either the
Genuine (mean=0.76 seconds) or Head Injury groups (mean=1.28 seconds),
which were not significantly different from one another. Table 17 presents these
data. A similar analysis was conducted for correct answers only, with
equivalent results. A highly significant main effect of group on response
latencies for correct responses was found, F (2,52)=25.57, pc.0001. Follow-up
mean contrasts produced the same ordering of means. Finally, an analysis
was conducted for the main effect of group on reaction time for incorrect
answers (Genuine subjects were excluded due to the absence of incorrect
answers). The results were nonsignificant (F c 1).
As contrasted with a general process of producing slowed or
exaggerated behavior, Malingering subjects may also demonstrate trends
towards inhibition or suppression of correct responses during the SVT
paradigm (i.e., "thinking about it"). This process could potentially be manifest
as differential response latencies for correct versus incorrect answers. A within-
group analysis was performed on the Malingering group only. The main effect
of answer status on response latency was nonsignificant (F < 1), but response
latency was slightly slower for incorrect answers.

167
Characteristics of malingering performance
The Malingering subjects’ performance on SVT is unexpected given what
has previously been reported in the literature. Pankratz and his colleagues
(Pankratz, 1983; Pankratz, Fausti, & Peed, 1975) designed SVT to function as a
clinical tool. One requirement necessary for SVT to be useful in this context is
that the results of SVT can be applied on an individual-subject basis. In order
to fulfill this requirement, the absolute criterion of random or chance
performance is used as the comparison value. Principles of binomial probability
theory are used to determine the probability associated with a particular
subject’s performance. The criterion of random or chance performance
provides strong and convincing, though not irrefutable, evidence that a subject
is exaggerating impairment. However, a careful examination of the results
presented here provides a strong indication that the criterion of chance
performance may be too rigorous and may result in insensitivity to malingering
response styles.
Table 18 presents SVT data for all Malingering subjects. A score of 41%
accuracy (out of 100 trials) is associated with the cumulative binomial
probability of .0443. Thus, a subject must obtain a score of 41% accuracy (for
100 trials) or less in order to be classified as performing significantly below
chance, at the .05 alpha level. No Malingering subject scored this low; only one
subject (# 34) scored below nominal chance performance (45/100, binomial
probability=0.184). Only three other Malingering subjects scored near chance

168
levels. At the other extreme, six of 20 Malingering subjects (30%) produced
perfect accuracy rates on SVT. In their debriefing interview, these subjects
consistently related their perceptions that SVT was an extremely easy task and
that producing even a few incorrect answers would render their performance
unbelievable. Table 19 shows quite clearly that Malingering subjects produced
remarkably consistent accuracy rates as they proceeded through the task.
Relation to clinical memory tests. Symptom Validity Testing appears to
be a generally easy task requiring very little effort to complete correctly.
Pearson product-moment correlations were computed between the two SVT
scores (accuracy rate and mean reaction time) and the major clinical memory
variables. Table 20 presents this data. Both SVT accuracy rate and mean
response latency were highly correlated with the clinical memory variables.
These relationships were essentially equivalent when computed from just the
Malingering group. Several aspects of these results bear comment. First, SVT
response latency shows consistently stronger relationships with the clinical
variables than the accuracy score. Second, accuracy rate on SVT bears no
statistically significant relationship with response latency on SVT, suggesting
that these two components may be independent. Third, the intriguing
relationship between performance on SVT and the WMS Delayed Visual
Reproduction is apparent from the inspection of Tables 18 and 20. As can be
seen, very poor scores on Delayed Visual Reproduction are associated with
lowered scores on SVT in the Malingering group.

169
Alternative data analysis strategies. Binomial principles can be applied to
SVT data in two other ways, both illustrating the difficulty in using a random or
chance level of performance as the criterion for malingering. Miller (1986)
presented a case study in which a patient was suspected of producing
hysterical sensory loss. This patient obtained a score of 56/120 on 2-item,
forced choice testing. This score was below nominal chance performance of
60/120, but failed to reach the necessary .05 binomial significance level of 50
out of 120. In order to further understand this patient’s performance, the author
subdivided the total of 120 trials into 24 blocks of 5 trials each. This data is
presented in Table 21. The subject could potentially produce 0 through 5
correct responses per trial block. Cross-tabulation frequency counts were then
computed for the number of trial blocks in which the subject produced all
possible number of correct responses (0 to 5). Finally, expected frequencies
for each cell were computed. A chi-square analyses demonstrated that the
subject obtained scores of 2/5 and 3/5 on a higher than expected number of
trial blocks. Using this statistical procedure, Miller was able to demonstrate that
his patient’s performance deviated significantly below chance for a portion of
the SVT procedure.
In the current dataset, one subject obtained a score of 45/100, which
falls below the nominal chance level but fails to reach statistical significance.
The subject only produced 1 correct response during trials 70 to 79. Refer to
Table 18 for this subject’s (# 34) data. Expected frequencies of each possible

170
score within each 10 trial block were computed based on binomial probability.
When these expected score frequencies were crossed with the obtained score
frequencies, a chi-square analysis on this subject’s data failed to reach
significance, X2=3.385, df=5. This failure of statistical and probability methods
to detect deviations from chance performance on a subject whose performance
is clearly in question highlights the difficulty with using the chance criterion.
The standard use of the binomial distribution is to calculate probabilities
and cumulative probabilities associated with chance performance. Another use
of binomial probability methods could potentially increase the ability of the
clinician to detect malingered or exaggerated performance. Rather than using
.50 (chance) as the estimate of the true population proportion, the subject’s
own total score, expressed as the accuracy rate, could instead be used to as
the estimate for the true population proportion. Next, the binomial distribution
could be constructed for 10 block trials, resulting in the cumulative probabilities
for obtaining scores of 0/10, 1/10, 2/10, etc. based on the subject’s own level of
overall performance.
To follow the previous example, Subject #34 obtained a score of 1/10
correct during trials 70 to 79. The cumulative binomial probability of obtaining
this score, based on the estimate of the true population proportion of .45, is
significant at the .05 level (p=.0236). Thus, it can be established for this
subject that a portion of her SVT performance fell significantly below what
would be expected given her performance over the 100 trials. It is important to

171
Table 17
Univariate Group Differences on Symptom Validity Testing
Group
Variable Genuine
Malinger
Head Injury
Amnesic
SVT Accuracy Rate
Mean 100a
SD 0
F(3,60) = 17.23***
81.6B
17.9
98.7*
1.9
99.8*
0.44
SVT Mean Overall Reaction Time
Mean 0.76*
SD 0.14
F(2,52) = 24.42***
2.46s
1.25
1.28*
.37
N/A
SVT Mean RT for Correct Responses
Mean 0.76*
SD 0.14
F(2,52) = 25.57***
2.45s
1.24
1.26*
0.33
N/A
SVT Mean RT for Incorrect Responses
Mean
SD
F(1,17)=0.12
2.90
1.57
2.62
1.74
N/A
* p<.05 ** p<.01 *** p<.001
Note. Means with different superscripts differ significantly at pc.05.

172
Table 18
SVT and Selected Clinical Data for Malingering Group
Subject
Number
SVT
%Cor
SVT
RT
WMS
MQ
WMS
VR
Delay
CVLT
Total
1-5
ROCF
Delay
34
45
1.85
80
0
35
2.5
36
57
2.10
57
0
31
0.5
20
58
3.87
64
1
31
10.5
12
59
3.58
59
0
44
3.5
24
62
1.70
72
1
24
9.0
28
69
1.69
87
2
60
10.5
16
74
3.77
86
6
61
18.0
9
77
2.45
73
0
36
12.5
15
82
1.50
90
0
36
15.5
33
84
5.07
53
0
14
2.0
39
86
3.87
93
3
27
11.0
23
89
1.85
93
2
39
14.0
14
90
1.48
90
6
47
12.0
27
99
4.30
80
4
44
14.5
2
100
1.73
94
4
38
15.0
5
100
2.11
87
4
36
15.5
8
100
3.52
84
1
57
8.0
18
100
0.67
103
13
40
16.5
31
100
0.59
97
10
57
19.0
38
100
1.34
106
9
51
15.0
Note. All data are raw scores.

173
Table 19
SVT Response Data for Malingering Group
Blocks of 10 Trials
Subject SVT
Number
%Cor
1
2
3
4
5
6
7
8
9
10
34
45
7
4
3
4
5
3
1
5
5
8
36
57
5
8
8
6
4
7
5
5
5
6
20
58
7
7
7
6
5
5
6
6
4
5
12
59
6
6
5
8
6
4
6
6
6
7
24
62
5
6
5
6
6
6
7
7
8
6
28
69
7
7
8
7
7
6
7
6
6
8
16
74
10
9
8
9
7
6
5
6
7
7
9
77
9
8
8
7
10
8
8
5
6
8
15
82
10
9
9
8
8
7
7
8
8
8
33
84
9
8
10
9
9
9
8
8
7
7
39
86
10
10
9
8
8
9
9
9
7
7
23
89
9
8
9
9
9
9
9
8
9
10
14
90
10
10
9
9
10
9
8
8
8
9
27
99
10
10
10
10
9
10
10
10
10
10
2
100
10
10
10
10
10
10
10
10
10
10
5
100
10
10
10
10
10
10
10
10
10
10
8
100
10
10
10
10
10
10
10
10
10
10
18
100
10
10
10
10
10
10
10
10
10
10
31
100
10
10
10
10
10
10
10
10
10
10
38
100
10
10
10
10
10
10
10
10
10
10
Note. All data are raw scores.

174
Table 20
Correlations between SVT and Clinical Memory Variables
SVT Mean
SVT %
Reaction
Correct
Time
SVT Mean Reaction Time
-0.16
WMS Memory Quotient
0.53***
-0.64***
Digits Backward
0.43***
-0.67***
WMS Immed. Logical Memory
0.37**
-0.40**
WMS Delayed Logical Memory
0.44***
-0.50***
WMS Immed. Visual Reprod.
0.52***
-0.57***
WMS Delayed Visual Reprod.
0.59***
-0.62***
CVLT Total Trials 1-5
0.31*
-0.47***
CVLT Short Delay Free
Recall
0.33*
-0.47***
CVLT Long Delay Free
Recall
0.41**
-0.55***
CVLT Recognition Hits
0.46***
-0.39**
ROCF Immediate Reprod.
Reproduction
0.45***
-0.25
ROCF Delayed Reprod.
0.48***
-0.41**
* pc.05
** pc.01
*** pc.001

Table 21
SVT Analyses based on Miller (1986)
Number of Correct Responses
'
0
1
2
3
4
5
Total
Expected
0.75
3.75
7.5
7.5
3.75
0.75
24
Observed
0
2
12
10
0
0
24
Note. The data represent the frequency of the correct responses per trial block
(out of 5 total). Row data should sum to 24.
Source. Miller (1986).

176
note that this method fails to detect any other Malingering subject, highlighting
the relative consistency from trial to trial that Malingering subjects are capable
of achieving. This is one additional example of the difficulty in firmly
establishing the presence of malingering or exaggeration.
Multivariate Statistical Detection of Malingering
Whereas previous statistical analyses have focused on establishing
group differences on the various experimental and clinical memory tests, the
current analysis addresses the overall question of whether some multivariate
combination of variables is capable of making a classification between no
memory impairment (Genuine group), malingered memory impairment
(Malingering group), and bona-fide memory impairment (Head Injury group).
Linear discriminant function analyses are routinely used to address questions
related to the clinical utility of tasks in detecting group membership (i.e.,
diagnosis).
Experimental memory tasks
Variables comprising the set of measures of experimental memory tasks
comprised two general types. The indirect memory measures included the
magnitude of priming for stem completion and perceptual identification as well
as the mean reaction time for correctly identified target words during PI.
Measures of explicit memory included the explicit recognition probes associated
with the PI and WSC tasks as well as the free recall and multiple choice
recognition tasks. Two separate questions could be addressed by dividing the

177
variables in this manner. The first issue pertains to the ability of all of the
experimental memory variables, implicit as well as explicit, to detect group
membership. The second issue pertains to the ability of the three implicit
memory variables, taken alone, to predict group membership.
All experimental memory variables. Table 22 presents the classification
rates produced from a linear discriminant function analysis based on the entire
experimental memory variable set. Overall, this variable set produced
surprisingly accurate group predictions. Whereas group differences on the
individual variables failed to separate the three groups, the linear combination of
all tasks would appear to offer a relatively useful clinical tool. Malingering
subjects were classified with the least amount of accuracy. However, the
sensitivity rate of 89.4% and the specificity rate of 11% offer clinically significant
improvements over chance diagnostic rates.
Genuine subjects were identified quite accurately; only one subject was
classified as belonging to the Malingering group. This subject’s scores on the
experimental memory tasks were characterized as below average performance
on implicit memory tasks and significantly below average performance on the
explicit memory tasks. Head Injury subjects were identified quite accurately as
well; only one subject was identified as belonging to the Genuine group. This
subject’s scores on the experimental memory tasks were characterized as
above average performance on implicit memory tasks but performance on
explicit memory tasks equivalent to that of Genuine subjects.

178
Malingering subjects were identified with less accuracy than subjects in
the other two groups. Three subjects were classified as belonging in the
Genuine group. These subjects produced scores on indirect and direct tests
equivalent to the Genuine group. Only one Malingering subject was classified
as belonging to the Head Injury group. This subject’s scores on the
experimental memory tasks were characterized as average performance on
implicit memory tasks but poor performance on explicit memory tasks,
equivalent to the bona-fide impairment of Head Injury subjects.
Indirect memory variables. Table 23 presents the classification rates
produced from a linear discriminant function analysis based on just the implicit
memory indices. Overall, implicit memory tasks failed to produce accurate
group predictions. The sensitivity rate of 43.9% and the specificity rate of 56%
were inadequate for clinical use. The group membership of Head Injury
subjects proved especially difficult to predict; only 1 of 15 was correctly
predicted. Additionally, these results confirm the hypothesis raised above that
the discriminant power exhibited by the experimental memory tasks as a group
was primarily the consequence of the direct rather than indirect memory tasks.
Clinical memory tasks
Within each clinical memory construct, one variable representing that
aspect of memory was selected to be included in this analysis based on the
highest F statistic. These variables included WMS Memory Quotient, Digits
Backward, WMS Immediate and Delayed Visual Reproduction, CVLT Total of

179
Trials 1 to 5, CVLT Short and Long Delay Free Recall, and CVLT Short and
Long Delay Cued Recall. Table 24 presents the classification rates produced
from a linear discriminant function analysis based on this variable set. Overall,
this variable set produced highly accurate group predictions. The sensitivity
rate of 92.2% and the specificity rate of 8% offer clinically significant
improvements over chance diagnostic rates.
Genuine subjects were classified with 100% accuracy. Malingering
subjects were classified with 90% accuracy; only two of 20 were classified as
belonging to the Head Injury group. Both of these subject’s scores on the
clinical tasks were characterized by (1) low but not impaired general memory
functioning; (2) low but not impaired list learning; and (3) poor attention and
concentration. Head Injury subjects were identified quite accurately as well; of
the 20 subjects, one subject was misclassified as Genuine and one as
Malingering.
Malingering subjects were identified with less accuracy than subjects in
the other two groups. Three subjects were classified as belonging in the
Genuine group. These subjects produced scores on clinical memory tests
equivalent to the Genuine group. Only one Malingering subject was classified
as belonging to the Head Injury group.
Experiential and De-Briefing Variables
Given the nature of this study, subjects in the Genuine and Malingering
conditions were interviewed at length about their experiences and perceptions

180
Table 22
Classification Rates for Experimental Memory Tasks
Actual Group
Membership
Classified into Group based on LDF
Genuine
Malingering
Head Injury
Genuine
95.0%
5.0%
0.0%
Malingering
15.0%
80.0%
5.0%
Head Injury
6.7%
0.0%
93.3%
Table 23
Classification Rates for Stem Completion and Perceptual Identification Tasks
Actual Group
Membership
Classified into Group based on LDF
Genuine
Malingering
Head Injury
Genuine
60.0%
30.0%
10.0%
Malingering
25.0%
65.0%
10.0%
Head Injury
53.3%
40.0%
6.7%
Table 24
Classification Rates for Selected Clinical Memory Variables
Classified into Group based on LDF
Actual Group
Membership Genuine Malingering Head Injury
Genuine 100.0% 0.0% 0.0%
Malingering 0.0% 90.0% 10.0%
Head Injury 6.7% 6.7% 86.6%

181
while playing their respective roles during the experiment. Immediately after the
role-playing phase of their participation, subjects were given verbal descriptions
of many of the memory tasks they completed and asked to make Likert ratings
concerning (1) their effort on that particular task; (2) their perceptions of the
difficulty of the task (for a "normal" person with genuine motivation); and (3) and
their perceived success at portraying their role (either "best effort possible" or
"severe but believable impairment"). Twenty two tasks were described; each
subject rated the three characteristics for each task. The form used for
obtaining these ratings is presented in Appendix C. Subjects were then given a
chance to discuss their perceptions and feelings about their role playing.
Debriefing ratinas
The following discussion will selectively evaluate the debriefing ratings
concerning several of the more important memory tasks. Table 24 presents
this data. Ratings from individual tasks were averaged to obtain a mean rating
of effort, task difficulty, and role-success for each subject. Analyses of variance
produced highly significant main effects of group on the Effort score,
F(1,39)=18.92, pc.0001, the Task Difficulty score, F(1,39)=12.72, pc.0012, and
the Role-Success score, F(1,29)=18.92, pc.0001. The variance observed in
these variables was highly constricted in both groups, suggesting that the
experiences and perceptions were highly similar within the respective groups.
Follow-up mean contrasts revealed that Malingering subjects perceived
their effort as significantly less than that perceived by Genuine subjects.

182
Genuine subjects perceived tasks as significantly more difficult than did
Malingering subjects. Malingering subjects perceived themselves as
significantly less successful in playing their role of producing "severe but
believable impairment' than did Genuine subjects in achieving their best
memory performance.
Both subject groups appeared to hold similar perceptions about the
implicit memory tasks. Word stem completion was perceived as relatively easy
by both groups. Similar effort scores supports the hypothesis that Malingerers
were engaged in effortful processing that involved explicitly-mediated
suppression. Genuine subjects were highly confident in their success in WSC.
One interpretation is that strong explicit memory traces contributed to their self-
knowledge of very high performance levels. Both groups rated PI as more
difficult and effort-demanding than WSC. Similar Success scores for PI suggest
the ambiguous aspects of the task make perceptions of successful and
unsuccessful performance difficult for the naive subject.
Malingering subjects rated themselves as putting forth less effort than
their Genuine counterparts on the SVT paradigm. Interestingly, Malingering
subjects rated SVT as quite easy and undemanding. On the other hand,
Genuine subjects were highly confident in their successful performance on SVT,
with Malingering subjects rating themselves as less confident of the success of
their role-playing.

183
Table 25
Debriefing Ratinas for Genuine and Malingering Subjects
Effort
Difficulty
Success
Task
G
M
G
M
G
M
Word Stem Completion
4.53
3.65
2.93
2.24
6.00
4.29
Perceptual Identification
6.40
5.24
5.93
5.06
4.00
4.47
Symptom Validity Testing
5.07
3.65
2.60
1.18
6.87
3.71
WMS Delayed Visual
Reproduction
5.73
3.94
4.60
3.59
4.87
4.41
Overall Rating Score
5.31
3.99
4.08
3.01
5.30
4.17
Note. Column subheadings are abbreviated as follows: G=Genuine and
M=Malingering. The data are raw scores (on a scale from 1 to 7), averaged
within group.

184
Responses to open-ended questions
Without exception, subjects in either the Genuine or Malingering
conditions reported how difficult their roles were to play. Genuine subjects
discussed the inherent difficulty of the tasks. Malingering subjects discussed
the necessity to simultaneously attend to both their own bona-fide memory
capabilities and their ongoing calibration of decreased performance levels. The
high demand placed on Malingering subject’s attention and concentration led to
an interesting phenomenon. It appeared that most Malingering subject’s
information processing capacities became overwhelmed during some tasks,
resulting in bona-fide memory problems for that task. This phenomena would
be analogous to encoding stimuli under degraded or attention-divided
conditions. In several subjects, this led to uncertainty and even anxiety over
their perceptions of their true memory abilities. All malingering subjects
reported their uncertainty over the believability of the impairment they
produced.

CHAPTER 4
DISCUSSION
Validity of Group Membership
Genuine and Head Iniurv Subjects
The data reviewed in Chapter 3 indicate that subjects in the Genuine
condition adequately invested themselves in their respective scenario and role-
playing to the extent that their performance on clinical memory tests was
normal. In fact, Genuine subjects demonstrated intact and even above average
memory abilities as indexed by the clinical memory tests. Debriefing and
interview data further establish that the participation of these subjects was
adequate. The overall level of performance was relatively high, but consistent
with what would be expected of these subjects based on their age, education
level, and measured intelligence.
Head Injury subjects demonstrated impairment on clinical tasks requiring
complex attentional processes and the learning and retention of new
information. As a group, their level of performance fell in the moderate-to-
significantly impaired range of scores. This group of subjects scored an
average of 2.3 standard deviations below the Genuine group. Relatively
equivalent performance declines were noted on verbal and nonverbal memory
185

186
tasks. Complex immediate memory functions were impaired as well as most
indices of recent memory. Finally, inefficiency in all process-oriented
distinctions (encoding, storage, retrieval) of memory was observed. As a
group, the performance of the Head Injury subjects was clearly consistent with
the moderate-to-severe nature of their injuries.
One possible criticism of this study would be that this sample of Head
Injury patients was not representative of the type of patients most often seen in
the medicolegal context for forensic neuropsychological evaluation. Given the
need to exclude patients involved in current litigation or even considering future
litigation, I would argue that there does not exist a large pool of CHI patients
which would closely match litigating head injury patients. Several factors may
be interacting here.
First, the definition of "compensable injury" would necessarily include the
presence of an external party which could potentially be responsible for the
injury. Thus, litigation status may be determined in part by the assignment of
"fault1, such that patients who caused their own injury are excluded from
litigation while innocent victims are not excluded from litigation. Second,
patients suffering an obviously severe injury which can be unequivocally
documented with neurological evaluation may receive compensation or
settlement of their legal claim more quickly than those patients with equivocal
findings. Nevertheless, the identification and participation of these Head Injury
patients was secured with great effort and expense.

