Sentence imagery

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Sentence imagery attention, emotion, and the startle reflex
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viii, 117 leaves : ill. ; 29 cm.
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English
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Vrana, Scott Richard, 1960-
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Startle Reaction   ( mesh )
Emotions   ( mesh )
Attention   ( mesh )
Clinical and Health Psychology thesis Ph.D   ( mesh )
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Notes

Thesis:
Thesis (Ph.D.)--University of Florida, 1988.
Bibliography:
Bibliography: leaves 70-74.
Statement of Responsibility:
by Scott Richard Vrana.
General Note:
Typescript.
General Note:
Vita.

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University of Florida
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notis - AFQ4281
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Full Text














SENTENCE IMAGERY:


ATTENTION, EMOTION, AND THE STARTLE REFLEX






By

SCOTT RICHARD VRANA


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


1988














ACKNOWLEDGEMENTS

After working on this project in relative isolation for

a year, it is a pleasure to think back on all those who

contributed to it. First and foremost, Peter Lang's counsel

has been invaluable during this dissertation and all other

aspects of my graduate training. Any future contribution I

may make to psychology will be due in no small part to Dr.

Lang's efforts.

The other members of the dissertation committee have

contributed in many ways to this document and to my

training. Barbara Melamed provided a wonderful model of a

researcher/clinician working in the anxiety disorders.

Russell Bauer was a fine teacher, clinical supervisor, and

research advisor during my years at University of Florida.

I can think of no better model than Rus as I engage in these

activities as a new faculty member. I was lucky to have

Keith Berg and Pat Miller on my committee and as teachers to

share my interest in developmental psychology. Jane

Pendergast provided answers to my statistical questions on

the dissertation and other projects.

I apologize to Bruce Cuthbert for being perpetually

underappreciative of his many talents and kind help. Alas,

there was too much to appreciate, and too little time.

Ellen Spence was a special friend from my first to my last






iii


day in Gainesville. Mark Greenwald, Margaret Bradley, Dan

McNeil, Ed Cook, and David York all provided intellectual

stimulation and friendship. The Lang lab was (and is) an

exciting, stimulating, unique place to work. I thank all

involved.















TABLE OF CONTENTS

Page
ACKNOWLEDGEMENTS. .. . . ii

ABSTRACT . . . vi

INTRODUCTION. . . 1

Startle Reflex Response . 1
Startle and Sensory Modality-Specific Attention 2
Startle and Affect. . . 4
Imagery and Affect. . . 6
Processing Task and Affective Text. . 7
Statement of the Experimental Problem .12

METHOD. . . . 17

Subjects. . . .17
Apparatus . . 17
Stimulus Materials. . . 19
Procedure . . 19
Startle Stimuli . . 22
Design. . . .23
Data Reduction and Analysis . .23

RESULTS . . . .26

Analysis Strategy . . .26
Self-report . . 27
Heart Rate . .. ... .27
Startle Reflex: Content Differences . .36
Startle Reflex: Modality-Specific Attention .49
Startle Reflex: Image Vividness . 51

DISCUSSION . . .57

Processing Fear Sentences . .58
Modality-Specific Effects of Sentence Processing. .60
Imagery as a Cognitive Task . .63
Summary and Conclusions . .67

REFERENCES. . . 70

APPENDIX A STIMULI AND SUBJECT INSTRUCTIONS. .75

APPENDIX B DIFFERENCES BETWEEN STARTLE AND NON-STARTLE
EXPERIMENT . . 82

APPENDIX C HEART RATE FIGURES. . 85








V



APPENDIX D TABLES OF STARTLE REFLEX DATA .90

APPENDIX E ANALYSIS OF VARIANCE TABLES FOR PRIMARY
STATISTICAL ANALYSES. . ... 104

BIOGRAPHICAL SKETCH .................. 117
















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


SENTENCE IMAGERY:

ATTENTION, EMOTION, AND THE STARTLE REFLEX


By

Scott Richard Vrana

December, 1988


Chairman: Peter J. Lang, Ph.D.
Major Department: Clinical and Health Psychology

The startle reflex response is modulated by the

emotional and attention-engaging properties of ongoing envi-

ronmental stimuli. This study investigated the efficacy of

the startle reflex as a measure of attention and emotion

during internally-generated information processing. Thirty-

six undergraduates memorized a neutral and fearful sentence,

then listened with their eyes closed to a series of tones,

one every six seconds. The tone pitch cued subjects to

either relax or to process the neutral or fearful sentence.

Each sentence was processed for two successive six-second

periods. Depending on subgroup assignment (n=12), subjects

received one of three sets of instructions for the first

period: 1) continue to relax; 2) silently articulate the

words of the sentence; or 3) imagine the sentence. All






vii


subjects, regardless of subgroup, imagined the cued sentence

during the second period. Acoustic probes (50 millesecond,

95 dB white noise) were presented at various times during

sentence processing. Magnitude and latency of eyeblink

response to the probes were measured, as well as heart beat

intervals, recorded continuously from six seconds prior to

sentence processing to the end of the six-second period

immediately following processing.

Heart rate increased more during fear processing rela-

tive to neutral. Startle responses were facilitated (larger

magnitude and shorter onset latency) when probes were pre-

sented during fear sentence processing; probe responses were

significantly smaller during neutral sentence processing and

during the intertrial intervals. The largest startle

responses were observed during fear imagery processing.

Fear imagery also prompted greater heart rate acceleration

than the other tasks.

An imaginal analog of sensory-selective attention

was also investigated. Half the neutral sentences referred

to visual imagery and half referred to auditory imagery.

Startle responses to the acoustic probe were of larger

magnitude when subjects were processing acoustically-

oriented sentences compared with processing visually-

oriented sentences. This effect was greatest in subjects

reporting good imagery ability. Furthermore, startle

responses were attenuated when presented during images rated

as very vivid compared with less vivid images, and self-








viii


reported good imagers had attenuated startle responses over-

all relative to poor imagers. In summary, the startle

response was highly sensitive to emotional and attentional

variables during internally-generated cognitive activity,

paralleling effects found when the same variables were

investigated with externally presented materials.
















INTRODUCTION

Modulation of tne startle reflex response has been

found as a function of the attentional and affective proper-

ties of environmental stimuli. A recent theory of affective

imagery (Lang, 1979; 1983; 1985) stresses similarity of

response processes in imaginal and environmental contexts.

This dissertation examines the notion that the startle ref-

lex response is modulated by the same factors in imagery as

in environmental perception. Specifically, it will test if

reflex responses to startle probes are augmented when pre-

sented in the context of fearful, aversive imagery; and

furthermore, if such probe responses are relatively

inhibited when the modality of the probe stimulus and the

modality (auditory or visual) of the image content are not

the same. In order to introduce the empirical portion of

this work, factors modulating the startle reflex are

reviewed, and a conception of imaginal processing is

presented.

Startle Reflex Response

The startle reflex response is a motor response to

sudden-onset, intense environmental stimulation in the audi-

tory, visual, or tactile modality. The reflex is found in

various species, and in human beings is found at all devel-

opmental levels. Whereas the motor reflex initially









involves the whole body, experimental investigations typi-

cally measure the eyeblink component of the human startle

response. Although the response is obligatory under certain

stimulus conditions, the magnitude, latency, and probability

of the reflex can be modified by a variety of circumstances.

Most important for the current study, the startle response

is modulated by the sensory modality and affective valence

of ongoing environmental stimuli.

Startle and Sensory Modality-Specific Attention

It is now quite well-established that allocation of

modality-specific attention modulates latency and magnitude

of the startle reflex response (Anthony, 1985). Startle

responses are facilitated when attention is directed to the

sensory modality that the reflex-eliciting stimulus occurs

in and is inhibited when attention is directed to a differ-

ent sensory modality. For example, the startle response is

facilitated when attention is drawn to the startle stimulus

by instructing subjects to judge the duration of the stimu-

lus, whereas the response is inhibited when subjects are

instructed to judge the duration of a co-occurring stimulus

in a different sensory modality (Bohlin & Graham, 1977;

Hackley & Graham, 1984; Silverstein, Graham & Bohlin, 1981).

Modality-specific attention modifies the startle response

using startle probes in the visual, auditory, and tactile

modalities (Anthony, 1985).

Modality-specific attention can modify startle response

in the absence of a task directing attention, when a










foreground stimulus is displayed which captures attention in

a particular modality. Anthony and Graham (1983; 1985)

presented either auditory or visual stimuli to subjects;

then elicited a startle reflex in either the acoustic or

visual modality. The visual and acoustic stimuli were

either interesting (a slide of a human face, a melody) or

dull (a blank slide, a pure tone). Startle responses were

larger and occurred more swiftly when the startle stimulus

was presented in the same modality as the foreground stimu-

lation, relative to conditions in which the startle and

foreground stimuli were presented in different modalities.

For example, response to the auditory startle was larger

when subjects were listening to, relative to when they were

viewing, a stimulus. Furthermore, this modality-matching

effect was greater for interesting foreground stimuli:

Response to the auditory startle was largest when subjects

were listening to a melody and smallest when viewing a slide

of a human face. Conversely, response to the visual startle

was largest when viewing a slide of a human face and smal-

lest when listening to a melody. These effects were found

in college students and in four-month-old infants.

Simons and Zelson (1985) investigated response to

acoustic startle probes during high-interest and low-

interest visual events. Slides of nude models (high inter-

est) or of a plain wicker basket (low interest) were shown

for six seconds each, and an acoustic startle-eliciting

probe was presented during slide viewing. Viewing high









interest slides inhibited startle magnitude and latency

relative to low interest slides, suggesting again that

attention directed towards a stimulus can be indexed by the

response to a startle probe.

Startle and Affect

Use of the startle reflex to probe classically-

conditioned fear has produced results which are conceptually

quite different from those described above. Several studies

used rats as subjects (Brown, Kalish & Farber, 1951; Davis &

Astrachan, 1978; Kurtz & Seigel, 1966). In these studies a

light was paired with shock for a number of trials. Subse-

quently, an acoustic startle stimulus presented while the

light was on produced a greater startle reflex relative to

an acoustic startle alone. Appropriate control conditions

ascertained that startle augmentation was a function of the

fear conditioning produced by explicit pairing of the light

and shock. Two studies (Ross, 1961; Spence & Runquist,

1958) found similar results with human subjects. Light was

paired with electric shock. For some subjects onset of the

light signaled shock (fear conditioning). For others, the

shock occurred prior to light onset (backward conditioning).

On test trials, a blink-eliciting airpuff followed light

onset. Blink magnitude was greater for subjects who had

undergone fear conditioning than for subjects who had under-

gone backward conditioning. More recently, Greenwald, Hamm,

Bradley, and Lang (1988) found greater startle eyeblink

magnitude to an acoustic probe presented while subjects were









watching a slide previously paired with electric shock,

relative to a probe presented while subjects viewed a slide

which had not been associated with shock.

Startle facilitation in the context of an aversive

stimulus in these studies occurred despite the fact that the

foreground stimulus (light or slides) and startle probe

(acoustic or tactile) were presented in different modal-

ities. In addition, the signal properties of the condi-

tioned stimulus suggest that attention would most likely be

directed toward the visual modality. Since neither modality

matching nor attentional involvement explain startle facili-

tation under these circumstances, this result can be inter-

preted as indicating that fear facilitates response to the

startle stimulus (Berg & Davis, 1984).

