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The Effects of lexical and semantic processing on visual selective attention

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Title:
The Effects of lexical and semantic processing on visual selective attention
Creator:
Petry, Margaret Carthas, 1966-
Publication Date:
Language:
English
Physical Description:
xiv, 232 leaves : ill. ; 29 cm.

Subjects

Subjects / Keywords:
Experimentation ( jstor )
Fingers ( jstor )
Hemispheres ( jstor )
High frequencies ( jstor )
Information resources ( jstor )
Language development disorders ( jstor )
Low frequencies ( jstor )
Selective attention ( jstor )
Semantics ( jstor )
Words ( jstor )
Attention ( mesh )
Department of Clinical and Health Psychology thesis Ph.D ( mesh )
Dissertations, Academic -- College of Health Related Professions -- Department of Clinical and Health Psychology -- UF ( mesh )
Neuropsychological Tests ( mesh )
Reading ( mesh )
Research ( mesh )
Semantic Differential ( mesh )
Genre:
bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Thesis:
Thesis (Ph.D.)--University of Florida, 1995.
Bibliography:
Bibliography: leaves 221-231.
General Note:
Typescript.
General Note:
Vita.
Statement of Responsibility:
by Margaret Carthas Petry.

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University of Florida
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University of Florida
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Copyright [name of dissertation author]. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
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028733893 ( ALEPH )
50414483 ( OCLC )
ALT4899 ( NOTIS )

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Full Text











THE EFFECTS OF LEXICAL AND SEMANTIC PROCESSING
ON VISUAL SELECTIVE ATTENTION
















By

MARGARET CARTHAS PETRY


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


1995




THE EFFECTS OF LEXICAL AND SEMANTIC PROCESSING
ON VISUAL SELECTIVE ATTENTION
By
MARGARET CARTHAS PETRY
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
1995


ACKNOWLEDGMENTS
Sincere thanks is extended to my supervisory committee
for their contributions to my dissertation, and in turn, to
my development as a researcher. Dr. Bruce Crosson,
chairperson of the committee, is given special thanks for
his invaluable guidance and support throughout this project.
Thanks is also offered to Dr. Ira Fischler for his
assistance during review of the dual-task literature and in
improving the methodology and design of this study. Dr.
Leslie Gonzalez Rothi is thanked for encouraging me to
broaden my original conceptualization of attention and
language as well as to set manageable objectives for this
project. Dr. Eileen Fennell is extended thanks for her
support and her assistance with methodological and design
issues. Dr. Russell Bauer is thanked for his help during
early conceptualization of this project as well as with
issues regarding its design. Dr. Alan Agresti is offered
thanks for his flexibility and provision of ready
statistical consultations.
Dan Edwards, Cliff LeBlanc, James Burnette, and Paula
Usita merit thanks for their assistance with subject
recruitment at Santa Fe Community College.


Extra special thanks is given to my family and friends
for their continued encouragement. My deepest thanks goes
to my husband, Andy, for his unending support and help.


TABLE OF CONTENTS
page
ACKNOWLEDGMENTS ii
LIST OF TABLES vii
LIST OF FIGURES x
ABSTRACT xiii
CHAPTERS
1 LITERATURE REVIEW 1
Attention 1
What is It? 1
How does Attention Operate? 3
Single Unshared Resource Theory 7
Single Shared Resource Theory 12
Multiple Unshared Resource Theory 15
Automatic and Controlled Processing of
Information 24
Anatomy 25
Language 31
Anatomy 32
Model of Recognition, Production, and
Comprehension of Written Words 40
Selective Attention and Language 44
Dual-Task Paradigm 49
Assumptions 49
Covert Orienting of Visual Attention Task 60
Experiment and Hypotheses 72
Experiment 72
Event-Related Potentials 74
Anatomy Proposed to be Primarily Involved in
Selective Attention and Subsequent Processing
of Language and Visuospatial Information 77
Hypotheses 81
2 MATERIALS AND METHODS 91
Subjects 91
Hand Preference 92
Apparatus 93
Covert Orienting of Visual Attention Task 93


95
Language Tasks
Covert Orienting of Visual Attention Task
Paired with Language Tasks 98
Procedure 104
3 RESULTS 112
Statistical Analyses 112
Covert Orienting of Visual Attention Task
Alone and Paired with Language Tasks 113
100 ms Word-COVAT Delay 116
250 ms Word-COVAT Delay 117
Transformed Data: 100 ms Word-COVAT Delay.... 121
Transformed Data: 250 ms Word-COVAT Delay.... 122
Language Tasks 123
Specific Types of Language Errors 125
Overall Language Errors 127
Language Task Order 129
Word Familiarity 131
Task Difficulty 132
Slow Responders During the Semantic
Association-COVAT Condition 133
4 DISCUSSION AND CONCLUSIONS 178
Covert Orienting of Visual Attention Task 178
Covert Orienting of Visual Attention Task
Alone and Paired with Language Tasks 179
100 ms Word-COVAT Delay 179
250 ms Word-COVAT Delay 186
Language Tasks 191
Language Task Order 194
Word Familiarity 194
Task Difficulty 195
Slow Responders During the Semantic
Association-COVAT Condition 196
Future Research 199
APPENDICES
A AAL SCREENING QUESTIONNAIRE 204
B BRIGGS-NEBES MODIFICATION OF THE ANNETT
HANDEDNESS QUESTIONNAIRE 206
C INSTRUCTIONS FOR CO VAT 207
D INSTRUCTIONS FOR THE READING TASK 208
E INSTRUCTIONS FOR THE SEMANTIC ASSOCIATION TASK.... 209


F LOW FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS
IN CONCRETENESS AND IMAGEABILITY USED IN THE
READING AND SEMANTIC ASSOCIATION TASKS 211
G HIGH FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS
IN CONCRETENESS AND IMAGEABILITY USED IN THE
SEMANTIC ASSOCIATION TASKS 212
H INSTRUCTIONS FOR THE COVAT PAIRED WITH THE
READING TASK 213
I INSTRUCTIONS FOR THE COVAT PAIRED WITH THE
SEMANTIC ASSOCIATION TASK 214
J LOW FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS
IN CONCRETENESS AND IMAGEABILITY USED IN THE
READING AND SEMANTIC ASSOCIATION TASKS WHEN
PAIRED WITH THE COVAT 216
K HIGH FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS
IN CONCRETENESS AND IMAGEABILITY USED IN THE
READING AND SEMANTIC ASSOCIATION TASKS WHEN
PAIRED WITH THE COVAT 218
L POST-EXPERIMENTAL QUESTIONNAIRE 220
REFERENCES 221
BIOGRAPHICAL SKETCH 232


LIST OF TABLES
Table page
2-1 Counterbalanced Order of Single-Task
Presentation 106
2-2 Counterbalanced Order of Dual-Task
Presentation 107
3-1 False Positive Errors: Statistics for the
Main Effect of Task 135
3-2 COVAT Alone: Statistics for the Main Effect
of Trial Type 136
3-3 100 ms Word-COVAT Delay: Statistics for the
Main Effect of Task 137
3-4 100 ms Word-COVAT Delay: Statistics for the
Main Effect of Trial Type 138
3-5 250 ms Word-COVAT Delay: Descriptive
Statistics for the Task by Target Side
Interaction 139
3-6 250 ms Word-COVAT Delay: Statistics for the
Task by Target Side Interaction 140
3-7 Transformed Data at the 100 ms Word-COVAT
Delay: Descriptive Statistics for the Task
by Trial Type Interaction 142
3-8 Transformed Data at the 100 ms Word-COVAT
Delay: Statistics for the Task by Trial
Type Interaction 143
3-9 Transformed Data at the 250 ms Word-COVAT
Delay: Descriptive Statistics for the Task
by Trial Type Interaction 145
3-10 Transformed Data at the 250 ms Word-COVAT
Delay: Statistics for the Task by Trial
Type Interaction
146


Table page
3-11 Overall Language Errors at the 100 Word-COVAT
Delay: Statistics for the Task Main Effect... 148
3-12 Overall Language Errors at the 250 ms Word-
COVAT Delay: Descriptive Statistics for the
Task by Frequency Interaction 149
3-13 Overall Language Errors at the 250 ms Word-
COVAT Delay: Statistics for the Task by
Frequency Interaction 150
3-14 Language Task Order: Statistics for the Task
Order by Word Frequency Interaction for
the Reading Only Condition 152
3-15 Language Task Order: Descriptive Statistics
for the Semantic Association Condition 153
3-16 Language Task Order: Descriptive Statistics
for the Dual-Task Conditions 154
3-17 Task Difficulty: Statistics for the Single-
and Dual-Task Conditions 155
3-18 Slow and Faster Responders During the
Semantic Association-COVAT Condition:
Descriptive Statistics for Response
Strategy 156
3-19 Slow and Faster Responders During the
Semantic Association-COVAT Condition:
Descriptive Statistics for False Positive
Errors 157
3-20 Slow and Faster Responders During the
Semantic Association-COVAT Condition:
Descriptive Statistics for Language Errors.... 158
3-21 Slow and Faster Responders During the
Semantic Association-COVAT Condition:
Descriptive Statistics for Word Familiarity... 160


Table page
3-22 Slow and Faster Responders During the
Semantic Association-COVAT Condition:
Descriptive Statistic for Task Difficulty 161


LIST OF FIGURES
Figure page
1-1 Model for the recognition, production, and
comprehension of written words, based on
Ellis and Young (1988) 84
1-2 Schematic of the covert orienting of visual
visual attention task 86
1-3 Schematic of dual-task performance with the
covert orienting of visual attention task
and a language task 88
1-4 Stimulus onset asynchronies for dual-task
performance of the covert orienting of
visual attention task and a language task 90
2-1 Stimulus onset asynchronies for the covert
orienting of visual attention task 109
2-2 Schematic of the language tasks: Reading
and generation of semantic associations ill
3-1 Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 100 ms delay between
language task and onset of the COVAT
(C=COVAT; RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 100=100 ms delay
between language task and onset of the
COVAT) 163


Figure
page
3-2 Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 250 ms delay between
language task and onset of the COVAT
(C=COVAT; RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 250=250 ms delay
between language task and onset of the
COVAT) 165
3-3 Relative frequency histograms for the mean
reaction time of the covert orienting of
visual attention task (COVAT) and
Reading-COVAT condition 167
3-4 Relative frequency histogram for the mean
reaction time of the Semantic Association-
COVAT condition 169
3-5 Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 100 ms delay between
language task and onset of the COVAT,
after equating for general response time
in each condition with no cue trials
(C=COVAT; RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 100=100 ms delay
between language task and onset of the
COVAT) 171


3-6
Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 250 ms delay between
language task and onset of the COVAT,
after equating for general response time
in each condition with no cue trials
(C=COVAT; RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 250=250 ms delay
between language task and onset of the
COVAT) 173
3-7 Language errors for single- and dual-task
conditions (Semantic Only=Semantic
association task; COV&Sem=Semantic
association-COVAT condition; Reading only=
Reading task; COV&Read=Reading-COVAT
condition; 100=100ms delay between language
task and onset of the COVAT; 250=250 ms
delay between language task and onset of
the COVAT) 175
3-8 Task difficulty ratings (COVAT only=Covert
orienting of visual attention task; Reading
Only=Reading task; Semantic Only=Semantic
association task; COV&Reading=Reading-COVAT
condition; COV&Semantic=Semantic association-
COVAT condition)
177


Abstract of Dissertation Presented to the Graduate School of
the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
THE EFFECTS OF LEXICAL AND SEMANTIC PROCESSING
ON VISUAL SELECTIVE ATTENTION
By
MARGARET CARTHAS PETRY
August 1995
Chairperson: Dr. Bruce Crosson
Major Department: Clinical and Health Psychology
Twenty-nine right-handed undergraduates completed the
covert orienting of visual attention task (COVAT) alone and
paired with two lexical tasks (reading aloud single words
and generating semantic associations to written words).
Subjects responded fastest to the COVAT alone, intermediate
to the COVAT-Reading condition, and considerably slower to
the COVAT-Semantic Association task. Because of left-
hemisphere dominance for language, differences between left
and right visual field responses were expected on the COVAT,
but none were found. With the exception of generating a
semantic associate for low-frequency words at a longer delay
between word and COVAT onset, interference from the language
task caused the COVAT validity effect for valid versus
invalid trials to disappear. Interference effects exhibited
during dual-task performance suggest that lexical processing


of familiar words, especially with an emphasis on semantics,
shares a common selective attentional resource with covert
orientation to visuospatial information.


CHAPTER 1
LITERATURE REVIEW
Attention
What is It?
According to William James (1890), "everyone knows what
attention is" (p. 403) yet psychology still lacks an
accepted definition of attention. James claimed that
attention "is the taking possession by the mind, in clear
and vivid form, one out of what seem several simultaneously
possible objects or trains of thought" (p. 403). Based on
James' description, attention has been commonly
characterized as the capacity for selective processing of
information (Kinchla, 1980; Navon, 1985).
In 1971, Posner and Boies refined the definition of
attention. They proposed that attention consists of three
components: arousal, selective attention, and vigilance.
Arousal is the general facilitation of cognitive processing
to any and all information, while selective attention is the
facilitation of cognitive processing to just a specific
source of information. Posner and Boies' definition of
selective attention corresponds to James' previously
mentioned popular description of attention. Vigilance is
the ability to sustain arousal and selective attention over
i


2
time. Posner and Boies conceptualized a hierarchical
arrangement for these three components of attention, such
that arousal is necessary in order to selectively attend
while arousal and selective attention are necessary for
sustained concentration. Although evidence exists that
arousal, selective attention, and vigilance depend upon
different neurophysiological systems (Moruzzi & Magoun,
1949; Pardo, Fox, & Raichle, 1991; Posner, Walker,
Friedrich, & Rafal, 1987; Watson, Valenstein, & Heilman,
1981), the three components of attention are often difficult
to distinguish in behavior, particularly with neurologically
intact individuals. Thus, it is not surprising that the
three components of attention are frequently referred to as
'attention1 or the capacity for selective processing of
information (i.e., selective attention) disregarding arousal
and vigilance. Unfortunately, this lack of specification
often causes confusion especially when attempting to compare
findings across studies of attention.
Another important distinction that is frequently
ignored is between attention and intention. While attention
(i.e., selective attention) is the facilitation of cognitive
processing for a specific source of sensory information,
intention is the facilitation of cognitive processing for a
specific type of motor activation. Thus, cognitive
processing can be enhanced for subsequent sensation, such as
detection of visuospatial information at a particular
location, or for subsequent movement, such as pressing a key


3
with a particular hand. Attentional facilitation and
intentional facilitation result in faster responding
(Heilman, Bowers, Valenstein, & Watson, 1987; Posner, 1980).
Based on studies with brain injured patients, failure to
respond can result from damage to one of four anatomical
systems: neurons responsible for the processes between
cognition and sensation (i.e., for selective attention),
neurons responsible for the processes between cognition and
movement (i.e., for intention), neurons responsible for
actual sensation, or neurons responsible for actual movement
(Heilman et al., 1987). When evaluating an individual's
performance, the effects of attention and intention, as well
as sensory and motor functioning, need to be considered.
How does Attention Operate?
Theories regarding how attention operates vary along
two main dimensions: (a) whether attention is a single
resource or multiple resources and (b) whether or not
attention is shared among cognitive tasks within a single
resource or between multiple resources (Green & Vaid, 1986;
Hiscock, 1986). From the various combinations (i.e., single
unshared resource, single shared resource, multiple unshared
resources, and multiple shared resources), four types of
information-processing theories emerge.
Welford's (1952) single channel theory and Broadbent's
filter model (1958) are examples of the single unshared
resource theory of attention. Humans are hypothesized to
have a single resource for selective processing of