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To sum to this point, the Genuine subjects demonstrated above average
memory abilities while the Head Injury patients demonstrated moderate-to-
significant memory impairment consistent with the severity of their injuries.
Given the nature of these two comparison groups, we turn our attention now to
the performance of the Malingering subjects.
Performance of Malingering Subjects
Schretlen (1988), in his review of the literature on the psychometric
detection of malingering, classifies studies into three levels of methodological
sophistication. The present study represents the highest level of sophistication
in that it includes all possible groups: experimental (Malingering subjects),
criterion (Head Injury patients with bona-fide memory impairment), and control
(Genuine subjects). Schretlen (1988) also discusses experimental procedures
which increase experimenter control but which operate at the cost of ecological
validity. He refers to these as "analog factors." Perhaps the three most
important analog factors in neuropsychological malingering research are (1) the
need to assess the extent to which malingering subjects actually portray their
role; (2) the degree of didactic information or "coaching" provided to
experimental malingerers; and (3) the desirability of providing an external
incentive to these subjects which rewards successful faking.
Data from the current study suggests that subjects in the Malingering
condition adequately invested themselves in their respective scenario and role-
playing to the extent that their performance on clinical memory tests was

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"impaired" and below that of the Genuine subjects. In terms of quantitative level
of memory abilities, Malingering subjects produced scores which were
remarkably similar to Head Injury subjects. Malingering subjects typically
performed much worse than Genuine subjects. The average effect size
associated with malingering was -2.2 standard deviations. This effect size
approached the average effect size of -3.4 computed from the literature. On
average, the impairment demonstrated by Malingering subjects surpassed that
of the Head Injury subjects, although univariate hypothesis tests rarely detected
a statistically significant difference between these two groups. Debriefing and
interview data further establish that the compliance with instructional set was
adequate for subjects in the Malingering condition.
Malingering subjects generally scored slightly higher than Head Injury
subjects on tasks measuring attention and concentration, immediate free and
cued recall of verbal material, and delayed cued recall of verbal material.
Malingering subjects scored lower than Head Injury subjects on tasks
measuring delayed free recall of verbal and nonverbal material. With few
exceptions, Malingering subjects successfully portrayed the qualitative aspects
of bona-fide memory impairment. This included the Malingering subjects’ ability
to accurately balance the omission of correct behavior with the commission of
incorrect behavior to produce responses similar in quality to bona-fide memory
impairment.

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Therefore, subjects in the Genuine and Head Injury groups appeared to
be representative of the larger population of subjects. Malingering subjects
performed similar to those in other reported studies of experimental simulation.
In general, clinical memory tests were not overwhelmingly useful in separating
Malingering subjects from Head Injury patients.
As regards the external incentive for the experimental subjects, the
University of Florida Introductory Psychology class required students to earn
eight credits based on participation in experiments. The UF Psychology
Department Subject Pool policies, however, forbade any use of performance-
based incentives. This meant that subjects could not receive additional rewards
beyond their participation, either in the form of extra class credit or money.
However, it should be noted that this study offered subjects the opportunity to
earn all but one of the credits they needed in one testing situation. Only one
study has directly examined this analog factor experimentally. Bernard (1990)
found no significant differences on memory performance between incentive-
based and non-incentive based experimental malingerers. Schretlen (1986)
provided prison inmates instructed to malinger monetary incentive to avoid
detection, but no comparison group was used. Therefore, the fact that
Malingering subjects were not given an additional external incentive does not
appear to be a serious threat to the validity of the findings.
Several studies have provided varying degrees of didactic information
and coaching to experimental malingerers (Boone, 1988; Hayward et al., 1987).

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Boone (1988) found that experimental malingerers who were coached on
techniques to avoid inconsistency in their performance subsequently performed
with less inconsistency than non-coached malingerers. In contrast with this
study, Hayward et al. (1987) asked neurological and neurosurgical nurses to
feign left frontotemporal brain dysfunction on neuropsychological tests. Despite
their presumably high levels of knowledge about the criterion impairment group,
these nurses were unsuccessful at mimicking either the quantitative and
qualitative aspects of the criterion impairment group. Little can be concluded
about the issue based on these somewhat divergent findings.
The results of the current study present similar interpretive problems. On
the one hand, the Malingering subjects would appear to have successfully
incorporated the didactic information into their performance. On the other
hand, these same subjects reported after the experiment that this information
was helpful in initially formulating their role-performance but that the on-line use
of this information during their role-playing was very difficult.
Experimental Memory Tasks
The main findings concerning performance on the experimental memory
tests were that (1) all three groups produced similar LOP effects for direct tests
in that semantically encoded words were retrieved significantly more frequently
than physically encoded words; and (2) all three groups produced similar null
LOP effects for indirect tests, although physically encoded words were
produced with slightly more frequency than semantically encoded words. The

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prediction that Malingering subjects would lower their overall level of
performance on WSC did not occur. Rather, Genuine subjects used explicit
memory to increase their WSC performance. This accounted for the observed
differences between these two groups. No detectable changes in response
strategies or response criteria were evident from analysis of WSC serial
position.
The prediction that the PI task would be relatively immune to the effects
of explicit memory was borne out from two perspectives. Malingering subjects
failed to lower their performance with explicit memory suppression, while
Genuine subjects were unable to raise their performance with explicit memory
mediation. The prediction that Malingering subjects would produce increased
response latencies was not accurate as well. When viewed from a clinical
perspective, the performance of Malingering subjects on the experimental
memory tests was indistinguishable from the memory-disordered Head Injury
patients in terms of quantitative level of performance, response latency, and
LOP effects.
Priming Effects
Study 1 established that the materials and procedure used in this study
were valid indices of direct and indirect memory. Amnesic subjects
demonstrated normal priming on word stem completion and perceptual
identification in spite of severely impaired explicit memory as indexed by free
recall and multiple choice recognition. Amnesic performance on indirect

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memory tests was equivalent to that of a group of age and education matched
control subjects.
Similarly, all three experimental groups in Study 2 demonstrated at least
normal priming effects on WSC and PI. Genuine subjects produced an
unexpectedly high magnitude of priming on WSC relative to any other group;
this was significantly greater than that produced by the Malingering and Head
Injury groups, which were not significantly different from each other. However,
this data pattern did not occur for the PI task: the three groups did not differ
with respect to magnitude of priming effects on PI. The present findings are
generally consistent with the two published studies which have used indirect
memory tests with experimental malingerers. Wiggins and Brandt (1988) found
that simulators demonstrated a normal magnitude of priming on word stem
completion when tested immediately after exposure to the study words. These
same subjects did, however, suppress responding with target words when
retested the next day. Williamsen et al., (1965) found experimental malingerers
to significantly attenuate their performance on other indirect memory tests, in
this case word fragment completion and free association. However, in that
study, malingering subjects were directly instructed on how to enact their role.
Levels of Processing Effects
In Study 1, Amnesic patients failed to recall almost all of the study words
on the FR test, consistent with their severe explicit memory impairment.
Amnesic patients had so little explicit memory that their recall could not benefit

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from semantic processing. Control subjects recalled approximately 17% of the
words, and demonstrated significantly higher levels of recall for semantically
encoded words relative to physically encoded words. The explicit memory
performance of both groups improved when tested with the multiple choice
recognition paradigm. Amnesic subjects recognized only 45% of the target
words (compared with the 25% rate associated with chance guessing) and
failed to demonstrate the LOP effect of recognition advantage for semantically
encoded words. The controls recalled significantly more (78%) words in
general and their recognition of semantically encoded words was significantly
greater than for physically encoded words.
In Study 2, all three groups demonstrated significant LOP effects when
tested on the FR paradigm in that a greater proportion of semantically encoded
words were recalled relative to physically encoded words. The interaction
between encoding condition and group was also nonsignificant, indicating that
all three groups demonstrated equivalent LOP effects. A similar data pattern
was observed for all groups when tested on the MCR paradigm. All three
groups demonstrated higher levels of recognition for semantically encoded
words relative to physically encoded words; however, this advantage was not
statistically significant for all three groups. These results are consistent with
other studies which failed to produce LOP effects on recognition paradigms
(c.f., Bradshaw & Anderson, 1982). These results can be explained by the
processing model, which holds that recognition memory tests usually involve a

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blend of data-driven and conceptually-driven processing. Thus, subjects
operate on perceptual data provided by the experimenter, but must often
reconstruct the study episode in order to perform accurately (Richardson-
Klavehn & Bjork, 1988).
To sum to this point, only the Amnesic subjects failed to produce LOP
effects on the FR paradigm. The recognition memory of all subject groups
benefitted from semantic processing, although the similarity between study and
test in MCR was such that physical processing did contribute to retrieval. The
defensible conclusion from this data pattern is that consistent LOP effects,
favoring conceptually encoded words, were found on the direct tests of
memory. Therefore, the Malingering subjects produced an equivalent pattern of
performance on the direct tests, in spite of a lowered level of performance.
The LOP data from the indirect memory tests is unequivocal: all subject
groups produced an equivalent proportion of conceptually and physically
encoded words when tested with WSC and PI. This data is highly consistent
with the other reports of null LOP effects in studies involving word stem
completion (Graf & Mandler, 1982; Graf, Squire, & Mandler, 1982) and
perceptual identification (Jacoby & Dallas, 1981). A relatively subtle retrieval
advantage was noted for physically encoded words relative to conceptually
encoded words. This finding is consistent with the predictions of the
processing model (Blaxton, 1989; Roediger & Blaxton, 1987). Additionally, a
similar result was obtained by Challis & Broadbeck (1992) who found null LOP

195
effects when processing conditions were mixed in the same study list for each
subject.
Regardless of the failure to observe statistically significant transfer-
appropriate processing in the indirect memory tests, this study has nevertheless
demonstrated an experimental dissociation between performance on direct and
indirect memory tests. I will return to discuss this matter further after
consideration of possible explanations for this dissociation.
Issues Related to Meta-Memorial Experience
The consideration of the meta-memorial experiences of participating
subjects warrants discussion independent of their possible effects on indirect
memory test performance. In general, the experience of test awareness during
WSC was frequently reported. All but one Malingering subject reported
experiencing test awareness during WSC, although 80% of Genuine subjects
did as well. However, this data pattern was not observed for PI: 65% of the
Genuine subjects and 73% of the Head Injury patients reportedly did not
experience test awareness during PI.
Given that Schacter & Bowers (1990) found that half of their sample
developed test awareness during stem completion, the fact that 80% of
Genuine subjects and 95% of the Malingering subjects reported developing test
awareness strongly suggests that the instructional and motivational sets given
to these subjects induced "meta-memorial vigilance". By this term I mean that
subjects were overly vigilant and attentive for previously presented information,

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resulting in an increased likelihood that the subjects would consciously make
the link between the study episode and producing a target word during the
indirect testing episode. Membership in either of these groups was highly
conducive to the experience of test awareness on supraliminal indirect memory
tests. Subliminal tests appear to provide a context which is much less
conducive to the experience of test awareness with subjects who are
responding genuinely. When viewed against this background, the finding that
only 30% of Malingering remained test-unaware on PI suggests that it is less
effortful to engage in explicitly-mediated suppression than it is to engage in
explicitly-mediated facilitation. Taken further, Malingering subjects may have
been directing their effort to the process of becoming test aware even on
subliminal tests.
Test-awareness and retrieval intentionality appear to be partially
independent and dissociable processes. In all subjects, the experience of test
awareness was a condition necessary for the experience of retrieval
intentionality in that no subject reported intentional retrieval without first
experiencing test awareness. On the other hand, test awareness did not
necessarily lead to intentional explicit retrieval. A significant proportion of each
subject group reported experiencing test awareness in the absence of
intentional explicit retrieval. These findings are supportive of the distinctions
discussed in literature between involuntary explicit memory (i.e, test awareness)
brought on as a consequence of implicit memory and intentional explicit

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memory used as a basis for implicit memory (Bowers & Schacter, 1990;
Richardson-Klavehn & Bjork, 1988; Schacter et al., 1989). However, it should
be kept in mind that the post-testing interview method is only the subject’s best
guess at his mental state at the time of testing. Subject’s responses could be
biased by any number of factors. Further research which attempts more
systematically to specify and isolate these factors is needed.
The Impact of Meta-Memorial Experiences
The experience of test awareness or absence of such experience had no
appreciable effects on the observation of normal priming for all three groups on
both indirect memory tests. Subjects who remained test unaware showed
essentially normal priming on WSC and PI. Similarly, subjects who experienced
test awareness but did not engage in intentional explicit retrieval also showed
normal priming effects on WSC and PI.
However, three lines of evidence can be marshalled to suggest that
postretrieval suppression (or the lack of it) impacted performance during WSC.
Conversely, little evidence can be found to support the same claim for
performance on PI. First, indirect evidence derives from the overall magnitude
of priming observed in each group. Genuine subjects completed an
unexpectedly high number of target words on WSC, which was significantly
greater than the other two groups. Head Injury patients, who had relatively little
explicit memory to draw upon, completed a significantly less proportion of
target words on WSC than did the Genuine subjects. Malingering subjects

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produced an equivalent proportion of target words on WSC as did the memory-
disordered Head Injury patients, thus successfully portraying this aspect of
memory impairment. The implication is that at least a portion of the Genuine
subjects used explicit memory to facilitate their performance. The results from
the PI task tell a different story. All three groups produced equivalent
magnitude of priming on PI; analyses of response latency data robustly
demonstrated no group differences across a range of comparisons.
Second, more direct evidence derives from the explicit recognition test
following WSC. Genuine subjects correctly recognized 88% of their correct
stem completions, compared to the 70% recognition rate for both the
Malingering and Head Injury subjects. This data pattern is consistent with the
interpretation that Genuine subjects may have used voluntary explicit retrieval to
complete stems, that Head Injury patients had relatively little explicit memory
upon which to use for intentional retrieval, and that Malingering subjects
withheld correct completion for at least some stems which they explicitly
remembered. Again, performance on PI presents an entirely different picture.
Stochastic independence was observed in all three groups, indicating that
performance on PI was functionally independent from explicit memory for the
stimuli.
Finally, subjects’ retrospective rating of meta-memorial experience
speaks directly to this issue. No significant differences of group on magnitude
of priming were detected within those subjects who reported no test awareness

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or test awareness but no explict retrieval. For subjects who reported
experiencing test awareness and explicit mediation, those in the Genuine and
Head Injury groups demonstrated a greater magnitude of priming than those in
the Malingering group. The difference between the Genuine and Malingering
groups was highly significant. The difference between the Head Injury and
Malingering groups approached but failed to reach significance. This suggests
that some Malingering subjects were successful at withholding completion of
target words which were explicitly retrieved. In contrast, PI was more resistant
to the effects of explicit retrieval by virtue of the subliminal nature of testing.
The Relationship Between LOP and Meta-Memory
No consistent statistical relationship was noted between different meta¬
memorial experiences and levels of processing effects in any of the three
groups for either WSC or PI. It was predicted that Malingering subjects could
lower their level of performance on indirect tests to the extent that they used
explicit retrieval and then used some form of postretrieval suppression.
Malingering subjects did in fact demonstrate a lowered reporting of semantically
encoded words. However, this same data pattern was observed in the other
two groups. Additionally, equivalent LOP effects were observed in Malingering
subjects in all awareness conditions. Given that over half the Genuine subjects
clearly engaged in explicit retrieval during WSC, the fact that these subjects
produced the same slight advantage for physically encoded words is quite
interesting.

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Two conclusions can be drawn from these data. First, implicit memory
as indexed in this study by indirect perceptual memory tests does not totally
exclude explicit memory from intruding upon consciousness and, in some
cases, impacting performance. Although statistically significant findings
supportive of the transfer-appropriate processing framework were not found in
this study, the trend in the data was in the direction of slight superiority of
physically encoded words. The findings that subjects who both maximize
(Genuine) and minimize (Malingering) their level of performance with explicit
memory indicates the strength of the processing model. This means that the
physical, perceptual cues present at testing may partially override the semantic
and conceptual contributions of explicit memory. Given the perceptual testing
context, subjects may be able to intentionally and explicitly access target words
while still retaining the benefit of the perceptual match between study and test
contexts. Second, the contribution of explicit retrieval during nominally indirect
tests appears to be a relatively subtle effect which failed to reach statistically
significance in this study. Explicit retrieval during PI did not appear to affect the
results, and it appears to operate only on a few words for a few subjects during
WSC. It could be argued that limited statistical power may have resulted in a
failure to detect group differences on the indirect memory tests. However, the
preexperimental computation of statistical power combined with the greater
effect sizes associated with the direct experimental tests (FR and MCR) would

201
mitigate against this argument. Rather, the contribution of explicit memory
during indirect memory tests appears to be a relatively subtle effect.
Implications for the Study of Implicit-Explicit Relationships
The present study has provided new information concerning implicit-
explicit memory relationships in that a subset of the Genuine subjects used
explicit memory to increase their strength of priming on WSC. Malingering
subjects did not, as a group, appear to engage in postretrieval response
suppression because they demonstrated normal strength of priming on WSC.
That is, it appears that a certain percentage of target words were completed
without the use of explicit memory. On the other hand, a subset of Malingering
subjects apparently experienced explicit memory for study words and elected
to not report these.
Two aspects of the design of this study may have confounded the
results. First, Genuine subjects did not represent an unbiased control group
due to their unanticipated use of explicit memory to increase their strength of
priming on WSC. The instructional set and motivational set given to these
subjects (i.e., to perform to "the best of their abilities") cannot be equated with
the motivational set associated with the "normal control subject" who is simply
given the task-related instructions at the time of testing. Irrespective of this
issue, however, Malingering subjects did not engage in postretrieval response
suppression when compared to the Head Injury subjects.

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Second, in this study the bias of both implicit and explicit memory was
towards the facilitation of task performance. When experimental effects act in
concert, performance on indirect memory tests might reflect implicit memory or
explicit memory or both (Jacoby, Lindsay, & Toth, 1992). Consider a
hypothetical scenario for a Malingering subject. When performing WSC, the
subject completes two to three words in the target direction and immediately
thereafter explicitly recognizes these words as study words. The Malingering
subject does not perceive that he or she has violated the faking role by simply
reporting relatively automatic behavior. Since no effortful retrieval occurred on
these trials, the Malingering subject feels free to proceed with the same
response criterion without undue fear of exposing their role. On some
subsequent trials the Malingerer also experiences fluent completion on several
stems and responds accordingly. On other trials, however, the subject may
experience explicit retrieval for a target words and engage in postretrieval
response suppression. The interpretive problem is that these instances of
response suppression are indistinguishable for instances of bona-fide incorrect
responses.
Several possible methodological manipulations would address this
problem. One solution to the problem of conflation of implicit and explicit
memory is the method of opposition (Jacoby et al., 1989). In this study,
Jacoby and his colleagues used a fame judgement task to assess unconscious
memory. The essence of this method is that subjects were informed that

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whenever they explicitly remembered a previously presented name they could
be sure that the name was in fact nonfamous. Any subsequent fame
judgements would be the effect of unconscious memory for the study episode.
This method places the effects of conscious memory in opposition to the effects
of unconscious memory. All contaminating influences of conscious memory
were effectively partialled out of the effects of unconscious memory.
It would be interesting to evaluate the performance of Malingering
subjects using the method of opposition. In Jacoby’s fame judgement
paradigm, Malingering subjects would be expected to produced an increase in
fame judgements to the extent that they suppressed or denied conscious
memory for the previously studied names. This would place Malingering
subjects in the confusing situation of producing additional behavior to represent
a deficit of memory.
Another solution similar to the method of opposition would be to give
subjects the paradoxical instructions "not to remember" any study words while
completing the indirect memory tests. Yet another solution would be to make
subjects aware of the fact that study words could potentially be used to
facilitate task performace. This manipulation would make for a stronger
interpretation of the data. It is predicted the Malingering subjects would
demonstrate a more discrepant (impaired) performance relative to the control
and criterion groups. Specifically, Malingerers would be expected to engage in
postretrieval suppression more frequently than they did in this study.

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Symptom Validity Testing
Whereas word stem completion and perceptual identification are
classified as indirect memory tests, Symptom Validity Testing is a direct test of
short-term memory. The art of SVT lies in the fact that expected performance
levels are not obviously apparent to the typical subject. The performance of the
Genuine and Head Injury groups provided compelling evidence that this version
of the SVT task places very little demand on subject’s memory capacities. The
fact that Head Injury subjects with bona-fide moderate-to-severe concentration
and memory impairment produced near-perfect accuracy rates further
reinforces this conclusion.
The main finding concerning the SVT paradigm was that Malingering
subjects, as a group, were impaired relative to other groups but scored well
above chance levels. Only one subject scored below nominal chance levels,
and even her score was not significantly different from chance in a probabilistic
sense. Accurate responding on SVT also appears to be dissociable from
performance on other clinical memory tests in Malingering subjects. While
statistically significant correlations were noted, cases existed in which significant
impairment was produced on clinical memory tests while SVT accuracy was
well above chance. The opposite pattern was also observed.
Several other statistical methods, based on binomial probability theory,
were presented to examine individual cases. Both of these methods were
designed to examine the consistency of responding across the lengthy number

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of trials, an ability which would at least initially appear difficult for the
Malingering subject to master throughout 100 trials. Unexpectedly, Malingering
subjects produced remarkably consistent accuracy rates across the 100 trials.
The method discussed by Miller (1986) breaks contiguous response
trials into discrete blocks. Observed accuracy rates were compared with those
expected based on binomial probability. While this method was able to
document below chance performance in Miller’s case study, it failed to establish
below chance performance in a very similar subject in this study with an
obviously questionable accuracy rate of 45% (as well as all other Malingering
subjects). The other method presented involves sampling the binomial
distribution using the subject’s own accuracy rate as the estimate of the true
population proportion. This method allows for the assignment of cumulative
probabilities associated with all possible accuracy rates within blocks of trials.
This method was useful in establishing that the above Malingering subject
produced an accuracy rate for one block of trials which was probabilistically
below what would be expected given her overall accuracy across 100 trials.
The criterion of chance performance (e.g., 50% in a 2-alternative forced-
choice paradigm) was originally suggested by Pankratz and his colleagues
(Pankratz et al., 1975). Data which support the criterion of chance performance
derive mainly from case studies of suspected malingerers (Binder, 1990b,
1992). The data from this study, however, are consistent with other between-
groups studies (Bickart et al, 1991; Wiggins & Brandt, 1988) which found only a

206
portion of experimental malingerers to produce below-chance performance on
forced-choice testing. It could be argued that the case study approach is
superior to the analogue studies on the grounds of ecological validity (see
Schretlen, 1988) and that experimental malingerers are not properly motivated
(i.e., compensated) to lower their SVT performance below chance levels.
However, our clinical experience has encountered a heterogeneous group of
litigating patients which produce accuracy rates somewhere between perfect
and chance levels. To conclude, while below chance SVT performance
provides the clinician with compelling evidence suggestive of malingering, these
data provide equally strong evidence that deviant response sets can produce
accuracy rates well above chance.
The findings concerning the reaction time component of the SVT
paradigm are offered only as heuristic due to the unreliable manner of data
collection. However, the findings do suggest that response latency may prove
sensitive to deviant response styles. Head Injury subjects produced slower
reaction times than Genuine subjects, consistent with past research (MacFlynn,
Montgomery, Fenton, & Rutherford, 1984; Miller, 1970; VanZomeren & Deelman,
1978). Malingering subjects produced significantly slower response latencies
than even the Head Injury patients. This data suggests that Malingering
subjects over-exaggerated impairment in the form of markedly increased
response latencies. Second, the correlation coefficient between SVT response
accuracy and SVT response latency was -0.16. This suggests that these two

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task components may be unrelated in Malingering subjects. One Malingering
subject produced an accuracy rate of 100% but a mean response latency of
\
3.52 seconds, while another produced an accuracy rate of 45% but a mean
response latency of 1.85 seconds.
Since Malingering subjects produced equivalent response latencies for
correct versus incorrect answers, this would suggest that these subjects
produced a more general slowing of behavior rather than slowing specific to a
particular cognitive decision (i.e., ascertaining and then inhibiting a correct
response). Given that differences in reaction time are often taken as evidence
for the existence of separate stages of information processing (Sternberg,
1969), this finding again highlights the difficulty in characterizing the mental
states of Malingering subjects. A minimum of four mental stages would be
necessary to model the reaction process involved in binary classification tasks:
stimulus encoding, comparison, binary decision, and response initiation (Taylor,
1973). The point to be made is that Malingering subjects could potentially fail
to adequately engage in any combination of the four stages on any particular
trial. Thus, within-subject differences in response latency could be obscured
when performance is averaged across trials.
Debriefing ratings and interview information strongly suggests that most
subjects accurately perceived two-alternative forced-choice testing as extremely
easy. An interesting finding was that Malingering subjects reported perceiving
SVT as easier than did Genuine subjects while they reported significantly less

208
confidence in their role-playing success on SVT. Additionally, Malingering
subjects frequently reported that they were suspicious of the task instructions
which characterized SVT as an "extremely difficult memory test." The fact that
these subjects produced incorrect answers at all suggests that the nature of the
instructions given to subjects may interact with the sophistication or savvy of
subjects in influencing overall accuracy rate.
Given the recent proliferation of various forced-choice testing paradigms,
it is especially important to caution against generalizing the results from one
SVT paradigm to another. White and Rice (1991) have adapted the stimuli
used in this study for use on the Macintosh computer system. Only two minor
changes were made: (1) foreground and background colors are reversed, and
(2) The subject is given a maximum of 10 seconds to respond; a nonresponse
in this time interval automatically results in an error score and administration of
the next trial. All other timing and presentation parameters are equivalent. A
validation study is in progress. The preliminary results from this adapted
paradigm diverge dramatically from the present findings in that normal subjects
have shown a mean accuracy rate between 85% and 95%; patients with
documented brain damage score well below the levels produced by the Head
Injury subjects in this study.
Several caveats concerning the clinical use of SVT are warranted as well.
A below-chance performance on SVT neither proves malingering nor disproves
bona-fide impairment. Similarly, suspicions of faking based on SVT

209
performance cannot be generalized to all of the patient’s symptoms. Such
performance would suggest malingering only insofar as the SVT is concerned.
However, evidence garnered from SVT would seem to justify the
inference that other tests probably do not reflect the patient’s true abilities
(Hiscock & Hiscock, 1989). Therefore, I would argue that SVT could
conceivably function in a manner similar to the F scale on the MMPI. The MMPI
F scale has high intercorrelations with some clinical scales, in particular with
scales 6 (paranoia) and 8 (schizophrenia). Graham (1987) states that the F
scale both (1) serves as an index of test-taking attitude and is useful in
detecting deviant response sets; and (2) serves as an indicator of degree of
psychopathology, if profile-invalidity can be ruled out.
Clearly, SVT accuracy rate could serve as an index of test-taking attitude
and response set, not as a binary variable (malingering versus not malingering)
but rather as an interval variable reflecting gradations of dissimulation. This use
would also be consistent with Rogers’ model of malingering (1987, 1988) which
holds that malingering is not a dichotomous construct but which exists on a
continuum with gradations of dissimulation. Future research involving
neuropsychological patient groups could proceed to validate SVT in a similar
manner as was done for the MMPI (see Graham, 1987). More precise cutting
scores could be derived such that scores falling below a certain level would call
into question the validity of the assessment process for that patient, negating
the interpretive yield of the other neuropsychological data.