A recent study (Vrana, Spence & Lang, 1988) integrated

these disparate lines of research. The study followed pro-

cedures used to investigate selective attention (Anthony &

Graham, 1985; Simons & Zelson, 1985) in that subjects viewed

slides while startle response to a co-occurring acoustic

probe was assessed. Each slide was viewed for six seconds,

during which time a startle probe was presented. Subjects

viewed twelve slides in each of three categories:

positive/interesting (nudes, food, babies), neutral/dull

(household objects) and negative/interesting (mutilated

bodies and faces, spiders, snakes). Negative slides pro-

duced the largest and shortest-onset startle response, whereas

the startle reflex magnitude was smallest during positive









slides. Further research (Bradley, Cuthbert & Lang, 1988;

Cook, Spence, Gray, & Davis, 1988) have replicated the find-

ing that startle probe amplitude varies significantly with

the emotional valence of foreground visual material.

Startle facilitation in the context of negative visual mate-

rial was interpreted as indicating a matching of response

elements to the aversive slide context and the aversive

startle stimulus: "The startle reaction is construed as an

aversion response, sharing with the response to negative

slides psychological, and perhaps, neurophysiological com-

ponents of avoidance and escape behavior." (Vrana et al.,

1988, page 490)

Imagery and Affect

Lang (1983; 1985) has emphasized the key role of

response processes both in emotion and imagery. His theory

follows other psychological models of memory representation

(Anderson & Bower, 1973) in holding that information is

stored in memory in conceptual units that are interconnected

in associative networks, and that activation spreads through

the network when individual concepts are cued. Lang (1979;

1983) has added to this framework the notion that informa-

tion about one's own responding is part of the network code

in emotion. These response concepts include information

about overt motor and verbal behavior, perceptual adjust-

ments, and autonomic nervous system support for the gross

motor movements. When activated, this information directs

actual context-appropriate responding.










Emotional networks are usually activated by the target

environmental context. However, they can also be accessed

by symbolic stimuli--descriptive text, slides or movies.

When emotional memories are evoked by these media represent-

ations, the overt action may be gated out (subjects report

only feelings of fear or anger). However, the physiological

support for the action (increased heart rate, respiration

increases, skin sweat activity) is still activated, albeit

at a reduced level. The experimental literature supports

this general view. A large number of studies (reviewed by

Cuthbert, Vrana & Bradley, in press) confirms that text-

prompted imagery of an emotional event prompts changes in

report of emotion, and also heart rate, palmar sweat acti-

vity, respiration, and facial expression which mirror the

changes found when people are exposed to the actual emo-

tional context. Memory representations activated in an

actual affective context are also activated during imagery

of the event, and these include codes defining the

supportive behaviors.

Processing Task and Affective Text

Imagery can determine the pattern of response activa-

tion. However, it is not clear that these responses are

obligatory, that is to say, the same text describing an

emotional event could perhaps be dealt with in different

ways. Some modes of processing might not engage associated

response concepts, i.e., if subjects were asked to do a

grammatical analysis or simply count the number of words









presented. This section reviews work on the physiological

correlates of instructional strategies for processing affec-

tive text. The studies use variants of an experimental

procedure, originated by Schwartz (1971), in which subjects

memorize text in advance, then retrieve it from memory cued

by a series of tones occurring at regular intervals. May

(1977a) applied this paradigm to compare imagery and

"thinking" fear material. Snake phobics memorized short

sentences describing touching a snake or reading a magazine.

Subjects were instructed to "think" the sentence and then

imagine the sentence in successive tone-cued ten-second

periods. Heart rate and respiration amplitude were greatest

when subjects imagined the snake sentence, compared to

"thinking" the snake sentence or thinking or imagining the

relaxing sentence. A follow-up study (May, 1977b) found

that imagery of a fearful sentence produced greater

physiological response than thinking the sentence, hearing

the sentence, or seeing a slide depicting the same

situation. Jones and Johnson (1978; 1980) used the same

procedure with unselected subjects and found greater heart

rate, muscle tension, and respiratory activity during im-

agery of "high activity" sentences (short sentences with

information about behavioral response) than imagery of "low

activity" relaxing sentences. Physiological differences

between high and low activity sentences were not apparent

when subjects were "thinking" the sentences.










Vrana, Cuthbert and Lang (1986) refined the methodology

of the above studies to support a clearer interpretation of

the imagery effect. They argued that the subject's task was

unclear when told to "think" a sentence (as opposed to

"image" it). They proposed instead to begin by comparing

imagery with the straightforward instruction to silently

articulate the words of the sentence. Half of the subjects

articulated the material for 10 seconds and imagined the

same sentence in the subsequent 10 second period. The

remaining subjects imagined the sentence first and silently

articulated it in the following period, thus controlling the

order of processing modes. Regardless of the order of proc-

essing, imagery of fearful material resulted in greater heart

rate increase than did silent repetition of fear material.

In these studies, thinking or silent rehearsal of

arousing material resulted in slightly, but not signifi-

cantly, greater physiological response than thinking or

rehearsal of neutral material, suggesting that response code

is contacted to some extent when text containing response

concepts is rehearsed in working memory. In these studies

subjects were cued as to which material to process prior to

the neutral baseline phase of the trial, allowing memory

retrieval of the material prior to the specified cue and

possibly contaminating baseline measurement. In fact, heart

rate during baseline periods differed depending on whether

the material to be processed was arousing or relaxing.

(Vrana et al., 1986). A new paradigm was developed to









control and examine the possibility of pre-instructed memory

retrieval. An initial experiment using this paradigm is

described in some detail here, as the same paradigm was

employed in the empirical portion of this dissertation.

In this study (Vrana, Cuthbert & Lang, in press) sub-

jects memorized a neutral and fearful sentence, and then

heard a series of tones, one every six seconds. The sub-

ject's task was to repeat the word "one" silently and relax

at this tone. A higher or lower frequency tone cued memory

retrieval of either the neutral or fearful sentence. Sen-

tence processing occurred for two consecutive six-second

periods following retrieval. All subjects imagined the

material during the second period, but differed as to ini-

tial cognitive task. Processing instruction for the first

period was a between-subjects variable. One group imagined

the sentence immediately upon hearing the memory retrieval

signal, another group silently articulated the words of the

sentence upon memory retrieval, and a third group continued

to repeat "one" and relax at the first signal tone (called

"null task"). After the second period all subjects returned

to relaxing and repeating the word "one" until the next

higher or lower tone. Figure 1 diagrams the structure of a

single trial for each group.1






1 Further details about the procedure and data reduction can
be found in the Method section, and differences between the
two studies are described in Appendix B.














Group 1


NULL IMAGE


"one"


"one"


"one"


"one"


Group 2 "one" "one" ARTICUL. IMAGE "one" "one"




Group 3


"one"


"one"


IMAGE


IMAGE


"one"


"one"


Time


6 sec.


ba n p peiods


base processing periods
period t 1 t 2


sentence cue tones


data collection interval 18 sec.


t
non-signal tones
- -_J -- >


Figure 1. Diagram of events that occurred during a single
trial for each experimental group. Pulse trains of 500
msec tones (one every six seconds) were presented to
all subjects. On hearing the initial non-signal tone
the subject said the number "one" silently. The pulses
with angled tops represent higher- or lower-pitched
tones that cued neutral or fear sentence processing.
Heart rate data was collected during the time period
represented in bold face. Processing instructions for
successive periods in the trial are written within the
appropriate interval.









Fearful sentences were rated as less pleasant, more

arousing, and involving less dominance than neutral sen-

tences. Table 1 lists mean heart rate change for Periods

one and two. Period one (Null task, Articulation, or

Imagery) data are considered first. Overall, processing

fearful sentences resulted in greater heart rate increase

than did processing neutral sentences (F(1,27)=15.00,

<.0006). Imagery resulted in greater heart rate increase

overall than did the null or articulation task

(F(2,27)=16.4, p<.02). There was a tendency for text proc-

essing instruction to determine the degree to which fear

sentences occasioned heart rate increase (Task X Content

F(2,27)=2.79, p<.08): Imagery of fear sentences resulted in

greater heart rate increase than either silent articulation

or null processing of the fear material (Task effect for

fear material F(2,27)=3.73, p<.04). During the second

period, when all subjects were imagining the material, heart

rate was equivalently greater for fear relative to neutral

imagery, regardless of group membership (F(2,27)=19.33,

<.0002). Results therefore show that this paradigm is

sensitive to the affective properties of processed sentences

during imagery and other processing tasks.

Statement of the Experimental Problem

The present experiment uses the same sentence imagery

paradigm (Vrana et al., in press) just described. Subjects

will learn fearful and neutral sentences which are subse-

quently retrieved according to the frequency of the cue










Table 1

Mean heart rate change and standard deviation (in paren-
theses) over six seconds for each group during processing of
neutral and fearful sentences. T-tests are for neutral-fear
comparisons within groups.


PERIOD ONE


PERIOD TWO


GROUP

NULL-IMAGE


ARTIC-IMAGE


IMAGE-IMAGE


MEAN


NEUTRAL


0.46
(0.67)


-0.66
(1.38)

0.57
(0.91)

0.12


FEAR


0.83
(0.59)


t, p<


2.87,
.02


0.82 2.00,
(2.30) .08

3.14 2.99,
(2.89) .02

1.60


NEUTRAL


0.20
(1.02)


FEAR


2.10
(2.02)


-0.16 2.63
(1.45) (4.83)

0.54 2.85
(1.05) (2.12)


0.19


2.53


Note: The data are presented separately for Period one (null
task, articulation, imagery) and Period two (imagery for all
groups). T-values have 9 degrees of freedom.


2.69,
.03

2.31,
.05

3.05,
.02









tones. Different groups will process the material diffe-

rently in an initial period (null task, articulation, im-

agery); in a second period all subjects will do the imagery

task. In addition, this research for the first time employs

an acoustic startle probe methodology to measure mental

imagery. Probe stimuli will be presented during all proc-

essing tasks. Three primary questions will be addressed.

1. Is the Startle Reflex Augmented During the Processing of
a Fear Image?

Heart rate will be recorded, and will be considered the

criterion for response element activation in memory. It is

expected that heart rate results from the previous study

will be replicated: Greater heart rate increase will be

evident during fear relative to neutral processing, with

this difference being greater during imagery than silent

articulation or null processing.

A number of studies have found that viewing fear-

eliciting material (slides depicting negatively-valent stim-

uli, a light signaling electric shock) facilitated the

startle response to an acoustic or tactile probe. This

effect was interpreted by Vrana et al. (1988) as a function

of response matching: The aversion response elicited by the

startle probe matched in affective valence the response

elements accessed from emotional memory by perceptual proc-

essing of the unpleasant slides. It is predicted that proc-

essing fear material in imagery will prompt a similar match

and facilitate the reflex (larger magnitude and shorter









latency), relative to the response during neutral processing

or no-task control periods.

The response matching hypothesis implies that startle

facilitation, like heart rate, will be greater to the extent

that a response set is activated during cognitive proc-

essing. Therefore, greater startle facilitation during fear

relative to neutral material should occur during imagery

than during silent articulation or under instructions to

refrain from processing the sentences.

2. Are Images Modality Specific? Is the Startle Reflex
Augmented When the Sensory Content of Imagery Matches the
Modality of the Probe?