4
information. This resource cannot be shared among
concurrent tasks. Attention can switch rapidly between
tasks but at a cost. Based on this theory, dual task
performance will always be worse (e.g., slower, more errors)
than performance on a single task.
Many researchers have proposed a single shared resource
theory of attention (Kahneman, 1973; Moray, 1967; Norman &
Bobrow, 1975). Although humans are hypothesized to have a
single resource of attention, this resource can be shared or
divided among concurrent tasks. Performance on simultaneous
tasks is hypothesized to require more attention than
performance on each individual task. However, impairments
in selective processing of information will only be observed
when the total demand for this resource exceeds the
available supply.
Other experimenters (Allport, Antonis, & Reynolds,
1972; Friedman & Poison, 1981; Wickens, 1984) have
postulated a multiple unshared resources theory of
attention. According to this type of theory, humans are
hypothesized to have multiple resources for selective
processing of particular information. For example, Wickens
proposes separate resources for visual and auditory
information as well as for verbal and spatial information.
Friedman and Poison claim a separate resource for each
cerebral hemisphere. Contrary to the single unshared
resource theory where attention could not be shared among
tasks, unshared now refers to the capacity for selective


5
processing of information within a particular resource of
attention. Attention can be shared between tasks that
utilize a particular resource (e.g., left cerebral
hemisphere); however, attention cannot be shared between
resources (e.g., left and right cerebral hemispheres).
While performing concurrent tasks, impairments will only
occur if the supply of one or more resources is exhausted.
If there is little overlap in task resource demand, then
dual-task performance will be essentially equivalent to
performance on each individual task.
Navon and Gopher (1979) proposed a multiple shared
resources theory of attention. Humans are hypothesized to
have multiple resources for selective processing of specific
types of information. In addition, these separate supplies
of attention are shared, such that part of one resource's
supply can be re-allocated temporarily in order to assist in
the processing of a type of information that is exhausting
another resource's supply. Based on this theory, dual-task
performance will tend to be unimpaired and similar to
performance on each of the individual tasks. Although
impairments may occur during performance of concurrent tasks
when compared to performance on each individual task, Navon
and Gopher advocate pairing these tasks with additional
tasks in order to discover whether the impairments are
spurious or actually the result of a depleted common
resource. For instance, in order to discover whether task A
and task B utilize a common processing resource, Navon and


6
Gopher recommend obtaining single-task and dual-task
performance with tasks A and B as well as with task A and a
task similar in difficulty to task B (i.e., task C). If
impairments result during concurrent performance of tasks A
and B as well as during tasks A and C when compared to
performance on each tasks individually, Navon and Gopher
suggest having subjects systematically vary the amount of
attention allocated to task A in a subsequent series of
dual-task experiments with B and with C. If the impairment
(e.g., slowed reaction time) varies systematically with the
amount of attention allocated to task A, then the two tasks
(e.g., tasks A and B) are presumed to depend on a common
resource. If the impairment does not vary systematically
with the amount of attention allocated to the primary task,
then the two tasks (e.g., tasks A and C) are presumed to use
independent resources.
Across these four types of theories, attention is
assumed to be essentially limited in overall amount of
supply. Although it has been shown that performance on
certain combinations of tasks is better than performance on
each of the individual tasks (Kinsbourne, 1970), the supply
of attention is presumed to fluctuate but not to increase
indefinitely. In an experimental situation, fluctuation of
attention can be minimized by asking human subjects to give
their best effort while performing the task(s) (Friedman &
Poison, 1981). To avoid fatiguing subjects, adequate rest
breaks should be provided.


7
Review of the recent dual-task literature revealed at
least six studies pertaining to the shared/unshared
resource/resources theories of attention. Two articles
(Gladstones, Regan, & Lee, 1989; Pashler, 1992) with
differing interpretations and results offered support for
the single unshared resource theory of attention. One
article (Ballesteros, Manga, & Coello, 1989) upheld the
single shared resource theory of attention. The multiple
unshared resources theory of attention was strengthened by
two articles (Friedman, Poison, & Dafoe, 1988; Herdman &
Friedman, 1985) but weakened by another article (Pashler &
O'Brien, 1993). Finally, no studies directly supported or
refuted the multiple shared resources theory of attention.
A lack of evidence for this latter theory may reflect
difficulties developing and implementing a reasonable
methodology for adequate testing. Navon and Gopher (1979)
advocate numerous dual-task experiments with subtle changes
of isolated variables. All articles but Herdman and
Friedman (1985) will be reviewed in detail. This latter
article will be omitted; instead, more recent articles,
where each author is the first author, will be described
(Friedman, Poison, & Dafoe, 1988; Herdman, 1992).
Single Unshared Resource Theory
According to the single unshared resource theory of
attention (Welford, 1952; Broadbent, 1958), humans are
hypothesized to have a single resource for selective
processing of information. This resource cannot be divided


8
or shared across concurrent tasks; thus, dual-task
performance will always be worse than performance on a
single task.
Support for Welford's (1952) single channel theory has
been offered by Pashler (1992) Although Welford's theory
can be considered an example of a single unshared resource
theory of attention, Pashler rejects this classification.
Instead of characterizing attention as a single mental
resource, Pashler suggested that it is composed of separate
mechanisms: one for facilitation of cognitive processing
for a specific source of sensory information (i.e.,
selective attention) and another for response selection
(i.e., intention).
In accordance with Welford (1952), Pashler (1992)
stated that a single mental mechanism exists for selecting
responses. This proposed mechanism can handle response
selection for only one task at a time. When presented with
concurrent tasks, response selection occurs for the primary
task. Upon completion of this process and initiation of
response production for the primary task, response selection
will commence for the secondary task. Impaired performance
in dual-task conditions was hypothesized to result from a
bottleneck in the response selection mechanism.
In Pashler's (1992) model, response selection occurs
after perception and prior to response production. Neither
perception nor response production are limited in


information capacity; therefore, more than one item can be
perceived and more than one response can be produced.
9
Pashler (1991) presented subjects with a concurrent
paradigm, where they were required to press a button to a
tone as well as report a briefly displayed letter. Reaction
time was measured in the tone task, while accuracy of oral
response was measured in the letter task. Because subjects
were able to quickly shift their attention in order to
accurately detect a letter while pressing a button to a
tone, Pashler maintained the distinction between selective
attention (i.e., facilitation of cognitive processing for a
specific source of sensory information) and response
selection (i.e., intention). Aside from concluding that
response selection (pressing a button) does not interfere
with selective attention (detecting a letter), Pashler did
not further address the relationship between selective
attention and response selection (i.e., intention).
Gladstones et al. (1989) claim support for a single
unshared resource theory of attention, despite obtaining
comparable performance during single-task and dual-task
conditions. Gladstones and colleagues studied the effects
of stimulus and response modality on the single- and dual-
task performance of "two forced-paced serial reaction time
tasks" (p. 1) where subjects were required to respond as
rapidly as possible to concurrent presentation of two
stimuli.


10
The stimuli were presented either visually or
auditorily. The visual stimulus was presentation of one of
three lights varying in color to either the left or right
side of space. The auditory stimulus was binaural
presentation of one of three tones varying in pitch. In
response to the visual stimuli, subjects responded either
manually or vocally. The manual response required subjects
to press one of three specified keys with either the left or
right hand. The vocal response required subjects to say
"a", "b", or "c". Subjects were administered all
combinations of these stimuli and responses in a single-task
and dual-task format.
Prior to actual performance on the experimental tasks,
ten subjects received extensive practice with each single-
and dual-task condition. Practice continued until the
shortest interstimulus interval (ISI) was determined,
allowing subjects to respond at a 93.94% accuracy level on
three or more successive trials. For single-task
conditions, the ISI was approximately 700 ms. For dual-task
conditions, the ISI was approximately 1400 ms. Practice and
test sessions were distributed over several weeks. Each
session lasted between 60 and 90 minutes. Total
participation required approximately eight hours. Nine
subjects were right-hand dominant, and one subject was left-
hand dominant.
Gladstones et al. (1989) measured performance accuracy.
They reported that single-task performance was not


11
significantly different from dual-task performance. They
interpreted this result based on an alternative
conceptualization of Welford's single channel theory (1952)
but they did not provide a rationale. According to
Gladstones et al., comparable single-task and dual-task
performance supports the single channel theory of
information processing (i.e., a single unshared resource
theory of attention). Many researchers (Allport et al.,
1972; Wickens, 1984) interpret such a finding as evidence
against the single channel theory and as support for a
multiple channel theory of information processing (e.g.,
multiple unshared or multiple shared attentional resources).
In addition, Gladstones et al. claimed that if dual-task
performance had exceeded single-task performance, then a
multiple channel theory would have been supported.
Gladstones et al. did not account for the numerous examples
in the literature of dual-task decrement, in comparison to
single-task performance.
Aspects of the methodology utilized by Gladstones et
al. (1989) may account for their finding. Subjects in this
study received extensive practice, yielding performance at
an optimal level and eliminating possible interference
effects that reflect the operation of underlying processes.
In addition, subjects were given twice as much time to
respond to stimuli in the dual-task condition than they were
allowed in the single-task condition. Finally, simultaneous
presentation of concurrent stimuli tends to not produce


12
differences between dual-task conditions; however, when
certain larger stimulus onset asynchronies are utilized,
differences are observed (Herdman, 1992).
Overall, the evidence provided by the recent dual-task
literature for the single unshared resource theory of
attention is not very strong.
Single Shared Resource Theory
The single shared resource theory of attention
(Kahneman, 1973; Moray, 1967; Norman & Bobrow, 1975)
proclaims that a single resource of attention can be shared
or divided among concurrent tasks. Impairments in selective
processing of information will only be observed when the
total demand for this resource exceeds the available supply.
Ballesteros et al. (1989) investigated the effects of
detecting nonmatching nonwords and nonmatching lines on
unilateral hand tapping. Sixteen subjects between the ages
of 20 and 23 years were selected for participation in this
study, based on their detection rate of nonwords and lines
differing from reference stimuli. Of the sixteen subjects,
eight were quick to identify the nonmatching stimuli. The
remaining eight subjects performed this task slowly. All
subjects were right-hand dominant.
In the single-task condition, subjects tapped as
quickly as possible with their right hand and then with
their left hand. In one of the dual-task conditions,
subjects tapped with one hand while they used the other hand
to point to the nonwords that differed from the reference


13
nonword. In a related dual-task condition, subjects tapped
one hand but pointed to the letter of the nonwords that made
it differ from the reference nonword. In another dual-task
condition, subjects tapped one hand while they used the
other hand to point to lines that differed in orientation
from the reference line. In the final dual-task condition
which relates to the previous condition, subjects tapped one
hand while they pointed to the part of the line causing it
to differ from the reference line. The number of taps as
well as the accuracy of detecting nonmatching nonwords and
nonmatching lines were collected over a 20 second period for
each dual-task condition. In addition, the number of taps
over a 20 second period were obtained for the single-task
condition with each hand.
Pertinent results from Ballesteros et al. (1989)
indicated a significant decline in hand-tapping when it was
paired with detection of the different nonwords; this effect
occurred only for the group of subjects who were fast to
detect nonmatching stimuli. Subjects who were slow to
detect different stimuli exhibited a significant decline in
hand-tapping when it was paired with detection of the
different lines (subject group by nonmatching task
interaction). In comparison to the single-task condition
(only hand-tapping), a significant reduction was observed
for right hand-tapping when it was paired with another task
(i.e., nonword and line detection tasks). Left hand-tapping
was comparable for the single- and dual-task conditions.


14
Significant differences between tapping hand and dual-task
performance with the nonword and line detection tasks were
not discovered.
Because performance decrement was identified in some
dual-task conditions in comparison to the single task
condition, Ballesteros et al. (1989) interpreted these
findings as support for Kahneman's (1973) limited
attentional resource theory. In accordance with a single
shared resource theory of attention, Ballesteros et al.
reported that impairments resulted after the demand for
attentional resources exceeded the available supply. They
explained the reduction of right hand-tapping performance
across the dual-task conditions as an indication of left-
hemispheric dominance for concurrent performance of a right-
handed motor task and these cognitive tasks (detection of
nonmatching nonwords and lines).
Methodological concerns may account for Ballesteros et
al. (1989) findings, which are difficult to explain. They
obtained a limited sampling of each single- and dual-task
condition; that is, only 20 seconds of behavior (one trial).
Future studies would benefit from the administration of more
than one trial to insure a more representative behavior
sample. Additionally, this experiment utilized the
detection of nonmatching "language" and "spatial" stimuli
for its primary task in the dual-task condition. These
elementary tasks may not have engaged the corresponding
hemispheres sufficiently to cause expected dual-task


15
decrements (i.e., reduction in left and right hand-tapping
performances when paired with detection of nonmatching
nonwords or lines for all subjects).
Multiple Unshared Resources Theory
According to the multiple unshared resources theory of
attention (Allport et al., 1972; Friedman & Poison, 1981;
Wickens, 1984), humans have multiple resources for selective
processing of particular information. Attention can be
shared between tasks that utilize a particular resource, but
not between resources.
Support for a multiple unshared resource theory of
attention has been provided by Friedman and her colleagues
(Friedman & Poison, 1981; Friedman, Poison, Dafoe, &
Gaskill, 1982; Herdman & Friedman, 1985) as well as by other
researchers (Hardyck, Chiarello, Dronkers, & Simpson, 1984;
Hellige & Wong, 1983). More specifically, these researchers
claim that independent processing resources exist for each
cerebral hemisphere. Processing resources can be shared
among tasks utilizing one hemisphere, but not between
hemispheres. When performing concurrent tasks, impairments
tend to result from tasks primarily using resources from the
same hemisphere in comparison to tasks using resources from
different hemispheres. Same hemisphere tasks reportedly
deplete available resources, causing impaired dual-task
performance in comparison to single-task performance.
Different hemisphere tasks reportedly have sufficient
resources for single-task and dual-task performances,


16
yielding comparable results. According to Friedman and
Poison (1981), two tasks share a common resource when
performance increases in the emphasized task and performance
decreases in the other task. If this performance trade-off
does not occur, then the two tasks presumably do not share a
common processing resource. This theory has been primarily
supported by evidence from pairs of perceptual or cognitive
tasks (e.g., reading aloud and remembering nonwords paired
with pressing a key indicating whether laterally presented
nonwords were the same or different; reading aloud and
remembering nonwords paired with remembering lateralized
tones) .
A recent study conducted by Friedman et al. (1988)
caused them to entertain the possibility that independent
processing resources may exist for cognitive and motor tasks
in addition to the independent resources existing for left
and right hemisphere tasks. Friedman et al. investigated
the effects of reading and remembering nonwords on
unilateral finger tapping. Eight right-handed male subjects
were selected for participation in this study, based on a
right-hand advantage for tapping and on a reading advantage
for nonwords presented to the right rather than the left
side of space.
In the single-task condition for nonwords, subjects
initially received a warning tone which was followed by a
fixation point at the center of a screen. The fixation
point remained present for 7 s, then it was replaced by


17
three five-letter nonwords (consonant-vowel-consonant-vowel-
consonant). The nonwords were displayed for 5 s. During
this interval, subjects were instructed to read the nonwords
aloud. Following this period, the nonwords were replaced by
the fixation point that remained present for 5 s.
Subsequently, a second tone sounded, signaling subjects to
recall the nonwords presented in this trial.
In the single-task condition for finger tapping,
subjects tapped as quickly as possible with the index finger
of one hand for 17 s. A tone signaled the beginning and
ending of this period. Tapping was assessed for the left
and right index finger.
In the dual-task condition, the nonword and finger
tapping tasks were combined. Upon hearing the tone,
subjects began tapping as rapidly as possible with one index
finger. Subjects kept their eyes focused on the central
fixation point, awaiting presentation of the three nonwords.
When the nonwords appeared on the screen, subjects read them
aloud. During subsequent presentation of the fixation
point, subjects presumably rehearsed the to-be-recalled
nonwords while focusing their eyes at the center of the
screen. Following another tone, subjects ceased finger
tapping and recalled the nonwords. Task emphasis was
manipulated in the dual-task condition. In one condition,
subjects were paid more money for their memory performance
(i.e., number of nonwords correctly recalled). In the other
dual-task condition, subjects were paid more money for their


18
tapping performance. Friedman et al. (1988) assumed that
subjects would devote more attentional resources to
performance of the task that would pay them substantially
more money.
Results revealed that subjects remembered more nonwords
when concurrently tapping with their left finger than with
their right finger. Regardless of finger used, subjects
remembered more nonwords when the nonword task was
emphasized than when the tapping task was emphasized.
Following correction for the significant difference in
finger tapping (i.e., more taps for the right than left
finger), results indicated that subjects significantly
reduced their rate of tapping for both fingers when they
concurrently read nonwords aloud in comparison to when they
fixated on a centrally located point. While reading
nonwords aloud and tapping, subjects' rate of tapping for
both fingers increased when the tapping task was emphasized
and then decreased when the nonword task was emphasized.
When concurrent rehearsal of nonwords and finger tapping was
compared to the other two dual-task conditions (i.e.,
fixation and tapping; reading and tapping), subjects
significantly reduced their rate of tapping with larger
decrements observed for the right finger. When task
emphasis was manipulated, a performance trade-off occurred
for the reading and tapping condition. Performance trade
offs did not occur for the fixation and tapping condition or
for the rehearsal and tapping condition.