210
Given that malingering and deviant responding can first be ruled out, the
use of SVT accuracy rate and response latency as indices of
neuropsychological impairment becomes straightforward. Reaction time
paradigms have been shown to be robustly sensitive to brain damage (Bruhn &
Parsons, 1971; Elass, 1986; Hahurin & Pirozzolo, 1986; Milner 1986)
Performance on SVT will be impaired to the extent that the requisite attentional
and cognitive processes necessary for normal performance are impaired. This
issue, of course, highlights the important need to validate SVT paradigms on
other neuropsychological patient groups.
Multivariate Detection of Malingering
The performance of the Malingering subjects has been shown to differ
substantially from the Genuine subjects, even on indirect tests. However, the
true task of a single test or a battery of tests designed to detect a malingering
response style is to discriminate the suspected malingerer from a patient with
bona-fide memory impairment. With the exception of SVT, univariate analytic
techniques consistently failed to produce significant differences between the
Malingering and Head Injury groups for both the clinical memory tests and the
indirect experimental memory tests.
Taken as a group, however, a multivariate combination of the
experimental memory tests (i.e., variables from both direct and indirect tests)
produced surprisingly accurate classification rates when entered into a linear
discriminant function analysis. Malingering subjects were classified with less

211
accuracy that the other two groups. An analysis of the incorrect classifications
was suggestive of the fact that the indirect memory tests contributed very little
to the classification process. A subsequent discriminant function performed just
on the variables from the indirect memory tests resulted in very poor
classification rates, suggesting the hypothesis that performance on indirect
memory tests offers little clinical utility in itself in the detection of malingering.
A variable set was then constructed based on selected clinical memory
indices and entered into a linear discriminant function analysis. The
classification rates were extremely high, with a sensitivity rate of 92% and a
specificity rate of 8%, averaged across the three groups. These rates were
slightly more accurate than those produced by the experimental memory tests.
Therefore, it appears that the experimental memory tests in general and the
indirect memory tests in particular do not offer the clinician any additional
information about the potential malingering patient not otherwise afforded by
the routine battery of clinical memory tests. Clearly, cross-validation is needed
for the discriminant equation for the clinical memory tests. It would be useful to
replicate these findings on an unselected groups of litigating and nonlitigating
consecutive clinic admissions with mild CHI.
The "Art11 of Detecting Malingering
Perhaps the most important conclusion to draw from this study is that,
with the notable exception of SVT, a single test or a "snapshot1 of memory
performance is insufficient to catch a Malingerer, even when the domain of such

212
tests is expanded to include indirect memory tests that, by their nature, seem
less vulnerable to direct manipulation by subjects. This should come as no
surprise because such an approach is rarely used to characterize the memory
of any type of patient. The "art" of catching Malingerers appears to lie in the
observance of the processes of memory as they change across difficulty levels
and decay across time. While a Malingering subject may accurately portray
impairment on the initial learning trials of the CVLT, he or she may have much
more difficulty titrating performance when the task difficulty changes (say, for
Short Delay Cued Recall). The job of malingering becomes even more
ambiguous and difficult when these free recall and cued recall tasks are again
tested at a 20 minute delay.
The findings concerning the WMS Visual Reproduction subtests provide
an intriguing illustration of these ideas. It is well accepted that the immediate
recall of the WMS figures is not an overly difficult task (Lezak, 1983). The
Malingerers demonstrated a nonsignificant trend towards over-exaggeration of
impairment on the immediate reproduction. However, when tested after the
delay interval their performance was very low, much lower than even the Head
Injury patients. When a forgetting score was computed for this task,
Malingerers again over-exaggerated their impairment. In contrast, Malingerers
were much more successful at calibrating their impairment on the more
complex and demanding ROCF memory trials.

213
This data pattern would suggest that a particularly difficult situation for
the Malingering subject is to be confronted with a test which allows for only a
limited range of possible responses. Impairment becomes even more difficult
to titrate when tested with this same task after a delay interval, when the subject
presumably has a less definite objective memory trace upon which to calibrate
his impairment. The more difficult, lengthy, and involved tests do not present
the same challenge due to the wider range of response alternatives (and the
inherent statistical variability of normal performance). It is as if the Malingering
subject perceives that he or she must refrain from a certain amount of behavior
irrespective of task difficulty. These omissions become more glaring on simple
tasks. Finally, there is some fairly convincing evidence from the debriefing
ratings which suggests that Malingerers consistently underestimate the difficulty
of most memory tasks.
Summary
Normal subjects, when instructed to malinger memory impairment,
significantly lowered their performance on clinical memory tests relative to
similar subjects who were given instructions to perform genuinely. The
qualitative aspects of malingered memory behavior were also found to be
different than that produced by Genuine subjects. Moreover, Malingering
subjects produced performance profiles on clinical memory tests which were
highly similar to those of a sample of Head Injury patients with documented
neurological damage and bona-fide neuropsychological memory impairment. In

214
general, no single clinical memory test or combination of several tests proved
useful in diagnosing experimental malingering.
Several indirect memory tests used by cognitive psychologists were
administered to these subject groups with the general idea that Malingering
subjects would first experience explicit memory for study items and them
engage in postretrieval suppression of correct responses. This general
prediction did not hold up in that Malingering subjects produced normal
strength of priming and LOP effects on both indirect memory tests. However,
evidence was generated which suggested that Genuine subjects used explicit
memory to increase their level of priming on word stem completion but not on
perceptual identification.
In contrast to the indirect memory tests, the Symptom Validity Testing
paradigm used in this study was designed as a direct test of short-term
memory. The art of SVT lies in the fact that expected performance levels are
not obviously apparent to the typical subject. The main finding concerning the
SVT paradigm was that Malingering subjects, as a group, were impaired relative
to other groups, but scored well above chance levels and demonstrated
surprisingly consistent responding across trials. Several statistical methods
demonstrated that the traditional criterion of chance performance may be
potentially insensitive to malingering response sets.

APPENDIX A
PREEXPERIMENTAL MATERIALS
Information about Closed Head Injury
1. The medical condition known as "Closed Head Injury", abbreviated CHI,
refers to damage to the head and skull area.
2. When a person sustains a CHI, they may lose consciousness for varying
periods of time, often as long as several hours.
3. Immediately after sustaining a CHI, a person may not remember where
they are, or what date and time it is.
4. In addition, CHI patients may not be able to remember events ocuring
before the trauma. The loss of memory for events prior to the accident
usually only goes back several minutes to an hour before the CHI.
5. After a CHI, a person may not be able to remember events ocuring after
the injury.
6. The loss of memory for events after the accident varies depending on
the severity of the injury, with more severe CHI’s resulting in more loss of
information.
7. After a person has recovered the ability to remember events occurring
after the injury, he or she will probably still have difficulty in learning and
remembering new information.
8. These learning and memory problems are very common after CHI.
9. CHI patients often have difficulty remembering words and sentences as
well as geometric shapes and human faces.
10. "Short Term Memory" refers to the ability to remember small amounts of
information for a few seconds. People with a CHI have a normal short
term memory.
215

216
11. "Long Term Memory" refers to the ability to remember larger amounts of
information for longer periods of time. People with a CHI often have
difficulty with long term memory.
12. In general, the more hints and cues given to a CHI patient about what
they are trying to remember, the easier it is for them to remember.
13. CHI patients usually can remember information that is presented to them
at the beginning and end of an event. They have the most difficulty
remembering information which is presented to them in the middle of the
event.
14. CHI patients usually have the same amount of difficult remembering
verbal information as they do remembering visual information.
15. CHI patients are likely to have a decrease in their intelligence.
16. In general, the more severe the CHI the more the person’s intelligence
decreases.
17. Approximately 50% of people having Closed Head Injuries have
moderate to severe impairment in their overall intelligence.
18. Especially difficult tasks for CHI patients involve tasks which require
quick and errorless peformance, paying attention for long periods of
time, and making complex decisions quickly.
19. People with CHI often respond to tasks slower than they did before they
had their injury.
20. CHI patients rarely have difficulty answering simple, yes/no questions
about words and sentences.

217
Faking Scenario
The primary experimenter would like for you to play a role as you participate in
this experiment. The role you are to play is based on the following scenario:
Scenario:
You have recently experienced an automobile accident about 1
month ago. This accident was not your fault; it was the other driver’s
fault. In this accident, you sustained a "moderate" Closed Head Injury
when you hit your head on the steering wheel. You were taken to the
hospital, where you received medical care. X-rays and scans were done.
The results of these tests did not turn up any severe damage to your
skull or brain. The doctor told you that you did not have to stay
overnight in the hospital and that the doctor did not need to see you in
the future for further medical treatment.
However, during the last few weeks you have been experiencing
some mental problems which are very much like the problems vou have
just read about. You have contacted your attorney who scheduled
psychological testing in order to determine if in fact your mental ability
and memory have been damaged.
Your attorney tells you that if you have sustained mental injury you
may be able to collect a large sum of money in damages from the driver
of the other car. The more mental impairment you have, the more
money you may be able to collect. However, if the psychologist, based
on your test scores, reports that you were exaggerating or faking mental
and memor problems, you will not be able to collect any money.
At the present time, you have arrived for your appointment for
psychological testing. Your role is to fake the most severe but believable
memory problems that you can on these memory tests. Your primary
job is to respond to the tests as you think a person with such memory
problems would. Your "acting ability" does not matter. The person who
will be working with you is also playing a role of 'tester". While he does
not know what role you will be playing, you should not be concerned
with 'tooling" or "convincing" him.
Please play this role until the experimenter tells you that the experiment is over.
You are to use vour knowledge about Closed Head Injury which vou iust
learned in order to play this role.
You will now be administered a brief test about your knowledge of CHI to make
sure you are able to use this information when playing your role.
After this test, you will be given 5 minutes in order to play how you will play
your role.

218
Best Effort Scenario
The primary experimenter would like for you to play a role as you participate in
this experiment. The role you are to play is based on the following scenario:
Scenario:
You have recently experienced an automobile accident about 1 month
ago. This accident was not your fault; it was the other driver’s fault. In
this accident, you sustained a "moderate" Closed Head Injury when you
hit your head on the steering wheel. You were taken to the hospital,
where you received medical care. X-rays and scans were done. The
results of these tests did not turn up any severe damage to your skull or
brain. The doctor told you that you did not have to stay overnight in the
hospital and that the doctor did not need to see you in the future for
further medical treatment.
However, during the last few weeks you have been experiencing
some mental problems which are very much like the problems vou have
just read about. You have contacted your attorney who scheduled
psychological testing in order to determine if in fact your mental ability
and memory have been damaged.
Your attorney tells you that if you have sustained mental injury you
may be unable to continue working at your lucrative job. The less
mental impairment you have, the more work you can do and the more
money you will be able to earn at your job. However, if the psychologist,
based on your test scores, reports that you have mental and memory
problems, you will no longer be able to work at your lucrative job.
At the present time, you have arrived for your appointment for
psychological testing. Your role is to put forth the best effort vou can, to
trv to perform as best as vou can on these memory tests. Your primary
job is to respond to the tests as you think a person with such memory
problems would. Your "acting ability" does not matter. The person who
will be working with you is also playing a role of "tester". While he does
not know what role you will be playing, you should not be concerned
with “fooling" or "convincing" him.
Please play this role until the experimenter tells you that the experiment is over.
You are to use vour knowledge about Closed Head Injury which vou iust
learned in order to play this role.
You will now be administered a brief test about your knowledge of CHI to make
sure you are able to use this information when playing your role.
After this test, you will be given 5 minutes in order to play how you will play
your role.

219
Tor F
lor F
lor F
lor F
lor F
lor F
lor F
Tor F
lor F
lor F
lor F
Tor F
Test of Knowledge about Closed Head Injury
1. Approximately 5% of people having Closed Head Injury (CHI)
have moderate to severe impairment in their mental abilities.
2. CHI patients often have difficulty remembering words and
sentences as well as geometric shapes and human faces.
3. CHI patients have normal short term memory abilities, so that
they are able to remember small amounts of information for a
brief period of time.
4. People with a CHI often have difficulty with tasks which require
long term memory, so that they have difficulty in remembering
larger amounts of information for a longer period of time.
5. In general, the more hints and cues given to a CHI patient
about what they are trying to remember, the easier it is for them
to remember.
6. CHI patients usually can remember information that is
presented to them at the beginning and at the end of an event.
They have the most difficulty remembering information which is
presented to them in the middle of an event.
7. CHI patients usually have the same amount of difficulty
remembering verbal information as they do remembering visual
information.
8. People who have a Closed Head Injury have no problem
remembering events which happened to them before the injury.
9. People who have a Closed Head Injury may have difficulty
remembering events which happened to them after the injury.
10. People with Closed Head Injury often have decreased overall
intelligence after their injury.
11. People with Closed Head Injuries perform tasks slower than
they did before their injury.
12. CHI patients rarely have difficulty answering simple yes/no
questions about words and sentences.

220
Tor F
Tor F
Tor F
Tor F
Tor F
Tor F
13. The role you have been asked to play during this experiment
has you trying to put forth the best effort vou can and to
perform as well as you can on the memory tests which will
follow.
14. In the scenario you were given, you will lose money because
you will be unable to work at your lucrative job if it appears that
you have real memory problems.
15. In the scenario you were given, you will be allowed to continue
working at your lucrative job if it appears that your memory is
normal.
16. The role you have been asked to play during this experiment
has you trying to fake the most severe but believable memory
problems as vou can on the memory tests which will follow.
17. In the scenario you were given, you will stand to gain a large
sum of money in damages from the other driver if you are
successful at faking the most severe but believable memory
problems you can.
18. In the scenario you were given, you will be embarrassed if you
are unsuccessful at faking the most severe but believable
memory problems that you can.

APPENDIX B
EXPERIMENTAL MATERIALS
Word Stem Completion Stimuli
Buffer Items
HOLIDAY
FERRY
CANCER
BALLOON
IMPRESS
Contain the letter "D". (Y)
The boy’s mother applied a to his cut. (N)
Contain the letter "R". (Y)
The signed the historic document at the conference. (N)
Contain the letter "E". (Y)
List A Target Words
IMMENSE The farmer hooked up the to his tractor. (N)
SUPPLY Contain the letter "U". (Y)
PERSON Contain the letter "F". (N)
SCOPE The doctor looked through a into the patient’s ear. (Y)
OBSCENE Contain the letter "N" (Y)
TRAIN The left Grand Central Station. (Y)
RANGER Contain the letter "B". (N)
CONCEPT The student could not understand the . (Y)
REVENGE Contain the letter "W. (N)
SPENT The players were ready to begin the . (N)
List B Target Words
GRAPE
STOCK
PRODUCE
FATIGUE
HANGAR
ASSUME
CHEESE
FRESH
SANDWICH
SHOULDER
The juice of a may be used to make wine. (Y)
Contain the letter "O". (Y)
Contain the letter "L". (N)
It must be 100 out here today. (N)
The old movie is a (N).
You too much by not asking for my permission. (Y)
Contain the letter "H". (Y)
Contain the letter "O". (N)
Contain the letter "D". (Y)
The family was glad to have returned to their . (N)
221

222
Perceptual Identification Stimuli
Buffer Items
CORPSE
LOCATE
RELAX
BURGLAR
MEDAL
The tourist had to his passport to customs officials. (N)
Contain the letter "D". (N)
The was rolled out to the launchpad. (N)
Contain the letter "G". (N)
The President pinned the on the hero. (Y)
Target Words
CAPTAIN Contain the letter "P". (Y)
INDEX Will you pick up a carton of eggs at the ? (N)
SHARE Contain the letter "T". (N)
BLANKET Contain the letter "A". (Y)
REGARD The running back scored a during Sunday’s game. (N)
SCARLET The ruby was a bright color. (Y)
EXPECT What did you me to say? (Y)
FLORIST Contain the letter "B". (N)
OFFICER The Army barked his orders to the platoon. (Y)
HARVEST The poor farmers needed a bountiful fall . (Y)
TENNIS Contain the letter "S". (Y)
THIRD Contain the letter "K". (N)
BELCH The millionaire lived a life of luxury and . (N)
DESIGN The architect will a new office builing. (Y)
SENTRY The swimmer came in place in the race. (N)
GROWTH Contain the letter "W". (Y)
APPEAL Contain the letter "E". (Y)
ACCESS Contain the letter "P". (N)
MUSKET The old haunded mansion was . (N)
PULLEY Contain the letter "M". (N)
Distractor Words
SPADE
PLANE
WORTH
COMPLEX
SLANG
QUART
GENDER
FOREST
BROTHER
SOLACE
PASSIVE
COUNCIL
SALMON
QUIET
AFFIRM
CHARGE
MANAGER
BLUNT
POLICE
DELAY

223
Free Recall Stimuli
Buffer Items
GARMENT
BANDAGE
ADOPT
GLOVE
CATALOG
She picked up her at the laundry. (Y)
Contain the letter "L". (N)
Contain the letter "E". (N)
Contain the letter "N". (N)
He ordered the present from the . (Y)
Target Stimuli
PRICE The of the new car was too expensive. (Y)
STRESS The man bought the at the store. (N)
ADJUST Contain the letter "J". (Y)
BLOOM Contain the letter "S". (N)
PARENT They ordered ham and for breakfast. (N)
RETAIN Contain the letter "I". (Y)
BASIN Contain the letter "C". (N)
HEROIN The secretary made two of the original. (N)
SKIRT The woman’s pleated matched her blouse. (Y)
TRUTH Contain the letter "H". (Y)
DRAGON The knight killed the with his sword. (Y)
CAREER Contain the letter "T". (N)
WINDOW The open was causing a draft. (Y)
SERVE Will you please me some food? (Y)
SOURCE Contain the letter "F". (N)
DEFECT The opened his shop for business. (N)
CLAIM Contain the letter "L". (Y)
THROAT The boys tossed the around the sandlot. (N)
CALORIE Contain the letter "O". (Y)
POSITIVE Contain the letter "B". (N)

224
Multiple Choice Recognition Stimuli
Buffer Items
BARGAIN
ABSENT
MASSAGE
ABOLISH
IMPRESS
The became enraged and violent. (N)
Contain the letter "R". (N)
The parlor was closed by the police. (Y)
Contain the letter "F". (N)
John tried to his girlfriend with his money. (Y)
Target Stimuli
TRIAL
STAFF
INCOME
BEARD
HEALTH
PRAISE
SHELF
DENTIST
PRESS
UNION
REACH
SCRATCH
REJECT
ADVERB
SNAIL
CLERGY
THEORY
PATTERN
PENDANT
MARRIAGE
Contain the letter "R". (Y)
The Chief of met with the President today. (Y)
The crept up and killed the mouse. (N)
The man’s needed trimming. (Y)
Contain the letter "T". (N)
Contain the letter "I". (Y)
Contain the letter "H". (Y)
Contain the letter M0". (N)
The reporter showed his pass to the guard. (Y)
Contain the letter "U". (Y)
Contain the letter "D". (N)
Contain the letter "K". (N)
The negotiator will the latest contract offer. (Y)
Contain the letter "J". (N)
The couple decided to have their picnic on the . (N)
People who belong to the should be moral. (Y)
The soldier was a true of the U.S.A. (N)
Contain the letter "G". (N)
The slowly pulled away from the funeral. (N)
The boy hated eating and onions for dinner. (N)

225
Symptom Validity Testing Stimuli
Trial#
Taraet Strina
Answer Label
Foil Strina
1, 51
8160833
B
6589769
2, 52
2290337
A
5329504
3, 53
3360583
A
8295417
4, 54
6655834
A
1325078
5, 55
1111512
A
6207291
6, 56
8335511
B
3581021
7, 57
7899177
B
2983969
8, 58
9775011
A
4731265
9, 59
1113297
B
4176819
10, 60
7711331
A
8738438
11, 61
4415925
A
3980317
12, 62
5933666
B
4672506
13, 63
9276322
A
6930376
14, 64
7896322
B
2656376
15, 65
5424788
A
8739490
16, 66
2630344
A
1804647
17, 67
8087955
B
3106950
18, 68
9871799
B
4835494
19, 69
5569401
A
4048413
20, 70
1196953
A
2109312
21, 71
6606220
A
9818751
22, 72
8819392
A
7159095
23, 73
1365033
A
4278304
24, 74
5518403
A
6142347
25, 75
1575688
B
4539021
26, 76
2058422
B
7151515
27, 77
2288097
B
5086712
28, 78
3770399
A
4924285
29, 79
5416977
B
2751389
30, 80
4072099
B
7640491
31, 81
7771260
A
6442532
32, 82
3367623
B
2380109
33, 83
2498788
B
5651732
34, 84
4203177
A
3980617
35, 85
7721728
B
6893924
36, 86
9587833
B
8426731
37, 87
6645301
B
9296568
38, 88
8868519
A
1453070
39, 89
7569766
B
8724680
40, 90
5540784
B
8903816
41, 91
4182444
B
5986154

226
Symptom Validity Testing Stimuli (continued)
Trial#
Taraet Strina
Answer Label
Foil Strina
42, 92
2291658
A
7153897
43, 93
4431908
A
1732267
44, 94
4430681
B
9462073
45, 95
1394844
B
6254262
46, 96
3563666
B
4152643
47, 97
9955251
A
4836759
48, 98
6405655
A
7851563
49, 99
3372417
A
8451201
50, 100
3015355
B
8276524

APPENDIX C
POSTEXPERIMENTAL MATERIALS
De-Briefing Rating Sheet
For each task that you participated in during the experiment, please rate the (1)
effort you put into playing your role; (2) the difficulty of the task for playing your
role; and (3) how successful/unsuccessful you think you were in responding
according to your role. Use the following 7-point scales.
Effort
1 2 3 4 5 6 7
Minimum Average Maximum
effort effort effort
Difficulty of Task
(if you would have been performing your best)
1 2 3 4 5 6 7
Minimum Average Maximum
difficulty difficulty difficulty
Success of Performing your Role
1 2 3 4 5 6 7
Minimum Average Maximum
success success success
Diffi- Succ-
Effort culty ess??
1. Remembering stories immediately after having
heard them.
227

2. Remembering stories a few minutes after
having heard them.
3. Drawing simple geometric designs
immediately after having studied them for 10
seconds.
4. Drawing simple geometric designs a few
minutes after having studied them.
5. Studying digits on the computer screen and
then choosing which one you studied from
two choices.
6. Copying the complex geometric figure while
looking at it.
7. Drawing the complex geometric figure from
memory immediately after having copied it.
8. Drawing the complex geometric figure from
memory a few minutes after having copied it.
9. Remembering the Monday Shopping List
immediately after having been read it.
10. Remembering the Monday Shopping List
when given hints immediately after having
read it.
11. Remembering the Monday Shopping List a
few minutes after having read it.
12. Remebering the Monday Shopping List when
given hints a few minutes after having been
read it.
13. Picking Monday Shopping List items out of a
larger list of shopping items.
14. Answering simple questions about personal
and current information.
228

229
15. Remembering digits immediately after having
been read them.
16. Remembering digits in the reverse order
immediately after having been read them.
17. Remembering words paired together.
18. Answering simple yes/no questions about
words and sentences.
19. Completing 3 letter word stems with the first
words that came to mind.
20. Identifying words that flash quickly on the
tachistoscope.
21. Writing down on blanks all the words you can
remember from a previous deck of words.
22. Picking out a word from 4 alternatives the
words you can remember from a previous
deck of words.