Imagery is hypothesized to activate the same response

disposition as that activated by the represented environmen-

tal situation. Previous work has shown augmentation of

startle probe responses when probe stimuli are in the same

sensory modality as the stimulus foreground to which sub-

jects are attending. Isomorphism between imagery and per-

ception implies that a parallel augmentation should occur if

the startle probe modality matches the modality of the

imaged stimulus material. This is tested in the current

experiment. Half of the neutral material is designed to

prompt primarily visual memory processing; the remaining

neutral sentences prompt processing in the auditory moda-

lity. All startle stimuli are presented auditorally. If

cognitive processing leads to similar modality specific

response dispositions as perceiving environmental events,

then augmented startle responses will be elicited during









auditory-oriented sentence processing, relative to visually-

oriented sentences.

3. Is Image Vividness Related to Startle Modulation?

Vivid imagery is associated with a disposition to

become absorbed in experience (Sheehan, McConkey & Law,

1978). In information processing terms, when cognitive

capacity is committed to an imaginal production, less capa-

city is available for processing other, external stimuli.

It may be deduced from this assumption that (a) more vivid

imagery will be associated with a reduced response to con-

current environmental input, i.e., less capacity is avail-

able to process the startle probe. A corollary hypothesis

is (b) that individuals who profess to be generally good

imagers (as defined by questionnaire, Sheehan, 1967) are

likely to show reduced responses to the startle probe rela-

tive to poor imagers.

Nested within this overall argument are two deductions

concerning the effects of match/mismatch between the sensory

modality of the startle probe and the dominant modality of

the image: (c) if imagery and the sensory intake differ-

entially activate the same perceptual processing sub-systems

(see number 2 above), then facilitation of acoustic probe

responses during auditory imagery (and relative inhibition

with visual imagery) should be greater when imagery is more

vivid; furthermore, (d) this modality-specific effect should

be larger for good than for poor imagers.















METHOD

Subjects

Subjects were 36 normal volunteers recruited from the

pool of students attending an introductory psychology course

at the University of Florida. The sample was randomly

divided into three subgroups of six males and six females

for this experiment.

Apparatus

Subjects sat in a comfortable reclining chair in a dimly

lit room adjacent to the equipment room. The timing of

events and collection of data were accomplished under the

control of a PDP-11/23 computer. All auditory stimuli were

presented to the subject binaurally through Pioneer SE-205

stereo headphones. Tones were generated using a Coulbourn

Voltage Controlled Oscillator with a Selectable Envelope

Rise/Fall Gate set for 80 msec rise/fall time. The low,

medium, and high tones were 800, 1100, and 1500 Hz, and were

measured monaurally at 71, 72.5, and 73.0 dB (A), respec-

tively. The acoustic startle-producing stimulus was a 50

msec burst of white noise (20-20,000 Hz) with a monaural

intensity of 95 dB (A) and instantaneous rise time. All

sound pressure level measurements were made using a Bruel

and Kjaer Type 2203 Precision Sound Level meter with a half-

inch Type 4134 condenser microphone and a Type 4153 artifi-

cial ear.









Lead I EKG was obtained using Beckman standard Ag-AgCl

electrodes filled with Beckman electrode electrolyte and

placed on each inner forearm. The signal was filtered

through a Coulbourn Instruments Hi Gain Bioamplifier/

Coupler, and a Schmitt trigger interrupted the computer each

time it detected a cardiac R-wave.

The startle response was measured as electromyographic

activity at the right obicularis oculi using Med Associates

miniature electrodes filled with Beckman electrode electro-

lyte. The signal was amplified by a Coulbourn S75 series

bioamplifier with high- and low-pass filters set at 100 and

1000 Hz, respectively, then fed through a Coulbourn S76-01

Contour Following Integrator set for a measured time con-

stant of 200 msec. The integrated signal was sampled at

1000 Hz once every msec for 250 msec after the onset of the

startle stimulus. The amplification for the muscle tension

measure was set at 60,000 for each subject at the beginning

of the session, and two calibrating startle stimuli were

presented. If the response to these startles exceeded the

limits of the analog-to-digital (A-D) converter, the

amplification was reduced to 50,000; if the startle response

was small relative to the limits of the A-D converter, then

amplification was increased to 70,000. The amplification

was reduced for four subjects and increased for 12 subjects.

The experimental groups did not differ in average

amplification.









Stimulus materials

Stimulus materials were six sentences describing moder-

ately positive, relaxing situations and six describing

common fearful, arousing situations. Each fear sentence

contained at least one reference to autonomic (e.g., "My

heart pounds") or behavioral ("I grip the chair")

responding. Three of the six neutral sentences referred

explicitly to stimuli in the auditory modality and three

contained explicit references to stimuli in the visual

modality. All twelve sentences were presented to the sub-

ject printed on index cards with key phrases in capital

letters; subjects had to repeat only these key phrases

verbatim in order to meet sentence memorization criterion.

The twelve sentences are presented in Appendix A. For each

subject the sentences were randomly grouped into six

neutral-fear pairs.

Procedure

After arriving at the laboratory subjects read and

signed an informed consent and filled out Sheehan's (1967)

short form of the Questionnaire Upon Mental Imagery (QMI;

Betts, 1909). Electrodes were then attached and the

instructions read. These instructions read in part: "In a

little while you will memorize two sentences, one fearful

and one neutral in content. You will use these sentences to

create images in your mind using the following procedure.

After you memorize the two sentences and I leave the room,

you will hear a series of short tones, one every six









seconds. Each tone will be at one of three different fre-

quencies. The tone that you will hear most often is the

middle tone. I'll call this the 'normal' tone. Whenever

you hear this tone, just relax and think the word 'one' to

yourself each time you breathe out. This is to help clear

your mind and help you remain relaxed." Subjects were then

told that tones which were higher or lower in pitch compared

to the "normal" tone would be presented every so often, and

that when they were presented they would occur twice in

succession at the usual six-second interval, cuing subjects

to retrieve one of the sentences from memory and process it

for two six-second periods in a row. The pitch of the tone

signaled subjects to retrieve either the fear or the neutral

sentence.

Instructions regarding sentence processing was a

between-groups variable. One group was told to imagine the

sentence specified immediately upon hearing the memory

retrieval tone, and then to imagine it again during the

second period (Image-Image group). Another group was

instructed to silently repeat the words of the sentence upon

memory retrieval, then imagine it at the second tone

(Articulate-Image group). A third group was told to con-

tinue to think "one" and relax at the first signal tone, and

then to imagine the sentence specified at the second signal

tone (Null task-Image group). Subject instructions are

presented in Appendix A. Thus, all subjects imagined the

material during the second period, but differed as to how









they processed the material immediately upon memory

retrieval. The second period ended after six seconds with

another "normal" tone, at which point all subjects returned

to relaxing and repeating the word 'one' until the next

signal tone. The interval of relaxation between processing

sentences varied randomly in six-second increments from 18

to 30 seconds. The tones occurred such that the subject

processed the neutral and the fearful sentence six times

each, with neutral and fearful material processed in a

pseudo-random order. A schematic of a single trial for each

group is presented in Figure 1.

After completing six neutral and six fear processing

trials, the subject heard two tones one-half second apart, a

signal to open his or her eyes and rate the images of each

sentence along the dimensions of affective valence, arousal,

dominance (Osgood, Suci & Tannenbaum, 1957), and vividness.

Each of these ratings was accomplished by marking a vertical

line through a horizontal line with words anchoring each

end. After making these ratings, subjects memorized another

neutral and fearful sentence, and processed these six times

each in the same manner as the earlier block of trials.

Each subject processed all six neutral and fearful sentences

six times each, for a total of 36 trials of each type.

After the experimental session, subjects rated each fear

sentence on a 1-7 scale for "how frightened you would be if

you were actually in this situation."









Startle stimuli

Subjects were instructed regarding the startle stimuli

as follows: "At times you will hear loud clicks, like a

finger snapping. These are meant to elicit a response we

wish to measure, but you just need to ignore them and

continue with the task".

Within each block of six trials, three startle probes

were presented during Period one (articulation, null task,

or imagery) and three were presented during Period two

(imagery for all subjects) for neutral and fearful trials,

totaling twelve startle probes during each block of sentence

processing. In addition, three startle probes were pre-

sented during unsignaled "Count 'one'" periods (intertrial

intervals). The three startle probes in each processing

period X affective content cell and in the intertrial

intervals were distributed as follows: One occurred one

second after tone onset (Early), one three seconds after

tone onset (Middle), and one 5.5 seconds after tone onset

(Late).

The six startle probes presented during sentence proc-

essing for each affective content were distributed in the

following way within a block of trials: One trial contained

a startle in the Early position of Period one and in one of

the three positions of Period two. Two trials contained one

startle during Period one only (one at the Middle and one at

the Late position), and two trials contained one startle

during Period two only (In the two positions not covered by









the only trial containing two startle probes). The

remaining trial contained no startle probe. This arrange-

ment was designed to maximize subject uncertainty regarding

occurrence of startle probes while providing an adequate

number of data points in each condition.

Design

Within each of the three groups, half the subjects proc-

essed the fear material at the high-pitched tone and the

neutral material at the low-pitched tone. This was reversed

for the remainder of the subjects. Each subject partici-

pated in 36 trials within each of the two stimulus contents

(fearful and neutral): six unique sentences with six trials

using each sentence.

Data reduction and analysis

Interbeat intervals were recorded and converted off-line

to heart rate in beats per minute for each half-second from

six seconds before a signal tone to six seconds after sen-

tence processing had ended. Mean heart rate was calculated

for the "Count 'one'" period before the tone signaling

sentence processing (baseline), the first period (null task,

silent articulation of the text, or imagery), and the second

period (imagery). Heart rate for the six second "Count

"one'" period before the signal tone was used as baseline to

create heart rate change scores for the first period and the

second period. Data from all trials of the same content

(fear or neutral) were averaged together. The imagery

ratings of valence, arousal, dominance and vividness were










recorded on a 15 centimeter horizontal line. This line was

divided into 30 half-centimeter sections for scoring pur-

poses and each rating was assigned a number from 0 to 29

based on the section of the line marked by the subject.

Each heart rate measure and each rating was subject to a

univariate Group X Content analysis of variance (ANOVA)

using the BMDP2V AVOVA program, with Content being a

repeated measure within subjects. Heart rate was also sub-

ject to an initial Group X Period (one, two) x Content

ANOVA, with Period and Content involving repeated measures.

The reflex eyeblink data were reduced off-line by a

computer program (Balaban, Losito, Simons, & Graham, 1986)

which eliminated trials with an unstable baseline and scored

each trial of reflex eyeblink data for latency to blink

onset (in milliseconds) and peak amplitude (in arbitrary A-D

units). Trials with an unstable baseline constituted 8.5%

of all trials and were treated as missing data. For trials

in which a startle response was not detected, amplitude was

scored as zero and latency was considered as missing data.

Trials in which no scorable blink occurred and latency was

treated as missing data comprised 8.4% of all remaining

trials.

For each block of trials, there was one startle probe

data point in each cell of the Content (Neutral, Fear) X

Period (One, Two) X Startle Probe Time (Early, Middle, or

Late) matrix and one data point at each startle probe time

during the intertrial interval period. The available data









points from each of the six blocks were averaged. An

initial Group (Null task-Image, Articulate-Image, Image-

Image) X Content (Neutral, Fear) X Period (one, two) X

Startle Probe Time (Early, Middle, Late) ANOVA was conducted

on the averaged latency and magnitude data. Group was a

between-subjects factor while Period, Content and Startle

Probe Time were within-subjects factors. The latency and

magnitude data from each period were then subject to sepa-

rate Group X Content (Neutral, Fear, intertrial interval) X

Startle Probe Time ANOVAs. Note that the same intertrial

data were used in the ANOVA for Period one and Period two.