19
Friedman et al. (1988) interpreted their findings from
the finger tapping and nonword reading condition as evidence
of left-hemisphere involvement in the coordination of
speaking and finger movements, accounting for the comparable
decrement in left and right finger tapping during concurrent
reading. These researchers also concluded that separate
resources are required for finger tapping and for rehearsal
of nonwords. If these behaviors shared a common resource,
then performance trade-offs would have resulted when one
task was emphasized over the other.
From the results of five dual-task experiments, Pashler
and O'Brien (1993) offered evidence against a multiple
unshared resource theory of attention and support for a
single unshared resource theory of response selection. One
pertinent experiment from this article (experiment 3) will
be described in detail.
In their third experiment, Pashler and O'Brien (1993)
studied the effects of reading nonwords on reaction time to
lateralized visual targets. This experiment lacked single
task conditions, utilizing only dual-task conditions. The
dual-task condition required subjects to keep their eyes
focused upon crossed lines at the center of a computer
monitor screen. For each trial, a six letter nonword
(consonant-vowel-consonant-consonant-vowel-consonant)
replaced the crossed lines. The nonword remained present
for 200 ms. After a stimulus onset asynchrony (SOA) of 50,
150, 500, or 1000 ms, a white disk was presented to a fixed


20
position in either the upper left, lower left, upper right,
or lower right quadrant of the computer screen. The disk
remained present for 100 ms. Twenty-four right-handed
subjects were instructed to read aloud each nonword and to
press one of four designated keys (one assigned to each
quadrant) when they detected the disk. Subjects responded
with a specified finger of the left hand to upper and lower
left-sided disks and with a specified finger of the right
hand to upper and lower right-sided disks. Reaction times
were recorded for both tasks. Subjects were instructed to
respond rapidly and accurately to the stimuli of each task.
Of the 24 subjects, 12 received a mixed presentation of
disks to the left and right sides of the computer screen
during dual-task performance. For the other 12 subjects,
disks were presented only to the left or only to the right
side of the screen. In this latter condition, side of disk
presentation alternated between dual-task blocks.
The primary finding from this experiment was a
significant increase in reaction times (i.e., slower
responses) for reading nonwords and for responding to disks
at the shorter SOA intervals. No significant differences in
reaction time were obtained between left- and right-sided
disks or between mixed or blocked presentation of the disks.
Thus, at longer SOA intervals, subjects read nonwords faster
and reacted faster to disks. Subjects responded comparably
to left- and right-sided targets while concurrently reading
nonwords.


21
According to Pashler and O'Brien (1993), results from
their third experiment reflect response selection
interference. Interference reportedly occurs because a
response to a second task can not happen until a response is
selected for the first task. Interference typically delays
responding to the second task. It may or may not affect
responding to the first task (Pashler & Johnston, 1989).
Response selection interference is most likely observed at
shorter SOA intervals. This interference has been termed
the psychological refractory period (PRP) effect, after
Welford (1952) .
Because no significant differences were detected
between left- and right-handed reaction times to respective
left- and right-sided disks during concurrent nonword
reading, Pashler and O'Brien postulated that response
selection is a single mechanism operating within the brain.
If separate mechanisms existed for each hemisphere as
postulated by Friedman and Poison (1981) then impaired
performance should have resulted for right-handed reaction
times to right-sided disks while reading nonwords (same
hemisphere tasks) in comparison to left-handed reaction
times to left-sided disks while reading nonwords (different
hemisphere tasks).
Results from the other four dual-task experiments in
Pashler and O'Brien (1993) corroborated their finding of
response selection interference. Briefly, the first
experiment measured the effects of orally responding "high"


22
or "low" to respective binaural tones on reaction time to
lateralized visual disks (this latter task was used in their
third experiment). The second experiment utilized the tasks
from the first experiment but the order of presentation was
reversed. The fourth experiment measured the effects of
reaction time to left-sided visual disks on reaction time to
right-sided visual disks. The fifth experiment measured the
effects of reaction time to left-sided visual disks on
reaction time to say whether two centrally presented words
rhymed or not (i.e., "rhyme" or "no rhyme"). The primary
findings from these four experiments were decreased reaction
times (i.e., faster responding) at longer SOA intervals for
the first task (experiments 2 and 5) and for the second task
(experiments 1, 2, 4, and 5). Unexpectedly, reaction times
were faster for the first task (experiments 1 and 2) and for
the second task (experiment 1), when disks were presented to
the right quadrants.
To account for findings from other studies that have
demonstrated exacerbation of dual-task interference when the
tasks were performed primarily by the same cerebral
hemisphere rather than different hemispheres, Pashler and
O'Brien (1993) began by noting that these studies tended not
to require selection of separate responses to dual-task
stimuli. According to Pashler and O'Brien, response
selection interference is most pronounced when subjects have
to select between at least two possible responses for each
stimulus. These investigators questioned whether response


23
selection caused the interference observed with same
hemisphere tasks. After expressing doubt, they concluded
that the source of the interference for same hemisphere
tasks was still unknown. The study would have benefited
from single-task conditions, in order to determine just how
much interference was occurring in the various dual-task
conditions.
Unfortunately, none of these information-processing
theories of attention (i.e., single unshared resource,
single shared resource, multiple unshared resources, or
multiple shared resources) accounts for all experimental
findings. There are supporting as well as conflicting data
for each theory (Kinsbourne, 1981). For example, impaired
performance on concurrent tasks relative to performance on
each individual task provides support for the single
unshared resource theory of attention (Kerr, 1973; Klapp,
1979; Noble, Trumbo, & Fowler, 1967; Peters, 1977). For
example, in the study conducted by Noble et al. (1967),
undergraduate college students exhibited significant
interference during concurrent performance of a visual
pursuit tracking task and an auditory number monitoring
task, in comparison to performance only on the pursuit
tracking task. However, the single unshared resource theory
of attention does not account for findings of comparable
performance on concurrent tasks as well as on each
individual task (Allport et al., 1972; Spelke, Hirst, &
Neisser, 1976). For example, in the study conducted by


24
Allport et al. (1972), five third-year undergraduate Music
students were able to shadow a taped verbal passage while
sight-reading and playing an unfamiliar piece of music. In
this study (Allport et al., 1972), dual-task performance was
comparable to their single-task performances. Nonetheless,
these theories have served as heuristics for further
exploration of how attention operates.
Automatic and Controlled Processing of Information
An alternative heuristic for how attention operates has
also been used (Cowan, 1988; Neisser, 1967; Posner & Snyder,
1975; Schneider & Shiffrin, 1977; Shiffrin & Schneider,
1977). The operation of attention varies according to the
type of information to-be-processed and whether or not this
information can be processed automatically. Humans are
hypothesized to have a central (i.e., single sharable)
attentional resource for controlled processing of selected
information. This central resource is voluntarily directed
by the individual for processing a limited amount of
information. According to Cowan (1988), the focus of
attention is limited to approximately two or three items.
However, humans are also hypothesized to process some
information automatically. This information tends to be
well learned, and according to Cowan (1988) the information
is processed automatically under the control of long-term
memory. Although automatic processing reportedly does not
require attentional resources from the central supply, it
seems likely that at least a very small amount of attention


25
would be required for adequate routine processing. In
addition, automatic processing is less limited by capacity
restrictions; therefore, often more than three items can be
processed automatically. According to Allport (1990), "the
attempt to apply the same dichotomy (automatic/controlled)
to the whole range of dual-task concurrency costs appears to
have been, for most practical purposes, abandoned" (p. 640).
Anatomy
Up to this point in time, the information-processing
heuristics have essentially ignored the necessary anatomy
for the operation of attention. Since Friedman and Poison
(1981) hypothesized separate attentional resources for each
cerebral hemisphere, investigation of the anatomy
responsible for dual-task performance has remained dormant.
A heuristic which accounts for the anatomy needed for
attention within a concurrent task paradigm may better
account for the findings from this particular literature.
While such heuristics are lacking in the dual-task
literature, they exist in the hemispatial neglect and the
neuropsychological literatures.
Based on studies with brain-impaired humans and animals
demonstrating neglect of the contralesional side of space
despite intact sensory or motoric abilities, Heilman,
Watson, and Valenstein (1985) and Mesulam (1990) proposed
neuroanatomical models for arousal, selective sensory
attention, and selective motor intention. According to
Heilman et al., arousal (i.e., general readiness for sensory


26
and motor processing) is produced by activity of the
mesencephalic reticular formation (MRF). The MRF affects
cortical processing of sensory information directly by
diffuse polysynaptic projections to areas of the cortex
(i.e., primary sensory cortex, unimodal sensory association
cortex, prefrontal cortex, superior temporal sulcus,
inferior parietal lobule, and posterior cingulate gyrus)
possibly through cholinergic pathways or indirectly by
projections to the nucleus reticularis of the thalamus. The
MRF indirectly influences the cortex by inhibiting the
nucleus reticularis, resulting in the facilitation of
sensory information flow from the thalamus to the primary
sensory cortex. Sensory information proceeds from the
primary sensory cortex to unimodal sensory association
cortices for further processing. From the unimodal sensory
association cortices, information may advance to the
multimodal sensory association cortices directly or
indirectly after processing by the prefrontal cortex and the
superior temporal sulcus. Arousal is maintained by
projections from the prefrontal cortex and superior temporal
sulcus to the MRF and or nucleus reticularis. The inferior
parietal lobule, prefrontal cortex, superior temporal
sulcus, and posterior cingulate gyrus have reciprocal
connections. The inferior parietal lobule receives
information about the individual's goals from the prefrontal
cortex, about the significance of the sensory information
and the individual's biological needs from the posterior


27
cingulate gyrus, and about the sensory stimulus from
specific neurons within the inferior parietal lobule (e.g.,
enhancement neurons), resulting in selective sensory
attention.
According to Heilman et al. (1985), selective motor
intention requires arousal, resulting from inhibition of the
nucleus reticularis by the MRF. Selective motor intention
(i.e., the facilitation of cognitive processing for
production of a motor response to a meaningful stimulus)
depends on projections from the centromedian
parafascicularis nuclear complex of the thalamus (CMPF) to
the dorsolateral prefrontal cortex to the nucleus
reticularis. This CMPF-prefrontal cortex-nucleus
reticularis system produces inhibition of the nucleus
reticularis, leading to a reduction of its inhibitory output
to the ventrolateral nucleus of the thalamus. Subsequently,
facilitation of motor preparedness occurs between the
ventrolateral thalamic nucleus and the motor and premotor
cortices. The dorsolateral prefrontal cortex receives
information about the individual's biological needs from the
anterior cingulate gyrus, and in turn, influences motor and
premotor cortices, resulting in selective motor intention.
The anterior cingulate gyrus has reciprocal connections with
the prefrontal cortex. Adjacent to the anterior cingulate,
the supplementary motor area projects to the basal ganglia
(Heilman, Watson, & Valenstein, 1993) which in turn project


28
to the ventrolateral and ventroanterior nuclei of the
thalamus.
Mesulam (1990) proposed a single network model for
spatially directed attention, incorporating neuroanatomy
necessary for arousal, selective sensory attention, and
selective motor intention. According to Mesulam, spatially
directed attention results from three main, reciprocally
connected cortical areas: dorsolateral posterior parietal
cortex, dorsolateral premotor-prefrontal cortex, and
cingulate gyrus. The dorsolateral posterior parietal cortex
along with associated areas (e.g., sensory association
cortex, superior temporal sulcus) are primary for selective
sensory attention, while the dorsolateral premotor-
prefrontal cortex and associated areas (e.g., superior
colliculus) are primary for selective motor intention. The
cingulate gyrus determines the significance of sensory or
motoric information. These three main neuroanatomic regions
are connected with the striatum and the pulvinar nucleus of
the thalamus. In addition, these main regions receive
projections from the brainstem and thalamic components of
the reticular activating system, providing arousal.
Subsequently, Posner and Peterson (1990) and Mirsky,
Anthony, Duncan, Ahearn, and Kellam (1991) proposed general
theories of attention along with corresponding anatomy.
Based on visual detection studies with brain-impaired and
neurologically normal humans and monkeys, Posner and
Peterson suggested the existence of two attention systems.


29
The posterior attention system controls covert orienting of
visual attention to select spatial locations (i.e.,
selective sensory attention), while the anterior system is
involved in attention to language and regulation of the
posterior attention system. The posterior attention system
is composed of the following anatomical areas: primary
visual cortex, posterior parietal lobe, superior colliculus
and or surrounding midbrain areas, and pulvinar of the
thalamus. According to Posner and Petersen, the posterior
parietal lobe disengages selective attention from its
current focus after receiving information from the primary
visual cortex, then the superior colliculus and or
surrounding midbrain areas move attention to the location of
interest, and the pulvinar engages the point of interest.
The primary component of the anterior attention system is
the anterior cingulate gyrus. Posner and Petersen purported
that the right cerebral hemisphere contains the necessary
anatomy for alertness (i.e., arousal), influencing the
posterior and anterior attention systems.
Mirsky et al. (1991) proposed four components of
attention (i.e., focus-execute, encode, shift, sustain),
based on principal components analyses of neuropsychological
data from neurological, psychiatric, and normal adults and
from normal children. Following these analyses, Mirsky and
his colleagues referred to the human and animal neurological
literature to identify likely anatomical structures that
could account for the proposed attention components.


30
According to Mirsky et al., focusing on the environment
(i.e., selective sensory attention) and executing responses
is controlled by the inferior parietal cortex and its
connections to the corpus striatum. The superior temporal
sulcus is also involved in the focus component of attention.
Encoding of information is managed by the hippocampus and
amygdala, while shifting selective attention is controlled
by the prefrontal cortex, medial frontal cortex, and
anterior cingulate gyrus. In addition to arousal,
sustaining selective attention is dependent upon the tectum,
mesopontine regions of the reticular formation, and midline
region and reticular nucleus of the thalamus.
Amongst these neuroanatomical models of attention
(Heilman et al., 1985; Mesulam, 1990; Mirsky et al., 1991;
Posner & Petersen, 1990), a number of commonalties exist.
These models tend to propose similar structures for arousal
(i.e., mesencephalic reticular formation and nucleus
reticularis of the thalamus), selective sensory attention
(i.e., inferior parietal lobule) and selective motor
intention (i.e., dorsolateral prefrontal cortex). In
addition, the cingulate gyrus is identified as an important
structure, influencing selective sensory attention and
selective motor intention. Most important, attention is not
purported to exist within only one brain structure. Rather,
attention is the result of a network of specific anatomical
areas and pathways activated by corresponding sensory
stimuli, motoric responses, and motivational factors.