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BIOGRAPHICAL SKETCH
Travis Gordon White, Jr., was bom in Austin, Texas, on April 23, 1965.
Upon graduation from Robert E. Lee High School in Houston, Texas, in 1983,
Travis matriculated at Southern Methodist University in Dallas, Texas. While at
Southern Methodist, Travis undertook an honor’s thesis project titled
"Environmental Potentiation of Taste Aversion Learning in Rats." Based on this
research project, Travis graduated from Southern Methodist with departmental
distinction in 1987.
Travis enrolled in the Department of Clinical and Health Psychology at
the University of Florida in August of 1987. He was awarded the degree of
Master of Science in 1989. His thesis, titled "Recall of Three Words after Five
Minutes: Its Relationship to Performance on Neuropsychological Memory Tests,"
was completed under the guidance of his present doctoral committee chairman,
Dr. Russell Bauer. While a graduate student at the University of Florida, Travis
was recognized with several honors, including the Molly Harrower Award for
Excellence in Psychodiagnostic Assessment, the Robert Levitt
Neuropsychological Research Award, and the Presidential Recognition Award
for distinguished service to the University.
252

I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope
and quality, as a dissertation for the degree of Doctor of Philosophy.
M
íussell M. Bauef, Chair
Associate Professor of Clinical
and Health Psychology
I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope
and quality, as a dissertation for the degree of Doctor of Philosophy.
Dawn Bowers
Associate Professor of Clinical
and Health Psychology
I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope
and quality, as a dissertation for the degree of Doctor of Philosophy.
-yj
Llit:
Bruce Cros'son
Associate Professor of Clinical
and Health Psychology
I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope
and quality, as a dissertation for the degree of Doctor of Philosophy.
Eileen B. Fennell
Professor of Clinical and Health
Psychology

I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope
and quality, as a dissertation for the degree of Doctor of Philosophy.
Michael Crary
Associate Profess
Communication
Processes and Disorders
This dissertation was submitted to the Graduate Faculty of the College
of Health Related Professions and to the Graduate School and was accepted
as partial fulfillment of the requirements for the degree of Doctor of Philosophy.
December 1992
~s.R.
Dean, College of Health Related
Professions
Dean, Graduate School




183
Table 25
Debriefing Ratinas for Genuine and Malingering Subjects
Effort
Difficulty
Success
Task
G
M
G
M
G
M
Word Stem Completion
4.53
3.65
2.93
2.24
6.00
4.29
Perceptual Identification
6.40
5.24
5.93
5.06
4.00
4.47
Symptom Validity Testing
5.07
3.65
2.60
1.18
6.87
3.71
WMS Delayed Visual
Reproduction
5.73
3.94
4.60
3.59
4.87
4.41
Overall Rating Score
5.31
3.99
4.08
3.01
5.30
4.17
Note. Column subheadings are abbreviated as follows: G=Genuine and
M=Malingering. The data are raw scores (on a scale from 1 to 7), averaged
within group.


33
subjects tended to produce very few omission, perseveration, and size errors,
opting instead to produce many more distortion errors than are often seen in
genuinely brain damaged populations.
Williamsen, Johnson, and Eriksen (1965) instructed a group of subjects
to feign hypnosis and post-hypnotic amnesia. The instructions given to this
group were nonspecific and provided no didactic information about
posthypnotic amnesia. No incentive was offered for successful malingering.
This group was compared with groups of nonsimulating/hypnotized subjects
and genuine/nonhypnotized subjects on free recall, word fragment completion,
"word association", and two-alternative, yes/no recognition measures. The
results obtained indicated that the malingering subjects level of performance
was significantly lower than the posthypnotic amnesics on all measures. A
critical finding was that the simulators abnormally suppressed their responding
on several measures of implicit memory.
In a brief report, Brandt, Rubinsky, and Lassen (1985) administered a 20
item word list to groups of normals, normals simulating amnesia, patients with
Huntingtons disease, and patients with unspecified head trauma. These
subjects were tested first with free recall and then with two-alternative, forced
choice recognition paradigm (cf. Pankratz, 1983). No information was reported
concerning the instructions used for the malingering group, nor was there any
apparent external incentive to malinger. Brandt and his colleagues found that
the malingering group performed the most poorly on free recall, though not


130
Table 7
Univariate Group Differences on Qualitative Clinical Memory Variables
Group
Variable
Genuine
Malinger
Head Injury
LM Percent Forget
Mean
3.38
34.4a
31.3B
SD
F(2,52) = 8.40***
10.4
22.4
40.9
VR Percent Forget
Mean
18.70
63.8A
35.4B
SD
F(2,52) = 12.16***
22.5
31.6
33.4
ROCF Percent Forget
Mean
-2.6B
19.6a
5.0a8
SD
F(2,52) = 4.30*
27.5
24.2
24.8
CVLT D-Prime
Mean
96.1A
78.9b
83.8B
SD
F(2,52) = 13.64***
3.7
13.2
12.2
CVLT Response Bias
Mean
-0.1
-0.1
0.00
SD
F(2,52) = 0.25
0.2
0.5
0.4
CVLT Recog. False Alarms
Mean
0.5B
4.6a
4.2a
SD
F(2,52) = 7.16**
1.0
4.7
4.2
* p<.05 ** p<.01 *** pc.001
Note. All data are raw scores. Means with different superscripts differ
significantly at pc.05.


209
performance cannot be generalized to all of the patients symptoms. Such
performance would suggest malingering only insofar as the SVT is concerned.
However, evidence garnered from SVT would seem to justify the
inference that other tests probably do not reflect the patients true abilities
(Hiscock & Hiscock, 1989). Therefore, I would argue that SVT could
conceivably function in a manner similar to the F scale on the MMPI. The MMPI
F scale has high intercorrelations with some clinical scales, in particular with
scales 6 (paranoia) and 8 (schizophrenia). Graham (1987) states that the F
scale both (1) serves as an index of test-taking attitude and is useful in
detecting deviant response sets; and (2) serves as an indicator of degree of
psychopathology, if profile-invalidity can be ruled out.
Clearly, SVT accuracy rate could serve as an index of test-taking attitude
and response set, not as a binary variable (malingering versus not malingering)
but rather as an interval variable reflecting gradations of dissimulation. This use
would also be consistent with Rogers model of malingering (1987, 1988) which
holds that malingering is not a dichotomous construct but which exists on a
continuum with gradations of dissimulation. Future research involving
neuropsychological patient groups could proceed to validate SVT in a similar
manner as was done for the MMPI (see Graham, 1987). More precise cutting
scores could be derived such that scores falling below a certain level would call
into question the validity of the assessment process for that patient, negating
the interpretive yield of the other neuropsychological data.


210
Given that malingering and deviant responding can first be ruled out, the
use of SVT accuracy rate and response latency as indices of
neuropsychological impairment becomes straightforward. Reaction time
paradigms have been shown to be robustly sensitive to brain damage (Bruhn &
Parsons, 1971; Elass, 1986; Hahurin & Pirozzolo, 1986; Milner 1986)
Performance on SVT will be impaired to the extent that the requisite attentional
and cognitive processes necessary for normal performance are impaired. This
issue, of course, highlights the important need to validate SVT paradigms on
other neuropsychological patient groups.
Multivariate Detection of Malingering
The performance of the Malingering subjects has been shown to differ
substantially from the Genuine subjects, even on indirect tests. However, the
true task of a single test or a battery of tests designed to detect a malingering
response style is to discriminate the suspected malingerer from a patient with
bona-fide memory impairment. With the exception of SVT, univariate analytic
techniques consistently failed to produce significant differences between the
Malingering and Head Injury groups for both the clinical memory tests and the
indirect experimental memory tests.
Taken as a group, however, a multivariate combination of the
experimental memory tests (i.e., variables from both direct and indirect tests)
produced surprisingly accurate classification rates when entered into a linear
discriminant function analysis. Malingering subjects were classified with less


109
Controls=10%) was not significantly different, F(1,16)=.30, p<.59, and was
equivalent to baseline rates reported in the literature (Graf & Williams, 1987).
Collapsed across groups, a significant main effect of word status (target versus
distractor) was found, F(1,16)=30.9, p<.0001. Computed within groups, a
significant main effect of target status was found for both the Amnesic group,
F(1,8)=16.96, p<.003, and the control group, F(1,8)=21.56, pc.002. These
findings suggest that both Amnesic and control groups demonstrated priming
on the WSC task. Follow-up mean comparisons confirmed that word stems
were completed in the target direction significantly more often when the word
was previously exposed compared to the unexposed condition. The interaction
between group and target status was nonsignificant, F(2,16)=0.00, pc.97,
suggesting that the strength of priming was similar in Amnesics and controls.
Figure 1 presents this data. Collapsed across groups, the main effect of
orienting task was nonsignificant. Additionally, the interaction between group
and orienting task was nonsignificant (Fs c 1). Control subjects showed a
slight trend towards higher percent correct stem completion when the target
words were encoded in the physical orienting condition, while Amnesic subjects
showed virtually identical performance in both orienting conditions.
An alternative analytic approach involved computing a binary variable
which reflected whether or not each subject demonstrated priming on stem
completion. For each subject, baseline performance for that subject was
subtracted from target performance, resulting in a variable which reflected the


235
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174
Table 20
Correlations between SVT and Clinical Memory Variables
SVT Mean
SVT %
Reaction
Correct
Time
SVT Mean Reaction Time
-0.16
WMS Memory Quotient
0.53***
-0.64***
Digits Backward
0.43***
-0.67***
WMS Immed. Logical Memory
0.37**
-0.40**
WMS Delayed Logical Memory
0.44***
-0.50***
WMS Immed. Visual Reprod.
0.52***
-0.57***
WMS Delayed Visual Reprod.
0.59***
-0.62***
CVLT Total Trials 1-5
0.31*
-0.47***
CVLT Short Delay Free
Recall
0.33*
-0.47***
CVLT Long Delay Free
Recall
0.41**
-0.55***
CVLT Recognition Hits
0.46***
-0.39**
ROCF Immediate Reprod.
Reproduction
0.45***
-0.25
ROCF Delayed Reprod.
0.48***
-0.41**
* pc.05
** pc.01
*** pc.001


68
target. But when given a yes/no recognition test that requires them to think
back to the study episode, subjects perform quite well, and consciously
remember having studied almost all of the words that were produced as
completions. This scenario represents normal implicit memory performance in
that absence of the spontaneous experience of test awareness, even though
the subjects later demonstrate strong explicit memory for the study episode.
The second represents an example of what Schacter (1987) referred to
as involuntary explicit memory. Subjects could encode target items under
elaborative study conditions, later complete each stem with the first words that
comes to mind, and produce a large number of study list items. For some
stems, all that comes to mind during completion performance is the target word
itself, but for others subjects are reminded by the stem of something that
occurred during the study episode. Nevertheless, the subject continues to
write down the first word that comes to mind. Thus, a cue involuntarily triggers
a recollection of a past event; the awareness of remembering is merely a
consequence of the implicit retrieval process.
The third scenario is more clearly a case of voluntary explicit memory. It
is identical to the preceding case, except that once subjects notice that one or
two of the stems can be completed with the study list items, they surmise that
the experimenter is surreptitiously trying to test their memory, and may decide
that they can improve their performance by thinking back to the study list and
trying to complete each stem with a target item. They have no problem


249
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99
bar to begin the testing. The first target string was presented in the middle of
the screen for a total of two seconds, after which it was briefly covered with a
mask for one second. The screen immediately cleared, presenting the subject
with two different digit strings, the correct target string and an incorrect foil
string. The string presented on the left side of the screen was labeled as "A"
and the string presented on the right side of the screen was labeled as "B".
Labels marked "A" and "B" were placed on the F and J keys on the keyboard,
respectively. Subjects held both index fingers on these keys throughout
testing. Subjects made their responses by first hitting the corresponding key
and then calling out their answer. Unfortunately, the computer software failed
to properly record the reaction times for the subjects. As a contingency to this
problem, the examiner unobtrusively sat behind the subjects and manually
recorded response latencies with a stopwatch. Reaction time data derived from
the SVT paradigm was subsequently analyzed but interpreted with the inherent
unreliability of the data collection method taken into account.
Clinical Memory Procedures
The WMS consists of seven subtests. Personal and Current Information
consists of six questions which tap recall of long established verbal information.
Orientation consists of five questions which tap immediate temporal orientation.
Mental Control consists of three subtasks, all of which are completed under
time pressure: counting backwards from 20; repeating the alphabet; and
counting in increments of threes. Logical Memory consists of two literary


APPENDIX A
PREEXPERIMENTAL MATERIALS
Information about Closed Head Injury
1. The medical condition known as "Closed Head Injury", abbreviated CHI,
refers to damage to the head and skull area.
2. When a person sustains a CHI, they may lose consciousness for varying
periods of time, often as long as several hours.
3. Immediately after sustaining a CHI, a person may not remember where
they are, or what date and time it is.
4. In addition, CHI patients may not be able to remember events ocuring
before the trauma. The loss of memory for events prior to the accident
usually only goes back several minutes to an hour before the CHI.
5. After a CHI, a person may not be able to remember events ocuring after
the injury.
6. The loss of memory for events after the accident varies depending on
the severity of the injury, with more severe CHIs resulting in more loss of
information.
7. After a person has recovered the ability to remember events occurring
after the injury, he or she will probably still have difficulty in learning and
remembering new information.
8. These learning and memory problems are very common after CHI.
9. CHI patients often have difficulty remembering words and sentences as
well as geometric shapes and human faces.
10. "Short Term Memory" refers to the ability to remember small amounts of
information for a few seconds. People with a CHI have a normal short
term memory.
215


187
To sum to this point, the Genuine subjects demonstrated above average
memory abilities while the Head Injury patients demonstrated moderate-to-
significant memory impairment consistent with the severity of their injuries.
Given the nature of these two comparison groups, we turn our attention now to
the performance of the Malingering subjects.
Performance of Malingering Subjects
Schretlen (1988), in his review of the literature on the psychometric
detection of malingering, classifies studies into three levels of methodological
sophistication. The present study represents the highest level of sophistication
in that it includes all possible groups: experimental (Malingering subjects),
criterion (Head Injury patients with bona-fide memory impairment), and control
(Genuine subjects). Schretlen (1988) also discusses experimental procedures
which increase experimenter control but which operate at the cost of ecological
validity. He refers to these as "analog factors." Perhaps the three most
important analog factors in neuropsychological malingering research are (1) the
need to assess the extent to which malingering subjects actually portray their
role; (2) the degree of didactic information or "coaching" provided to
experimental malingerers; and (3) the desirability of providing an external
incentive to these subjects which rewards successful faking.
Data from the current study suggests that subjects in the Malingering
condition adequately invested themselves in their respective scenario and role-
playing to the extent that their performance on clinical memory tests was


171
Table 17
Univariate Group Differences on Symptom Validity Testing
Group
Variable Genuine
Malinger
Head Injury
Amnesic
SVT Accuracy Rate
Mean 100a
SD 0
F(3,60) = 17.23***
81.6B
17.9
98.7a
1.9
99.8a
0.44
SVT Mean Overall Reaction Time
Mean 0.76a
SD 0.14
F(2,52) = 24.42***
2.46s
1.25
1.28a
.37
N/A
SVT Mean RT for Correct Responses
Mean 0.76a
SD 0.14
F(2,52) = 25.57***
2.45s
1.24
1.26a
0.33
N/A
SVT Mean RT for Incorrect Responses
Mean
SD
F(1,17)=0.12
2.90
1.57
2.62
1.74
N/A
* p<.05 ** p<.01 *** p<.001
Note. Means with different superscripts differ significantly at pc.05.


5
as early as biblical times (Jones & Llewellyn, 1917, cited in Bash & Alpert,
1980). In military populations, an increase in the prevalence of malingering can
be directly linked to times of war (Anderson, Trethowan, & Kenna, 1959).
Excluding wartime, the emergence of malingering as a diagnostic and legal
entity largely resulted from the Industrial Revolution (Miller & Cartlidge, 1974).
Regler (1879, cited in Miller & Cartlidge, 1974) documented the increased
frequency of malingering as the result of the first accident insurance laws in
Prussia. As technology has progressed, industrial machinery has become
more complex, resulting in more dangerous working conditions and a higher
frequency of both legitimate and malingered injury. Mental health
professionals, including psychologists and neuropsychologists, are testifying as
expert medicolegal witnesses with increasing frequency (Lees-Haley, 1984).
Differential Diagnosis
The concepts of intentionalitv and goal-orientation are central to the
definition of malingering (Cunnien, 1988) and form the basis for differential
diagnosis. Before making the diagnosis of malingering, the clinician must rule
out genuine impairment, factitious disorder, and somatoform disorder.
Factitious disorders are characterized by the "intentional production or feigning
of psychological [or physical] symptoms" due to a "psychological need to
assume the sick role, as evidenced by the absence of external incentives for
the behavior, such as economic gain, better care, or physical well-being." This
disorder must not occur exclusively during the time course of an Axis I mental


43
were printed on index cards and presented to subjects to study for five
seconds. Response cards were printed with the target digit etring along with a
foil, also a five digit number. Response trials were grouped into three blocks of
24 trials. Presentation of the response card was delayed five seconds in the
first block of 24 trials, ten seconds in the second block, and 15 seconds in the
final block. No intervening distractor activity occurred between presentation of
the study and test cards. Prior to the first block of trials, the patient was told
that the task constituted a "memory test." Following the first and second
blocks, the patient was told that he had performed well and that, consequently,
the retention interval would be increased to make the task more difficult in the
next block of trials. This procedure created the illusion of difficulty for the
suspected malinger. In actuality, correct answers could be produced by simply
recalling the first of the five digits.
Three subjects were then tested with this procedure: a patient suspected
of malingering, a severely demented patient, and a normal five year-old girl.
The results indicated that although the suspected malingerer scored exactly at
the chance level for the first block of trials, his scores showed a progressive
decline across the second and third blocks. His overall accuracy rate of 29%
fell significantly below chance (z=-3.54, pc.0002). The normal childs score of
82% was significantly above chance. Perhaps most important, the demented
patient obtained a score of 51 % accuracy, which was not significantly different
from chance. This finding correctly highlights the need to determine the


12
trauma. The condition has been well documented and mimics the retrograde
amnesic aspects of organic amnesia (Abeles & Schilder, 1935; Schacter, Wang,
Tulving, & Friedman, 1982). Amnesia secondary to fugue states (Berrington,
Liddel & Foulds, 1956) and the act of committing a violent crime (see Hopwood
& Snell, 1933) are two examples of temporally discrete amnesias.
Amnesia presents a clinical picture manifesting four distinct
characteristics (Butters & Miliotis, 1985). All amnesics have anterograde
amnesia, or impairment in the ability to learn new information. Second, all
amnesics have some degree of retrograde amnesia (impairment in retrieving
information learned prior to illness onset). Attentional capacity is spared in
"pure" cases. The above mentioned deficits exist in the presence of intact
intellectual and other higher cortical functions.
Closed Head Injury
An adequate understanding of malingering in the neuropsychological
context warrants a careful review of the literature involving the etiology and
nature of memory impairment following closed head injury (CHI), a condition
frequently associated with malingering (Binder, 1990). Impaired memory
functioning is one of the most frequently cited neurobehavioral sequelae of
closed head injury (Brooks, 1972; Levin, Benton, & Grossman, 1982; Schacter
& Crovitz, 1977). Neurotic symptoms are the most common psychiatric
symptoms associated with closed head injury (Lishman, 1973; Miller, 1961) and
include the so-called "accident neurosis" (Miller, 1961), reactive depression in


CHAPTER 3
RESULTS
The first part of the results section will provide descriptive and
demographic information in order to fully characterize the composition of the
five experimental groups. Results from Experiment 1 involving the amnesic
patients and controls will be presented with the goal of establishing the
concurrent validity of the experimental memory tasks as representative of those
found in the literature. Extensive results from Experiment 2 involving the
Genuine, Malingering, and Head Injury subjects will then be presented.
A note concerning the use of various statistical procedures is warranted.
The use of multivariate analysis of variance procedures (MANOVA) will be
employed only when analyzing multiple response variables which represent
theoretically dissociable constructs of memory functioning (e.g., free recall of
verbal material, cued recall of verbal material, etc.). This will protect against an
inflated experiment-wise error rate. Inflated comparison-wise error rates will be
controlled by employing additive (Bonferroni) error splitting. In this case, alpha
levels will be divided by the number of comparisons made on related variables.
103


246
Russell, W. R., & Smith, A. (1961). Post-traumatic amnesia in closed head injury.
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Sattler, J. M. (1988). Assessment of children. (3rd. ed.). San Diego: Jerome M.
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Schacter, D. L. (1983). Feeling-of-knowing in episodic memory. Journal of
Experimental Psychology: Learning. Memory, and Cognition. 9, 39-54.
Schacter, D. L. (1985a). Priming of old and new knowledge in amnesic patients
and normal subjects. Annals of the New York Academy of Sciences. 444. 41-
53.
Schacter, D. L. (1985b). Multiple forms of memory in humans and animals (pp.
351-379). In N. M. Weinberger, J. L. McGaugh, & G. Lynch (Eds.). Memory
systems of the brain. New York: Guilford.
Schacter, D. L. (1986a). Feeling-of-knowing ratings distinguish between genuine
and simulated forgetting. Journal of Experimental Psychology: Learning.
Memory, and Cognition. 12, 30-41.
Schacter, D. L. (1986b). On the relation between genuine and simulated
amnesia. Behavioral Sciences and the Law. 4, 47-64.
Schacter, D. L. (1987). Implicit memory: History and current status. Journal of
Experimental Psychology: Learning. Memory, and Cognition. 13(3), 501-518.
Schacter, D. L. (1989). On the relation between memory and consciousness:
Dissociable interactions and conscious experience. In H. L. Roediger III & F.
I. M. Craik (Eds.), Varieties of memory and consciousness: Essays in honor
of Endel Tulvina (pp. 355-389). Hillsdale, NJ: Erlbaum.
Schacter, D. L, Bowers, J., & Booker, J. (1989). Intention, awareness, and
implicit memory: The retrieval intentionality criterion (pp 47-65). In S.
Lewandowsky, J. Dunn, & K. Kirsner (Eds.) Implicit Memory: Theoretical
Issues. Hillsdale, NJ: Erlbaum.
Schacter, D. L, & Crovitz, H. F. (1977). Memory function after closed head
injury: A review of the quantitative research. Cortex. 13, 150-176.
Schacter, D. L, & Graf, P. (1986a). Effects of elaborative processing on implicit
and explicit memory for new associations. Journal of Experimental
Psychology. 12, 432-444.