Other analyses are described in the relevant sections of

Results. Tables detailing ANOVA results for all major

analyses are located in Appendix E. For all analyses,

Greenhouse-Geisser (Greenhouse & Geisser, 1959) corrected

degrees of freedom are reported to correct for unequal

correlation among repeated measures. Follow-up t-tests were

conducted for significant ANOVA results.

















RESULTS

Analysis Strategy

The present experiment repeats the method used by Vrana

et al. (in press). An assessment of the replication's

success is presented first, based on results for heart rate

and self-report, the measures common to this and the earlier

study. The remainder of the results section will address

the questions about the startle response posed in the state-

ment of the problem. Startle modulation during neutral and

fear processing will be examined first. Image processing of

modality-specific sensory information will be described

next. Finally, the relationship between image vividness and

the startle response will be assessed by analyzing the

startle response as a function of each subject's rated

vividness of the image. Individual differences in imagery

ability will also be examined in these latter two analyses.

For these analyses, only a subset of the subject sample will

be used; namely, those receiving extreme scores on the

Questionnaire Upon Mental Imagery2



2 For all imagery ability analyses, good imagers were
defined as scoring below 75 on the Questionnaire Upon Mental
Imagery; poor imagers were defined as scoring above 95 on
this questionnaire. Subjects scoring between 75 and 95 were
omitted from this analysis. These cutoff scores resulted in









Self-report

Subject ratings of image valence, arousal, dominance,

and vividness, and fear of being in the situation depicted

in the fear sentences are presented in Table 2. Subjects

felt less happy (F(1,33)= 471.3), more aroused

(F(1,33)=381.5) and less dominant (F(1,33)= 167.9) during

fear than during neutral imagery (all p<.0001). The

Articulate-Image group rated themselves as feeling more

dominant during imagery than did the other two groups

(F(2,33)=3.58, 2<.05). This occurred for both neutral and

fear processing and may have been because silent articula-

tion was the most straightforward task required of subjects

in this study. There were no other significant effects for

valence, arousal, and dominance, and no effects found for

image vividness or fear rating.

Heart Rate

Baseline

A Group X Content ANOVA was conducted to assess heart

rate during the six seconds prior to the signal tone, used

as a baseline measure for the subsequent change scores. No

significant differences in baseline heart rate emerged as a

function of subject group assignment or the content of the

upcoming processing trial.




four subjects per group in each Group X Imagery Ability
cell, with the following exceptions: three subjects were
represented in the Articulate-Image/Good imager cell and
the Image-Image/Poor imager cell, and there were five sub-
jects in the Null Task-Image/Poor imager cell.










Table 2

Self-reported ratings of image valence, dominance, arousal, and
vividness as a function of processing group and content of
sentence. Standard deviations are in parentheses).

GROUPS


RATING
BY CONTENT


VALENCE
NEUTRAL


FEAR



AROUSAL
NEUTRAL


FEAR



DOMINANCE
NEUTRAL


FEAR


VIVIDNESS
NEUTRAL


FEAR



FEAR RATING


NULL-IMAGE


24.6
(2.5)

5.8
(3.3)



3.8
(2.1)

22.3
(3.6)



21.7
(5.6)

9.3
(3.3)


22.0
(3.1)

22.0
(4.0)


4.9
(0.6)


ARTIC-IMAGE


25.4
(1.9)

5.7
(2.4)



4.6
(3.7)

23.1
(2.7)



24.8
(3.3)

11.3
(5.1)


24.4
(1.9)

22.2
(2.5)


4.7
(0.5)


IMAGE-IMAGE


23.7
(3.7)

6.1
(2.9)



4.6
(3.6)

22.3
(3.2)



21.1
(3.8)

8.9
(3.4)


21.1
(5.1)

21.5
(3.5)


4.9
(0.7)


Note: Ratings of fear in the actual context ("fear ratings")
were recorded for the fear sentences only. Standard deviations
are in parentheses. All ratings are on a 0-29 point scale except
for the fear rating, which is 1-7.


TOTAL


24.6
(2.8)

5.8
(2.8)



4.3
(3.1)

22.5
(3.1)



22.5
(4.5)

9.8
(4.0)


22.5
(3.8)

21.9
(3.3)


4.8
(0.6)









Overall analysis

Mean heart rate change for Period one (null task,

articulation, imagery) and Period two (imagery) by Group and

Content (neutral, fear) can be seen in Table 3. An initial

analysis including both processing periods was conducted.

Overall, heart rate increase from baseline was greatest on

trials involving retrieval of the fear sentence relative to

neutral trials (F(l,33)=29.9, p<.0001). Heart rate evi-

denced no significant change from Period one to Period two

on neutral trials (t(33)=1.14, 2>.10), while increasing from

Period one to Period two on fear trials (t(33)=2.40, p<.05,

overall Content X Period F(1,33)=18.5, 2<.0001). No other

effects were significant.

Period one (Null task, Articulation, Imagery)

Just as in a previous study (Vrana et al., in press),

processing fearful text resulted in more pronounced heart

rate increase than did processing neutral text (F(1,33)=

15.22, 2<.0004). As can be seen in Table 3, all three proc-

essing modes again elicited significant neutral-fear diffe-

rentiation. Imagery again produced the largest mean heart

rate overall--higher than null processing or articulation of

the fear sentence. However, the overall difference between

processing modes (Group F(2,33)=1.18, 2>.30) and the inter-

action between modes of processing and fearfulness of the

materials (F(2,33)=1.36, p>.25) did not achieve an accep-

table confidence level.










Table 3

Mean heart rate change over six seconds for each group
during processing of neutral and fearful sentences,
Presented separately for Period one (null task,
articulation, imagery) and Period two (imagery for all
groups). Standard deviations are in parentheses.


PERIOD ONE


PERIOD TWO


GROUP


NULL-IMAGE


NEUTRAL


0.37
(0.83)


ARTIC-IMAGE -0.08
(0.86)

IMAGE-IMAGE 0.37
(1.12)


MEAN


0.22


FEAR t, 2<


0.93 2.29,
(0.99) .05

0.69 2.35,
(1.50 .04

1.86 3.16,
(2.68) .01

1.16


NEUTRAL FEAR


-0.33
(1.06)

0.10
(1.25)

0.00
(1.25)

-0.08


1.39
(1.37)

1.88
(2.02)

2.10
(2.50)


1.79


11 degrees of freedom.


t, p<


2.98,
.02

3.45,
.006

4.34,
.002


Note: T-values have










Period two (Imagery)

During this period all subjects imagined the textual

material. As can be seen in Table 3 (right panel), fear

imagery resulted in greater heart rate increase than did

neutral imagery (F(1,33)=36.0, p<.0001). No other effects

approached significance. Imagery effects found in the ear-

lier study (Vrana et al., in press) were thus replicated in

this experiment.

Combined Study analysis

The current experiment and the earlier, non-startle

study (Vrana et al., in press) separately show strong

differences in heart rate following memory retrieval of fear

and neutral sentences. However, while each study found that

imagery tended to increase the neutral-fear difference in

heart rate relative to the other processing instructions,

neither study individually found conclusive statistical

evidence for this apparent pattern. Two questions were

raised. First, is this pattern of results a chance finding,

or is the lack of statistical support a power problem, e.g.,

too few subjects in each individual study? Second, did the

addition of the startle probe produce reliable differences

in heart rate response, compared to the no-startle

situation? To address these questions, data were combined

across experiments, and mean heart rate change for each

Period was subject to a Study X Group X Content ANOVA.

Figure 2 shows heart rate for the combined sample

during the first processing period and the immediately










preceding "Count 'one'" period, presented on a half-second

basis for each processing instruction for neutral and fear.

Table 4 presents mean heart rate change for the combined

sample in the same manner as each sample was presented sepa-

rately. During Period one, heart rate increase was greater

overall following the tone cueing fear material relative to

the tone cueing neutral material (F(1,60)=30.81, 2<.0001).

All three groups exhibited significantly greater heart rate

increase during fear relative to neutral trials (see t-test

comparisons, Table 4). Imagery resulted in greater heart

rate increase than the other two tasks (F(2,60)=5.44,

2<.007). When the two studies are combined, imagery of fear

sentences prompted greater heart rate increase than did the

null task or silent articulation (Content X Group

F(2,60)=4.16, p<.03). During Period two, fear imagery

resulted in greater heart rate increase than neutral imagery

(F(1,60)=50.22, R<.0001) and no other effects were signifi-

cant. Subjects in the two studies did not differ in heart

rate response, either alone or in interaction with other

variables, for Period one or two (all Fs <1.50).

In summary, the two studies combined produced robust

results indicating greater heart rate increase while proc-

essing fear relative to neutral sentences. Furthermore,

they provided clear statistical evidence that heart rate

increase was greater during fear imagery than silent

articulation or null processing of the fear sentences. In

both studies, all groups rated themselves as feeling less










Table 4

Mean heart rate change from baseline over six seconds for
each group during processing of neutral and fearful sen-
tences for both studies combined, presented separately for
Period one (null task, articulation, imagery) and Period two
(imagery for all groups). Standard deviations are in
parenthesis.


PERIOD ONE


PERIOD TWO


GROUP


NULL-IMAGE



ARTIC-IMAGE


IMAGE-IMAGE


MEAN


NEUTRAL


0.40
(0.75)


-0.34
(1.14)


0.47
(1.01)


0.18


FEAR t, p<


0.90 3.36
(0.82) .003


0.75 3.04
(1.86) .007


2.43 3.78
(2.78) .002


1.36


NEUTRAL


-0.09
(1.06)


-0.02
(1.31)


0.25
(1.17)


0.05


FEAR


1.72
(1.71)


2.22
(3.51)


t, p<


4.11
.0005


3.81
.001


2.43 4.67
(2.30) .0001


2.12


Note: T-values have 21


degrees of freedom.












Figure 2. Continuous heart rate waveform in half-second
intervals for each group for the "Count 'one'" period
and the first sentence processing period for the com-
bined sample (startle and no-startle studies). The
tone cueing retrieval of the neutral or fearful sen-
tence is signified by a vertical line at the six second
mark in each graph.
























ARTICULATE


--o- NEUTRAL
70 ----- FEAR


"ONE"


6
SECONDS


IMAGE


"ONE"










pleasant, more aroused, and less dominant during fear rela-

tive to neutral imagery. Because startle response facilita-

tion, like heart rate increase, is assumed here to indicate

more extensive fear processing, the heart rate results pro-

vide an empirical basis for the previous (pp. 14-15) predic-

tions regarding the effect of sentence processing on the

startle response.

Startle Reflex: Content Differences

Overall analysis

Magnitude. Table 5 shows that startles elicited during

fear trials were consistently larger in magnitude relative

to those elicited during neutral trials (overall

F(1,33)=25.5, p<.0001). Table 6 illustrates how the sen-

tence content effect was modulated by the processing task.

The neutral-fear difference was larger in Period two (when

all subjects were imagining the material) than in Period

one, when subjects were performing different processing

tasks (Content X Period F(1,33)=5.99, p<.02). Still,

responses during fear trials were reliably larger than

responses during neutral trials in both Period one and

Period two (see later sections on individual Period

analyses).