31
It is proposed that the results of dual-task studies,
investigating how attention operates, would be explained
best by considering the interaction of activated
neuroanatomical structures and pathways. Such a proposal is
outlined in the Experiment and Hypotheses section of this
chapter. However, the viability of this or any other theory
concerning the operation of attention would be best tested
with studies that monitor brain activity in addition to
cognitive performance for subsequent correlation of results.
In addition to experiments recording event related
potentials during performance of dual-task paradigms,
functional neuroimaging studies with magnetic resonance
imaging (MRI), positron emission tomography (PET), and
single photon emission computed tomography (SPECT) offer
mediums for elucidating the relationship among attention,
cognitive functioning, and involved anatomy.
Language
Language has been defined as the "code whereby ideas
about the world are represented through a conventional
system of arbitrary signals for communication" (Bloom &
Lahey, 1978, p. 4). This code has been conceptualized as
consisting of three main components: phonology, semantics,
and syntax (Mesulam, 1990). Phonology is the process that
sequences individual phonemes (i.e., sounds) to form words.
Semantics is the process that associates meaningful concepts
with their corresponding symbolic and lexical


representations (i.e., words). Syntax is the process that
designates relationships between words (Nadeau, 1988) .
Anatomy
32
In the 1800s, investigators began studying brain-
injured patients in an attempt to discover areas of the
brain necessary for language. Broca (1964a/1861;
1964b/1861) provided some important evidence by describing
patients with impaired language production following a
common lesion in the third frontal convolution of the left
hemisphere. In 1874, Wernicke presented data associating a
lesion in the temporal-parietal cortex of the left
hemisphere with impaired language comprehension (Benson,
1985). Subsequently, these two regions of the left
hemisphere became known respectively as Broca's and
Wernicke's areas. These areas along with the
neuroanatomical connections between them were incorporated
into a model of how language functions within the left
hemisphere by Wernicke. In 1885, Lichtheim postulated a
model with two separate processing routes for speech
production: a phonological route and a semantic route.
In the 1965, Geschwind integrated past and then current
theories and studies of brain-injured humans demonstrating
impairments of language processing or speech production as
well as studies of brain-impaired animals, yielding a
neuroanatomical model of language. In order to read aloud a
written word, Geschwind proposed that written language is
initially processed by the primary visual cortex



33
(Broadmann's area 17) then by the visual association
cortices (Broadmann's area 18 and 19) in each hemisphere.
Subsequently, visual information is transferred to the left
angular gyrus directly in the left hemisphere and indirectly
from the right hemisphere by way of the following two
pathways: (1) right visual association cortices to right
angular gyrus to left angular gyrus via the corpus callosum
and (2) right visual association cortices to left visual
association cortices via the corpus callosum to left angular
gyrus. The left angular gyrus transforms the visual word
form (i.e., written language) into the auditory word form
(i.e., spoken language) and vice versa. After visual-to-
auditory transformation, this information proceeds to
Broca's area via the arcuate fasciculus for motor
programming of subsequent speech. From Broca's area,
processing occurs in the primary motor cortices of the
inferior frontal lobes (i.e., Brodmann's area 4), resulting
in formation of actual movements of the face and throat and
subsequently in spoken language. According to Geschwind,
Wernicke's area is the association cortex for auditory
information in the left hemisphere. Damage to these areas
or their connections will tend to yield predictable patterns
of impairment, otherwise known as aphasia syndromes.
Subsequently, support has amassed from clinical-
pathological (Taylor, 1969) and carotid sodium amytal
studies (Wada & Rasmussen, 1960) as well as from cerebral
stimulation (Rasmussen & Milner, 1977) and blood flow


34
(Lassen, Ingvar, & Skinhoj, 1978) studies demonstrating the
dominance of the left hemisphere for primary language
functions in approximately 96 % of right-handed individuals
and 70 % of left-handed individuals (Rasmussen & Milner,
1977) .
Currently, the search continues to identify important
structures and pathways within the brain for phonological,
semantic, and syntactic aspects of language. In 1990,
Mesulam postulated a neuroanatomical model, involving two
main areas (i.e., Wernicke's and Broca's areas), to account
for these components of language. According to Mesulam,
Wernicke's area (i.e., posterior one-third of the left
superior temporal gyrus in Brodmann's area 22) along with
associated areas in the left temporal and parietal cortices
(i.e., Brodmann's areas 37, 39, and 40) are primarily
involved in processing of phonological, lexical (i.e.,
word), and semantic information. Within these anatomical
areas, information pertaining to sound, word, and meaning
relationships is stored, allowing transformation of auditory
information into visual word forms and vice versa as well as
access to semantics. Broca's area (i.e., peri-sylvian area
of the inferior gyrus in the frontal cortex, otherwise known
as Brodmann's area 44) and associated areas in the left
frontal cortex (i.e., Brodmann's area 6 in the pre-motor
cortex and Brodmann's areas 45, 47, and 12 in the prefrontal
cortex) are involved mainly in the processing of
articulatory and syntactic information. Within this region


35
of the left hemisphere, transformation of lexical
information into articulatory sequences occurs as well as
arrangement of words into sentences. Within Brodmann's area
6, the supplementary motor cortex is involved in planning
and initiation of speech. Brodmann's areas 12, 45, and 47
in the prefrontal cortex are involved in the retrieval of
words from superordinate categories. Mesulam's model
includes interconnections between the Wernicke's, Broca's,
and their associated areas, allowing for normal language
functioning.
Rapcsak, Rothi, and Heilman (1987) provided evidence
that separate routes exist for phonological and lexical
reading. They studied one patient who experienced a
cerebral hemorrhage, damaging the posterior portion of the
middle and inferior gyri of the left temporal cortex (i.e.,
Brodmann's areas 21 and 37) and underlying white matter.
This patient exhibited selective impairment of phonological
reading; thus, he was unable to read most nonwords.
However, he was able to read lexically the majority of words
with regular and irregular print-to-sound correspondence.
According to Rapcsak et al., the phonological reading route
involves the transfer of visual information from the ventral
visual association cortex to Wernicke's area via the middle
and inferior gyri and or underlying white matter of the left
temporal cortex. The patient's lesion in these connection
areas and pathways disrupted the phonological system. The
lexical reading route involves the transfer of visual


36
information from the ventral visual association cortex to
the angular gyrus and then to Wernicke's area, enabling the
patient to read irregular words.
Further support for the existence of separate
processing routes for language is offered by Coslett,
Roeltgen, Rothi, and Heilman (1987). These researchers
studied four patients with preserved repetition, impaired
comprehension, and fluent but semantically empty speech
(i.e., transcortical sensory aphasia), following different
areas of neuroanatomical damage (i.e., cortical atrophy and
symmetrically enlarged ventricles from a primary
degenerative dementia; left posterior parietal infarction;
bitemporal involvement from herpes simplex encephalitis; and
left basal ganglia and thalamic hemorrhage). Based on
results from assessment of language functioning (i.e.,
spontaneous speech, auditory comprehension, repetition,
naming, reading aloud, reading comprehension, lexical
decision making, and syntax), Coslett et al. concluded that
the following three processing components support repetition
and reading aloud: phonology without lexical (whole word)
access, semantics with lexical and syntactic access, and
lexical and syntactic access without semantics. Consistent
with an impairment in the mechanism for semantics despite
lexical and syntactic access, two of the patients exhibited
limited comprehension but they were able to read nonwords
because of an intact mechanism for phonology without lexical
access as well as read irregular words because of an intact


37
mechanism for lexical and syntactic access. Based on data
from two other patients, impairments of lexical, syntactic,
and semantic access were noted. One of the two patients
with complete assessment data exhibited difficulty reading
irregular words along with semantic and syntactic errors,
suggesting impairment of the mechanism for semantics with
lexical and syntactic access. However, this patient
demonstrated relative preservation in the ability to read
nonwords, suggesting an intact mechanism for phonology
without lexical access.
More recently, a case study has been reported that
identified the importance of Brodmann's area 37 (i.e., that
part of area 37 consisting of the posterior portion of the
left middle temporal gyrus) in the lexical-semantic system
(Raymer, Foundas, Maher, Greenwald, Morris, Rothi, &
Heilman, 1995). Following primary lesion of Brodmann's area
37, a patient developed significant word-finding problems
(anomia), despite relatively intact comprehension. More
specifically, the patient experienced impairments in oral
and written naming of pictures, oral naming to auditory
definition, writing to dictation, as well as oral reading of
real words and nonwords. Raymer et al. concluded that
Brodmann's area 37 appears fundamental in the provision of
access to lexical information within the lexical-semantic
route for language processing.
In support of Lichtheim's model (1885), McCarthy and
Warrington (1984) provide evidence that separate routes


38
exist for phonological (i.e., lexical in this case) and
semantic processing of information. They studied two
patients with impaired repetition and relatively preserved
spontaneous speech (i.e., conduction aphasia) and one
patient with the opposite pattern, that is, relatively
preserved repetition and impaired spontaneous speech
(transcortical motor aphasia). The repetition and speech
production of the two patients with conduction aphasia only
improved when semantic processing was emphasized, while the
repetition and speech production of the patient with
transcortical motor aphasia worsened under the same
conditions.
Based on findings from cerebral blood flow studies with
normal humans as well as cognitive studies with normal and
brain-impaired humans, Petersen, Fox, Posner, Mintun, and
Raichle (1989) proposed a neuroanatomical model for lexical
processing of written and spoken language. According to
Petersen et al., a written word is initially processed in
the left and right primary visual cortices. Subsequently,
information is transferred to the visual association areas
(extrastriate cortex) for lexical access. To read aloud a
written word, the information is transferred from the visual
association areas to the supplementary motor area, sylvian
cortex, and left premotor area in the frontal lobe for motor
programming and articulatory coding. Following motor
programming and articulatory coding, processing continues in
the primary motor cortex for actual motoric output (i.e.,


39
speech) of the written word. To produce a semantic
associate to a written word, information is transferred from
the visual association cortices to the left anterior
inferior frontal cortex for generation of semantic
associations to the written word. Subsequently, this
information is transferred to the supplementary motor area,
sylvian cortex, and left premotor area in the frontal cortex
for motor programming and articulatory coding. Further
processing occurs in the primary motor cortex, yielding
motoric output of the semantic associate. Petersen et al.
did not find activation in either Wernicke's area or the
angular gyrus, while normal subjects viewed, read, or
generated a semantic associate to written words contrary to
Geschwind's model. Steinmetz and Seitz (1991) suggested
that methodological procedures, employed by Petersen et al.
(i.e., intersubject averaging of positron emission
tomography scans), increased data variability, obscuring
likely activation of these areas.
To summarize the findings from the literature
pertaining to language functioning and corresponding
neuroanatomy within the left hemisphere, the posterior
cortices have been primarily associated with phonological,
lexical, and semantic processing. More specifically,
Wernicke's area appears important for phonological
processing. Brodmann's area 37 appears important for access
to lexical information within the lexical-semantic route for
language processing. The angular gyrus (Brodmann's area 39)


40
has been identified as a likely structure for the
transformation of visual word forms into auditory word forms
and vice versa (i.e., lexical processing and for access to
meaning (i.e., semantic processing). Reading can occur by
way of any of the three following processing routes:
phonological, lexical without access to semantics, lexical
with access to semantics. The frontal cortex in the left
hemisphere has been mainly associated with processes related
to output and syntax. More specifically, Broca's area has
been identified as a structure important in motor
programming for subsequent speech. The supplementary motor
area is hypothesized to be involved in the initiation and
planning of speech. The arcuate fasciculus connects
Wernicke's with Broca's area. Similar to models of
attention, language is proposed to be the result of a
network of specific anatomical areas and pathways.
Model of Recognition, Production, and Comprehension of
Written Words
Ellis and Young (1988) proposed a fairly comprehensive
model for the recognition and production of spoken and
written words that accounts for the findings from Rapcsak et
al. (1987), Coslett et al. (1987), Raymer et al. (1995),
McCarthy and Warrington (1984) as well as the results from
many other studies documenting similar dissociations within
the field of reading (e.g., Schwartz, Saffran, & Marin,
1980; Warrington & Shallice, 1979). Because the present
investigation will examine selective attention as it relates


41
to language at the lexical and semantic level with single
written words, only a subset of Ellis and Young's composite
model is presented in Figure 1-1. From this model, only the
components necessary for reading a familiar word aloud and
for producing a similar meaning or a highly associated word
(i.e., a semantic association) will be defined. In
addition, neuroanatomical structures and pathways proposed
to be important for these components, based on the above
literature review, will be included.
According to Ellis and Young (1988), the visual
analysis system identifies letters as letters and notes
their position within a written word (visual association
cortices; Brodmann's areas 18 and 19). This system also
begins to identify whether the letters form a familiar or an
unfamiliar word. The visual input lexicon contains the
representations of familiar words in their written form
(Brodmann's area 37; angular gyrus, Brodmann's area 39),
while the auditory input lexicon contains the
representations of familiar words in their heard form. The
meanings of words are represented in a distributed semantic
system (McCarthy & Warrington, 1990) with access by way of
the angular gyrus (Brodmann's area 39). The speech output
lexicon contains the pronunciations of familiar words
(angular gyrus, Brodmann's area 39). The phoneme level
activates the motor programs for the phonemes in words
(Broca's area and surrounding frontal cortex; Brodmann's
area 44, 45, 47, 12 and 6).