7
unrecognized malingerer, as well as the high costs to the patient incorrectly
labeled as a malingerer (Pankratz & Erickson, 1990; Wasyliw & Cavanaugh,
1989). Although debated in the literature, malingering is essentially an act,
performed in specific situations for the purpose of obtaining positive or negative
reinforcement, which exists apart from the actual mental status of the patient
(but see Menninger, 1963 for a discussion of the minority opinion that
malingering is a mental illness). However, malingering can certainly coexist with
mental illness (APA, 1987) and personality disorder (Clark, 1988). The
distinction between an act and a mental status is endorsed by several sources.
First, the American Psychiatric Association (APA, 1987) classifies malingering as
a "V Code," i.e., "a condition not attributable to a mental disorder that is a focus
of treatment" (p. 359). Second, Gorman (1982) states that an act is
differentiated from status in both statute and case law, in the sense that
landmark decisions have established that it is constitutional to punish a person
for performing a wrongful act (e.g., for consuming illegal drugs) but not for his
or her mental status (e.g., for being intoxicated on illegal drugs).
Recent empirical and theoretical work (Rogers, 1987, 1988) has
suggested that the traditional view of malingering as a dichotomous construct
(presence versus absence) is not consistent with clinical observations. Rather,
Rogers states that malingering may in fact be a continuous construct reflecting
gradations of dissimulation. Several authors have advanced classification
schemes for malingering which take this issue into account. Schroeder (1966)


118
MANOVAs were followed with multiple univariate analyses of variance of the
constituent variables.
Quantitative variables
Eighteen variables comprised the variable set representing quantitative
memory functioning. Table 4 presents the specific memory processes, the
constituent clinical variables which tap the processes, and MANOVA results.
Univariate ANOVA alpha levels for these comparisons were corrected to provide
Type I error protection, yielding an alpha level of .003 as the criterion necessary
to obtain statistical significance (alpha of .05/18 comparisons=.0027). Table 5
presents this data.
Composite, general memory functions. A MANOVA performed on the set
of variables representing composite, general memory functions was highly
significant, Wilks Lambda F(4,100) = 12.26, p<.0001. Univariate ANOVA
procedures showed significant main effects of group on WMS Memory
Quotient, F(2,51)=17.13, pc.0001, and CVLT Total of Trials 1 to 5,
F(2,51)=17.13, p<.0001. Follow-up mean contrasts showed that Genuine
subjects produced significantly higher scores on these two indices than either
Malingering or Head Injury groups, which were not significantly different from
each other.
Attention and concentration. A MANOVA performed on the set of
variables representing attention and concentration functions was highly
significant, Wilks Lambda F(6,98)=3.51, pc.004. Univariate ANOVA


Injured patients with documented neurological damage and bona-fide
neuropsychological memory impairment. In general, no single clinical memory
test or combination of several tests proved useful in diagnosing experimental
malingering.
Word stem completion and perceptual identification, two commonly used
indirect memory tests, were administered to these subject groups with the
general idea that Malingering subjects might first experience explicit memory for
study items and then engage in postretrieval suppression of correct responses.
This general prediction did not hold up in that Malingering subjects produced
normal strength of priming and levels of processing effects on both indirect
memory tests. However, the results indicated that the Genuine subjects used
explicit memory to increase their strength of priming on word stem completion
but not on perceptual identification.
In contrast to the indirect memory tests, the Symptom Validity Testing
paradigm used in this study was designed as a direct test of short-term
memory. The "art" of SVT lies in the fact that expected performance levels are
not apparent to the typical subject. The main finding concerning the SVT
paradigm was that Malingering subjects, as a group, were impaired relative to
other groups, but scored well above chance levels and demonstrated
surprisingly consistent responding across trials. Several statistical methods
demonstrated that the traditional criterion of chance performance may be
potentially insensitive to malingering response sets.
VI


123
Table 4
Multivariate Group Differences on Quantitative Clinical Memory Variables
Memory Process
Wilks
Lambda
Variable
Composite, Overall Memory
Functions
12.26***
WMS Memory Quotient
CVLT Total from Trials 1-5
Attention and
Concentration
3.50**
WMS Mental Control subtest
WMS Digits Forward
WMS Digits Backward
Immediate Free Recall
of Verbal Material
5.73***
WMS Immed. Logical Memory
CVLT Trial 1
CVLT Trial 5
Immediate Cued Recall
of Verbal Material
6.23***
WMS "Easy" Paired Associates
WMS "Hard" Paired Associates
CVLT Short Delay Cued Recall
Delayed Free Recall
of Verbal Material
14.23***
WMS Delayed Logical Memory
CVLT Long Delay Free Recall
Delayed Cued Recall
of Verbal Material
11.18***
CVLT Long Delay Cued Recall
CVLT Recognition Hits
Immediate Reproduction
of Nonverbal Material
5.09**
WMS Immed. Visual Reprod.
ROCF Immed. Reproduction.
Delayed Reproduciton
of Nonverbal Material
7.47***
WMS Delayed Visual Reprod.
ROCF Delayed Reproduction
* pc.05 ** pc.01 *** pc.001


137
Table 11
Performance on the Copy of the Rev-Osterreith Complex Figure
Absent (score=0)
Distorted (.5/1)
Unit G
M
HI
G
M
HI
Configurational Elements 0*
12a
3a
19b
25b
33B
Detail Elements 0C
10
T
22
37
35
Table 12
Performance on the Immed. Reorod. of the Rev-Osterreith ComDlex Fiaure
Absent (score=0)
Distorted (.5/1)
Unit G
M
HI
G
M
HI
Configurational Elements 12E
31E
25e
21F
\T
28f
Detail Elements 38G
49s
49s
32H
37H
38H
Table 13
Performance on the Delayed. Reprod. of the Rev-Osterreith Complex Figure
Absent (score=0)
Distorted (.5/1)
Unit G M HI
G M HI
Configurational Elements 14' 33' 31'
Detail Elements 35K 63K 51K
20J
38L 29L 34L
Note. Column subheadings are abbreviated as follows: G=Genuine,
M=Malingering, and HI=Head Injury. All data are percentages of each subject
group obtaining the indexed score for the indexed scoring unit. Means within
each scoring category and element type with different superscripts differ
significantly at p<.05.


178
Malingering subjects were identified with less accuracy than subjects in
the other two groups. Three subjects were classified as belonging in the
Genuine group. These subjects produced scores on indirect and direct tests
equivalent to the Genuine group. Only one Malingering subject was classified
as belonging to the Head Injury group. This subjects scores on the
experimental memory tasks were characterized as average performance on
implicit memory tasks but poor performance on explicit memory tasks,
equivalent to the bona-fide impairment of Head Injury subjects.
Indirect memory variables. Table 23 presents the classification rates
produced from a linear discriminant function analysis based on just the implicit
memory indices. Overall, implicit memory tasks failed to produce accurate
group predictions. The sensitivity rate of 43.9% and the specificity rate of 56%
were inadequate for clinical use. The group membership of Head Injury
subjects proved especially difficult to predict; only 1 of 15 was correctly
predicted. Additionally, these results confirm the hypothesis raised above that
the discriminant power exhibited by the experimental memory tasks as a group
was primarily the consequence of the direct rather than indirect memory tasks.
Clinical memory tasks
Within each clinical memory construct, one variable representing that
aspect of memory was selected to be included in this analysis based on the
highest F statistic. These variables included WMS Memory Quotient, Digits
Backward, WMS Immediate and Delayed Visual Reproduction, CVLT Total of


2. Remembering stories a few minutes after
having heard them.
3. Drawing simple geometric designs
immediately after having studied them for 10
seconds.
4. Drawing simple geometric designs a few
minutes after having studied them.
5. Studying digits on the computer screen and
then choosing which one you studied from
two choices.
6. Copying the complex geometric figure while
looking at it.
7. Drawing the complex geometric figure from
memory immediately after having copied it.
8. Drawing the complex geometric figure from
memory a few minutes after having copied it.
9. Remembering the Monday Shopping List
immediately after having been read it.
10. Remembering the Monday Shopping List
when given hints immediately after having
read it.
11. Remembering the Monday Shopping List a
few minutes after having read it.
12. Remebering the Monday Shopping List when
given hints a few minutes after having been
read it.
13. Picking Monday Shopping List items out of a
larger list of shopping items.
14. Answering simple questions about personal
and current information.
228


96
The experimenter read aloud the corresponding processing question. The
subject made his response verbally. After responding, the subject proceeded
to the next word. Following the distractor task, the subject was then given a
sheet of paper with 20 word stems and asked to complete the stems to form
the first words that came to mind. No reference was made to the study list.
Subjects were encouraged to complete the stems in the order listed. After
completing all 20 word stems to form words, each subject then was asked to
mark "Y" by each words which he or she explicitly remembered from the study
list. This is a variant of the traditional paradigm used to analyze stochastic
independence (e.g., Jacoby & Witherspoon, 1983). In these studies, subjects
are given the original study words with which to make yes/no recognition
judgements. In the current study, subjects made recognition judgements
based on the words which they produced.
Words were scored as correct only if they were exactly the same word
as was studied. Correct performance was calculated as the proportion of
words correctly completed in the target direction. Correct completion was also
calculated within each processing condition. Baseline performance was
calculated as the proportion of unexposed distractor words completed in their
target direction. Thus, each subject served as his or her own control by
producing words to distractor stems.
Perceptual identification. Subjects studied the PI study list in the same
manner as above. They were told their task was to answer questions about


250
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Brooks, D. N. (1974). Recognition memory and head injury. Journal of
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Butters, N., & Cermack, L. S. (1974). Some comments on Warrington and
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NeuroDSvcholooia. 12, 283-285.
Butters, N., & Cermack, L. S. (1980). Alcoholic Korsakoffs Syndrome: An
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128
WMS Visual Reproduction Percent Forget score, F(2,52)=12.16, pc.0001, but
not the ROCF Percent Forget score, F(2,52)=4.30, pc.02.
Follow-up mean contrasts showed that Malingering subjects produced
significantly higher forgetting scores on the WMS Logical Memory and Visual
Reproduction subtests than either Genuine or Head Injury groups. The
performance of the Genuine and Head Injury groups was not significantly
different on these two indices.
Recognition memory. Variables derived from the CVLT Recognition list
provided a good opportunity to evaluate group differences in variables
generated from a signal detection framework. A MANOVA performed on this
variable set was highly significant, Wilks lambda F(8,96)=4.92, pc.0001.
Univariate ANOVA procedures showed significant main effects of Group on d-
Prime, F(2,52) = 13.64, pc.0001, and False Alarms, F(2,52)=7.16, pc.002, but
not on Response Bias, F(2,52)=0.25, pc.78. Follow-up mean contrasts
revealed that the Genuine group demonstrated superior discriminability and
fewer false positive errors than either the Malingering or Head Injury group.
The Malingering and Head Injury groups did not differ significantly with respect
to these recognition indices. The groups did not differ significantly on their
tendency to favor "yes" or "no" responses irrespective of the stimulus type.
ROCF qualitative scoring. Performance on the Rey-Osterrieth Complex
Figure provided an excellent opportunity to analyze qualitative aspects of
memory performance. The copy, immediate reproduction, and delayed


166
significant main effect of group on SVT response latencies, F(2,52)=24.42,
pc.0001. Follow-up mean contrasts revealed that Malingering subjects
(mean=2.46 seconds) produced significantly longer response latencies to
respond to items, irrespective of correctness of response, than either the
Genuine (mean=0.76 seconds) or Head Injury groups (mean=1.28 seconds),
which were not significantly different from one another. Table 17 presents these
data. A similar analysis was conducted for correct answers only, with
equivalent results. A highly significant main effect of group on response
latencies for correct responses was found, F (2,52)=25.57, pc.0001. Follow-up
mean contrasts produced the same ordering of means. Finally, an analysis
was conducted for the main effect of group on reaction time for incorrect
answers (Genuine subjects were excluded due to the absence of incorrect
answers). The results were nonsignificant (F c 1).
As contrasted with a general process of producing slowed or
exaggerated behavior, Malingering subjects may also demonstrate trends
towards inhibition or suppression of correct responses during the SVT
paradigm (i.e., "thinking about it"). This process could potentially be manifest
as differential response latencies for correct versus incorrect answers. A within-
group analysis was performed on the Malingering group only. The main effect
of answer status on response latency was nonsignificant (F < 1), but response
latency was slightly slower for incorrect answers.


197
memory used as a basis for implicit memory (Bowers & Schacter, 1990;
Richardson-Klavehn & Bjork, 1988; Schacter et al., 1989). However, it should
be kept in mind that the post-testing interview method is only the subjects best
guess at his mental state at the time of testing. Subjects responses could be
biased by any number of factors. Further research which attempts more
systematically to specify and isolate these factors is needed.
The Impact of Meta-Memorial Experiences
The experience of test awareness or absence of such experience had no
appreciable effects on the observation of normal priming for all three groups on
both indirect memory tests. Subjects who remained test unaware showed
essentially normal priming on WSC and PI. Similarly, subjects who experienced
test awareness but did not engage in intentional explicit retrieval also showed
normal priming effects on WSC and PI.
However, three lines of evidence can be marshalled to suggest that
postretrieval suppression (or the lack of it) impacted performance during WSC.
Conversely, little evidence can be found to support the same claim for
performance on PI. First, indirect evidence derives from the overall magnitude
of priming observed in each group. Genuine subjects completed an
unexpectedly high number of target words on WSC, which was significantly
greater than the other two groups. Head Injury patients, who had relatively little
explicit memory to draw upon, completed a significantly less proportion of
target words on WSC than did the Genuine subjects. Malingering subjects


82
concentration and memory problems. On average, patients were tested
approximately two years after sustaining their injury (median injury-test interval
= 26 months; range = 4 to 73 months). By all accounts, most all of these
subjects survived severe head injuries. Those with more minor injuries
nevertheless suffered significant neuropsychological impairment.
Clinical characteristics were analyzed as a function of referral setting
(inpatient rehabilitation versus outpatient clinic). Exploratory analyses of
variance failed to find significant main effects of referral setting on age at time of
testing, injury-test interval, duration of coma, or duration of post-traumatic
amnesia. Because of this, all HI patients were treated as a single group of
patients.
Design
The design of the study consisted of a combination of within-subjects
and between-groups factors. The overriding independent variable of interest
was group membership: the Malingering group served as the experimental
group, the Genuine group served as the normal control group, and the Head
Injured group served as the criterion group with bonafide memory impairment.
The effect of group membership was observed on all dependent measures
deriving from the clinical and experimental memory tasks. Levels of processing
were manipulated in a within-subjects manner.


6
disorder, such as bipolar disorder (manic phase) (APA, 1987, p. 318). Thus,
the malingerer and the patient with factitious disorder both voluntarily respond
deceptively, with the former being voluntarily motivated to dissimulate by the
prospect of external secondary gain, while the latter reflects an involuntarily
adopted psychological goal to assume the role of sickly patient (Drob & Berger,
1987).
Somatoform disorders refer to a group of psychiatric disorders in which
there are "physical symptoms suggesting physical disorder for which there are
no demonstrable organic findings or known physiologic mechanisms, and for
which there is positive evidence, or a strong presumption, that the symptoms
are linked to psychological factors or conflicts" (APA, 1987, p. 255). Conversion
disorder is subsumed by this category. In somatoform disorders the
mechanisms linking mind and body are presumably not under conscious
control (Reich & Gottfried, 1983). Therefore, a malingerer and an individual with
somatoform disorder both demonstrate physical symptoms that have no known
etiologically significant physical cause, with the former intentionally dissimulating
for an obvious environmental goal, and the latter unintentionally altering his
presentation and no obvious environmental goal.
Classification
One of the most difficult clinical aspects associated with malingering is
classification (Bash & Alpert, 1980). The diagnostic task is made all the more
difficult for the clinician due to the high costs to the medical system from an


186
tasks. Complex immediate memory functions were impaired as well as most
indices of recent memory. Finally, inefficiency in all process-oriented
distinctions (encoding, storage, retrieval) of memory was observed. As a
group, the performance of the Head Injury subjects was clearly consistent with
the moderate-to-severe nature of their injuries.
One possible criticism of this study would be that this sample of Head
Injury patients was not representative of the type of patients most often seen in
the medicolegal context for forensic neuropsychological evaluation. Given the
need to exclude patients involved in current litigation or even considering future
litigation, I would argue that there does not exist a large pool of CHI patients
which would closely match litigating head injury patients. Several factors may
be interacting here.
First, the definition of "compensable injury" would necessarily include the
presence of an external party which could potentially be responsible for the
injury. Thus, litigation status may be determined in part by the assignment of
"fault1, such that patients who caused their own injury are excluded from
litigation while innocent victims are not excluded from litigation. Second,
patients suffering an obviously severe injury which can be unequivocally
documented with neurological evaluation may receive compensation or
settlement of their legal claim more quickly than those patients with equivocal
findings. Nevertheless, the identification and participation of these Head Injury
patients was secured with great effort and expense.


58
circumstances intentional retrieval does not contribute to repetition priming
(Tulving, Schacter, & Stark, 1982). Second, studies testing implicit memory
after degraded encoding demonstrate that implicit memory can occur in the
absence of explicit memory (Eich, 1984). Third, as levels of processing
manipulations have been shown to robustly affect direct memory tests, LOP
manipulations may increase the likelihood that explicit retrieval may intrude
during indirect memory tests (Schacter, 1987). This review will lay the
groundwork for a careful review of the work of Bowers and Schacter (1990)
which directly investigated implicit memory, LOP, and test awareness.
Stochastic independence
The concept of stochastic (statistical) independence between direct and
indirect memory tests has been taken as evidence for a dissociation between
implicit and explicit forms of memory (Tulving, Schacter, & Stark, 1982).
Stochastic independence is the name given to the relation between two events
in which the probability of their joint occurrence is equal to the product of the
probabilities of the occurrence of each event alone (Tulving, 1985). In a typical
experiment, a subject completes an indirect test of memory, such as word stem
completion. He then completes a yes/no recognition memory test for the study
words. Two scores are then computed. The simple probability of word stem
completion refers to the proportion of study words which were correctly
completed in their target direction. The simple probability of recognition
memory refers to the proportion of target words which were correctly


161
F(1,19)=4.28, pc.06. The interaction between group and orienting task failed
to reach significance, F(2,52)=.82, pc.44. Figure 12 presents this data. The
failure of subjects in each group to demonstrate the expected advantage for
conceptually encoded words is consistent with other reports in the literature of
an absence of orienting task effects in recognition paradigms (see Bradshaw &
Anderson, 1982). The task demands of this task were not difficult, permitting
subjects to accurately recognize words encoded in the physical condition.
Trial-bv-trial analysis. A Malingering subject could potentially suppress
his multiple choice recognition performance to the extent that he perceived that
he is "over-responding" or portraying memory ability of insufficient impairment,
not understanding the undemanding task requirements of MCR. The change in
a subjects response strategy or criterion was operationalized as changes in
percent correct recognition for successive blocks of test words. The stimuli
were divided into groups of 4 words, representing partitions of 20% of the
overall list.
Figure 13 presents this data. Main effects of serial order were analyzed
within groups. Within-group analyses were nonsignificant for main effects of
serial position of blocks of target words for the Genuine group, F(4,18)=1.68,
pc.16, or the Malingering group, F(4,18)=2.66, pc.039. A significant main
effect of serial order was found for the Head Injury group, F(4,13)=4.72,
pc.002. Follow-up mean contrasts revealed that Head Injury subjects
recognized significantly fewer words on the last 20% of the test list than from


APPENDIX C
POSTEXPERIMENTAL MATERIALS
De-Briefing Rating Sheet
For each task that you participated in during the experiment, please rate the (1)
effort you put into playing your role; (2) the difficulty of the task for playing your
role; and (3) how successful/unsuccessful you think you were in responding
according to your role. Use the following 7-point scales.
Effort
1 2 3 4 5 6 7
Minimum Average Maximum
effort effort effort
Difficulty of Task
(if you would have been performing your best)
1 2 3 4 5 6 7
Minimum Average Maximum
difficulty difficulty difficulty
Success of Performing your Role
1 2 3 4 5 6 7
Minimum Average Maximum
success success success
Diffi- Succ-
Effort culty ess??
1. Remembering stories immediately after having
heard them.
227


223
Free Recall Stimuli
Buffer Items
GARMENT
BANDAGE
ADOPT
GLOVE
CATALOG
She picked up her at the laundry. (Y)
Contain the letter "L". (N)
Contain the letter "E". (N)
Contain the letter "N". (N)
He ordered the present from the (Y)
Target Stimuli
PRICE The of the new car was too expensive. (Y)
STRESS The man bought the at the store. (N)
ADJUST Contain the letter "J". (Y)
BLOOM Contain the letter "S". (N)
PARENT They ordered ham and for breakfast. (N)
RETAIN Contain the letter "I". (Y)
BASIN Contain the letter "C". (N)
HEROIN The secretary made two of the original. (N)
SKIRT The womans pleated matched her blouse. (Y)
TRUTH Contain the letter "H". (Y)
DRAGON The knight killed the with his sword. (Y)
CAREER Contain the letter T. (N)
WINDOW The open was causing a draft. (Y)
SERVE Will you please me some food? (Y)
SOURCE Contain the letter "F". (N)
DEFECT The opened his shop for business. (N)
CLAIM Contain the letter "L". (Y)
THROAT The boys tossed the around the sandlot. (N)
CALORIE Contain the letter "O". (Y)
POSITIVE Contain the letter "B". (N)