The startle response also differed with the timing of

the probe (Table 5, Probe Time F(1.7,27.5)=5.42, <.02). It

was smaller in magnitude at the Early relative to the Middle

(t(66)=2.28, p<.05) position and was marginally inhibited









Table 5

Startle reflex magnitude and latency for neutral, fear, and
intertrial interval startles by startle probe times during
periods one and two. Standard deviations are in paren-
theses. These data are presented separately for each exper-
imental group in Tables 7 through 12 of Appendix C.


MAGNITUDE


Intertrial


Neutral


Fear


Period one


Early


Middle


Late


222
(196)

192
(191)

185
(163)


210
(180)

244
(203)

227
(221)


230
(197)

271
(229)

273
(212)


Period two


Early


Middle


195
(170)

220
(183)

200
(177)


Late


249
(202)

285
(250)

275
(239)










Table 5--continued


LATENCY

Intertrial Neutral


Period one

Early


Middle


Late

Period two

Early


Middle


Late


40.9
(9.9)

40.5
(10.4)

40.5
(9.1)


Fear


41.0
(11.3)

38.4
(9.1)

38.6
(9.2)


39.1
(9.3)

37.5
(8.8)

38.1
(8.5)


38.9
(10.6)

37.2
(7.5)

37.1
(8.5)


37.2
(10.5)

36.4
(9.5)

36.0
(8.5)










Table 6

Startle reflex magnitude and latency for each group separately
for neutral, fear, and intertrial interval startle probes.
Standard deviations are in parentheses.

MAGNITUDE


Null-Image


Intertrial


Period one

Neutral


Fear


Period two


Neutral


Fear


166
(186)


164
(178)

177
(177)


156
(170)

201
(193)


Artic-Image


211
(152)


266
(204)

290
(197)


219
(139)

293
(212)


Image-Image


223
(177)


LATENCY


Null-Image


Intertrial


Period one

Neutral


Fear


Period two

Neutral


Fear


43.6
(10.8)


42.9
(8.9)

41.2
(8.4)


39.8
(9.5)

39.1
(9.2)


Artic-Image


37.6
(3.8)


37.2
(5.2)

35.8
(4.0)


36.4
(3.4)

35.5
(5.6)


Image-Image


40.8
(10.0)


Mean

200
(177)


251
(197)

308
(219)


227
(193)

258
(201)


239
(201)

315
(258)


205
(171)

270
(222)


Mean

40.6
(8.9)


37.9
(9.9)

36.2
(9.3)


38.4
(9.0)

35.0
(7.9)


39.3
(8.4)

37.7
(7.8)


38.2
(7.7)

36.5
(7.7)









relative to the Late (t(66)=1.47, .10
Middle and Late did not differ (t(66)=0.80).

Latency. Latency measures produced results generally

consistent with magnitude (see also Tables 5 and 6): Over-

all, startle response was facilitated (shorter onset latency)

during fear relative to neutral trials (F(1,33)=8.49,

p<.007); reflex latency also tended to vary with the timing

of the startle probe (overall F(1.8,29.9)=3.05, p<.06),

reflecting a tendency toward inhibition at the Early rela-

tive to Middle (t(66)=1.55, .10
.10
startles did not differ (t(66)=0.07). Finally, startle

latency was shorter during Period two relative to Period one

(F(1,33)=4.57, p<.05).

Statistical differences for processing groups did not

appear in these omnibus analyses. However, a more focused

test was planned for the first sentence recall period, where

the actual processing task manipulation occurred. For compa-

rison, a parallel analysis was done on the second recall

period, where instructions to groups did not differ (Group X

Content (Neutral, Fear, Intertrial interval) X Time).

Period one (Null Task, Articulation, Imagery)

Magnitude. Consistent with the omnibus analyses,

startles elicited while processing fear material in Period

one were generally of larger magnitude than startles pre-

sented during neutral processing (t(66)=2.37, p<.03, overall

Content F(1.95,64.4)=14.83, p<.0001). Fear sentence









startles were also greater in magnitude than probe reaction

during intertrial intervals (t(66)=4.43, p<.0001), as were

responses elicited during neutral processing (t(66)=2.06,

p<.05).

As is evident in Figure 3, we can also infer differ-

ences in the way groups processed the neutral and fearful

material, i.e., the different sentence recall tasks appear

to have differentially modulated the startle response

(Content X Group, F(3.9,64.4)=2.95, p<.03). Thus, a sepa-

rate analysis of the imagery group confirmed a significant

sentence content effect (F(1.5,16.8)=10.13, p<.003):

Startles elicited during fear imagery were larger than those

elicited during neutral imagery (t(22)=2.44, p<.05) or

intertrial intervals (t(22)=3.64, p<.005), while the latter

probes did not differ from each other (t(22)=1.20, 2>.20).

Startles elicited during silent rehearsal (Articulate-

Image group) also showed a main effect for Content

(F(1.8,20.2)=6.25, p<.01). Probe responses during sentence

processing were larger than startles elicited during inter-

trial periods (neutral t(22)=1.95, .05
t(22)=2.80, 2<.02). However, probe reflexes during fear

material were not significantly larger than neutral sentence

probes (t(22)=0.85, p>.40).

Instructions not to process the sentences (Null Task-

Image group) appeared to further reduce the sentence recall

effect and the overall analysis was not significant (F<1.0).

Nevertheless, an individual t-test suggested that startles












Figure 3. Magnitude of response to the startle probes for
each content (neutral, fear) presented separately for
each group. The bars in the left-hand columns depict
data from Period one (null task, articulation,
imagery), while the bars in the right-hand column
depict data from Period two (imagery). The horizontal
line across each graph represents magnitude of inter-
trial interval startle responses for each group.










PERIOD 2


INTERTRIAL
STARTLES


NULL TASK IMAGE


PERIOD 2


NEUTRAL
FEAR


-- INTERTRIAL
SSTARTLES


ARTICULATE


PERIOD 1


PERIOD 2


INTERTRIAL
STARTLES


IMAGE IMAGE


210-


160 -


110 4--


300


250-


PERIOD I


IMAGE


315-


265


215-


PERIOD I


200









elicited during fear trials might yet be greater than those

elicited during neutral trials (t(ll)=3.07, p<.02).

Probe timing and processing task. Startle magnitude

was affected differently at different times in the six-

second period, depending on whether subjects were processing

sentences or in an intertrial period (Content X Time, F(3.6,

118.2)=4.54, p<.003). To explore possible probe time dif-

ferences for the specific Period one processing tasks, a

Content X Group ANOVA was undertaken separately for the

Early, Middle, and Late startle positions. The mean values

tested are presented in Table 5. No significant differences

emerged at the Early startle position (Fs <1.5). In con-

trast, the nature of the Content differences at the Middle

(F(1.9, 63.4)=10.12, p<.0002) and Late (F(1.9, 61.2)=11.57,

p<.0001) positions is that described earlier for the overall

data. Thus, the affective content appeared to have its

greatest impact on startle modulation at the Middle and Late

probe positions; magnitude at the Early position seemed to

be controlled by the temporal relationship between the

startle probe and preceding tone (see Graham, 1975).

Latency. Latency to startle responses elicited after

retrieving fear material from memory was shorter than

latency to startles presented during intertrial intervals

(overall F(1.96, 64.5)=7.27, 2<.002; t(66)=3.08, 2<.005);

and marginally shorter than neutral processing (t(66)=1.70,

.05
fer less from each other (t(66)=1.38, p>.20). The overall









Group X Content effect was not significant. However, given

the hypothesized affective content differences as a function

of mode of processing, individual group analyses (Content X

Startle Probe Time) were conducted for latency.

Startles varied significantly with content for the

Image-Image group (overall F(1.9,20.4)=6.61, p<.007).

Reflexes elicited during intertrial periods were inhibited

(longer in onset latency) relative to startles elicited

during fear imagery (t(22)=2.93, p<.01). Intertrial

startles were less clearly inhibited relative to neutral

imagery (t(22)=1.84, .05<2<.10). Mean startle latency

during fear imagery was shorter than during neutral imagery,

but this result was not significant (t(22)=1.08, p>.20).

Finally, there were no content differences in startle onset

latency either during the null task (F(l.8,19.8)=1.55,

p<.25) or during articulation of sentences

(F(1.7,18.6)=0.99, p<.40).

Period Two (Imagery)

Magnitude. As illustrated in Figure 3, startles eli-

cited during fear imagery were larger in magnitude than

startles elicited during neutral (t(66)=4.19, p<.0001, over-

all F(1.8,59.0)=18.90, p<.0001) or intertrial periods

(t(66)=4.52, 2<.0001), while neutral and intertrial interval

startles did not differ in magnitude of response (t=0.32).

As expected, when all subjects were engaged in the same

imagery task, there was no overall group difference.

The relationship between sentence processing and









intertrial periods again differed as a function of the time

of the startle probe within the interval (Content X Time

F(3.2,105.5)=4.30, p<.006). During intertrial intervals,

startle responses were larger at the Early relative to the

Middle (t(132)=3.16, p<.002) or Late (t(132)=3.89, p<.0002)

positions. Conversely, for fear imagery, startle responses

were smaller at the Early relative to Middle probe position

(t(132)=3.79, p<.0005) and the Late probe position

(t(132)=2.74, 2<.01). Like fear imagery, startle responses

during neutral imagery were smaller at Early relative to the

Middle Startle Probe Time (t(132)=2.63, p<.01). Late probe

startles during neutral imagery were also smaller than

Middle probe startles (t(132)=2.11, R<.05). Again, there

were no group effects in Period two, when all subjects

imaged the sentence.

Latency. Figure 4 shows that mean onset latency was

shorter to startles elicited during fear imagery than those

elicited during neutral imagery (t(66)=1.70, .05
which in turn exhibited shorter onset than those elicited

during intertrial periods (t(66)=2.39, p<.02, overall

F(1.96,64.7)=12.80, p<.0001). As for magnitude, the experi-

mental groups did not differ in latency of response in

Period two.












Figure 4. Latency of response to the startle probes for
each content (neutral, fear) presented separately for
each group. The bars in the left-hand columns depict
data from Period one (null task, articulation,
imagery), while the bars in the right-hand column
depict data from Period two (imagery). In this Figure
smaller bars represent facilitated startles, i.e.,
those with a faster onset latency. The horizontal line
across each graph represents latency of intertrial
interval startle responses for each group.











PERIOD I PERIOD 2


INTERTRIAL
STARTLES


NULL TASK IMAGE


PERIOD I


PERIOD 2


ARTICULATE


PERIOD I


INTERTRIAL
STARTLES






NEUTRAL
FEAR
IMAGE


INTERTRIAL
STARTLES
PERIOD 2


IMAGE IMAGE


PERIOD I


PERIOD 2









Startle Reflex: Modality-Specific Attention

Of the six neutral sentences, three referred explicitly

to the auditory modality and three referred to the visual

modality. It was hypothesized that modality-specific proc-

essing would have similar effects as attending to

environmental stimuli in a specific modality. Data from

neutral sentence processing trials were subject to a Sensory

Modality (Auditory, Visual) X Processing Period (One, Two) X

Time X Group X Imagery Ability (Good, Poor) ANOVA (Tables 13

through 20 in Appendix D present these data).

Magnitude

Magnitude of response to the acoustic probes was larger

while subjects were processing auditory sentences (mean=248

A-D units) relative to visual sentences (mean=222 A-D units;

Sensory modality F(1,17)=4.67, p<.05). As Figure 5 illus-

trates, this modality-specific modulation was strongest at

the middle probe positions, and was less clear or reversed

when the acoustic probe immediately followed a tone cue

(Early) or preceded the cue to cease sentence processing

(Late in Period two; Sensory Modality X Period X Time,

F(1.8,30.8)=4.08, p<.04).