42
In order to read a familiar word aloud, the written
word enters the cognitive processing system from visual
sensation. Many of the word's physical properties are
preserved in a brief sensory store for up to several hundred
milliseconds (Cowan, 1988). Perceptual processing of the
word occurs next, within the visual analysis store. Because
the word is familiar, it is further processed by the visual
input lexicon. When the word is recognized as familiar, the
spoken form of the word can be retrieved from the speech
output lexicon. Once the correct pronunciation of the word
is obtained, then the phoneme store becomes activated for
subsequent motor programming of the word.
To produce a semantically associated word for a read
word, the written word receives sensory processing, then
perceptual processing within the visual analysis system.
Because the word is familiar, it activates the corresponding
entry in the visual input lexicon. The meaning of the
familiar written word is obtained within the semantic
system. In addition, synonyms or highly associated words
are coactivated by input from the semantic system to the
output lexicon and the most strongly activated associate can
be chosen for production. Correct pronunciation of the
semantic associate is triggered from the speech output
lexicon. Subsequently, the proper phoneme sequences are
activated for motor programming.
Based on Ellis and Young's (1988) model for the
recognition, comprehension, and naming of written words,


43
these two language tasks (reading a word aloud; producing a
semantic associate for a word that is read) presumably
require differing amounts of cognitive processing. After
sensation, reading a familiar word aloud reportedly requires
processing by four language components (visual analysis
store, visual input lexicon, speech output lexicon, phoneme
store). Producing a semantic association requires
processing by five language components (visual analysis
store, visual input lexicon, semantic system, speech output
lexicon, phoneme store), following sensory processing.
Therefore, it is proposed that producing a semantic
association requires more cognitive processing than reading
a word aloud.
The attentional demands of these two tasks (i.e.,
lexical processing with and without an emphasis on
semantics) are the subject of the current study. Because
task difficulty may influence performance on these tasks in
addition to or rather than the number of processing steps,
high and low frequency words will be used to decipher the
possible effects of these factors. Investigators have
demonstrated differences between high and low frequency
words when utilized in single-task and dual-task paradigms.
While reading a passage in a single-task paradigm, subjects
fixated longer on low frequency than high frequency words
(Just & Carpenter, 1980). In another single-task study
(Polich Sc Donchin, 1988) subjects responded slower to low
frequency than to high frequency words when required to make


44
a lexical decision (i.e., deciding whether or not a word is
a real word). Additionally, these subjects exhibited a
longer P300 (event-related potential) latency and a reduced
P300 amplitude when making a lexical decision about low
frequency words, in comparison to high frequency words.
Polich and Donchin concluded that word frequency affects the
length of time spent searching the visual input lexicon for
the presented word. In dual-task paradigms, subjects
responded slower when low frequency words were paired with a
secondary task than when high frequency words were paired
with a secondary task (Becker, 1976; Herdman, 1992; Herdman
& Dobbs, 1989).
Selective Attention and Language
While theorists have postulated varied relationships
between vigilance and language (Glosser & Goodglass, 1990;
Luria, 1977), two consistent theories have been proposed
regarding selective attention and language (Nadeau &
Crosson, in press; Ojemann, 1983) in addition to Posner and
Petersen's theory (1990; see Anatomy in the Attention
section). Based on research from electrical stimulation
mapping studies (e.g., Ojemann, 1975; Ojemann, 1977),
Ojemann (1983) postulated two unique roles for the thalamus
within the hemisphere dominant for language (usually the
left). According to Ojemann, the left thalamus selectively
directs attention to language (a) by activating the relevant


45
areas of the brain for subsequent language processing (b) in
a simultaneous manner.
Nadeau and Crosson (in press) offered further support
for Ojemann's theory, while also expanding it. Following
examination of research on thalamic infarction, Nadeau and
Crosson proposed that the frontal lobe in the language
dominant hemisphere of the brain influences the nucleus
reticularis of thalamus via the inferior thalamic peduncle.
In turn, the nucleus reticularis influences the centromedian
nucleus of the thalamus, resulting in selective engagement
of cortical areas necessary for language processing (e.g.,
semantics) via diffuse connections of the centromedian
nucleus with various cortical regions. Meanwhile, the
frontal cortical-nucleus reticularis-centromedian system
reportedly holds other regions (i.e., those not necessary
for language) of the cortex in a state of relative
disengagement.
Nadeau and Crosson's (in press) theory suggests an
intrahemispheric mechanism for selective processing of
language, resulting from differential activation of the left
centromedian nucleus by the frontal lobe via the nucleus
reticularis. Posner and Petersen (1990) also proposed that
a frontal cortical structure (i.e., anterior cingulate
gyrus) is involved in attention to language as well as
regulation of the posterior attention system. While
Friedman and Poison (1981) concur that the left hemisphere
contains a mechanism and resources for selectively


46
processing language, they propose that the left hemisphere
hosts additional resources for selective processing of
information relevant to other left hemisphere functions
(e.g., motor control of the right hand). A similar left
intrahemisphere mechanism for directing selective attention
to information preferentially processed by the left
hemisphere has been considered by Petry, Crosson, Rothi,
Bauer, and Schauer (1994). Friedman and Poison differ from
this group of researchers with their view that the
attentional resources of the hemispheres can not be
differentially activated, despite inconsistent data from
functional neuroimaging studies (Binder, Rao, Hammeke,
Frost, Bandettini, Jesmanowicz, & Hyde, 1995; Demonet,
Chollet, Ramsay, Cardebat, Nespoulous, Wise, Rascol, &
Frackowiak, 1992; Petersen et al., 1989). Friedman and
Poison (1981) hypothesized that the left and right
hemispheres become equally activated for all information
processing even when one of the hemispheres participates at
a minimum level in the cognitive activity.
Based on results from a correlational study
investigating selective visual attention and language
functioning with neurologically normal and left-hemisphere
brain-damaged subjects, Petry et al. (1994) raised the
hypothesis that a left intrahemispheric mechanism with
associated resources exists for selective processing of left
hemisphere functions, such as language and detection of
right-sided visuospatial information. Relative to the


47
neurologically normal group, their left-hemisphere brain
damaged subjects exhibited a deficit in the ability to
direct selective attention to the right side of space in
order to detect visuospatial information.
According to Petry et al. (1994), the left-hemisphere
brain-damaged subjects did not exhibit impairments on a test
of visual neglect or on a test of visual vigilance, when
compared to the neurologically normal control group.
Additionally, for the left-hemisphere brain-damaged group,
only the deficit of re-directing selective attention to the
right side of space significantly correlated with more
severe impairments on measures of verbal fluency, auditory
comprehension, naming, and repetition.
Petry et al. (1994) essentially hypothesized a multiple
unshared resources theory of attention, where a mechanism
within each hemisphere selectively engages various resources
for a particular type of information processing. Resource
limitations exist within each processor (hemisphere). These
researchers considered possible effects of an injury to the
left intrahemisphere mechanism. They postulated that damage
to this mechanism may result in inefficient engagement of
resources for processing of information in the left
hemisphere. Inefficient processing may then exacerbate
impairments from damage already present in structures and
pathways necessary for the function. For example, disorders
of attention and language are commonly reported after injury
to left hemisphere. Petry et al. hypothesized that the


48
level of difficulty experienced by language disordered
patients may be in part determined by an inefficiency in the
selective engagement of needed cortical processes. While
impaired selective engagement may influence language
dysfunction, it was not purported to be the primary cause of
language difficulties. Petry et al. maintained that damage
to important areas and pathways involved in language
processing (e.g., Broca's area, Wernicke's area, and arcuate
fasciculus) was the primary cause of language dysfunction.
As an alternative to a general left intrahemispheric
mechanism for selective engagement of information
processors, Petry et al. (1994) also considered the possible
existence of a more refined attention mechanism. Instead of
a mechanism where attention resources are shared across all
left hemisphere processing tasks, additional unsharable
mechanisms may coexist for selective processing of
particular types of information within the left hemisphere.
For example, there may be separate attention mechanisms for
language processing and for processing right-sided
visuospatial information. The resources from these separate
mechanisms can not be shared. Thus, the mechanisms for
processing language and right-sided visuospatial information
may coexist rather than relate within the left hemisphere.
In an attempt to clarify whether language is subserved
by a general selective attention mechanism that also engages
other cognitive systems (i.e., right-sided visuospatial
information) or by a specific selective attention mechanism


that engages only language within the left hemisphere, the
current project will employ the dual-task technique.
49
Dual-Task Paradigm
The dual-task method consists of comparing concurrent
performance on two tasks to performance on each individual
task. Traditionally, this paradigm has been used to study
the operation of selective attention, leading to the
development of the previously reviewed theories of attention
(i.e., single unshared resource, single shared resource,
multiple unshared resources, multiple shared resources, and
automatic/controlled processing). More recently, this
methodology has been used to investigate the lateralization
of functions within the brain. However, Ojemann (1983)
suggests that the dual-task procedure more applicably
measures the lateralization and operation of attentional
mechanisms rather than the lateralization of cognitive
functions.
Assumptions
Regarding the operation of selective attention, a
variety of dual-task methodologies, such as dichotic
listening, visual half-field presentation, and pairing of a
manual task with a cognitive task, have been employed.
While performing two concurrent tasks, the allocation of
attention is manipulated by varying task priority or task
difficulty (Green & Vaid, 1986) Subjects may be instructed
to focus their attention primarily on task A or B, or


50
equally on both tasks. When attention is primarily directed
to task A, results may then reflect the influence of task A
on task B. Typically, performance on task B will worsen
reflecting less attention to this task. When attention is
directed equally to both tasks, results then reflect the
bidirectional influence of each task. Additionally,
different levels of difficulty may be introduced for either
task A or B. It is generally presumed that more processing
resources are expended on a task with more focused
attention. For example, when task A receives more attention
than task B, typically performance on task B will decline.
It is also assumed that more attentional resources are
activated with increasingly difficult tasks. However, a
point is eventually reached when additional resources no
longer benefit an individual's performance, that is, when
the costs outweigh the benefits.
Because the current project will investigate whether
language is subserved by a general or a specific selective
attention mechanism within the left hemisphere, five
relevant studies (Herdman, 1992; Hiscock, Cheesman, Inch,
Chipuer, & Graff, 1989; Milner, Jeeves, Ratcliff, &
Cunnison, 1982; Posner, Early, Reiman, Pardo, & Dhawan,
1988; Posner, Inhoff, Friedrich, & Cohen, 1987) will be
reviewed. These studies were selected because they utilized
a language task in their methodology and because they were
representative of typical findings in the dual-task
literature. In comparison to single-task performance, dual-


51
task performance typically produces interference (Friedman
et al. 1988; Herdman, 1992; Hiscock et al., 1989; Milner et
al., 1982; Posner et al., 1988; Posner et al., 1987). The
interference tends to be greater for same hemisphere tasks
(Milner et al. 1982; Posner et al. 1988) than for
different hemisphere tasks. The next most frequent finding
in this literature is no change in performance from the
single-task to the dual-task conditions (Gladstones et al. ,
1989; Pashler, 1992). Occasionally, concurrent performance
of same hemisphere tasks will yield enhancement in
comparison to the single-task performance (Hiscock et al.,
1989; Pasher & O'Brien, 1993). Overall, most studies report
a mixture of these types of findings; for example,
interference in one condition and no change in another
(Ballesteros et al., 1989; LaBarba, Bowers, Kingsberg, &
Freeman, 1987; Urbanczyk, Angel, & Kennelly, 1988). In
comparison to single-task performance, the following
variables tend to enable concurrent performance:
integration of the task into long-term memory, use of simple
stimuli and responses, dissimilar stimuli and responses for
tasks; and predictable presentation of task stimuli (Cohen,
1993; Hiscock, 1986).
Hiscock et al. (1989) investigated the effects of
reading aloud on a variety of unilateral finger tapping
tasks. Forty-eight right-handed subjects participated in
this experiment. In the single-task condition for reading,
subjects were instructed to read aloud, for 15 s, a summary


52
paragraph selected from an introductory psychology textbook.
Additionally, subjects were told to remember as much as
possible from the paragraph. Following the 15 s reading
period, subjects were asked to say three to five key words
reflecting the content of the paragraph.
In the single-task conditions for finger tapping,
subjects performed assorted tasks based on combinations of
the following variables: rate (speeded tapping vs.
consistent tapping), movement (repetitive tapping of one key
vs. alternating tapping between two keys), and hand used
(left vs. right). Thus, subjects received one trial (15 s)
of the following tasks: speeded-repetitive tapping,
speeded-alternating tapping, consistent-repetitive tapping,
and consistent-alternating tapping. This combination of
tasks was performed separately with the left hand and with
the right hand.
In the dual-task conditions for reading aloud and
finger tapping, the single-task condition for reading aloud
was paired with each combination of the single-task
conditions for finger tapping. Additionally, task emphasis
(reading vs. finger tapping) was manipulated, such that,
subjects received one trial (15 s) of each dual-task
condition where reading was the most important task as well
as one trial of each dual-task condition where finger
tapping was the most important task. Therefore, each dual-
task condition varied across four variables: rate,
movement, hand used, and task emphasis. An example of one


53
dual-task trial was speeded, repetitive, left-handed finger
tapping paired with reading aloud and remembering aspects of
the paragraph, where performance on the reading task was
emphasized.
Results from Hiscock et al. (1989) revealed that
reading aloud decreased the rate of speeded finger tapping
(7 %) but increased the rate of consistent finger tapping (3
%), regardless of task emphasized. In both conditions, the
right hand was significantly more affected than the left
hand; thus, when tapping rapidly right-handed tapping was
significantly reduced as compared to left-handed tapping,
and when tapping consistently right-handed tapping
significantly improved as compared to left-handed tapping.
Hiscock et al. interpreted this mixed finding of right-hand
interference (when reading and rapidly tapping) and of
right-hand facilitation (when reading and consistently
tapping) as evidence for the role of the left-hemisphere in
coordinating speech with right-hand movements in right-
handed individuals. Based on results from this study,
Hiscock et al. proposed that the left-hemisphere adjusts
right-hand movements in order to coordinate this activity
with speech.
Analysis of reading performance indicated a trend
toward faster reading and less errors in the single-task
conditions in comparison to the dual-task conditions when
reading was or was not emphasized. Hiscock et al. (1989)


54
concluded that the dual-task paradigm was a valid method for
the investigation of lateralized verbal processing.
Because Hiscock et al. (1989) compared such a large
number of dual-task conditions within subjects, the number
of trials per condition was constrained. The conclusions
from this study would be bolstered with replication as well
as with utilization of a design allowing for more than one
trial (15 s) in each dual-task condition.
Herdman (1992) investigated the effects of reading
words aloud as well as determining whether words were real
words or nonwords on reaction time to a tone discrimination
task. The methodology and results from Herdman's second
experiment will be described in detail. This second
experiment is a replication as well as an extension of the
first experiment listed in this article.
In the single-task condition for reading words aloud,
subjects were required to keep their eyes focused on a dot
that was located at the center of a computer monitor screen.
Subjects initiated a trial by pushing and holding a key with
the index finger of their preferred hand. After 500 ms, the
fixation dot was replaced by a high, medium, or low
frequency word, ranging from 4 to 6 letters. The words were
selected from Kucera and Francis (1967). Subjects were
instructed to read each word aloud as quickly as possible,
initiating removal of the word from the screen. Subjects
were given a maximum of 2 s to respond. Response times were
recorded.


55
In the single-task condition for determining whether
words were real words or nonwords (i.e., lexical decision
making), the procedure was the same as the one used in the
single-task condition for reading except for the following
differences: on half of the trials, the fixation dot was
replaced by a 4 to 6 letter nonword whereas on the other
half of the trials, the dot was replaced by a high, medium,
or low frequency 4 to 6 letter word. When subjects were
presented with a nonword, they responded aloud with
"nonword". When they received a real word, subjects said
"word". Because response times were recorded, subjects were
instructed to respond as quickly as possible.
In the single-task condition for the tone
discrimination task, subjects were instructed to keep their
eyes fixated on the central dot. Subjects started a trial
by pushing and holding a key with the index finger of their
preferred hand. After 500 ms, the fixation dot was replaced
by five asterisks, simulating the visual complexity of word
presentation in this position during the dual-task
conditions. Additionally, either a low or high pitch tone
was presented. When subjects received a low pitch tone
(distractor), they were instructed to continue holding the
key which they pushed to start the trial. When they
received a high pitch tone (probe), subjects were told to
remove their finger from the key as quickly as possible.
Reaction times were recorded. For distractor tones,
reaction times would be approximately 2 s (i.e., the maximum


56
amount of time allowed for a trial). Reaction times for
probe trials would be less than 2 s.
In one dual-task condition, reading words aloud was
paired with the tone discrimination task. In the other
dual-task condition, the lexical decision task was paired
with the tone discrimination task. For these dual-task
conditions, subjects were told to keep their eyes focused on
the central dot. Subjects initiated a trial by pushing and
holding a key with the index finger of their preferred hand.
After 500 ms, the fixation dot was replaced by a word
(reading task) or by either a word or a nonword (lexical
decision task). In addition, one of two tones was
presented. When subjects received a distractor tone, they
were instructed to respond to the letter string (i.e., read
it aloud or say either "word" or "nonword") while they
continued holding the key which started the trial. When
subjects received a probe tone, they were instructed to stop
performing the letter string task and to remove their finger
from the start key as rapidly as possible. On probe trials,
subjects did not provide a response for the reading task or
for the lexical decision task. This paradigm has been
referred to as the dual-task change paradigm because
subjects forfeit a response to the primary task in order to
respond only to the secondary task. The tone discrimination
task began 0, 84, or 167 ms, after the presentation of a
letter string (i.e., the primary task).