40
Bernard (1991), in a later article, further analyzed the performance of this
same sample of subjects on the Rey Auditory Learning Test. The inclusion of a
group of 18 CHI subjects with relatively severe injuries who were tested early in
their recovery improved the methodology of the study. The results indicated
that the malingering group scored significantly lower than the control group, but
scored significantly higher than the CHI group. Thus, the malingerers portrayed
deficits of insufficient magnitude to resemble patients with bona-fide memory
impairment secondary to severe CHI. Further inspection of the data revealed
that malingering subjects obtained low scores by suppressing their recall of
words from the primacy portion of the list.
Iverson, Franzen, & McCracken (1991) used a verbal list-learning
paradigm to investigate the performance of experimental malingerers, patients
with bona-fide memory impairment of mixed etiology, and normal controls
performing to the best of their ability. Two procedures, free recall of stimuli and
two-item, forced recognition, were employed. The mean free recall score for
the normals was significantly greater than those for malingerers and memory-
disordered patients; the latter two groups did not differ significantly. Main
effects of group on serial position for recall and recognition were nonsignificant.
In the forced-choice task both normals and memory-disordered patients
outperformed malingerers. Sixty percent of malingering subjects scored
significantly below chance levels, while the remaining 40% scored within the
confidence interval constructed around chance performance. No malingering


81
University of Florida Health Science Center. The remaining five outpatient Head
Injury referrals agreed to participate in the study after undergoing a
neuropsychological evaluation at the Mental Hygiene Clinic at the Veterans
Affairs Medical Center in Gainesville, Florida. Outpatient CHI patients were paid
twenty dollars for their participation. Eight additional Head Injured patients were
recruited from the Sandybrook Center of Rebound, Inc., which is located in Mt.
Dora, Florida.
Duration of post-traumatic amnesia (PTA) and coma are frequently used
indicators of injury severity in the CHI population (c.f., Levin, Benton, &
Grossman, 1982). Coma was judged to end when the patient was able to
follow verbal commands. Post-traumatic amnesia was judged to end when the
patient regained full temporal and personal orientation. In a few cases, this
information was unavailable from medical records. In these instances, length of
coma and/or PTA was estimated by interview with the patient. Eleven of the 15
patients experienced coma. The median length of coma for these patients was
25 days (range = 1 to 120 days). The median duration of post-traumatic
amnesia was 504 hours or 21 days (range = 0 minutes to 44 days). The
median length of PTA was lower than the median length of coma because
severe and lengthy coma occurred frequently in this sample (11 of 15 patients
sustained coma). All of these patients were judged to be fully oriented after
their coma resolved. Only one patient did not experience either coma or post-
traumatic amnesia, but this patient nevertheless demonstrated significant


49
malingering subjects (Le, "coaching"), and the saliency of incentive to produce
believable deficits vary widely from study to study.
An informal meta-analysis was conducted on the studies involving
experimental malingering Table 1 presents this data. This sample of studies is
neither random or representative. Studies were included in the meta-analysis if
they presented means and standard deviations on the outcome measures. A
study had to have directly compared the performance of subjects instructed to
malinger dysfunction with either normals performing their best (control group)
or neuropsychological patients with bona-fide impairment (criterion group). In
general, studies were excluded if they failed to present means and standard
deviations.
The results of the meta-analysis corroborate the conclusions drawn from
the qualitative review of the literature. First, an average effect size of -3.5 is
attributed to 'treating" subjects with instructions to malinger. Following Smith &
Glass (1974) interpretative framework, this effect size means that a subject
scoring at the mean of the control group would fall to 3.5 standard deviations
below the mean of the control group when given instructions to malinger. This
is an exceptionally large effect size which may be the result of floor and ceiling
effects associated with some dependent measures. For example, Mensch &
Woods (1986) employed the LNNB scales as outcome measures which defined
normality very close to zero, resulting in both mean scores near zero and
artificially constricted variance. On the other hand, normal subjects often obtain


51
near perfect scores on other outcome measures, such as recognition
paradigms, resulting in very high mean scores and artificially constricted
variance. Nevertheless, the effect size computed is no doubt significant and
fulfills Cohens (1977) criteria for a "large" effect size.
Second, an effect size of -1.7 is attributed to bona-fide organic
impairment. That is, a subject scoring at the mean of the control group would
fall to approximately 1.7 standard deviations below the mean of the control
group if he were to sustain organic impairment. The true litmus test is applied
when malingerers are compared with the criterion group representing bona-fide
impairment or deficiency. An average effect size of -0.5 is associated with the
comparison between organic patients and malingering subjects, which prompts
the conclusion that malingerers are able to successfully suppress the
quantitative level of their performance to levels associated with organic
impairment.
Given that malingering subjects fall to 3.5 standard deviations below the
mean of normals and subjects with bona-fide impairment only fall to 1.7
standard deviations below the mean of normals, it would seem at first glance
that malingering subjects should score approximately 1.8 standard deviations
below organic patients instead of the observed effect size of -0.5. Upon further
inspection, however, it becomes clear that these values cannot be validly
compared because the referent comparison group (i.e., the group whose
standard deviation represents the denominator of the effect size equation) is


242
McAndrews, M. P., Glisky, E. L, & Schacter, D. L (1987) When priming
persists: Long-lasting implicit memory for a single episode in amnesic
patients. Neuropsvcholoaia. 25(3), 497-506.
McKinlay, W. W., Brooks, D. V., & Bond, M. R. (1983). Post-concussional
symptoms, financial compensation and outcome of severe blunt head injury.
Journal of Neurology. Neurosurgery, and Psychiatry. 46. 1084-1091.
McKoon, G., & Ratcliff, R. (1979). Priming in episodic and semantic memory.
Journal of Verbal Learning and Verbal Behavior. 18, 463-480.
Menninger, K. A. (1935). Psychology of a certain type of malingering. Archives
of Neurology and Psychiatry. 33. 507-515.
Menninger, K. A. (1963). The vital balance. New York: Viking.
Mensch, A., & Woods, D. (1986). Patterns of feigning brain damage on the
LNNB. The International Journal of Clinical Neuropsychology. 8, 59-63.
Metcalfe, J., & Fisher, R. P. (1986). The relation between recognition memory
and classification learning. Memory and Cognition. 14, 164-173.
Miller, E. (1986). Detecting hysterical sensory symptoms: An elaboration of the
forced choice technique. British Journal of Clinical Psychology. 25. 231-232.
Miller, F. (1970). Simple and complex choice reaction time following severe
head injury. Cortex. 6, 121-127.
Miller, H. (1961). Accident neurosis. British Medical Journal. 1, 919-925, 992-
998.
Miller, H., & Cartlidge, N. (1974). Simulation and malingering in relation to
injuries of the brain and spinal cord. In E. H. Feiring (Ed.), Brocks injuries of
the brain and spinal cord (pp. 638-657, 5th ed.). New York: Springer
Publishing Company.
Milner, A. D. (1986). Chronometric analysis in neuropsychology.
Neuropsvcholoaia. 24(1), 115-128.
Milner, B., Corkin, S., & Teuber, H. L. (1968). Further analysis of the
hippocampal amnesic syndrome: 14 year follow-up of H.M.
Neuropsvcholoaia. 6, 215-234.


114
PERCEPT. IDENTIFICATION
Target Advantage
% correct identification
70 i
AMNESICS CONTROLS
Targets 43.3 44.4
Distractors 22.2 20.6
Encoding Process
% correct identification
Sentence
Lette
Process
iHH Sentence
Letter
Letter 42.2 44.4
Figure 2. Perceptual Identification Performance for Experiment 1.


159
Table 16
Test Awareness and Retrieval Intentionalitv in Perceptual Identification
%of
Group
Priming
Levels of
Processing
Sen. Let.
Not Aware
Genuine
65
+21*
46
48
Malinger
30
+ 13*
36
33
Head Injury
73
+28*
51
51
Aware but No Explicit Mediation
Genuine
30
+30*
50
62
Malinger
25
+33*
56
54
Head Injury
20
+32*
53
67
Aware and Explicit Mediation
Genuine
5
+40*
50
50
Malinger
45
+ 18*
28
34
Head Injury
7
+20*
30
20
Note. Within level of test awareness, means with different superscripts differ
significantly at p<.05.


24
(Hartings, 1989). Therefore, clinicians are rarely certain of the true nature of
impairment in cases of questionable motivation. This gives rise to the need for
experimental analog studies which attempt to mimic the clinical situation by
instructing subjects to portray or "simulate" impairment on testing.
Malingered Mental Deficiency
Pollaczek (1952) investigated the ability of normal college males and
normal Navy recruits to feign feeblemindedness on the "CVS" abbreviated
intelligence scale, a measure which consists of the Comprehension and
Similarities subtests from the Wechsler-Bellevue test and selected vocabulary
items from the Stanford-Binet Intelligence test (Hunt, French, Klebanoff, Mensh,
& Williams, 1948). Fifty male mental retardates were used as the criterion
comparison group. The results indicated that malingering subjects
demonstrated mental impairment equivalent to that of true mental defectives.
Thus, malingerers could not be detected with the use of the CVS total raw
score. An item-by-item analysis revealed significant between-groups differences
on 17 of 37 test items. These critical items were of two types: (1) relatively
easy items occurring at the beginning of each subtest which mental defectives
complete accurately while malingerers failed; and (2) relatively difficult items
occurring at the end of each subtest which mental defectives fail but which
malingerers passed. Cut-off scores were derived and a linear discriminant
function classification produced an 87% sensitivity rate for malingering
subjects, with a 10% false positive rate.


203
whenever they explicitly remembered a previously presented name they could
be sure that the name was in fact nonfamous. Any subsequent fame
judgements would be the effect of unconscious memory for the study episode.
This method places the effects of conscious memory in opposition to the effects
of unconscious memory. All contaminating influences of conscious memory
were effectively partialled out of the effects of unconscious memory.
It would be interesting to evaluate the performance of Malingering
subjects using the method of opposition. In Jacobys fame judgement
paradigm, Malingering subjects would be expected to produced an increase in
fame judgements to the extent that they suppressed or denied conscious
memory for the previously studied names. This would place Malingering
subjects in the confusing situation of producing additional behavior to represent
a deficit of memory.
Another solution similar to the method of opposition would be to give
subjects the paradoxical instructions "not to remember" any study words while
completing the indirect memory tests. Yet another solution would be to make
subjects aware of the fact that study words could potentially be used to
facilitate task performace. This manipulation would make for a stronger
interpretation of the data. It is predicted the Malingering subjects would
demonstrate a more discrepant (impaired) performance relative to the control
and criterion groups. Specifically, Malingerers would be expected to engage in
postretrieval suppression more frequently than they did in this study.


125
Table 5--continued
Univariate Group Differences on Quantitative Clinical Memory Variables
Group
Variable
Genuine
Malinger
Head Injury
CVLT Trial 1
Mean
8.4*
5.1B
5.0B
SD
F(2,52) = 11.76***
2.2
1.8
2.9
CVLT Trial 5
Mean
13.6*
9.9B
8.7B
SD
F(2,52) = 10.48**
1.9
3.5
3.8
WMS "Easy" Assoc.
Mean
17.7*
15.70
15.3B
SD
F(2,52) = 9.88**
0.5
2.2
1.7
WMS "Hard" Assoc.
Mean
9.7*
5.7
4.3B
SD
F(2,52) = 16.52***
1.9
3.2
3.1
CVLT SD Cued Recall
Mean
13.6*
8.6B
7.3B
SD
F(2,52) = 17.66***
1.7
3.7
3.6
* p<.05 ** p<.01 *** pc.001
Note. All data are raw scores. Means with different superscripts differ
significantly at pc.05.


BIOGRAPHICAL SKETCH
Travis Gordon White, Jr., was bom in Austin, Texas, on April 23, 1965.
Upon graduation from Robert E. Lee High School in Houston, Texas, in 1983,
Travis matriculated at Southern Methodist University in Dallas, Texas. While at
Southern Methodist, Travis undertook an honors thesis project titled
"Environmental Potentiation of Taste Aversion Learning in Rats." Based on this
research project, Travis graduated from Southern Methodist with departmental
distinction in 1987.
Travis enrolled in the Department of Clinical and Health Psychology at
the University of Florida in August of 1987. He was awarded the degree of
Master of Science in 1989. His thesis, titled "Recall of Three Words after Five
Minutes: Its Relationship to Performance on Neuropsychological Memory Tests,"
was completed under the guidance of his present doctoral committee chairman,
Dr. Russell Bauer. While a graduate student at the University of Florida, Travis
was recognized with several honors, including the Molly Harrower Award for
Excellence in Psychodiagnostic Assessment, the Robert Levitt
Neuropsychological Research Award, and the Presidential Recognition Award
for distinguished service to the University.
252


APPENDIX B
EXPERIMENTAL MATERIALS
Word Stem Completion Stimuli
Buffer Items
HOLIDAY
FERRY
CANCER
BALLOON
IMPRESS
Contain the letter "D". (Y)
The boys mother applied a to his cut. (N)
Contain the letter "R". (Y)
The signed the historic document at the conference. (N)
Contain the letter "E". (Y)
List A Target Words
IMMENSE The farmer hooked up the to his tractor. (N)
SUPPLY Contain the letter "U". (Y)
PERSON Contain the letter "F". (N)
SCOPE The doctor looked through a into the patients ear. (Y)
OBSCENE Contain the letter "N" (Y)
TRAIN The left Grand Central Station. (Y)
RANGER Contain the letter "B". (N)
CONCEPT The student could not understand the (Y)
REVENGE Contain the letter "W. (N)
SPENT The players were ready to begin the (N)
List B Target Words
GRAPE
STOCK
PRODUCE
FATIGUE
HANGAR
ASSUME
CHEESE
FRESH
SANDWICH
SHOULDER
The juice of a may be used to make wine. (Y)
Contain the letter "O". (Y)
Contain the letter "L". (N)
It must be 100 out here today. (N)
The old movie is a (N).
You too much by not asking for my permission. (Y)
Contain the letter "H". (Y)
Contain the letter "O". (N)
Contain the letter "D". (Y)
The family was glad to have returned to their (N)
221




63
The study by Jacoby, Woloshyn, and Kelley (1989) warrants a more
detailed review. In Experiment 1, famous and nonfamous names were
presented to be read aloud under conditions of divided or full attention. Gains
in familiarity of names were tracked by changes in performance on a later fame-
judgement task. Explicit memory for the previous presentation of the names
was tested with a standard recognition memory test. Gains in familiarity were
demonstrated even when studied with divided attention, while explicit
recognition memory was lower after divided attention than full attention.
Additional experiments were conducted to preclude the possibility that
the familiarity measure actually reflected some instances of conscious
recollection. Gains in familiarity were placed in opposition to conscious
recollection to further separate the two processes. All names presented in the
study phase were nonfamous and the subjects were told so. Subsequent
conscious recollection of a name during the fame-judgment task would allow
subjects to be certain that the name was nonfamous. Familiarity without
conscious recollection would result in the opposite, calling a name "famous".
Attention was divided again at study and later during the fame-judgement task.
The accurate recognition of old nonfamous names in the full-attention condition
allowed those names to be called "famous" less often. In contrast, dividing
attention radically reduced list recognition. The failure to recognize old
nonfamous names in combination with a gain in their familiarity was revealed by
the finding that old nonfamous names were more likely to be called "famous"


231
Benton, A. L. (1955). The Revised Visual Retention Test: Clinical and
experimental Applications. New York: The Psychological Corporation.
Benton, A. L, & Spreen, O. (1961). Visual memory test: The simulation of
mental incompetence. Archives of General Psychiatry. 4, 79-83.
Bernard, L. (1990). Prospects for faking believable memory deficits on
neuropsychological tests and the use of incentives in simulation research.
Journal of Clinical and Experimental Neuropsychology. 12(5), 715-728.
Bernard, L. (1991). The detection of faked deficits on the Rey Auditory Learning
Test: The effect of serial position. Archives of Clinical Neuropsychology. 6,
81-88.
Bernard, L, & Fowler, W. (1990). Assessing the validity of memory complaints:
Performance of brain-damaged and normal individuals on Reys task to
detect malingering. Journal of Clinical Psychology. 46(4), 432-436.
Berrington, W. P., Liddel, D. W., & Foulds, G. A. (1956). A reevaluation of the
fugue. Journal of Mental Science. 102, 281-286.
Bickart, W. T., Meyer, R. G., & Connell, D. K. (1991). The symptom validity
technique as a measure of feigned short-term memory deficit. American
Journal of Forensic Psychology. 9(2), 3-11.
Bigler, E. D. (1990). Neuropsychology and malingering: Comment on Faust,
Hart, and Guilmette (1988). Journal of Consulting and Clinical Psychology.
58(2), 244-247.
Binder, L. M. (1986). Persisting symptoms after mild head injury: A review of the
postconcussive syndrome. Journal of Clinical and Experimental
Neuropsychology. 8, 323-346.
Binder, L. M. (1990). Malingering following minor head trauma. Clinical
Neuropsvcholoaist. 4(1), 25-36.
Binder, L. M. (1992). Malingering detected by forced choice testing of memory
and tactile sensation: A case report. Archives of Clinical Neuropsychology. 7,
155-163.
Binder, L. M., & Pankratz, L. (1987). Neuropsychological evidence of a factitious
memory complaint. Journal of Clinical and Experimental Neuropsychology. 9,
167-171.


THE USE OF INDIRECT TESTS IN THE EVALUATION OF MALINGERED
OR EXAGGERATED MEMORY PERFORMANCE
By
TRAVIS G. WHITE, JR.
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1992


11
Memory Impairment Following Brain Damage
Amnesia
Amnesia refers to a condition characterized by the impairment of normal
memory functioning in which a person has an acquired difficulty in learning new
material and in recalling remote events. Amnesia can be classified according to
etiology (organic versus psychogenic) and chronicity (discrete episodes versus
persistent impairment) (Kopelman, 1987). As it is most frequently used,
amnesia refers to a neurological condition that can result from a variety of
etiologic agents and loci of lesions (Butters & Miliotis, 1985). Anoxia,
encephalitis, electroconvulsive therapy (ECT), cerebrovascular accidents, closed
head injuries, and surgical damage have all produced amnesia in patients
(Drachman & Arbit, 1966; Milner, 1970; Squire, Chace, & Slater, 1976; Levin,
Benton, & Grossman, 1982). Lesions to the medial diencephalic structures,
including the dorsomedial nucleus of the thalamus and the mammillary bodies
(Victor, Adams & Collins, 1971; Butters & Cermak, 1980), the fornix (Heilman &
Sypert, 1977), and the retrosplenial area (e.g., splenium, retrosplenial cortex,
and cingulate bundle) (Valenstein, Bowers, Verfaellie, Heilman, Day & Watson,
1987) have all produced amnesia.
However, amnesia can have a psychogenic etiology as well (Kopelman,
1987). This phenomenon, which has also been referred to as functional
amnesia (Schacter, 1986a), refers to amnesia for a discrete episode of time
occurring in the past. It is produced by severe psychological and emotional


97
words; no reference was made to the memorial aspects of the study episode.
A four-channel Gerbrands tachistoscope equipped with a voice-activated
response timer was used to present the stimuli. At PI testing, target words
were tachistoscopically presented one after another at a fixed exposure
duration in the following manner. After a subject signaled his readiness to
proceed, an orienting stimulus was exposed on the screen for 500 msec
indicating to the subject where the word was to be presented. The word was
then exposed for the appropriate duration, followed immediately by a mask
which remained for 2 seconds. The subject attempted to read the word as
quickly as he could. The subjects verbal answer and response latency were
recorded for each trial. This was repeated for every word in the test list. After
the PI test, subjects were given a list of the same 40 words and asked to circle
"Y" or "N" based on whether they recognized the word from the study list.
(Note: this procedure conforms directly with the traditional procedure used to
compute stochastic independence.). Responses were scored as correct only if
they were exactly the same word as was studied. Correct performance was
calculated as the proportion of target words correctly identified. Correct
identification rate was also calculated within each processing condition.
Baseline performance was calculated as the proportion of distractor words
correctly identified. Thus, each subject served as his or her own control by
attempting to identify distractor words.


59
recognized on a direct recognition test, irrespective of word stem completion
status. The conditionalized probability of recognition memory refers to the
proportion of correctly generated target words that were later correctly
recognized on a direct recognition test.
Therefore, stochastic independence exists when the conditionalized
probability of correct recognition does not exceed the product of the two simple
probabilities. Unlike functional independence, stochastic independence is not
based on comparing the average performance on two tests, but rather on
determining whether performance on a particular item on one test predicts
performance on that same item on another test. If no predictive relationship is
found, then the tests are assumed to be independent (Witherspoon &
Moscovich, 1989).
In the present context, the concept of stochastic independence becomes
relevant because it allows the researcher to examine the relative contribution of
explicit memory processes on indirect memory tests. In general, a number of
studies have firmly demonstrated stochastic independence between direct and
indirect memory tests (Richardson-Klavehn & Bjork, 1988). Jacoby and
Witherspoon (1982) biased the homophone spelling for amnesic patients and
normal control subjects. The spelling of homophones required in the second
phase of the experiment provided an indirect measure of the effect of the prior
presentation of the homophone on its later interpretation. Both groups of
subjects demonstrated intact implicit memory for the biased spelling. Yes/no


107
Table 3
Descriptive Information for Experiment 2
Group
Variable
Genuine
Malinger
Head Injury
Number of Subjects
20
20
15
Age
Mean
SD
F(2,52)
= 7.09**
21.1*
3.6
21.6a
5.1
26.9B
6.1
Education
Mean
SD
F(2,52)
= 2.03
12.9a
1.0
12.8a
0.8
12.3a
1.1
Full Scale IQ
Mean
SD
F(2,52)
= 9.88**
108.3a
11.5
110.3a
14.0
92.4b
12.1
* p<.05
** p<.01
*** p<.001
Note. Means with different superscripts differ significantly at p<.05.