Latency

Latency of response was not significantly facilitated

during auditory relative to visual sentences (F(1,15)=0.90,

p>.30) for all subjects. However, this effect was found

specifically in questionnaire-defined good imagers and was

most pronounced at the Middle startle position (Sensory







































EARLY MID LATE EARLY MID


PERIOD 1


L VISUAL
AUDITORY

LATE


PERIOD 2


Figure 5. Startle response magnitude during processing of
neutral sentences which refer to the visual or auditory
modality, presented as a function of startle onset time
during Period one and Period two.


320 -




285-


250 -


215 -




180-









modality X Imagery Ability X Time, F(1.8,26.6)=3.58, p<.05).

This effect can be seen in Figure 6. It should also be

noted from this Figure that poor imagers produced startles

with generally shorter onset latency than did good imagers

(35.5 msec vs. 39.3 msec, Imagery Ability, F(1,15)= 5.08,

p<.04). No differences between sentence processing groups

were found for latency or magnitude of startle.

ANOVAs were then conducted individually for Period one

and Period two. Trends in the data were the same in each

period; however, because of the small number of datapoints

per cell statistically significant effects were not found

for either period when analyzed separately.

Heart rate

Mean heart rate was slower during acoustically-oriented

sentences relative to visually-oriented sentences (-0.18 vs.

0.25) beats/minute over Periods one and two). To determine

if this trend was statistically significant, a Group X

Imagery Ability X Sensory Modality X Period ANOVA was con-

ducted for heart rate change, to parallel the analysis of

startle data. None of the resulting F values were signifi-

cant (Modality F(1,17)=1.39, p>.25).

Startle Reflex: Image Vividness

It was hypothesized that overall, more vivid images

would result in attenuated response to the startle probe

relative to less vivid images. In order to test this hypo-

thesis, the six neutral and six fear sentences were sepa-

rately ranked for each subject from least to most vivid










GOOD IMAGERS


EARLY MIDDLE
TIME


EARLY


IIIDDLE


LATE


LATE


TlrIE


Figure 6. Startle response latency during processing of
neutral sentences which refer to the visual or auditory
modality, presented as a function of startle onset time
for good and poor imagers. Smaller bars indicate faci-
litated startles relative to larger bars.


* VISUAL
M AUDITORY


POOR IMAGERS


35 --


30-4-










based on ratings of image vividness for each specific sen-

tence. A Group X Imagery Ability X Content (Neutral, Fear)

X Vividness (six levels nested within each content) ANOVA

was conducted for magnitude and latency of startle probe.

Because ratings were made based on image vividness, only

data from Period two were considered. Only results

revealing a significant linear trend over the six levels of

vividness are reported here.

Magnitude

Figure 7 shows that for both neutral and fear imagery

magnitude of startle response decreased as rated vividness

of the image increased (overall linear trend for vividness,

F(1,17)=16.43, g<.0008). Although the vividness effect was

evident for both good and poor imagers, it was most pro-

nounced for poor imagers (Vividness X Imagery Ability linear

trend, F(1,17)=4.93, p<.05). The good imagers also tended

to show smaller magnitude startles overall than did poor

imagers (F(1,17)=3.87, .05
The results suggest that prior processing task may have

modulated imagery vividness (Vividness X Group linear trend

F(1,17)=6.18, p<.01). The linear trend for rated vividness

was clear for the Image-Image and Null Task-Image groups,

but not the Articulation-Image group.

Latency

Startle latency was significantly shorter for poor

relative to good imagers (F(1,17)=4.63, p<.05). However,

latency did not vary consistently as a function of rated

vividness of imagery.
















350




300


3 250- o




0
200-
o NEUTRAL
FEAR


0 1 2 3 4 5 6

VIVIDNESS RANK (1 =MOST VIVID)


Figure 7. Startle response magnitude during Period two
presented as a function of within-subject image
vividness ranking presented separately for neutral and
fear image trials.









Vividness and Sensory Modality

The previous section reported vivid imagery as being

associated overall with inhibited startle response. Earlier

it was predicted that acoustic imagery rated as very vivid

would be associated with facilitated startle responses,

while more vivid visual imagery should be associated with

inhibited acoustic startle responses. To test this hypo-

thesis, each subject's three neutral acoustic sentences and

three neutral visual sentences were separately ranked based

on that subject's ratings of vividness, and a Sensory

Modality X Group X Imagery Ability X Vividness (3 levels

nested within each sensory modality) ANOVA was conducted for

magnitude and latency. Sensory Modality and rated Vividness

did not interact significantly as predicted. Nevertheless,

because the modality effect on the reflex was strongest at

the Middle startle position, the analysis was repeated for

these startle responses only. Figure 8 shows the pattern of

results for this middle stimulus. Startle latency was in-

hibited with increasing vividness during visual sentences

and was facilitated with increasing vividness during acous-

tic sentences (Sensory Modality X Vividness

F(1.9,23.1)=4.11, p<.04). No reliable results were found

for magnitude in the parallel analysis.

















42-












'J



--0- AUDITORY
32 -9- VISUAL
0 1 2 3

SENTENCE VIVIDNESS RANK (I =MOST VIVID)



Figure 8. Latency of response to Middle startle probes as a
function of sensory modality of the neutral sentence
(auditory or visual) and subject's ranking of the
vividness of that sentence.
















DISCUSSION

Clear evidence appeared for startle reflex augmentation

during processing of fear sentences. Blink responses to the

acoustic probes were larger and faster onset during

cued recall of sentences with fear content than during cued

recall of neutral sentences or during uncued intertrial

periods. This effect tended to occur under all

instructional conditions, but was greatest when subjects

were instructed to imagine the sentence content.

The dominant modality of the image appeared to modulate

the startle response: The blink reflexes to mid-image

acoustic probes were relatively facilitated when subjects

recalled sentences with primarily auditory sensory content

than when recalling sentences with visual sensory content.

Image vividness influenced startle modulation in two

ways. First, images reported to be vivid were generally

associated with smaller blink reflexes. Second, images

rated as vivid were associated with response facilitation

during recall of auditory sentences relative to visual con-

tent sentences. Vivid imagery had a similar effect between-

subjects, as self-rated good imagers showed smaller and

longer onset startle responses relative to poor imagers;

good imagers also exhibited greater reflex facilitation

during auditory relative to visual sentence imagery. These

major results are explicated in the sections below.









Processing Fear Sentences

The activation of fearful, effectively negative mate-

rial in memory resulted in heart rate acceleration and self

report of unpleasantness, high arousal, and low dominance,

all relative to activation of relaxing, moderately positive

material from memory. This result obtained here replicates

previous findings with this (Vrana et al., in press) and

other experimental paradigms (Bauer & Craighead, 1979; Lang,

Kozak, Miller, Levin & McLean, 1980).

The overall results also indicated that processing mode

instruction modulated heart rate: When the sentences were

imagined, response information was more completely acti-

vated, as evidenced by greater heart rate during fear

imagery relative to silent articulation or null processing

of the fear material. However, silent articulation of the

text, and even explicit instructions not to process the

text, also resulted in greater heart rate acceleration fol-

lowing signals to retrieve fearful relative to neutral sen-

tences from memory.

Startle reflex facilitation was expected during fear

sentence retrieval, on the assumption that such negative

material evokes in the organism a general aversive response

disposition, and that this matched the negative response

valence of the startle reflex. Facilitated magnitude and

latency were in fact found while subjects were processing

fear sentences, relative to when subjects were processing

neutral sentences or performing the intertrial "Count 'one'"










task. This result is consistent with findings of reflex

facilitation as a component of the conditioned fear response

to a visual stimulus in man (Greenwald et al., 1988; Ross,

1961; Spence & Runquist, 1958) and animals (Berg & Davis,

1985; Brown et al., 1951); as well as human startle facili-

tation while viewing unpleasant visual material (Bradley et

al., 1988; Cook et al., 1988; Vrana et al., 1988). In the

current experiment, unlike previous work, no external stim-

ulus initiated fear processing. Comparison of these studies

emphasizes the specificity of the startle reflex as a mea-

sure of an aversive response disposition. That is, the

startle response is facilitated regardless of the media

evoking the response disposition aversivee slide content,

conditioned visual signal, or cued recall of fear sen-

tences). Across experiments, it is also independent of the

heart rate response. Heart rate accelerates during fearful

imagery, signaling activation of response code, but decele-

rates while subjects maintain an attentive set to the aver-

sive slides (Vrana et al., 1988). In each case, the reflex

to the aversive startle input is primed.

Imagery of negative material produced startle responses

of larger magnitude and shorter onset latency than neutral

imagery. As for heart rate, null processing and silent

articulation produced smaller differences in the same direc-

tion. Two conclusions are warranted here. First, the

spread of activation from language to affective response

elements in memory (i.e., from processing the words of the









sentence to processing the associated emotional response) is

to a considerable extent automatic. Second, instructions to

image may facilitate this natural process, while other

instructions may involve competing tasks (e.g., speech) which

differently engage the motor domain.

Other recent studies have also found an inability to

inhibit memory-cued material (Wegner, Schneider, Carter &

White, 1987). It is clear that instructional control over

cognitive processing, in affective or nonaffective contexts,

is only partially successful. Factors which may affect

processing include developmental level, affective valence of

the processed material, specific input (e.g., slides, text,

video) and output (physiology, self-report) variables, ima-

gery ability, and the context in which processing occurs.

For example, some of the results found here may be specific

to contexts in which processing occurs immediately upon

memory retrieval, and would not occur following a prepara-

tory period (May, 1977a; 1977b; Vrana et al., in press).

Rather than focus specifically on the instruction to image,

it is recommended that research focus more broadly on speci-

fying the conditions in which affective memory networks,

including response elements, are activated, and the implica-

tion of this process for memory network modification.

Modality-specific Effects of Sentence Processing

Attending to stimulus input in a particular sensory

modality predisposes one to greater responding to a startle

probe in that modality (Anthony, 1985). Sensory modality









effects found with environmental stimuli were replicated

here with processing of modality-specific sentence content.

That is, startle response magnitude was larger when the

sensory modality referred to in the neutral sentence matched

the startle probe modality (acoustic sentence with acoustic

probe), relative to mismatched startle and sentence modali-

ties (visual sentence with acoustic probes). A trend toward

less heart rate acceleration in acoustic relative to visual

neutral sentences suggests this magnitude difference was not

due to greater response activation in the acoustic sentences.

The "modality specific" effect found here cannot be

construed as a competition for attentional resources in a

purely perceptual context. Instead, the reflex was appar-

ently tuned to respond to information in a particular modal-

ity by activation of the event memory. Segal and Fusella

(1970) also found modality specific effects of imagery; in

that study an auditory or visual image disrupted detection

of a threshold stimulus in the same modality. It is unclear

why image activation facilitates a modality-matched reflex

elicitor but attenuates detection of modality-matched sig-

nals at the threshold level. The tasks are quite different:

Segal and Fusella presented subjects with the dual tasks of

image processing and signal detection, relying on subjective

judgment of detection as the performance measure. Imagery

was of discrete objects or sounds. In contrast, the current

study involved imagery of complete events, perhaps engaging

a more broad attentional set than Segal and Fusella, a set









known to generally enhance reflex response (Bohlin, Graham &

Silverstein, 1981). The response measure was the startle

reflex which, unlike the controlled signal detection task,

can be automatically elicited (Anthony, 1985). The auto-

matic response may be more conducive to facilitation by

activation of a particular sensory channel, while the con-

trolled process of signal detection may be more susceptible

to interference when competing with previously engaged sen-

sory pathways. Future work with various image processing

tasks, sensory signals (from threshold to startle), and

response measures (startle, orienting, subjective signal

detection) will doubtlessly shed more light on these re-

sults, and on the relationship between image activation of

sensory channels and perception.