57
Primary task (reading and lexical decision) and
stimulus onset asynchrony (0, 84, and 167 ms) were between
subjects factors. Therefore, each subject was randomly
assigned to one of six dual-task conditions. Each of the
six dual-task conditions was performed by 16 subjects,- thus
a total of 96 subjects participated in this study. In
addition, these subjects performed the corresponding single
task conditions. For example, subjects assigned to reading
and 0 ms condition performed the single-task condition for
reading words aloud, the single-task condition for tone
discrimination and the dual-task condition for reading and
tone discrimination with a stimulus onset asynchrony (SOA)
of 0 ms between the tasks. Handedness of subjects was not
assessed.
Results from Herdman (1992) revealed significantly
slower responding to the probe tones during the tone
discrimination task when it was paired with the reading or
lexical decision tasks than when it was performed alone. In
addition, subjects took longer to respond to probe tones
paired with the lexical decision task in comparison to probe
tones paired with the reading task. Subjects also responded
slower to probe tones at later SOAs (84 and 167 ms) than to
probe tones presented simultaneously with a letter string (0
ms). Based on prior research demonstrating slower reaction
times to an auditory probe when it was paired with a low
frequency word in comparison to a high frequency word
(Becker, 1976; Herdman & Dobbs, 1989), Herdman (1992)


58
concentrated his analyses on the reaction times to probe
tones occurring with or after the presentation of high and
low frequency words. Results indicated that subjects took
longer to respond to probe tones paired with low frequency
words in comparison to probe tones paired with high
frequency words. Herdman concluded that "(a) lexical access
requires attentional resources and (b) more resources are
required to recognize low- as compared with high-frequency
words" (p. 466).
Milner et al. (1982) measured the effects of counting
backward as well as manually adjusting the orientation of
screws on reaction times to lateralized light flashes. In
the single-task condition, right-handed subjects were
required to keep their eyes continually focused on a
fixation spot appearing at the center of a computer monitor
screen. Following a brief warning tone, a small light flash
was randomly presented to a fixed location at the left or
right of the central fixation spot. Each light flash lasted
for 2 ms. Subjects were instructed to press a key with
either their left or right thumb whenever they detected a
light flash. On half of the trials, subjects responded with
their left thumb. On the other half of the trials, they
responded with their right thumb.
In one of the dual-task conditions utilized by Milner
et al. (1982), twelve right-handed subjects counted
backwards by 3, 4, or 6 while detecting light flashes.
Light flashes were presented only when subjects were in the


59
process of saying a number. In the other dual-task
condition, sixteen right-handed subjects adjusted the
orientation of screws to match the orientation of other
screws while detecting light flashes. Light flashes were
presented only when subjects were in the process of turning
a screw. In both dual-task conditions, an instruction to
focus on the central fixation spot replaced the warning
tone, prior to each trial.
Results from Milner et al. (1982) revealed a
significant increase in reaction times for each dual-task
condition in comparison to the single-task condition. When
the backwards counting task was paired with the light flash
detection task, larger reaction times were obtained to light
flashes appearing in the right visual field than in the left
visual field. When the manual orientation task was paired
with the light flash detection task, no differences existed
in the reaction times for the right and left visual fields.
This study replicated results obtained by Rizzolatti,
Bertoloni, and Buchtel (1979). According to Milner et al.,
the effect of the verbal task (i.e., slower responding to
right-sided light flashes) does not seem to be the result of
a "nonspecific cognitive overload" (p. 594) because the
manual orientation task did not also cause selectively
slower responses to right-sided light flashes.
Posner and his colleagues conducted two dual-task
experiments that utilized a task involving language and a
covert orienting of visual attention task (COVAT; Posner et


60
al., 1988; Posner et al., 1987). Before explaining the
dual-task experiments, the COVAT must be explained.
Covert Orienting of Visual Attention Task
The covert orienting of visual attention task (COVAT)
was developed by Posner in 1980. Since this time, it has
been used in an extensive number of studies with
neurologically normal subjects as well as brain-injured
patients. The task, which employs nonverbal symbols and
requires only a key-press response, yields a consistent
pattern of results with normal subjects (Posner, 1980;
Posner et al., 1988) For brain damaged patients, specific
patterns of impairment result following lesions of the left
or right hemisphere (Posner et al., 1984; Rafal & Posner,
1987) .
The COVAT requires subjects to keep their eyes focused
on a fixation point at the center of a computer monitor
screen ("+") and to press a key as soon as they see the
target ("*"). The target appears in a box either to the
left or to the right of the central fixation point. On a
majority of trials, subjects receive a cue (i.e., the
brightening of one of the two boxes) indicating where the
target is likely to appear. For most cued trials (i.e., 80
% of cued trials), the target appears in the box which has
brightened (valid trials), but for some cued trials (i.e.,
20 % of cued trials), the target appears in the box which
has not brightened (invalid trials). On other trials,


neither box is brightened before the target appears (no cue
trials; see Figure 1-2).
61
When all three trials are randomly intermixed within
blocks, neurologically normal subjects respond fastest to
valid trials, slowest to invalid trials, and intermediately
to no cue trials (Posner, 1980; Posner et al., 1988). The
advantage in reaction time for valid over invalid trials has
been termed the validity effect (Posner, Sandson, Dhawan, &
Shulman, 1989), and it has been attributed to the effects of
the cue. In addition to alerting subjects to an upcoming
target, the cue is a sensory stimulus that covertly directs
attention to a particular location. The cue affects
processing within 50 ms of onset (Posner & Cohen, 1984) If
the target subsequently appears at the cued location, then
processing is facilitated. If the target appears elsewhere,
then processing is inhibited. The effects of facilitation
and inhibition of processing occur 100 ms after the onset of
the cue even when the cue's accuracy is reduced to chance,
that is, when the target has a 50 % chance of appearing in
the box that brightened (Friedrich & Rader, 1990) .
In accordance with instructions, subjects do not move
their eyes during this task because the most efficient
strategy is to keep the eyes centered (Posner, 1980; Posner
& Cohen, 1984) With their eyes centrally fixated, subjects
attend, covertly and selectively, to cued locations for
rapid target detection. Posner, Synder, and Davidson (1980)
have characterized selective visual attention as a spotlight


varying in size with task demands. The spotlight enhances
processing of the selected information.
62
Posner and his colleagues described three mental
operations involved in covert orienting of visual selective
attention (Posner & Rafal, 1987; Posner, Walker, Friedrich,
& Rafal, 1984; Rafal & Posner, 1987; Rafal, Posner,
Friedman, Inhoff, & Bernstein, 1988) Covert orienting
involves the mental shifting of the spotlight (i.e.,
selective attention) to the source of interest. First,
selective attention 'disengages' from its current focus;
next attention 'moves' to the location of interest; and
finally attention 'engages' the point of interest.
Regarding performance on the COVAT, when the cue is
presented, subjects move selective attention covertly to the
cued location and engage attention in anticipation of the
upcoming target. If the target appears at this engaged
location (valid trials), then subjects tend to respond
quickly. However, if the target does not appear at this
engaged location (invalid trials), then subjects must
disengage attention, move it to the target location, and
engage the target, resulting in a slower response time. If
a cue is not presented (no cue trials), then subjects move
attention to the target and engage it at this location.
According to Posner and his collaborators, subjects do
not engage attention at the central fixation point; thus,
when they are presented with a cue or target, covert
orientation begins with movement of selective attention


63
rather than with disengagement. However, it appears that
some amount of engagement is present at the central fixation
point as well as at each possible target location. At the
fixation point, it is hypothesized that a small amount of
attention is engaged since subjects are instructed to keep
their eyes focused there. In addition, the most efficient
strategy for target detection entails keeping one's
attention centered at the beginning of each trial. At the
possible target locations, a small amount of attention is
engaged prior to the presentation of a cue or target
enabling detection of these stimuli.
Posner et al. (1987) investigated whether selective
attention to visuospatial information was managed by an
isolated resource or by a general resource that also
selectively attends to language. In addition to the COVAT,
Posner et al. used one of two tasks involving language for
the dual-task condition. One task required subjects to
count the number of auditorily presented words beginning
with a particular phoneme. The other task required subjects
to count backwards by one from an auditorily presented
three-digit number. The phoneme counting task was performed
silently, while the counting backward task was performed
aloud.
Eight neurologically normal subjects and nine patients
with parietal lesions performed the COVAT paired with the
phoneme counting task. Eight different neurologically
normal subjects and five patients from the parietal lesion


64
group performed the COVAT paired with the counting backwards
task. Before and after the dual-task condition, all
subjects completed the COVAT alone.
Posner et al. (1987) hypothesized that if visuospatial
information is processed by an isolated attentional
resource, then subjects should still benefit from the cue on
valid trials during the dual-task condition. However, a
general increase in reaction times would be anticipated for
the dual-task condition "due to interference with output or
reliance on some very general common resource" (p. 108). If
visuospatial information is processed primarily by a general
attentional resource, then subjects should no longer benefit
from the cue on valid trials during the dual-task condition.
A general increase in overall reaction times would also be
expected.
Because patients with lesions of the parietal lobe have
been shown to have difficulty re-directing attention to the
side of space contralateral to their lesion (Posner et al.,
1984; Posner et al., 1987), these patients were expected to
respond even slower to invalid trials with contralateral
targets during the dual-task condition. This deficit was
expected, if visuospatial information and language are
processed by a general attentional resource. If slower
response times do not result for these trials during the
dual-task condition, then "the attention system common to
language and spatial orienting is quite different from that
used by spatial orienting alone" (p. 109).


65
Regarding results for the neurologically normal
subjects, responses were slower during the dual-task
conditions than during the COVAT condition. When the
phoneme counting task was paired with the COVAT, subjects
continued to benefit from the cue on valid trials. When the
counting backwards task was paired with the COVAT, normal
subjects benefited less from the valid cues. Posner et al.
(1987) suggested that the counting backward task was more
difficult than the phoneme counting task, thus interfering
with orienting toward valid COVAT cues.
Performance of the parietal damaged patients varied
with the target-onset interval. When the target appeared
100 ms after the cue, patients did not benefit from the cue
on valid trials during the dual-task conditions. However,
at 500 or 1000 ms, the patients benefited from the valid
cues. Response times tended to be larger during the dual-
task conditions than the COVAT condition. The parietal
damaged patients did not exhibit extraordinarily slow
responding to the invalid trials with contralateral targets.
Posner et al. (1987) suggested that orienting toward valid
cues at short intervals (100 ms) was more difficult than
orienting toward valid cues at longer intervals (500 ms).
Posner et al. (1987) concluded that the "spatial
orienting system must share some operations with the two
secondary tasks, causing a delay in orienting when they are
sufficiently difficult" (p. 112). According to Posner et
al., the results suggest an interaction of two attention


66
systems: (a) an isolated system and set of resources for
selective processing of visuospatial information and (b) a
general system and set of resources for selective processing
of visuospatial information and language. The general set
of resources reportedly directs orienting to all types of
information, while the resources specific to visuospatial
information permit subjective report of this information.
Posner et al. hypothesized that the frontal lobes were
important in the general system for selective processing of
visuospatial information and language.
During the dual-task conditions in Posner et al.
(1987), it is difficult to know what the response times to
the COVAT reflect because presentation of the language tasks
was not controlled. While performing the COVAT, subjects
responded to an audiotape presenting stimuli for the
language tasks. The language stimuli were not coordinated
with the COVAT; therefore, the COVAT data in the dual-task
condition probably reflect multiple influences. If a COVAT
trial occurred prior to processing language stimuli, then
some of the results may reflect the interference of the
COVAT on language. If a language stimulus occurred prior to
processing the COVAT, then some of the results may reflect
the interference of language on the COVAT. Additionally,
some of the results probably reflect that lack of
interference between the COVAT and language.
Although Posner et al. (1987) reportedly wanted to
study selective attention, the vigilance component of


67
attention was likely influenced by including a large number
of trials (e.g., 100, 300) in each block in the various
conditions possibly inducing fatigue and reducing vigilance
in the later trials within each block. Surprisingly, Posner
et al. (1987) neglected to report whether the neurologically
normal subjects responded differently to the COVAT targets
appearing on the left and right side of space during the
dual-task conditions. While concurrently performing the
COVAT and a language task, differential processing demands
are made on the left and right cerebral hemispheres. The
left hemisphere primarily processes right-sided COVAT
targets as well as language, whereas the right hemisphere
primarily processes only left-sided COVAT targets. Because
of this difference in the amount of cerebral hemispheric
processing, slower reaction times would be expected for
right-sided COVAT targets, when compared to left-sided
targets, during a concurrent language task.
In a subsequent study, Posner et al. (1988) did examine
differential responding to left- and right-sided COVAT
targets during concurrent performance with a language task.
The language task required subjects to repeat aloud, with
minimal lagtime, material from an audiotaped book (i.e.,
"Lincoln"). Before and after completion of the COVAT alone,
20 normal subjects performed the COVAT paired with this
repetition task.
Results from Posner et al. (1988) revealed that
subjects responded slower to the 100 ms trials of the COVAT


68
during dual-task performance than during single-task
performance. In the single-task condition, subjects
responded comparably to left- and right-sided COVAT targets.
In addition, they responded faster to valid than to invalid
trials when the COVAT was performed alone, demonstrating the
validity effect. In the dual-task condition, Posner et al.
reported that subjects responded slower to invalid trials
with right-sided targets, after the no cue trials were
excluded from the dataset. During these particular trials,
subjects received a left-sided cue followed by a right-sided
target. Posner et al. interpreted this finding as evidence
of the effect of attention to language on visuospatial
orienting. Additionally, this latter dual-task finding was
similar, but less severe, to the pattern obtained by
schizophrenics performing the COVAT alone.
For slower responding to invalid trials with right
sided targets during the dual-task condition, an alternative
interpretation (Posner & Early, 1990) has been offered
instead of the one provided by Posner et al. (1988) .
Instead of subjects responding slower to invalid trials with
right-sided targets, alternatively subjects responded faster
to invalid trials with left-sided targets. The basic
finding was a significant difference between left- and
right-sided targets on invalid trials with faster reaction
times to left-sided targets and slower reaction times to
right-sided targets. Therefore, this finding of slower
responses to invalid trials with right-sided targets can be


69
interpreted as difficulty shifting attention from the left
sided cue to the right-sided target (Posner et al., 1988).
Alternatively, this same finding as well as the finding from
Petry et al. (1994) can be interpreted as limited response
(i.e., attraction of covert attention) to right-sided cues,
resulting in faster responses to left-sided targets on
invalid trials (Posner & Early, 1990) When the difference
between valid and invalid trials is compared, comparable
differences are obtained for single-task performance with
left-sided targets and for single-task and dual-task
performance with right-sided targets. The difference in
reaction times for valid and invalid trials is reduced only
for dual-task performance with left-sided targets (i.e.,
absence of a validity effect). As a result, the
interpretation that limited response (i.e., attraction of
covert attention) to right-sided cues resulting in faster
responses to left-sided targets on invalid trials may be
more viable. However, subjects do not appear to display
slower reaction times to valid trials with right-sided cues
and targets. These subjects appear to benefit from right
sided cues, facilitating fast reaction times to subsequent
right-sided targets (valid trials with right-sided cues and
targets). Additionally, subjects respond comparably to
valid trials with right- and left-sided cues and targets.
In comparison to Posner et al. (1987), the study
conducted by Posner et al. (1988) is an improvement because
differential responding to left- and right-sided targets was


70
explored. However, Posner et al. (1988) still retained the
following two methodological flaws: (a) uncontrolled
presentation of the language task in relation to the COVAT
during the dual-task condition and (b) large number of
trials (i.e., 240) in each block of the various conditions.
When presentation of the language stimuli is not controlled
with regards to presentation of stimuli in the COVAT task,
the data from the COVAT in the dual-task condition likely
reflect multiple influences (i.e., interference of the COVAT
on language, interference of language on the COVAT, and lack
of interference between the COVAT and language). When a
large number of trials are administered, vigilance may be
reduced in the selective attention task.
In addition to Posner and his colleagues (Posner et al.
1988; Posner et al., 1987), Pashler and O'Brien (1993) as
well as Milner et al. (1982) measured reaction times to
lateralized targets during concurrent performance of a
language task. These latter two experiments differed from
the Posner et al. studies in that sensory cues were not
administered prior to the presentation of left- and right
sided targets. During dual-task performance, Pashler and
O'Brien found no significant differences in reaction times
to left- and right-sided targets. In contrast, Milner et
al. found significantly slower responses to right-sided
targets as compared to left-sided targets, during dual-task
performance. Pashler and O'Brien required subjects to read
nonwords while they also responded to one of four possible