112
the expected free recall advantage afforded by the conceptual orienting
condition. Their grossly impaired explicit memory likely prevented them from
learning any new information. The interaction between group and orienting task
was also highly significant, F(1,16)=12.90, p<.002, with control subjects
showing a significantly greater levels of processing effect than Amnesic
subjects. Figure 3 presents this data.
Multiple Choice Recognition
The main effect of group on multiple choice recognition performance was
highly significant, F(1,16)=47.06, p<.0001. Amnesic subjects demonstrated
grossly impaired explicit memory (mean=45%) as measured by multiple choice
recognition of previously presented words when compared with control
subjects (mean=78.3%). The MCR performance of Amnesics subjects was not
significantly greater than chance performance (Z=1.39, pc.08). The interaction
between group and orienting task was nonsignificant, F(1,16)=.05, pc.82, with
Amnesic and control subjects showing equivalent orienting task effects. Figure
4 presents this data.
Experiment 2: Main Study
Validity of Group Membership: Clinical Memory Performance
The data generated from the clinical memory tests were used as a
validity check to establish that each subject group produced a pattern of
performance similar to that reported in the literature. Performance on clinical
memory tests provides an easily interpretable benchmark upon which to later


169
Alternative data analysis strategies. Binomial principles can be applied to
SVT data in two other ways, both illustrating the difficulty in using a random or
chance level of performance as the criterion for malingering. Miller (1986)
presented a case study in which a patient was suspected of producing
hysterical sensory loss. This patient obtained a score of 56/120 on 2-item,
forced choice testing. This score was below nominal chance performance of
60/120, but failed to reach the necessary .05 binomial significance level of 50
out of 120. In order to further understand this patients performance, the author
subdivided the total of 120 trials into 24 blocks of 5 trials each. This data is
presented in Table 21. The subject could potentially produce 0 through 5
correct responses per trial block. Cross-tabulation frequency counts were then
computed for the number of trial blocks in which the subject produced all
possible number of correct responses (0 to 5). Finally, expected frequencies
for each cell were computed. A chi-square analyses demonstrated that the
subject obtained scores of 2/5 and 3/5 on a higher than expected number of
trial blocks. Using this statistical procedure, Miller was able to demonstrate that
his patients performance deviated significantly below chance for a portion of
the SVT procedure.
In the current dataset, one subject obtained a score of 45/100, which
falls below the nominal chance level but fails to reach statistical significance.
The subject only produced 1 correct response during trials 70 to 79. Refer to
Table 18 for this subjects (# 34) data. Expected frequencies of each possible


88
or her mind. Ten of the stems could be completed to form the target words
which were studied. The remaining 10 unexposed words were used as
distractor stimuli. The percentage of these words completed in the target
direction served as baseline performance.
Perceptual identification (PIT A pool of 45 words were used for WSC.
Subjects studied a group of 25 words. Five words were used as primacy and
recency buffers. Of the remaining 20 words on the study list, 10 words were
encoded with a semantic processing task and 10 were encoded with an
physical processing task. Study words were printed on four by six inch white
index cards. The PI test list consisted of 40 words, the 20 target words plus 20
unexposed distractor words. Assignment to serial position in the test list was
random. A yes/no recognition test followed the PI task; it consisted of the
same 40 words.
Free recall. A pool of 25 words were used for FR. The FR study list was
composed of five buffer words, 10 words which were encoded in a semantic
processing task, and 10 words which were encoded in an physical processing
task. Study words were printed on four by six inch white index cards. Subjects
made their FR responses on a sheet of lined paper. Buffer words produced at
test were not counted as correct.
Multiple choice recognition. A pool of 25 words were used for MCR.
The MCR study list was composed of five buffer words, 10 words which were
encoded in a semantic processing task, and 10 words which were encoded in


54
itself with the phenomena of repetition priming (c.f., Cofer, 1967), which refers
to the facilitative effects of a learning episode on performance of a subsequent
task, such as word stem completion or tachistoscope identification (Graf &
Schacter, 1985).
Definitions
Richardson-Klavehn and Bjork (1988) contrast implicit and explicit forms
of memory with direct and indirect measures of memory. Forms of memory are
definitionally hypothetical and require an assumption to be made concerning
the subjects mental content or mental state at the time of testing. Explicit
memory is commonly assumed to involve the deliberate, directed retrieval of
information about specific episodes. Explicit memory is demonstrated when
performance on a task requires conscious recollection of a previous
experience. Implicit memory does not depend on directed, conscious
demonstrations of memory when performance on a memory task is facilitated
or somehow altered in the absence of conscious recollection (Graf & Schacter,
1985).
Measures of memory can be categorized with respect to task
instructions and measurement criteria (Johnson & Hasher, 1987). This
nomenclature avoids excessive assumptions concerning mental states and
processes involved in performing tasks. Explicit memory is commonly tested
by direct measures of memory such as free recall, cued recall, and recognition.
Implicit memory is tested with indirect memory tasks in which the measures of


95
portion of the WMS Digit Span subtest was used as the distractor activity for PI.
The WMS Orientation and Personal and Current Information subtests were used
as the distractor activity for FR. The WMS Mental Control subtest was used as
the distractor activity for MCR. The second blocks of tests concluded with the
delayed memory trial of the ROCF. The third block of tests began with the
study and immediate testing trials of the CVLT. Forms C and D (and E if
necessary) of the Benton VRT were then administered, followed by the Milner
Facial Recognition Test. The 20 minute delayed testing of the CVLT followed.
Testing culminated with administration of the WMS Associate Learning subtest.
Experimental memory procedures
For Study 1, a computer software program was written which presented
study words and corresponding orienting questions to the Amnesic patients
and the control subjects. Several factors necessitated a change in presentation
of stimuli in Study 2. The computerized version required too much
administration time. Additionally, some Malingering subjects portrayed
problems in interacting with the computer, causing it to become inoperable on
several occasions. Therefore, the following modifications were made for all
subjects participating in Study 2.
Word stem completion. Each subject studied either WSC List A or List
B. Words were printed on four by six inch white index cards. Subjects held
the deck of cards. They were told their task was to answer questions about
words; no reference was made to the memorial aspects of the study episode.


222
Perceptual Identification Stimuli
Buffer Items
CORPSE
LOCATE
RELAX
BURGLAR
MEDAL
The tourist had to his passport to customs officials. (N)
Contain the letter "D". (N)
The was rolled out to the launchpad. (N)
Contain the letter "G". (N)
The President pinned the on the hero. (Y)
Target Words
CAPTAIN Contain the letter "P". (Y)
INDEX Will you pick up a carton of eggs at the ? (N)
SHARE Contain the letter "T". (N)
BLANKET Contain the letter "A". (Y)
REGARD The running back scored a during Sundays game. (N)
SCARLET The ruby was a bright color. (Y)
EXPECT What did you me to say? (Y)
FLORIST Contain the letter "B". (N)
OFFICER The Army barked his orders to the platoon. (Y)
HARVEST The poor farmers needed a bountiful fall (Y)
TENNIS Contain the letter "S". (Y)
THIRD Contain the letter "K". (N)
BELCH The millionaire lived a life of luxury and (N)
DESIGN The architect will a new office builing. (Y)
SENTRY The swimmer came in place in the race. (N)
GROWTH Contain the letter "W". (Y)
APPEAL Contain the letter "E". (Y)
ACCESS Contain the letter "P". (N)
MUSKET The old haunded mansion was (N)
PULLEY Contain the letter "M". (N)
Distractor Words
SPADE
PLANE
WORTH
COMPLEX
SLANG
QUART
GENDER
FOREST
BROTHER
SOLACE
PASSIVE
COUNCIL
SALMON
QUIET
AFFIRM
CHARGE
MANAGER
BLUNT
POLICE
DELAY


48
Summary. All three of Reys tasks attempt to capitalize on the potential
malingerers lack of requisite knowledge about brain-behavior relationships and
on his inability to simulate behavior that is foreign to him while monitoring the
effectiveness of this behavior in the testing situation. Morgan (1991) cautions
against the use of any of these techniques in isolation.
Summary and Critique of Experimental Studies of Malingering
The performance of normal subjects instructed to malinger
neuropsychological dysfunction has been shown to vary widely from study to
study. On indices of quantitative performance, some studies have found
malingerers to appear significantly more impaired than the organic populations
they are portraying (Benton & Spreen, 1961; Hayward et al.t 1987; and Iverson
et al., 1991; Schacter, 1986; and Spreen & Benton, 1963) while other studies
have found malingerers to appear more impaired than normals but less
impaired than organic patients (Anderson et al., 1959; Bernard, 1991; Brandt et
al., 1985; and Wiggins & Brandt, 1988). Other studies have found malingerers
to exhibit similar levels of impairment as organic patients (Heaton, Smith,
Lehman & Vogt, 1978; and Mensch & Woods, 1983). Many studies have found
malingerers to perform qualitatively differently than either normals or organic
patients (Benton & Spreen, 1961; Boone, 1989; Goebel, 1983; Heaton, Smith,
Lehman & Vogt, 1978; Spreen & Benton, 1963; and Wiggins & Brandt, 1988).
At this point, a call must go out for a more standardized methodology. The
nature of instructional set, the amount of didactic information provided to


201
mitigate against this argument. Rather, the contribution of explicit memory
during indirect memory tests appears to be a relatively subtle effect.
Implications for the Study of Implicit-Explicit Relationships
The present study has provided new information concerning implicit-
explicit memory relationships in that a subset of the Genuine subjects used
explicit memory to increase their strength of priming on WSC. Malingering
subjects did not, as a group, appear to engage in postretrieval response
suppression because they demonstrated normal strength of priming on WSC.
That is, it appears that a certain percentage of target words were completed
without the use of explicit memory. On the other hand, a subset of Malingering
subjects apparently experienced explicit memory for study words and elected
to not report these.
Two aspects of the design of this study may have confounded the
results. First, Genuine subjects did not represent an unbiased control group
due to their unanticipated use of explicit memory to increase their strength of
priming on WSC. The instructional set and motivational set given to these
subjects (i.e., to perform to "the best of their abilities") cannot be equated with
the motivational set associated with the "normal control subject" who is simply
given the task-related instructions at the time of testing. Irrespective of this
issue, however, Malingering subjects did not engage in postretrieval response
suppression when compared to the Head Injury subjects.


192
memory tests was equivalent to that of a group of age and education matched
control subjects.
Similarly, all three experimental groups in Study 2 demonstrated at least
normal priming effects on WSC and PI. Genuine subjects produced an
unexpectedly high magnitude of priming on WSC relative to any other group;
this was significantly greater than that produced by the Malingering and Head
Injury groups, which were not significantly different from each other. However,
this data pattern did not occur for the PI task: the three groups did not differ
with respect to magnitude of priming effects on PI. The present findings are
generally consistent with the two published studies which have used indirect
memory tests with experimental malingerers. Wiggins and Brandt (1988) found
that simulators demonstrated a normal magnitude of priming on word stem
completion when tested immediately after exposure to the study words. These
same subjects did, however, suppress responding with target words when
retested the next day. Williamsen et al., (1965) found experimental malingerers
to significantly attenuate their performance on other indirect memory tests, in
this case word fragment completion and free association. However, in that
study, malingering subjects were directly instructed on how to enact their role.
Levels of Processing Effects
In Study 1, Amnesic patients failed to recall almost all of the study words
on the FR test, consistent with their severe explicit memory impairment.
Amnesic patients had so little explicit memory that their recall could not benefit


14
Neuropathology of closed head iniurv
The brain experiences many pathophysiological changes during a
closed head injury. Important determinants of these effects are the direction of
the blow, its force and velocity, and whether the head was free to move at
impact (Nilsson and Ponten, 1977; Lishman, 1973). Regardless of the nature of
the injury, the traumatically injured brain is subject to manifold rotational and
linear stresses which tear and damage nerve fibers (Lishman, 1973). These
changes have been noted after even mild head injury (Strich, 1969). Cortical
lesions are maximal in portions of the frontal and temporal poles (Sekino,
Nakamura, Yuki, Satoh, Kikuchi, & Sanada, 1981). White matter damage is
often found in subcortical tracts, the corpus callosum, and the long tracts of the
brain stem (Lishman, 1987). Adams and colleagues (Adams, Mitchell, Graham,
& Doyle, 1977) have noted that these changes occur immediately after injury
and play an important role in mortality. Concussion and loss of consciousness
are more likely to result from injuries in which the brain is free to move at
impact, producing rotational and shearing forces. Damage to brain stem
centers is usually necessary to produce concussion and loss of consciousness.
In addition to structural damage which occurs following closed head injury,
changes have also been noted in the biochemistry and cerebrovascular
circulation (Lishman, 1973).


224
Multiple Choice Recognition Stimuli
Buffer Items
BARGAIN
ABSENT
MASSAGE
ABOLISH
IMPRESS
The became enraged and violent. (N)
Contain the letter "R". (N)
The parlor was closed by the police. (Y)
Contain the letter "F". (N)
John tried to his girlfriend with his money. (Y)
Target Stimuli
TRIAL
STAFF
INCOME
BEARD
HEALTH
PRAISE
SHELF
DENTIST
PRESS
UNION
REACH
SCRATCH
REJECT
ADVERB
SNAIL
CLERGY
THEORY
PATTERN
PENDANT
MARRIAGE
Contain the letter "R". (Y)
The Chief of met with the President today. (Y)
The crept up and killed the mouse. (N)
The mans needed trimming. (Y)
Contain the letter "T". (N)
Contain the letter "I". (Y)
Contain the letter "H". (Y)
Contain the letter M0". (N)
The reporter showed his pass to the guard. (Y)
Contain the letter "U". (Y)
Contain the letter "D". (N)
Contain the letter "K". (N)
The negotiator will the latest contract offer. (Y)
Contain the letter "J". (N)
The couple decided to have their picnic on the (N)
People who belong to the should be moral. (Y)
The soldier was a true of the U.S.A. (N)
Contain the letter "G". (N)
The slowly pulled away from the funeral. (N)
The boy hated eating and onions for dinner. (N)


73
The following specific predictions are made concerning performance on
clinical memory tests.
1. Malingering subjects will lower their overall level of performance relative
to honest subjects. This simulated impairment will be roughly equivalent
to the bona-fide memory impairment produced by closed head injury
patients.
2. Malingering subjects will lower their overall level of memory performance
to the extent that they adopt response strategies which emphasize the
omission of behavior, meaning that these subjects will be unlikely to
commit acts of incorrect behavior (i.e., perseverations, distortions, etc.).
3. While succeeding in lowering their quantitative memory performance to
levels seen in CHI patients, it is predicted that Malingering subjects will
be unable to also mimic the qualitative aspects of bona-fide memory
impairment.
4. Analysis of temporal, material, and process-oriented distinctions of
memory functioning will demonstrate Malingering subjects to be
unsuccessful at accurately portraying memory impairment as it occurs in
the CHI patients.
Performance on Indirect Memory Tests
The overriding hypothesis to be evaluated in the present study is that
explicit memory does affect performance on indirect memory tests. The
likelihood of observing the conflation of explicit and implicit memory on indirect
memory tests would appear highest when the words were encoded under
elaborative study conditions.
1. Given that explicit memory may affect performance on word stem
completion, it is predicted that Malingering subjects will produce
abnormally low performance due to postretrieval suppression.
2. Analysis of recognition memory following WSC and analysis of changes
in accuracy rate as these subjects proceed through the task will further
demonstrate the susceptibility of WSC to postretrieval suppression.


196
resulting in an increased likelihood that the subjects would consciously make
the link between the study episode and producing a target word during the
indirect testing episode. Membership in either of these groups was highly
conducive to the experience of test awareness on supraliminal indirect memory
tests. Subliminal tests appear to provide a context which is much less
conducive to the experience of test awareness with subjects who are
responding genuinely. When viewed against this background, the finding that
only 30% of Malingering remained test-unaware on PI suggests that it is less
effortful to engage in explicitly-mediated suppression than it is to engage in
explicitly-mediated facilitation. Taken further, Malingering subjects may have
been directing their effort to the process of becoming test aware even on
subliminal tests.
Test-awareness and retrieval intentionality appear to be partially
independent and dissociable processes. In all subjects, the experience of test
awareness was a condition necessary for the experience of retrieval
intentionality in that no subject reported intentional retrieval without first
experiencing test awareness. On the other hand, test awareness did not
necessarily lead to intentional explicit retrieval. A significant proportion of each
subject group reported experiencing test awareness in the absence of
intentional explicit retrieval. These findings are supportive of the distinctions
discussed in literature between involuntary explicit memory (i.e, test awareness)
brought on as a consequence of implicit memory and intentional explicit


147
Table 15
Test Awareness and Retrieval Intentionalitv in Word Stem Completion
%of
Group
Priming
Levels of
Processing
Sen. Let.
Not Aware
Genuine
20
+23*
50
30
Malinger
5
+10*
0
40
Head Injury
33
+34*
36
48
Aware but No Explicit Mediation
Genuine
25
+22*
36
40
Malinger
35
+20*
37
31
Head Injury
27
+30*
45
45
Aware and Explicit Mediation
Genuine
55
+68*
72
87
Malinger
60
+ 18B
30
35
Head Injury
40
+48*b
50
57
Note. Within level of test awareness, means with different superscripts differ
significantly at pc.05.


57
measured by indirect tests is primarily indexing data-driven processes and
explicit memory as measured by direct tests is primarily indexing conceptually-
driven processes. It should be emphasized that these concepts represent two
end-points on a single continuum rather than discrete categories.
Roediger (1988) spells out the assumptions which follow from the
processing model. First, performance on memory tests should be facilitated to
the extent that the cognitive operations at test recapitulate those engaged
during the study episode. Second, direct and indirect tests typically, but not
always, require different retrieval operations and consequently benefit from
different types of processing during learning. Most direct memory tests draw
on the encoded meaning of concepts or on semantic or elaborative processing.
Conversely, most indirect tests rely heavily on the match between perceptual
operations between study and test.
The Relationship between Explicit and Implicit Memory
The central concept that this study will attempt to use to "catch"
malingering subjects is the idea that intentional, explicit retrieval (or suppression
of retrieval) can affect performance during nominally indirect memory tests. In
order to fully understand the circumstances under which this can occur, a
discussion concerning the relationship between implicit and explicit forms of
memory is necessary. Three areas of research speak to this issue. First, some
studies have demonstrated stochastic independence between implicit and
explicit memory tasks and have used this data to argue that under some


143
that their performance was impacted by explicit memory (for Malingering
subjects, this means that they engaged in postretrieval suppression. For
notational purposes, this score will be referred to as test awareness.
Table 15 presents data concerning the relationship between group
membership, test awareness, magnitude of priming on WSC, and LOP effects.
A chi-square analysis failed to detect a relationship between group membership
and test awareness (X*=4.91, df=4). However, only one Malingering subject
failed to develop awareness during WSC, compared with 4 of the Genuine
subjects and 5 of the Head Injury subjects.
Because test awareness was not an independent variable that was
experimentally manipulated in the design, these data were examined with a
nonparametric test for the comparison of two proportions. Main effects of
Group on strength of priming on WSC were analyzed within level of test
awareness. No significant main effects of Group were found for the Not Aware
condition or the Test Aware/No Explicit Mediation condition (all Zs < 1). A
different data pattern was noted in the Test Aware/Explicit Mediation condition.
In this condition, Genuine subjects demonstrated a significantly greater strength
of priming on WSC (mean target advantage=68%) than Malingering subjects
(mean target advantages8%), Z=-2.43, p<.007. The difference between the
Malingering subjects and the Head Injury subjects approached but failed to
reach significance, Z=-1.34, p<.09. The Genuine and Head Injury groups did
not differ significantly, Z < 1.


87
The remaining words were target words. Within each task, each word was
randomly assigned to a processing condition which either focused subjects
attention on the semantic/conceptual aspects or the physical/orthographic
aspects of the particular word. The processing tasks were adapted from Craik
and Tulving (1975). The semantic encoding condition had subjects verify
whether the word would make sense if inserted in a specified place in a
sentence by responding with "yes" or "no." The physical encoding condition
had subjects verify whether a word contained a specified letter by responding
with "yes" or "no." Within each processing condition, the correct answer ("yes"
versus "no") for the words processing task was randomly assigned. The
proportion of correct "yes" and "no" responses were equivalent within orienting
conditions and within study lists. Appendix B provides the complete study and
test lists used in the four experimental memory tasks.
Word stem completion (WSC). A pool of 25 words was used for WSC.
The 20 target word were divided into two separate lists of 10 words each, List A
and List B. Each subject studied only one of the two lists. Five words were
encoded with a semantic processing task and five words were encoded with a
physical processing task. WSC study lists (A versus B) were counterbalanced
within group. The five words used as primacy and recency buffers were
invariant across both lists. Study words were printed on four by six inch white
index cards. At test, each subject was given a sheet of paper with 20 word
stems and asked to complete the stems to form the first words that came to his


241
Lees-Haley, P. (1984). Detecting the psychological malingerer. American
Journal of Forensic Psychology. 2, 165-169.
Levin, H.( Benton, A., & Grossman, R. (1982). Neurobehavioral consequences
of closed head iniurv. New York: Oxford University Press.
Levin, H. S., & Goldstein, F. C. (1986). Organization of verbal memory after
severe closed-head injury. Journal of Clinical and Experimental
Neuropsychology. 8, 643-656.
Levin, H. S., Grossman, R. G., & Kelly, P. J. (1976) Short-term recognition
memory in relation to severity of head injury. Cortex. 12. 175-182.
Lezak, M. D. (1979). Recovery of memory and learning functions following
traumatic brain injury. Cortex. 15, 63-72.
Lezak, M. (1983). Neuropsychological assessment. (2nd Ed.), New York: Oxford
University Press.
Lidvall, H. F., Linderoth, B., & Norlin, B. (1974). Causes of the post-concussional
syndrome. Acta Neurolooica Scandanavica. 50. Supplement 6.
Light, L. L, & Singh, A. (1987). Implicit and explicit memory in young and old
adults. Journal of Experimental Psychology: Learning. Memory, and
Cognition. 13, 531-541.
Lishman, W. A. (1973). The psychiatric sequelae of head injury: A review.
Psychological Medicine. 3, 304-318.
MacFlynn, G., Montgomery, E. A., Fenton, G. W., & Rutherford, W. (1984).
Measurement of reaction time following minor head injury. Journal of
Neurology, Neurosurgery, and Psychiatry. 47, 1326-1331.
Mahurin, R. K., & Pirozzolo, F. J. (1986). Chronometric analysis: Clinical
applications in aging and dementia. Developmental Neuropsychology. 2(4),
345-362.
Masson, M. E. J. (1984). Memory for the surface structure of sentences:
Remembering with and without awareness. Journal of Verbal Learning and
Verbal Behavior. 23, 579-592.
Mayes, A. R., & Heudell, P. R. (1981). How similar is the effect of cueing in
amnesics and normal subjects following forgetting? Cortex. 17, 113-124.


70
from the study-uninformed condition. The critical finding was that both aware
and unaware subjects showed normal and equivalent priming effects on word
stem completion. Thus, normal priming was observed in the absence of test
awareness. However, the finding that test-aware subjects completed a
statistically significantly higher proportion of semantically encoded words and a
relatively low proportion of structurally encoded words suggests that explicit
memory did impact WSC performance. No LOP effect was noted for test
unaware subjects. Additional evidence of the relationship between test
awareness and explicit retrieval was found on subsequent experiments which
found that only test-aware subjects demonstrated normal implicit memory for
new associations, an indirect test which may be more susceptible to explicit
mediation than other indirect tests.
Conclusions
Several lines of evidence have been reviewed which suggest that implicit
and explicit memory are functionally independent under certain situations.
Implicit memory has been observed when explicit memory was at chance levels
due to restricted or degraded encoding conditions (Eich, 1984; Jacoby,
Woloshyn, & Kelley, 1989; Kunst-Wilson & Zajonc, 1980). Stochastic
independence between performance on direct and indirect memory tests has
been observed in several studies (Chandler, 1983; Jacoby & Witherspoon,
1982; Tulving et al., 1982).