The sentence modality effect was in turn modulated by

two other variables. First, Figures 5 and 6 make clear the

magnitude difference between visual and acoustic startle

content sentences occurred most clearly at the Middle

startle position. A similar effect occurred during the

affective valence modulation (see Table 5), as the startle

magnitude difference between neutral and fear sentence

trials is smallest immediately following the signal tone

(Early probe position). Thus for both the affective valence

and sensory content analyses, the Early startle probe

responses appear the least sensitive to sentence content or

cognitive processing variables. The Early startle probe

occurred approximately 420 msec following offset of the










preceding tone. A change in stimulus energy (onset or off-

set of a stimulus) can inhibit startle reflex responding to

a subsequent probe within this time interval (Graham, 1975).

Future studies can determine if the Early inhibition is due

to inhibition of the startle reflex response by tone offset,

or reflects the time course of the cognitive and affective

processing tasks.

The second variable to influence sensory content modu-

lation of the sentences was image vividness. Startle

latency was facilitated with matching sentence and startle

modalities, but only among questionnaire-defined good

imagers (Figure 6). Vivid imagery produced the same effect

within subjects: Modality-specific effects were more evident

in each subject's self-reported most vivid imagery (Figure 8).

This is consistent with other studies finding content-

specific physiological activation to be more pronounced

during imagery by good relative to poor imagers (Miller,

Levin, Kozak, Cook, McLean & Lang, 1987; White, 1978), and

with the theory that the central feature of imagery is acti-

vation of context-specific response disposition (Lang, 1979).

Imagery as a Cognitive Task

Imagery of sentences containing auditory-specific con-

tent facilitated reflex response to the acoustic probe.

However, regardless of content, imagery involves internal

processing and the consequent shutting out of external stim-

uli, or "stimulus rejection" (Lacey, Kagan, Lacey, & Moss,

1963). Such tasks have been theoretically associated with









heart rate acceleration (e.g., Lacey et al., 1963). Stimu-

lus rejection should be associated with decreased response

to that input, i.e., attenuated startle response. It seems

reasonable to assume intra- and inter-individual differences

in ability to shut out environmental stimulation while proc-

essing the sentences, and that this ability might be reflec-

ted in rated image vividness, which is related to one's

ability to become absorbed in an experience (Sheehan et al.,

1978). This was in fact the case. Images ranked as more

vivid by a subject produced an inhibited startle response

relative to less vivid imagery (Figure 7). In addition,

people who rate themselves as good imagers on an imagery

questionnaire reported more vivid images overall, and exhib-

ited less response overall to startle probes than self-rated

poor imagers.

Good imagers evidenced a less pronounced relationship

between startle magnitude and vividness than did poor

imagers. Good imagers can create vivid affective images (as

evidenced by physiological activation) to familiar and unfa-

miliar situations, while poor imagers require highly fami-

liar, personally-relevant scenarios in order to create a

vivid image (Miller et al., 1987). The sentences here depi-

cted a range of situations, some extremely familiar to sub-

jects, some not. This different relationship between

startle magnitude and image vividness may be a difference in

range of imaginal experience: Good imagers had consistently

good images (generally attenuating magnitude), while poor

imagers created images of more variable quality.










From the perspective of within-task changes in startle

response as a function of vividness, the internal orienta-

tion of the cognitive productions attenuated the startle

reflex. When compared with response to startle probes

during intertrial periods, however, sentence processing

appeared to have an activating effect on the reflex. During

Period one, sentence articulation of neutral material

resulted in facilitated startle magnitude relative to unsig-

naled intertrial periods. Neutral sentence imagery facili-

tated latency relative to intertrial startles during Period

one and Period two. It may be that startle facilitation in

these contexts involves task-induced activation; that is,

engagement in a cognitive task or changing from one task to

another increases non-specific arousal. This is consistent

with Putnam's (1975) finding of startle facilitation during

a meaningless but arousing foreground of white noise. Ano-

ther possibility is that all of the sentence contents (even

primarily visual ones) engage the tendency to respond to

auditory stimuli to a greater extent than does the inter-

trial "Count 'one'" task. Further, there may be some task-

specific priming of the auditory channel: The speech-like

task of silent articulation may engage subjects' readiness

to listen, resulting in facilitated response in the acoustic

modality.

It may appear contradictory to suggest that sentence

processing has facilitating and attenuating effects; how-

ever, several processes are hypothesized to occur during









this time. First, the context of the entire experiment

requires an internal processing orientation, including the

well-practiced, meditation-like "Count 'one"' task

(Cuthbert, Kristeller, Simons, Hodes & Lang, 1981). This

leads to a general attenuation of the startle response which

is highlighted during sentence imagery rated as particularly

vivid. Second, sentence processing generally facilitated

the startle response relative to the "Count 'one'" task.

Whether this was due to task-induced activation or sensory

engagement could be teased out by designing tasks which,

unlike the sentence processing tasks, minimized sensory

content. Third, the particular content of the sentence

materials modulated the startle response: Fear facilitated

relative to neutral content; auditory facilitated relative

to visual content. Finally, the sentence content diffe-

rences were generally attenuated at the Early startle probe

position, caused either through direct inhibition by the

preceding signal tone (Graham, 1975) or perhaps because

subjects had not yet fully initiated sentence processing.

Thus the influence on startle reflex of most interest in

this experiment (sentence content differences) occurred in

the context of other events known to modulate the startle

reflex. The various modulating variables were apparent in

the influences of different aspects of the experimental

design on the startle response.

Several investigators have proposed that startle magni-

tude is more sensitive to sensory content while latency









responds to generalized activation (Bohlin et al., 1981;

Silverstein et al., 1981). There was some indication of

this in the current study in that latency differentiated

sentence imagery and intertrial startle responses more con-

sistently than did magnitude. For the most part, however,

magnitude and latency results were similar in pattern with

latency being somewhat less sensitive to the experimental

variables. This lack of sensitivity is not surprising.

Resolution of measurement for reflex latency was one milli-

second, and the overall latency difference between startles

elicited during neutral and fear processing was 1.7 milli-

second. In contrast, resolution of startle magnitude was

one A-D unit, a fraction of the 48 A-D unit magnitude dif-

ference between neutral and fear startles.

Summary and Conclusions

Whereas much has been written about human cardiac re-

sponsivity in affective (Cuthbert et al., in press) and

nonaffective contexts (Jennings, 1986; van der Molen, Somsen

& Orlebeke, 1985), the recent human startle literature has

focused on nonaffective weak prestimulation and selective

attention to environmental stimuli (Anthony, 1985). Current

results require several modifications and additions to the

startle reflex modulation literature. First, the startle

reflex is enhanced in negatively-affective contexts regard-

less of task requirements (e.g., stimulus intake, internal

processing). Thus, consistent with earlier human subject

research (Ross, 1961; Spence & Runquist, 1958) and recent









animal research (Berg & Davis, 1984; 1985), startle facili-

tation following engagement of an aversive response disposi-

tion appears to override the modality-specific modulation

which has been the focus of startle reflex research over the

past decade (Anthony, 1985). The generality of this reflex

facilitation suggests the startle as an important, and per-

haps unique, measure of the valence dimension of emotion.

Second, finding modulation of the startle during internally-

generated processing of modality-specific content, rules out

some environmentally-driven accounts of the selective atten-

tion effect (Anthony, 1985), and suggests a top-down effect,

involving associative priming of a disposition to respond to

stimuli in the selected modality. There was also evidence

that the startle response provided an index for degree of

internal orientation involved in cognitive processing (modu-

lation of the response by image vividness), as well as gene-

ralized activation and/or sensory engagement by a cognitive

task.

In summary, negatively-valent stimulus material, acti-

vation, sensory engagement, and internal-external processing

orientation all seem to have well-defined effects on the

startle reflex. Given these well-defined parameters, the

startle reflex presents itself as a unique tool in the study

of emotion. It appears to retain a directionally-specific

sensitivity to the valence of affective stimuli, even in

contexts where heart rate and other autonomic responses are

drastically altered by the cognitive task (Jones & Johnson,









1978; 1980; Vrana et al., 1986). The eyeblink is reflexive,

and therefore not subject to the vagaries of verbally-

mediated measures of emotion. Because the startle can be

measured without preparatory instruction or verbal response,

it is ideal for developmental, cross-cultural, and cross-

species investigations. Indeed, animal studies already

suggest startle as a measure of treatment outcome in anxiety

disorders (Berg & Davis, 1984). The startle response, par-

ticularly in combination with other measures of affect,

promises to be a versatile and fruitful means to study emo-

tional processing.



















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APPENDIX A
STIMULI AND SUBJECT INSTRUCTIONS

Subject Instructions: Null Task-Image Group,
High Tone=Fear Sentences

I am now going to read you the instructions for this

experiment. In a little while you will memorize two sen-

tences, one fearful and one neutral in content. You will

use these sentences to create images in your mind using the

following procedure. After you memorize the two sentences

and I leave the room, you will hear a series of short tones,

one every six seconds. Each tone will be at one of three

different frequencies. The tone that you will hear most

often is the middle frequency tone. I'll call this the

"normal" tone. Whenever you hear this tone, just relax and

think the word "one" to yourself each time you breathe out.

This is to help clear your mind and help you remain relaxed.

Sometimes you will hear a higher-pitched tone, which

will always be presented twice in a row at the usual six-

second interval. When you hear this tone the first time,

just continue to think "one" to yourself and clear your

mind. At the second high tone, begin to imagine the fear

scene as a vivid, personal experience. When you do this,

try to imagine you are actually in the situation and parti-

cipating in the events described, and not just "watching

yourself" in the scene. To review, you will hear the normal

tone, and think "one" to yourself until the next tone. At









the first higher-pitched tone, continue to think "one" to

yourself. At the second high tone, imagine the fear scene.

Continue with your image until the next normal tone, then

begin to think "one" to these tones again.

Sometimes you will hear a tone that is at a lower

frequency than the normal tone. As for the high tones, the

low tones will always be presented twice in a row at the

normal six-second interval. When you hear the first low

tone, continue to clear your mind and think "one" to your-

self. At the second low tone, imagine the neutral scene as

vividly as you can. Once again, try to imagine you are

actually participating in the situation described. To

review, when you hear the lower-pitched tone for the first

time, continue thinking "one" to yourself; at the second low

tone, imagine the neutral scene until the next normal tone,

then begin to think "one" to these tones again.

Let me summarize. You will hear short tones occurring

every six seconds. Most of the tones will be normal tones,

and when you hear these clear your mind by thinking "one" to

yourself. Every once in a while you will hear a pair of

tones that are either higher or lower in frequency than the

normal tone. When you hear one of these tones, continue to

think one to yourself, then at the next such tone, create an

image to the appropriate sentence. If the different tones

are higher-pitched, create an image to the fear sentence.

If the different tones are lower-pitched, create an image to

the neutral sentence. At times you will hear loud clicks,









like a finger snapping. They are meant to elicit a response

we wish to measure, but you just need to ignore them and

continue with the task. In just a minute I will play

examples of the tones and noise clicks and we can go through

this sequence of events. Do you have any questions about

this procedure?