71
lateralized targets. Milner et al. required subjects to
count backwards while they responded to one of two possible
lateralized targets. Posner et al. (1988) did not report
significant differences between left- and right-sided
targets on the uncued trials or on the valid trials, during
dual-task performance. However, a significant difference
between left- and right-sided targets was reported for
invalid trials during dual-task performance. Because the
cues utilized in the Posner et al. studies are sensory
(i.e., the temporary brightening of a likely location for
subsequent target presentation), the COVAT is a useful
paradigm for studying the effects of language processing on
visual selective attention. The methodology proposed for
the present study is most similar to the methodology
utilized by Posner et al. (1988), as the proposed study
paired a reading task and a semantic association task with
the COVAT while Posner et al. paired a text repetition
(shadowing) task with the COVAT.
The current project utilized a similar but improved
methodology to one used by Posner and his colleagues (Posner
et al., 1987; Posner et al., 1988). While investigating
whether a specific or a general selective attention
mechanism exists within the left hemisphere for processing
language, the present study controlled the presentation of
both tasks during the dual-task conditions. The language
tasks were presented prior to the COVAT on each trial, so
that, the effects of language on the COVAT would be


72
reflected in the dual-task COVAT data. In addition, the
effect of vigilance was reduced by decreasing the number of
trials in each block. The present study also examined
whether subjects responded differently to left- and right
sided COVAT targets, while they concurrently performed a
language task.
Experiment and Hypotheses
A dual-task paradigm was employed in order to
investigate whether a specific or a general selective
attention mechanism existed within the left hemisphere for
processing language. With regard to theories about the
operation of attention, the proposed study examined whether
a single or multiple resources of attention existed and
whether or not the resource(s) were shared between multiple
attentional resources and or cognitive functions. This main
question was assessed within the context of a proposed model
for selective processing of language and visuospatial
information based on assumptions about the anatomical system
needed to engage these cortical regions of the brain.
Experiment
In the current study, language was examined at the
lexical level with single written words with minimal or
maximal emphasis on semantic processing. Although all the
language tasks required lexical access (i.e., access to
words), one task emphasized semantics (i.e., producing


73
semantic associates) while the other task did not (i.e.,
reading familiar words). The following two language tasks
were administered: reading a familiar word, and producing a
similar meaning or a highly associated word. Selective
attention was examined at two levels within the present
study. At one level, the COVAT assessed selective attention
to visuospatial information, appearing to the left and right
of a central fixation point. At another level, selective
attention was examined during the dual-task condition; that
is, the effect of semantic and non-semantic lexical
processing on visual selective attention. Since the purpose
was to examine the effects of lexical or lexical-semantic
processing on visual selective attention, the language tasks
were emphasized as primary and were presented before the
visuospatial attention task (COVAT).
The study utilized neurologically normal subjects.
Prior to the dual-task condition, all subjects performed the
two language tasks and the COVAT alone. All subjects then
performed each of the two language tasks paired with the
COVAT. During the dual-task condition, single words
replaced the central fixation point while subjects then
performed the COVAT (see Figure 1-3). Accuracy of response
was recorded for the language tasks, while reaction time was
recorded for the COVAT. Subjects responded with their non
dominant left hand while performing the COVAT alone and
paired with a language task, in order to facilitate
comparison to other COVAT studies utilizing neurologically


normal adults and left-hemisphere brain damaged patients
(Petry et al., 1994).
74
To insure concurrent performance during the dual-task
conditions, the stimulus onset asynchronies (SOAs) between
presentation of the language task (i.e., single words to be
read aloud or single words for subsequent generation of a
semantic associate) and the COVAT (i.e., brightened box
attracting covert selective attention to the cued area and a
star signaling a key-press response) were determined based
on a review of the event-related potential literature.
Event-Related Potentials
Event-related potentials (ERPs) are changes in membrane
potential for a group of cells occurring before, during, or
after a physical or psychological event (Picton, 1988). To
summarize the results from a survey of relevant event-
related potential studies, exposure to a high contrast
pattern visual stimulus results in processing from the
peristriate cortex at 100 ms post-stimulus onset (Galaburda
& Livingstone, 1993; Vaughan & Gross, 1969). At this point,
it appears that the first output from the stimulus leaves
the occipital cortex for further processing in other
cortical areas. If the pattern stimulus is psychologically
significant, then the potentials appear to reflect such
influences. In the context of a visual selective attention
task, Rugg, Milner, Lines, & Phalp (1987) reported larger
occipital potentials during an attend than during an
unattend condition. These potentials occurred 20 ms later


than the ones recorded to pattern stimulation lacking
psychological significance (Galaburda & Livingstone, 1993).
75
Potentials recorded from the frontal cortex during a
visual selective attention task (Rugg et al., 1987) and from
the frontal and parietal cortices during a category priming
task (Boddy, 1981) yielded a similar significant finding.
During both tasks, an enlarged negative wave peaked around
130 and 145 ms. Rugg et al. interpreted this potential as
reflecting further cortical processing of the visual
stimuli. Boddy interpreted this similar potential as
reflecting selective attention to words associated with a
particular category prime. Thus, Boddy proposes an effect
of selective attention as well as early access to semantics
(i.e., further cortical processing).
From additional recordings of frontal and parietal
cortices, Rugg et al. (1987) reported enhanced negativity of
a negative wave peaking at 250 ms and of a positive wave at
350 ms during an attend rather than during an unattend
condition. These potentials were also interpreted as
reflecting further information processing (Hillyard & Munte,
1984; Picton, 1988). From additional recordings of the
frontal cortex in Boddy (1981), an enlarged positive wave
peaking at 216 ms was registered. This wave was interpreted
as reflecting effects of selective attention and early
access to the meanings of words.
Neville, Kutas, & Schmidt (1982) reported an enhanced
negative wave peaking at 409 ms from left frontal and


76
temporal cortices during unilateral and bilateral
presentation of vertically-oriented words. This potential
was proposed to reflect processes related to reading.
During the reading condition in Stuss, Sarazin, Leech, &
Picton (1983), two negative waves were recorded: One
peaking at 262 ms and the other at 421 ms.
Regarding presentation of visual stimuli in the present
experiment in order to insure concurrent task performance,
appropriate intervals between the language task and the
COVAT would be 100 ms and 250 ms; thus, following
computerized presentation of a word, the COVAT cue would
randomly begin after a 100 or 250 ms delay followed by the
COVAT target after the typically used 100 or 800 ms delay
(cued trials). Thus, on cued trials, the COVAT target
randomly appeared after a 200 ms, 350 ms, 900 ms, or 1050 ms
delay from the "start" of the language task in the dual-task
conditions (see Figure 1-4). On no cue trials, the COVAT
target randomly appeared after a 200 ms, 350 ms, 900 ms, or
a 1050 ms delay after word onset.
With a 100 ms delay between the presentation of a word
from the language tasks and the COVAT, the word would nearly
have completed processing within the occipital cortex when
the COVAT cue began. Thus, this 100 ms interval would
assess the effects of early single word reading or semantic
association on visual selective attention. With the 250 ms
delay, words would be in the midst of processing by cortical
areas other than the occipital cortex, when the COVAT cue


77
began. This COVAT cue would complete processing within the
occipital cortex at 370 ms. With the 900 ms or 1050 ms
intervals, primary cortical processing of the word would
have ceased, when the COVAT began.
Anatomy Proposed to be Primarily Involved in Selective
Attention and Subsequent Processing of Language and
Visuospatial Information
Based on a review of studies involving lesions of the
thalamus, Nadeau and Crosson (in press) described a system
within each hemisphere involving the frontal cortex, nucleus
reticularis, inferior thalamic peduncle (which connects the
frontal cortex with the nucleus reticularis), and
centromedian that selectively engages the specific cortical
areas necessary for information processing while maintaining
unneeded cortical areas in a state of relative
disengagement. With regard to language, the fronto-nucleus
reticularis-centromedian system in the language dominant
hemisphere (i.e., the left hemisphere for the majority of
right-handed individuals) differentially activates needed
areas for language processing while keeping other cortical
regions (i.e., those not necessary for language processing)
relatively disengaged. This left intrahemisphere system is
also proposed to activate other structures and pathways of
the brain that are needed for attention to other cognitive
activities, for example, detection of right-sided
visuospatial information.


78
The intrahemisphere system, proposed by Nadeau and
Crosson (in press), for selective engagement of attention
and corresponding anatomical structures and pathways for
cognitive processing can be considered an example of a
multiple resources theory of attentional operation, even
though it was not originally conceptualized in this manner.
As implied by their theory, separate systems of attentional
engagement are proposed for each hemisphere. Although
resources may be shared within a hemisphere, it will be
assumed that they cannot be shared between hemispheres;
thus, their proposal satisfies the conditions for a multiple
unshared (between hemispheres, not between tasks within a
single hemisphere) resources model of attention.
Alternatively, if these anatomical systems are not separate
but shared between tasks within a hemisphere, then dual-task
performance should be impaired relative to single-task
performance because single or multiple anatomical regions
would be overloaded within the left hemisphere.
With regard to the proposed experiment, the anatomical
systems for selective processing of language and right-sided
visuospatial information are purported to share common
anatomical structures and pathways, resulting in
demonstrable impairments during concurrent performance of
these tasks relative to single-task performance. In
addition to the shared use of the selective engagement
mechanism in the left hemisphere, the language tasks and the
right-sided cues and targets of the COVAT will share use of


79
the primary sensory and motor areas as well as unimodal and
multimodal cortical areas (i.e., occipital cortex, angular
gyrus, premotor cortex, and motor cortex). During dual-task
performance, it was hypothesized that complex processing and
responding required at the level of the left frontal cortex
overloads the selective engagement attentional system,
leading to impairment of language and right-sided COVAT
performance. In addition to a decrement in language
performance during dual-task conditions, impairment of only
right-sided COVAT cues and targets would support a general
system for attention within the left hemisphere where
attentional resources are shared among cognitive tasks
within this hemisphere but not between hemispheres. If the
anatomical systems for selective processing of written
language and visuospatial information are separate and not
shared within the left hemisphere, then dual-task
performance should be comparable to single-task performance
in the present study. This latter finding would also be
predicted by a multiple resources theory of attention where
all resources share attention among cognitive tasks.
If performance to left- and right-sided COVAT cues and
targets are equally impaired during dual-task performance in
addition to a decrement in language performance, then a
single resource rather than a multiple resources model of
attention would be bolstered. According to the single
resource theory of attention, dual-task performance is
always worse than single-task performance. It is


80
hypothesized that the performance deficits would interfere
with processing in both hemispheres regardless of whether
structures and pathways were primarily engaged in one
hemisphere over the other hemisphere. If the attentional
resource was not shared between cognitive tasks, then marked
impairments would occur for all dual-task combinations
regardless of the attentional demands inherent in each task
because of interference from rapid switching of attention
between tasks. If the resource was shared between cognitive
tasks, then dual-task impairments would be graded as based
on each task's demands for attention. As an example of
possible performance on the COVAT paired with the proposed
language tasks, more marked deficits would be expected in
response to left- and right-sided COVAT stimuli as well as
to language stimuli when the COVAT was paired with the
semantic association task in comparison to the reading task
if the single resource was shared. With a more attention
demanding task, like semantic association, paired with the
COVAT, more deficits would be expected because more
interference is hypothesized in order to achieve successful
performance of both tasks. Less attentional interference is
hypothesized for the reading task when it is performed
concurrently with the COVAT, therefore, less impairment of
responses to left- and right-sided COVAT stimuli and to
language stimuli would be expected, in comparison to dual
task performance of the COVAT with the semantic association
task.


81
Hypotheses
Based on the proposed relationship between attention
and language as well as findings from the dual-task
literature (particularly Posner et al., 1988), a general
left intrahemispheric mechanism for engagement of attention
and subsequent cognitive processing is proposed. This
mechanism can be conceptualized as a multiple unshared
resources theory of attention where resources are shared
among cognitive tasks executed within a particular
hemisphere but not between hemispheres. Given the above
conceptual framework for selective attention, the following
hypotheses were proposed:
1. Dual-task performance would show effects of
interference; that is, slower reaction times to COVAT
targets and increased language errors (mispronunciation on
reading task, incorrect answer or no response on semantic
association task).
2. More specifically, slower reaction times would be
anticipated for invalid COVAT trials with right-sided
targets during dual-task performance. In addition, subjects
would respond significantly slower to invalid trials as
compared to valid trials with right-sided targets,
demonstrating the validity effect.
3. Faster reaction times would be expected for invalid
COVAT trials with left-sided targets during dual-task
performance. Additionally, a validity effect would not be
anticipated for left-sided targets during dual-task


performance; thus, no significant difference in reaction
times for valid and invalid trials with left-sided targets.
82
4. Because the semantic association task was
hypothesized to require more processing than the reading
task, more interference would be expected when the COVAT was
paired with this task than with the reading task; thus, the
pattern of responding identified in (2) and (3) would be
more pronounced. Within each dual-task condition, subjects
would respond slower to low frequency words than to high
frequency words. A significant difference in reaction time
would be anticipated between low frequency words of the
semantic association-COVAT condition and high frequency
words of the reading-COVAT condition.
5. Although more language errors were expected during
the dual-task conditions in comparison to the single-task
conditions, this result would not be significant, only a
trend (Herdman, 1992; Hiscock et al., 1989). More errors
would be anticipated for the semantic association task than
for the reading task. In addition, subjects would be
expected to make more errors with low frequency rather than
high frequency words.


Figure l-l. Model for the recognition, production, and
comprehension of written words, based on
Ellis and Young (1988).


34
Heard Word Written Word
i
Speech


Figure 1-2. Schematic of the covert orienting of visual
attention task.


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81,9(56,7< 2) )/25,'$


THE EFFECTS OF LEXICAL AND SEMANTIC PROCESSING
ON VISUAL SELECTIVE ATTENTION
By
MARGARET CARTHAS PETRY
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
1995

ACKNOWLEDGMENTS
Sincere thanks is extended to my supervisory committee
for their contributions to my dissertation, and in turn, to
my development as a researcher. Dr. Bruce Crosson,
chairperson of the committee, is given special thanks for
his invaluable guidance and support throughout this project.
Thanks is also offered to Dr. Ira Fischler for his
assistance during review of the dual-task literature and in
improving the methodology and design of this study. Dr.
Leslie Gonzalez Rothi is thanked for encouraging me to
broaden my original conceptualization of attention and
language as well as to set manageable objectives for this
project. Dr. Eileen Fennell is extended thanks for her
support and her assistance with methodological and design
issues. Dr. Russell Bauer is thanked for his help during
early conceptualization of this project as well as with
issues regarding its design. Dr. Alan Agresti is offered
thanks for his flexibility and provision of ready
statistical consultations.
Dan Edwards, Cliff LeBlanc, James Burnette, and Paula
Usita merit thanks for their assistance with subject
recruitment at Santa Fe Community College.

Extra special thanks is given to my family and friends
for their continued encouragement. My deepest thanks goes
to my husband, Andy, for his unending support and help.