204
Symptom Validity Testing
Whereas word stem completion and perceptual identification are
classified as indirect memory tests, Symptom Validity Testing is a direct test of
short-term memory. The art of SVT lies in the fact that expected performance
levels are not obviously apparent to the typical subject. The performance of the
Genuine and Head Injury groups provided compelling evidence that this version
of the SVT task places very little demand on subjects memory capacities. The
fact that Head Injury subjects with bona-fide moderate-to-severe concentration
and memory impairment produced near-perfect accuracy rates further
reinforces this conclusion.
The main finding concerning the SVT paradigm was that Malingering
subjects, as a group, were impaired relative to other groups but scored well
above chance levels. Only one subject scored below nominal chance levels,
and even her score was not significantly different from chance in a probabilistic
sense. Accurate responding on SVT also appears to be dissociable from
performance on other clinical memory tests in Malingering subjects. While
statistically significant correlations were noted, cases existed in which significant
impairment was produced on clinical memory tests while SVT accuracy was
well above chance. The opposite pattern was also observed.
Several other statistical methods, based on binomial probability theory,
were presented to examine individual cases. Both of these methods were
designed to examine the consistency of responding across the lengthy number


86
Several nonverbal clinical memory tests were employed primarily as
interpolation tasks occurring between the immediate and delayed testing of
verbal memory tasks. Forms C, D, and E of the Benton Visual Retention Test
(Benton, 1974) and the Milner Facial Recognition Test (Milner, 1968) were used
for this purpose. These data were not scored or analyzed.
Experimental memory tasks
A total of 120 low (less than 30 occurrences per million) and high
frequency (between 60 and 200 occurrences per million) words were selected
from Kucera and Francis (1967) according to the following criteria. Each word
had between five and eight letters. The first three letters of each word (i.e.,
stem) uniquely defined each word in the set. However, each word stem was
common to at least 10 different words in Websters Pocket Dictionary. The total
pool of words was randomly divided into four subsets, with 25 words used for
the study and test of Word Stem Completion (WSC), 45 words used for the
study and test of Perceptual Identification (PI), 25 words used for the study and
test of Free Recall (FR), and 25 words used for the study and test of Multiple
Choice Recognition (MCR). Therefore, each experimental paradigm (WSC, PI,
FR, and MCR) had individual study and test lists which were administered
independently of lists associated with the other tasks in order to prevent
contamination at testing.
The first two and last three words of each study list contained "filler"
words which served as buffer items to control for primacy and recency effects.


232
Binder, L M., & Willis, S. C. (1991). Assessment of motivation following
compensable minor head trauma. Psychological Assessment. 3, 175-181.
Blaxton, T. A. (1989). Investigating dissociations among memory measures:
Support for a transfer-appropriate processing framework. Journal of
Experimental Psychology: Learning. Memory. & Cognition. 15, 657-668.
Bond, M. J. (1986). Neurobehavioral sequelae of closed head injury. In I. Grant
& K. M. Adams (Eds.) Neuropsychological assessment of neuropsvchiatric
disorders. New York: Oxford University Press.
Boone, J. R. (1989). Detection of malingering on neuropsychological memory
tasks. (Doctoral dissertation, University of South Florida). Dissertation
Abstracts International. 50, ADG90-03709.
Borkowski, J. G., Benton, A. L, & Spreen, O. (1967). Word fluency and brain
damage. Neuropsvcholooia. 5, 135-140.
Borod, J., Goodglass, H., & Kaplan, E. (1980). Normative data on the Boston
diagnostic aphasia exam, the parietal lobe battery, and the Boston naming
test. Journal of Clinical Neuropsychology. 2, 209-215.
Bowers, J. S., & Schachter, D. L. (1990). Implicit memory and test awareness.
Journal of Experimental Psychology: Learning. Memory. & Cognition. 16(3),
404-416.
Bradford, J. W., & Smith, S. M. (1979). Amnesia and homocide: The Padola
case and a study of thirty cases. Bulletin of the American Academy of
Psychiatry and Law. 7, 219-231.
Bradshaw, G. L, & Anderson, J. R. (1982). Elaborative encoding as an
explanation of levels of processing. Journal of Verbal Learning and Verbal
Behavior. 21, 165-174.
Brandt, J. (1988). Malingered amnesia. In R. Rogers (Ed.). Clinical assessment
of deception and malingering (pp. 65-83). New York: The Guilford Press.
Brandt, J., Rubinsky, E., & Lassen, G. (1985). Uncovering malingered amnesia.
Annals of the New York Academy of Sciences. 444, 502-503.
Brooks, D. N. (1972). Memory and head injury. Journal of Nervous and Mental
Disease. 155. 350-355.


163
MC RECOGNITION
Overall Performance
% correctly recognized
100
90
80
70
60
50
40
30
20
10
0
GENUINE MALINGER CHI
MC Recognition 93.8 62.5 70.7
't
Encoding Process
% correctly recognized
100
90
80
70
60
50
40
30
20
10
0
GENUINE
MALINGER
CHI
Sentence
96
71.4
78.6
Letter
91.6
54
62.6
Figure 12. MC Recognition: Overall Performance and Encoding Effects


157
P.l. REACTION TIME
Encoding Process
seconds
3.5
3 T
GENUINE
MALINGER
CHI
Sentence
1.765
1.88
1.938
Letter
1.686
1.956
1.847
VARS
R
Sentence
9
Letter
Processing by Answer Interaction
seconds
Groups
~^ Genuine
Malinger
CHI
Cor. Letter Cor. Sent. Incor. Letter Incor. Sent.
Genuine 1.327 1.397 2.043 2.131
Malinger 1.588 1.421 2.232 2.338
CHI 1.578 1.612
Figure 9. PI Reaction Time Data:
2.116 2.236
Encoding Process Effects.


170
score within each 10 trial block were computed based on binomial probability.
When these expected score frequencies were crossed with the obtained score
frequencies, a chi-square analysis on this subjects data failed to reach
significance, X2=3.385, df=5. This failure of statistical and probability methods
to detect deviations from chance performance on a subject whose performance
is clearly in question highlights the difficulty with using the chance criterion.
The standard use of the binomial distribution is to calculate probabilities
and cumulative probabilities associated with chance performance. Another use
of binomial probability methods could potentially increase the ability of the
clinician to detect malingered or exaggerated performance. Rather than using
.50 (chance) as the estimate of the true population proportion, the subjects
own total score, expressed as the accuracy rate, could instead be used to as
the estimate for the true population proportion. Next, the binomial distribution
could be constructed for 10 block trials, resulting in the cumulative probabilities
for obtaining scores of 0/10, 1/10, 2/10, etc. based on the subjects own level of
overall performance.
To follow the previous example, Subject #34 obtained a score of 1/10
correct during trials 70 to 79. The cumulative binomial probability of obtaining
this score, based on the estimate of the true population proportion of .45, is
significant at the .05 level (p=.0236). Thus, it can be established for this
subject that a portion of her SVT performance fell significantly below what
would be expected given her performance over the 100 trials. It is important to


160
(mean=35%) than either the Malingering (mean=15.5%) or Head Injury groups
(mean=10.3%), which were not significantly different from each other.
Within-group analyses of variance showed the main effect of orienting
task was highly significant for the Genuine group, F(1,19)=24.21, pc.0001, the
Malingering group, F(1,19)=33.62, pc.0001, and the Head Injury group,
F(1,19)=8.65, pc.01. Figure 11 presents this data. Follow-up mean contrast
tests established that all experimental groups recalled significantly more words
encoded in the conceptual orienting condition than words encoded in the
physical orienting condition. The interaction between group and orienting task
approached but failed to reach significance, F(2,52)=2.70, pc.08.
Multiple choice recognition
Main task analysis. Multiple choice recognition was employed as another
indirect memory test. Figure 12 presents this data. A between-groups ANOVA
revealed the main effect of group on multiple choice recognition was highly
significant, F(2,52) = 18.39, pc.0001. Follow-up mean contrasts revealed that
genuine subjects demonstrated significantly higher explicit memory
(mean=93.8%) as measured by recognition of previously presented words than
either the Malingering (mean=62.5%) or Head Injury groups (mean=70.7%),
which were not significantly different from the other.
Within-group analyses of variance showed the main effect of orienting
task was nonsignificant for the Genuine group, F(1,19)=1.43, pc.25, the
Malingering group, F(1,19)2.70, pc. 12, and the Head Injury group,


150
greater difference in response latency between correct versus incorrect
answers.
The previous results have shown that perceptual identification of
physically encoded words shows slight but nonsignificant superiority to
identification of conceptually encoded words. While Malingering subjects failed
to significantly lower their accuracy rate by responding with fewer physically
encoded words, trends towards explicitly driven suppression (i.e., "thinking
about it") may be evident in reaction time differences between words encoded
semantically versus physically in the Malingering group. Figure 9 presents this
data. Collapsed across groups, the main effect of orienting task on reaction
time was nonsignificant (F < 1). The interaction between group and orienting
task was also nonsignificant (F < 1). All three groups showed a trend towards
increased response latencies for target words relative to distractor words. A
very subtle but interesting trend was evident in the data. Genuine and Head
Injury subjects showed slightly faster response latencies for physically encoded
words relative to conceptually encoded words, in line with the increased ability
to accurately identify these words. In contrast, the Malingering subjects
showed the opposite pattern of slightly higher response latencies for physically
encoded words. One possible explanation for this would be that Malingering
subjects experienced normal facilitation of identification of physically encoded
words but then engaged in an explicitly driven suppression before responding.


139
F(2,52)=1.27, p<.29, and was equivalent to baseline rates reported in the
literature (Graf, Squire, & Mandler, 1984) which average approximately 11
percent. Collapsed across groups, the main effect of word status (target
versus distractor) was highly significant, F(1,52)=80.49, pc.0001.
Within-group analyses of variance revealed that all three experimental
groups demonstrated priming on the word stem completion task. Figure 5
presents this data. The main effect of word status (target versus distractor)
was significant for the Genuine group, F(1,19)=67.29, pc.0001, the Malingering
group, F(1,19)=22.79, pc.0002, and the Head Injury group, F(1,14)=39.88,
pc.0001. Follow-up mean comparisons confirmed that word stems were
completed in the target direction significantly more often when the word was
previously exposed compared to the unexposed condition for all three groups.
The interaction between group and target status was significant, F(2,52)=9.00,
pc.0004. Follow-up analyses indicated that Genuine subjects demonstrated
significantly more priming on WSC than either the Malingering or Head Injury
groups.
Collapsed across groups, the main effect of orienting task was
nonsignificant, F(1,52) = 1.75, pc.19. The interaction between group and
orienting task was also nonsignificant, F(2,52)=.03, pc.97. Computed within
group, the main effect of orienting task was nonsignificant for the Genuine
group, F(1,19)=.17, pc.69, the Malingering group, F(1,19)=.17, pc.69, and the
Head Injury group, F(1,14)=.26, pc.62. Figure 5 presents this data. All three


105
Correlations and covariances were computed between age and the
response variables for (1) the overall sample, and (2) by each subject group
separately. The results indicated that age was not statistically related to any
response variable, both for the overall sample and within each subject group.
Nevertheless, age was used as a covariate in all between-group analyses for
the main experiment.
A similar pattern of results was noted for Full Scale IQ, F(2,52)=9.88,
pc.001, with Head Injury subjects showing significantly lower FSIQ estimates
than the Genuine or Malingering subjects, which were not significantly different
from the other. A one-way analysis of variance showed no significant
differences between the three groups on level of education at time of testing,
F(2,52)=2.03, pc.14. Lowered FSIQ is one manifestation of the
neuropsychological sequelae of head injury. Because differences between
Genuine and Malingering subjects cannot be explained by FSIQ differences,
FSIQ was not treated as a covariate. It could be argued that the difference in
education level between the college groups and the head injured patients was
clinically significant, even though this difference failed to reach statistical
significance. However, eleven of the head injury patients had completed their
high school diploma. Three had completed at least one year of college and six
other were reportedly enrolled in college prepatory classes prior to their injury.


55
interest reflect a change (typically a facilitation) in task performance observed
by comparing performance with relevant prior experience to performance
without such experience (a control condition). The term indirect is particularly
suitable because the relevant tasks do not direct the subject to a target event
(Richardson-Klavehn & Bjork, 1988).
Theories of Implicit Memory
Two main classes of theories of implicit memory currently occupy the
attention of researchers: multiple memory systems models and processing
models (Roediger, 1990). Experimental manipulations have been shown to
differentially affect direct and indirect memory tests with both normal subjects
and amnesic patients (Shimamura, 1986; Schacter, 1987). Therefore, the task
of any theoretical model is to account for the numerous dissociations between
these forms and measures of memory (Richardson-Klavehn & Bjork, 1988).
Researchers postulating distinct and separate memory systems derive
support from experimental studies of amnesic patients. The central concept is
that certain forms of brain damage selectively affect the memory system for
conscious recollection but leave the system responsible for other forms of
learning relatively intact. Squire and Cohen (Cohen, 1984; Cohen & Squire,
1980; Squire, 1987) have advanced a taxonomy consisting of functionally
separate memory stores for declarative and nondeclarative (formerly
"procedural") memory. Declarative memory (i.e., "knowing that") is available to
consciousness and can be accessed by processes congruent with the


18
all serial list positions. However, a 20-second interpolated delay interval
between presentation and recall selectively impaired recall in the CHI group.
Brooks then categorized recall words as either STM or LTM, based on Tulving
and Colotlas (1970) criteria. The results indicated that CHI patients scored
lower but not significantly different from controls for STM items. However, the
CHI patients scored significantly lower than did controls for LTM items. Brooks
interpreted his findings as evidence for impaired LTM storage in CHI patients,
with relative sparing of STM processes. Schacter and Crovitz (1977) have been
highly critical of this interpretation, citing methodological flaws in the
experimental memory tasks employed in this study.
Brooks (1976) investigated Wechsler Memory Scale performance in a
sample of 82 severely head-injured patients. With the exception of Mental
Control subtest errors and Digits Forward, CHI patients were inferior to controls
on all other WMS subtests. On Logical Memory, CHI patients were significantly
poorer at an immediate and delayed recall, although their rate of forgetting was
not significantly greater than controls. CHI patients were significantly lower on
Associate Learning and their rate of learning across trials was lower. In
general, CHI patients demonstrated proportionately more impairment on
delayed memory tasks. Neither focal neurological signs, the presence and site
of skull fracture, nor the elapsed time since injury had appreciable effects on
memory performance. The finding concerning elapsed time since injury is


181
while playing their respective roles during the experiment. Immediately after the
role-playing phase of their participation, subjects were given verbal descriptions
of many of the memory tasks they completed and asked to make Likert ratings
concerning (1) their effort on that particular task; (2) their perceptions of the
difficulty of the task (for a "normal" person with genuine motivation); and (3) and
their perceived success at portraying their role (either "best effort possible" or
"severe but believable impairment"). Twenty two tasks were described; each
subject rated the three characteristics for each task. The form used for
obtaining these ratings is presented in Appendix C. Subjects were then given a
chance to discuss their perceptions and feelings about their role playing.
Debriefing ratinas
The following discussion will selectively evaluate the debriefing ratings
concerning several of the more important memory tasks. Table 24 presents
this data. Ratings from individual tasks were averaged to obtain a mean rating
of effort, task difficulty, and role-success for each subject. Analyses of variance
produced highly significant main effects of group on the Effort score,
F(1,39)=18.92, pc.0001, the Task Difficulty score, F(1,39)=12.72, pc.0012, and
the Role-Success score, F(1,29)=18.92, pc.0001. The variance observed in
these variables was highly constricted in both groups, suggesting that the
experiences and perceptions were highly similar within the respective groups.
Follow-up mean contrasts revealed that Malingering subjects perceived
their effort as significantly less than that perceived by Genuine subjects.


72
due to the indirect nature of its task demands, the indirect memory tests
employed by cognitive psychologists may prove useful in the same regard. In
a more theoretical sense, the effects of different motivational response sets will
extend the domain of knowledge concerning indirect memory tests.
Specifically, this manipulation would allow for subjects to spontaneously
experience test awareness and/or employ explicit retrieval strategies to either
facilitate or suppress their indirect memory performance. The present study
could potentially extend the literature by providing a situation in which
malingering subjects would be motivated to use explicit memory to lower, rather
than raise, their performance on indirect memory tests.
Hypotheses and Predictions
Performance on Clinical Memory Tests
The clinical memory tests will serve two simultaneous functions. First,
performance on these tests provides an easily interpretable benchmark upon
which to later understand performance on laboratory-based experimental
memory tests. Performance profiles can be readily compared with the extant
literature to check the validity of the malingering subjects participation.
Second, the performance on clinical memory tests is useful in its own right in
that (a) the present battery of tests employed in this study is distinct from
others reported in the literature, and (b) it affords a unique opportunity to
evaluate qualitative aspects of memory behavior which may provide the clinician
with useful interpretive information.


220
Tor F
Tor F
Tor F
Tor F
Tor F
Tor F
13. The role you have been asked to play during this experiment
has you trying to put forth the best effort vou can and to
perform as well as vou can on the memory tests which will
follow.
14. In the scenario you were given, you will lose money because
you will be unable to work at your lucrative job if it appears that
you have real memory problems.
15. In the scenario you were given, you will be allowed to continue
working at your lucrative job if it appears that your memory is
normal.
16. The role you have been asked to play during this experiment
has you trying to fake the most severe but believable memory
problems as vou can on the memory tests which will follow.
17. In the scenario you were given, you will stand to gain a large
sum of money in damages from the other driver if you are
successful at faking the most severe but believable memory
problems you can.
18. In the scenario you were given, you will be embarrassed if you
are unsuccessful at faking the most severe but believable
memory problems that you can.


23
disability or persisting subjective symptomatology (Miller, 1961; Cartlidge, 1978).
However, this relationship is not causal; it seems reasonable to assume that a
patient with prolonged symptoms after compensable trauma would be more
likely to make a claim than a patient who recovers quickly (Binder, 1986).
Conversely, research has also shown that prolonged symptoms can persist in
patients with mild head injury who are not seeking compensation (Rimel,
Giordani, Barth, Boll, & Jane, 1981). Binder concludes that the literature does
not support the contention that patients become less symptomatic after a legal
claim is settled.
The point to be made here is that the issue of persisting subjective
symptoms and complaints, in the absence of definitive neuropathological
findings, essentially fulfills one of the DSM-lll-R criteria for diagnosing
malingering (Binder, 1990). It is in these cases where there is "discrepancy
between the persons claimed stress or disability and the objective findings"
(APA, 1987, p.360) that malingering becomes a viable yet precarious differential
diagnosis.
Experimental Studies of Malingering
The foregoing discussion emphasizes the importance of thoroughly
evaluating neuropsychological symptomatology in cases of suspected
malingering. Only a few cases have been reported in the literature in which the
patient suspected of malingering either relinquished his symptoms in favor of
genuine responding (Pankratz, 1979) or admitted to having faked impairment


I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope
and quality, as a dissertation for the degree of Doctor of Philosophy.
M.
ussell M. Bauef, Chair
Associate Professor of Clinical
and Health Psychology
I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope
and quality, as a dissertation for the degree of Doctor of Philosophy.
Dawn Bowers
Associate Professor of Clinical
and Health Psychology
I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope
and quality, as a dissertation for the degree of Doctor of Philosophy.
-yj
LlifcJ
Bruce Cros'son
Associate Professor of Clinical
and Health Psychology
I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope
and quality, as a dissertation for the degree of Doctor of Philosophy.
3. lA-
Eileen B. Fennell
Professor of Clinical and Health
Psychology


188
"impaired" and below that of the Genuine subjects. In terms of quantitative level
of memory abilities, Malingering subjects produced scores which were
remarkably similar to Head Injury subjects. Malingering subjects typically
performed much worse than Genuine subjects. The average effect size
associated with malingering was -2.2 standard deviations. This effect size
approached the average effect size of -3.4 computed from the literature. On
average, the impairment demonstrated by Malingering subjects surpassed that
of the Head Injury subjects, although univariate hypothesis tests rarely detected
a statistically significant difference between these two groups. Debriefing and
interview data further establish that the compliance with instructional set was
adequate for subjects in the Malingering condition.
Malingering subjects generally scored slightly higher than Head Injury
subjects on tasks measuring attention and concentration, immediate free and
cued recall of verbal material, and delayed cued recall of verbal material.
Malingering subjects scored lower than Head Injury subjects on tasks
measuring delayed free recall of verbal and nonverbal material. With few
exceptions, Malingering subjects successfully portrayed the qualitative aspects
of bona-fide memory impairment. This included the Malingering subjects ability
to accurately balance the omission of correct behavior with the commission of
incorrect behavior to produce responses similar in quality to bona-fide memory
impairment.


179
Trials 1 to 5, CVLT Short and Long Delay Free Recall, and CVLT Short and
Long Delay Cued Recall. Table 24 presents the classification rates produced
from a linear discriminant function analysis based on this variable set. Overall,
this variable set produced highly accurate group predictions. The sensitivity
rate of 92.2% and the specificity rate of 8% offer clinically significant
improvements over chance diagnostic rates.
Genuine subjects were classified with 100% accuracy. Malingering
subjects were classified with 90% accuracy; only two of 20 were classified as
belonging to the Head Injury group. Both of these subjects scores on the
clinical tasks were characterized by (1) low but not impaired general memory
functioning; (2) low but not impaired list learning; and (3) poor attention and
concentration. Head Injury subjects were identified quite accurately as well; of
the 20 subjects, one subject was misclassified as Genuine and one as
Malingering.
Malingering subjects were identified with less accuracy than subjects in
the other two groups. Three subjects were classified as belonging in the
Genuine group. These subjects produced scores on clinical memory tests
equivalent to the Genuine group. Only one Malingering subject was classified
as belonging to the Head Injury group.
Experiential and De-Briefing Variables
Given the nature of this study, subjects in the Genuine and Malingering
conditions were interviewed at length about their experiences and perceptions


36
was given to the simulators concerning the severity of their feigned amnesia nor
were the simulators offered an incentive or reward for successful malingering.
In Experiment 1, the malingers performance was characterized by (1)
extremely poor performance on overlearned, autobiographical information
(worse than the performance of even the most impaired patients); (2)
performance on free recall lower than normals but greater than amnesics; (3) a
normal serial position effect, and (4) essentially normal priming effects on
measures of implicit memory. The simulators demonstrated essentially normal
priming effects on an immediate test. However, when retested after a 24 hour
delay the simulators produced significantly fewer target words than the other
groups, thus slightly suppressing their word stem completion performance. On
a word association task, simulators did not differ significantly from normals and
amnesics, with all three groups exhibiting slight priming effects. Of note is the
fact that virtually no differences were detected between the three subgroups of
malingerers, prompting the conclusion that lay people are not generally aware
of symptomatic differences between various types of amnesia.
In Experiment 2, Wiggins and Brandt administered two, 20-item lists of
concrete nouns to the same groups described above, and elicited free recall
and recognition using a two-alternative, forced-choice recognition test (c.f.
Pankratz, 1983). The amnesic group recalled fewer words than the
malingerers, who recalled fewer words than the normal controls. The
malingerers replicated a normal serial position curve. Twenty one percent of


127
Table 5--cont¡nued
Univariate Group Differences on Quantitative Clinical Memory Variables
Group
Variable Genuine
Malinger
Head Injury
WMS Delayed Vis. Reprod.
Mean 9.9a
3.3C
6.4B
SD 3.0
F(2,52) = 16.49***
2.7
4.1
ROCF Delayed Reprod.
Mean 19.0a
11.3B
13.6a8
SD 7.3
F(2,52) = 7.07**
5.5
6.3
* p<.05 ** p<.01 *** pc.001
Note. Means with different superscripts differ significantly at pc.05.


22
Summary. The literature reviewed provides overwhelming evidence for
memory impairment following CHI. While survivors of CHI perform normally on
simple memory tasks, impairment is noted on more complex memory and
learning tasks requiring active and effortful processing of to-be-remembered
information. These patients acquire information at a slower rate than do
normals. They evidence greater forgetting of information after acquisition,
resulting in more marked impairment on delayed memory tests.
The effects of compensation and litigation
Postconcussion syndrome (PCS) refers to a constellation of common
symptoms which incl