After you have heard a sequence of tones lasting about

ten minutes, you will hear two tones in quick succession.

At this point open your eyes and rate your images for their

pleasantness, arousal, and vividness. I will show you how

to do this in a little while. After you rate your images,

you will memorize another two sentences, and then go through

the tone series again. There will be a number of sentence

pairs and tone sequences. Now I will start the tone sequence.

Start Practice Trials

These are the normal tones. They will occur every six

seconds. When you hear these tones, just clear your mind

and think "one" to yourself each time you exhale. That was

a high tone. Continue thinking one to yourself. When you

hear this high tone imagine the fear sentence. Continue

your image until was one of the noise clicks. Just ignore

it and continue counting "one" to yourself. That was the

lower tone. When you hear that tone continue to think one

until this low tone. Continue your image until the next

normal tone. Now go back to thinking "one" to yourself.

Continue with this until you hear a double tone. Like this

one; then open your eyes to rate your images to the









sentences. I want you to make each rating based on the

average of all your images to that sentence.

Sentence Memorization

Here are the first two sentences to memorize. Tell me

when you have them memorized, and then I will have you

repeat the parts in capital letters back to me. Please read

the whole sentence and use all the information in it for

your image, but you only have to memorize and repeat the

phrases in capital letters.

Good. I would like to remind you how the tone sequence

will go. When I leave the room, close your eyes and get as

comfortable as you can in the chair. When you hear each

"normal" tone think "one" to yourself. Try to clear your

mind and not think of anything but the number "one" at this

point. When you hear a high-pitched tone, continue to clear

your mind and think one and then at the next, high-pitched,

tone create an image to the fear sentence you just memo-

rized. When you hear a low-pitched tone, continue thinking

one and then at the next, low-pitched, tone create an image

to the neutral sentence you just memorized. Stop your image

at the next normal tone and go back to thinking "one" at

each tone until you hear the next high- or low- pitched

tone. Continue this until you hear two quick tones, then

make your ratings. Do you have any questions?

Remember, your main job in this experiment is to create

vivid images, and to imagine you are really participating in

the scene. Just ignore the noise clicks--the first few may










make you jump a bit but after that you'll get used to them.

I will tell in just a minute when the tones will start. Try

to move as little as possible through the whole tone

sequence, as this will effect the physiological recording.

Put the headphones on and get yourself seated as comfortable

as possible now and we will get started in just a minute.

Other Subject Group Instructions

Articulate-Image Group

Instructions for this group were the same, except they

were told that at the first high- or low-pitched tone they

were to "'think' the sentence. This means repeat the words

of the sentence over in your head. At the second high tone,

begin to imagine the scene as a vivid, personal experience."

Image-Image Group

Instructions for this group were the same, except they

were told that at the first high- or low-pitched tone they

were to "create an image to the sentence as a vivid,

personal experience. When you do this, try to imagine you

are actually in the situation and participating in the

events described, and not just watching yourself in the

scene. At the second high tone, again create an image to the

scene as a vivid, personal experience."










Sentence Materials
Fear Sentences

The bell sounds, the students wait impatiently, MY

HEART POUNDS AS I BEGIN MY SPEECH TO THE CLASS.

I grip the chair, heart racing, as THE DENTIST HOOKS MY

GUMLINE AND COLD STEEL SCRAPES ACROSS MY TEETH.

I tense as THE NURSE SLOWLY INJECTS THE SHARP NEEDLE

INTO MY UPPER ARM, and beads of sweat cover my forehead.

I flinch at the screech of brakes; MY COMPANION IS

STRUCK BY A SPEEDING CAR; HER LEG IS CRUSHED, bone

protruding, AND BLOOD PUMPS ONTO THE ROAD.

Taking a shower, ALONE IN THE HOUSE, I HEAR THE SOUND

OF SOMEONE FORCING THE DOOR, and I panic.

ALONE IN BED, I FEEL a scuttling along my bare leg; I

switch on the light, and trembling, see A LARGE, BLACK

SPIDER MOVING UP MY THIGH.










Neutral Sentences

Visual modality

I AM RELAXING on my living room couch LOOKING OUT THE

WINDOW ON A SUNNY AUTUMN DAY.

I AM sitting in a lawn chair on the front porch

WATCHING THE SOFT SUMMER BREEZE SWAY THE LEAVES ON THE

TREES.

A wood fire dances in the hearth, I FEEL SNUG AND WARM

IN THE CABIN, READING THE BOOK ON MY LAP, enjoying a well-

deserved rest.

Auditory modality

SOFT MUSIC IS PLAYING ON THE STEREO, AS I SNOOZE LAZILY

on my favorite chair.

I AM LYING ON THE SAND on a warm day, LISTENING TO

CHILDREN PLAYING DOWN THE BEACH, their soft voices mingling

with the sound of the waves.

I AM LYING IN BED on a Sunday morning, half asleep and

LISTENING TO THE DISTANT SOUND OF BELLS, relaxing on my day

off.
















APPENDIX B
DIFFERENCES BETWEEN STARTLE AND NON-STARTLE EXPERIMENT

The startle experiment reported in the Results section

and the non-startle study reported in the Introduction are

nearly identical in design, procedure, and materials. The

differences between the two studies are stressed here in

order to assist in clear interpretation of the results. The

greatest difference between the two studies is the inclusion

of the startle reflex measure in the second study; this

required two additional electrodes placed near the subject's

eye as well as presenting the white noise bursts during and

between trials, as described in Methods. All auditory stim-

uli in the startle experiment were presented using head-

phones, rather than the speaker used in the non-startle

study, in order to present the 95 dB noise burst without

disrupting other activities in the laboratory. The fre-

quency of the low, medium, and high tones in the startle

study were 800, 1100, and 1500 Hz, respectively, rather than

the 500, 800, and 1100 Hz tones presented in the non-startle

experiment. This was to eliminate the sound pressure level

differences found in the three tone frequencies in the

initial, non-startle study.

The materials were somewhat different in the two

studies. Four neutral sentences were slightly re-written to

explicitly refer to the auditory or visual modality, and










word-for-word sentence memorization in the non-startle study

was modified to word-for-word memorization of only key

phrases of each sentence for the startle study. The dif-

ferences in sentences can be examined by comparing the non-

startle sentence materials at the end of this Appendix with

the startle study sentence materials in Appendix A. Imagery

ratings (pleasure, arousal, dominance and vividness) were

performed by making a numerical rating in the non-startle

study; in the startle study these ratings were performed by

marking a horizontal line. These ratings were quantified so

that each dimension had the same range (0-29) and the same

meaning in each experiment (for example, a rating of twenty-

nine on the valence dimension represents maximum pleasure in

each study).

Finally, obtaining the desired number of data points

for the startle reflex required increasing the number of

trials in each block from eight (four neutral and four fear

trials) to twelve (six neutral and six fear). This

increased the length of each block of trials from about five

and a half minutes in the non-startle experiment to over

eight minutes in the startle experiment.

Fear Sentences: Non-Startle Study

The bell sounds, the students wait impatiently, my

heart pounds as I begin my speech to the class.

I grip the chair, heart racing, as the dentist hooks my

gumline and cold steel scrapes across my teeth.









I tense as the nurse slowly injects the sharp needle

into my upper arm, and beads of sweat cover my forehead.

I flinch at the screech of brakes; my companion is

struck by a speeding car; her leg is crushed, bone

protruding, and blood pumps onto the road.

Taking a shower, alone in the house, I hear the sound

of someone forcing the door, and I panic.

Alone in bed, I feel a scuttling along my bare leg; I

switch on the light, and trembling, see a large, black

spider moving up my thigh.

Neutral Sentences: Non-Startle Study

I am relaxing on my living room couch looking out the

window on a sunny autumn day.

I am sitting in a lawn chair on the front porch

enjoying the soft summer breeze.

A wood fire dances in the hearth, I feel snug and warm

in the cabin, a good book in my lap, enjoying a well-

deserved rest.

Soft music is playing on the stereo, as I snooze lazily

on my favorite chair.

I am lying on the sand on a warm day, children are

playing down the beach, and their soft voices mingle with

the sound of the waves.

I am lying in bed on a Sunday morning, half asleep and

listening to the distant sound of bells, relaxing on my day

off.


















APPENDIX C

HEART RATE FIGURES













Figure 9. No-startle study data: Continuous heart rate
waveform in half-second intervals for each group for
the "Count 'one'" period and the first sentence proc-
essing period. The tone cueing retrieval of the neut-
ral or fearful sentence is signified by a vertical line
at the six second mark in each graph.










76 "ONE" NULL


74-


72-


70 2


68 h/ -
0 6 12


S 72 "ONE" ARTICULATE


U(
70
w -0-- NEUTRAL
S 68 -*- FEAR







0 6 12


"ONE" IMAGE


74
726








684
0 6 12
SECONDS












Figure 10. Startle study data: Continuous heart rate
waveform in half-second intervals for each group for
the "Count 'one'" period and the first sentence proc-
essing period. The tone cueing retrieval of the neut-
ral or fearful sentence is signified by a vertical line
at the six second mark in each graph.







NULL


0
"ONE"




E.Ew-I


69-

68
0


73

72

71 -

70-

69-

68


"ONE"


6
ARTICULATE



N


a-0-- NEUTRAL
S--e- FEAR


IMAGE





2'
orA- -9\'


// coq,\3


SECONDS


"ONE"















APPENDIX D
TABLES OF STARTLE REFLEX DATA

Table 7


Null-Image Group: Startle Reflex Magnitude
and Startle Probe Time


Intertrial


Neutral


by Content, Period,


Fear


Period one


Early


Middle


Late


Mean


181
(218)

166
(199)

151
(153)

166


164
(185)

189
(196)

138
(189)

164


173
(187)

174
(199)

183
(167)


Mean
(neutral
+ fear)


168
(185)

182
(191)

161
(173)


177


Period two


139
(156)

186
(219)

144
(141)


177
(183)

215
(208)

212
(200)


156


Early


Middle


Late


Mean


158
(169)

200
(212)

178
(168)


201












Null-Image Group: Startle
and Startle Probe Time


Intertrial


Period one

Early


Middle


Late


Mean


Period two

Early


Middle


Late


44.4
(11.3)

42.7
(13.8)

43.7
(9.9)

43.6


Table 8


Reflex Latency by Content, Period,


Neutral


45.8
(12.2)

41.8
(11.8)

41.0
(9.8)

42.9


41.9
(11.0)

37.9
(9.8)

39.7
(11.5)


Fear


45.4
(11 .9)

39.7
(7.8)

38.4
(8.5)


Mean
(neutral
+ fear)


45.6
(10.3)

40.8
(9.3)

39.7
(8.1)


41.2


39.1
(10.5)

38.2
(8.9)

40.2
(11.6)


40.5
(10.1)

38.0
(8.6)

39.9
(10.2)


Mean


39.1


39.8











Table 9

Articulate-Image Group: Startle Reflex Magnitude by Content,
Period, and Startle Probe Time


Intertrial


Neutral


Fear


Mean
(neutral
+ fear)


Period one

Early


Middle


Late


Mean



Period two

Early


Middle


Late


Mean


253
(193)

180
(152)

199
(153)

211


254
(166)

282
(196)

263
(189)

266


276
(207)

305
(199)

289
(167)


265
(185)

294
(217)

276
(198)


290


217
(144)

217
(127)

223
(165)


297
(220)

281
(216)

299
(229)


257
(178)

249
(163)

261
(190)


219