TABLE OF CONTENTS
page
ACKNOWLEDGMENTS ii
LIST OF TABLES vii
LIST OF FIGURES x
ABSTRACT xiii
CHAPTERS
1 LITERATURE REVIEW 1
Attention 1
What is It? 1
How does Attention Operate? 3
Single Unshared Resource Theory 7
Single Shared Resource Theory 12
Multiple Unshared Resource Theory 15
Automatic and Controlled Processing of
Information 24
Anatomy 25
Language 31
Anatomy 32
Model of Recognition, Production, and
Comprehension of Written Words 40
Selective Attention and Language 44
Dual-Task Paradigm 49
Assumptions 49
Covert Orienting of Visual Attention Task 60
Experiment and Hypotheses 72
Experiment 72
Event-Related Potentials 74
Anatomy Proposed to be Primarily Involved in
Selective Attention and Subsequent Processing
of Language and Visuospatial Information 77
Hypotheses 81
2 MATERIALS AND METHODS 91
Subjects 91
Hand Preference 92
Apparatus 93
Covert Orienting of Visual Attention Task 93

95
Language Tasks
Covert Orienting of Visual Attention Task
Paired with Language Tasks 98
Procedure 104
3 RESULTS 112
Statistical Analyses 112
Covert Orienting of Visual Attention Task
Alone and Paired with Language Tasks 113
100 ms Word-COVAT Delay 116
250 ms Word-COVAT Delay 117
Transformed Data: 100 ms Word-COVAT Delay.... 121
Transformed Data: 250 ms Word-COVAT Delay.... 122
Language Tasks 123
Specific Types of Language Errors 125
Overall Language Errors 127
Language Task Order 129
Word Familiarity 131
Task Difficulty 132
Slow Responders During the Semantic
Association-COVAT Condition 133
4 DISCUSSION AND CONCLUSIONS 178
Covert Orienting of Visual Attention Task 178
Covert Orienting of Visual Attention Task
Alone and Paired with Language Tasks 179
100 ms Word-COVAT Delay 179
250 ms Word-COVAT Delay 186
Language Tasks 191
Language Task Order 194
Word Familiarity 194
Task Difficulty 195
Slow Responders During the Semantic
Association-COVAT Condition 196
Future Research 199
APPENDICES
A AAL SCREENING QUESTIONNAIRE 204
B BRIGGS-NEBES MODIFICATION OF THE ANNETT
HANDEDNESS QUESTIONNAIRE 206
C INSTRUCTIONS FOR CO VAT 207
D INSTRUCTIONS FOR THE READING TASK 208
E INSTRUCTIONS FOR THE SEMANTIC ASSOCIATION TASK.... 209

F LOW FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS
IN CONCRETENESS AND IMAGEABILITY USED IN THE
READING AND SEMANTIC ASSOCIATION TASKS 211
G HIGH FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS
IN CONCRETENESS AND IMAGEABILITY USED IN THE
SEMANTIC ASSOCIATION TASKS 212
H INSTRUCTIONS FOR THE COVAT PAIRED WITH THE
READING TASK 213
I INSTRUCTIONS FOR THE COVAT PAIRED WITH THE
SEMANTIC ASSOCIATION TASK 214
J LOW FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS
IN CONCRETENESS AND IMAGEABILITY USED IN THE
READING AND SEMANTIC ASSOCIATION TASKS WHEN
PAIRED WITH THE COVAT 216
K HIGH FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS
IN CONCRETENESS AND IMAGEABILITY USED IN THE
READING AND SEMANTIC ASSOCIATION TASKS WHEN
PAIRED WITH THE COVAT 218
L POST-EXPERIMENTAL QUESTIONNAIRE 220
REFERENCES 221
BIOGRAPHICAL SKETCH 232

LIST OF TABLES
Table page
2-1 Counterbalanced Order of Single-Task
Presentation 106
2-2 Counterbalanced Order of Dual-Task
Presentation 107
3-1 False Positive Errors: Statistics for the
Main Effect of Task 135
3-2 COVAT Alone: Statistics for the Main Effect
of Trial Type 136
3-3 100 ms Word-COVAT Delay: Statistics for the
Main Effect of Task 137
3-4 100 ms Word-COVAT Delay: Statistics for the
Main Effect of Trial Type 138
3-5 250 ms Word-COVAT Delay: Descriptive
Statistics for the Task by Target Side
Interaction 139
3-6 250 ms Word-COVAT Delay: Statistics for the
Task by Target Side Interaction 140
3-7 Transformed Data at the 100 ms Word-COVAT
Delay: Descriptive Statistics for the Task
by Trial Type Interaction 142
3-8 Transformed Data at the 100 ms Word-COVAT
Delay: Statistics for the Task by Trial
Type Interaction 143
3-9 Transformed Data at the 250 ms Word-COVAT
Delay: Descriptive Statistics for the Task
by Trial Type Interaction 145
3-10 Transformed Data at the 250 ms Word-COVAT
Delay: Statistics for the Task by Trial
Type Interaction
146

Table page
3-11 Overall Language Errors at the 100 Word-COVAT
Delay: Statistics for the Task Main Effect... 148
3-12 Overall Language Errors at the 250 ms Word-
COVAT Delay: Descriptive Statistics for the
Task by Frequency Interaction 149
3-13 Overall Language Errors at the 250 ms Word-
COVAT Delay: Statistics for the Task by
Frequency Interaction 150
3-14 Language Task Order: Statistics for the Task
Order by Word Frequency Interaction for
the Reading Only Condition 152
3-15 Language Task Order: Descriptive Statistics
for the Semantic Association Condition 153
3-16 Language Task Order: Descriptive Statistics
for the Dual-Task Conditions 154
3-17 Task Difficulty: Statistics for the Single-
and Dual-Task Conditions 155
3-18 Slow and Faster Responders During the
Semantic Association-COVAT Condition:
Descriptive Statistics for Response
Strategy 156
3-19 Slow and Faster Responders During the
Semantic Association-COVAT Condition:
Descriptive Statistics for False Positive
Errors 157
3-20 Slow and Faster Responders During the
Semantic Association-COVAT Condition:
Descriptive Statistics for Language Errors.... 158
3-21 Slow and Faster Responders During the
Semantic Association-COVAT Condition:
Descriptive Statistics for Word Familiarity... 160

Table page
3-22 Slow and Faster Responders During the
Semantic Association-COVAT Condition:
Descriptive Statistic for Task Difficulty 161

LIST OF FIGURES
Figure page
1-1 Model for the recognition, production, and
comprehension of written words, based on
Ellis and Young (1988) 84
1-2 Schematic of the covert orienting of visual
visual attention task 86
1-3 Schematic of dual-task performance with the
covert orienting of visual attention task
and a language task 88
1-4 Stimulus onset asynchronies for dual-task
performance of the covert orienting of
visual attention task and a language task 90
2-1 Stimulus onset asynchronies for the covert
orienting of visual attention task 109
2-2 Schematic of the language tasks: Reading
and generation of semantic associations ill
3-1 Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 100 ms delay between
language task and onset of the COVAT
(C=COVAT,- RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 100=100 ms delay
between language task and onset of the
COVAT) 163

Figure
page
3-2 Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 250 ms delay between
language task and onset of the COVAT
(C=COVAT; RC-Lo=Reading-COVAT condition with
low frequency words,- RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 250=250 ms delay
between language task and onset of the
COVAT) 165
3-3 Relative frequency histograms for the mean
reaction time of the covert orienting of
visual attention task (COVAT) and
Reading-COVAT condition 167
3-4 Relative frequency histogram for the mean
reaction time of the Semantic Association-
COVAT condition 169
3-5 Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 100 ms delay between
language task and onset of the COVAT,
after equating for general response time
in each condition with no cue trials
(C=COVAT; RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 100=100 ms delay
between language task and onset of the
COVAT) 171

3-6
Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 250 ms delay between
language task and onset of the COVAT,
after equating for general response time
in each condition with no cue trials
(C=COVAT; RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 250=250 ms delay
between language task and onset of the
COVAT) 173
3-7 Language errors for single- and dual-task
conditions (Semantic Only=Semantic
association task; COV&Sem=Semantic
association-COVAT condition; Reading only=
Reading task; COV&Read=Reading-COVAT
condition; 100=100ms delay between language
task and onset of the COVAT; 250=250 ms
delay between language task and onset of
the COVAT) 175
3-8 Task difficulty ratings (COVAT only=Covert
orienting of visual attention task; Reading
Only=Reading task; Semantic Only=Semantic
association task; COV&Reading=Reading-COVAT
condition; COV&Semantic=Semantic association-
COVAT condition)
177

Abstract of Dissertation Presented to the Graduate School of
the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
THE EFFECTS OF LEXICAL AND SEMANTIC PROCESSING
ON VISUAL SELECTIVE ATTENTION
By
MARGARET CARTHAS PETRY
August 1995
Chairperson: Dr. Bruce Crosson
Major Department: Clinical and Health Psychology
Twenty-nine right-handed undergraduates completed the
covert orienting of visual attention task (COVAT) alone and
paired with two lexical tasks (reading aloud single words
and generating semantic associations to written words).
Subjects responded fastest to the COVAT alone, intermediate
to the COVAT-Reading condition, and considerably slower to
the COVAT-Semantic Association task. Because of left-
hemisphere dominance for language, differences between left
and right visual field responses were expected on the COVAT,
but none were found. With the exception of generating a
semantic associate for low-frequency words at a longer delay
between word and COVAT onset, interference from the language
task caused the COVAT validity effect for valid versus
invalid trials to disappear. Interference effects exhibited
during dual-task performance suggest that lexical processing

of familiar words, especially with an emphasis on semantics,
shares a common selective attentional resource with covert
orientation to visuospatial information.

CHAPTER 1
LITERATURE REVIEW
Attention
What is It?
According to William James (1890), "everyone knows what
attention is" (p. 403) yet psychology still lacks an
accepted definition of attention. James claimed that
attention "is the taking possession by the mind, in clear
and vivid form, one out of what seem several simultaneously
possible objects or trains of thought" (p. 403). Based on
James' description, attention has been commonly
characterized as the capacity for selective processing of
information (Kinchla, 1980; Navon, 1985).
In 1971, Posner and Boies refined the definition of
attention. They proposed that attention consists of three
components: arousal, selective attention, and vigilance.
Arousal is the general facilitation of cognitive processing
to any and all information, while selective attention is the
facilitation of cognitive processing to just a specific
source of information. Posner and Boies' definition of
selective attention corresponds to James' previously
mentioned popular description of attention. Vigilance is
the ability to sustain arousal and selective attention over
i

2
time. Posner and Boies conceptualized a hierarchical
arrangement for these three components of attention, such
that arousal is necessary in order to selectively attend
while arousal and selective attention are necessary for
sustained concentration. Although evidence exists that
arousal, selective attention, and vigilance depend upon
different neurophysiological systems (Moruzzi & Magoun,
1949; Pardo, Fox, & Raichle, 1991; Posner, Walker,
Friedrich, & Rafal, 1987; Watson, Valenstein, & Heilman,
1981), the three components of attention are often difficult
to distinguish in behavior, particularly with neurologically
intact individuals. Thus, it is not surprising that the
three components of attention are frequently referred to as
'attention1 or the capacity for selective processing of
information (i.e., selective attention) disregarding arousal
and vigilance. Unfortunately, this lack of specification
often causes confusion especially when attempting to compare
findings across studies of attention.
Another important distinction that is frequently
ignored is between attention and intention. While attention
(i.e., selective attention) is the facilitation of cognitive
processing for a specific source of sensory information,
intention is the facilitation of cognitive processing for a
specific type of motor activation. Thus, cognitive
processing can be enhanced for subsequent sensation, such as
detection of visuospatial information at a particular
location, or for subsequent movement, such as pressing a key

3
with a particular hand. Attentional facilitation and
intentional facilitation result in faster responding
(Heilman, Bowers, Valenstein, & Watson, 1987; Posner, 1980).
Based on studies with brain injured patients, failure to
respond can result from damage to one of four anatomical
systems: neurons responsible for the processes between
cognition and sensation (i.e., for selective attention),
neurons responsible for the processes between cognition and
movement (i.e., for intention), neurons responsible for
actual sensation, or neurons responsible for actual movement
(Heilman et al., 1987). When evaluating an individual's
performance, the effects of attention and intention, as well
as sensory and motor functioning, need to be considered.
How does Attention Operate?
Theories regarding how attention operates vary along
two main dimensions: (a) whether attention is a single
resource or multiple resources and (b) whether or not
attention is shared among cognitive tasks within a single
resource or between multiple resources (Green & Vaid, 1986;
Hiscock, 1986). From the various combinations (i.e., single
unshared resource, single shared resource, multiple unshared
resources, and multiple shared resources), four types of
information-processing theories emerge.
Welford's (1952) single channel theory and Broadbent's
filter model (1958) are examples of the single unshared
resource theory of attention. Humans are hypothesized to
have a single resource for selective processing of

4
information. This resource cannot be shared among
concurrent tasks. Attention can switch rapidly between
tasks but at a cost. Based on this theory, dual task
performance will always be worse (e.g., slower, more errors)
than performance on a single task.
Many researchers have proposed a single shared resource
theory of attention (Kahneman, 1973; Moray, 1967; Norman &
Bobrow, 1975). Although humans are hypothesized to have a
single resource of attention, this resource can be shared or
divided among concurrent tasks. Performance on simultaneous
tasks is hypothesized to require more attention than
performance on each individual task. However, impairments
in selective processing of information will only be observed
when the total demand for this resource exceeds the
available supply.
Other experimenters (Allport, Antonis, & Reynolds,
1972; Friedman & Poison, 1981; Wickens, 1984) have
postulated a multiple unshared resources theory of
attention. According to this type of theory, humans are
hypothesized to have multiple resources for selective
processing of particular information. For example, Wickens
proposes separate resources for visual and auditory
information as well as for verbal and spatial information.
Friedman and Poison claim a separate resource for each
cerebral hemisphere. Contrary to the single unshared
resource theory where attention could not be shared among
tasks, unshared now refers to the capacity for selective

5
processing of information within a particular resource of
attention. Attention can be shared between tasks that
utilize a particular resource (e.g., left cerebral
hemisphere); however, attention cannot be shared between
resources (e.g., left and right cerebral hemispheres).
While performing concurrent tasks, impairments will only
occur if the supply of one or more resources is exhausted.
If there is little overlap in task resource demand, then
dual-task performance will be essentially equivalent to
performance on each individual task.
Navon and Gopher (1979) proposed a multiple shared
resources theory of attention. Humans are hypothesized to
have multiple resources for selective processing of specific
types of information. In addition, these separate supplies
of attention are shared, such that part of one resource's
supply can be re-allocated temporarily in order to assist in
the processing of a type of information that is exhausting
another resource's supply. Based on this theory, dual-task
performance will tend to be unimpaired and similar to
performance on each of the individual tasks. Although
impairments may occur during performance of concurrent tasks
when compared to performance on each individual task, Navon
and Gopher advocate pairing these tasks with additional
tasks in order to discover whether the impairments are
spurious or actually the result of a depleted common
resource. For instance, in order to discover whether task A
and task B utilize a common processing resource, Navon and

6
Gopher recommend obtaining single-task and dual-task
performance with tasks A and B as well as with task A and a
task similar in difficulty to task B (i.e., task C). If
impairments result during concurrent performance of tasks A
and B as well as during tasks A and C when compared to
performance on each tasks individually, Navon and Gopher
suggest having subjects systematically vary the amount of
attention allocated to task A in a subsequent series of
dual-task experiments with B and with C. If the impairment
(e.g., slowed reaction time) varies systematically with the
amount of attention allocated to task A, then the two tasks
(e.g., tasks A and B) are presumed to depend on a common
resource. If the impairment does not vary systematically
with the amount of attention allocated to the primary task,
then the two tasks (e.g., tasks A and C) are presumed to use
independent resources.
Across these four types of theories, attention is
assumed to be essentially limited in overall amount of
supply. Although it has been shown that performance on
certain combinations of tasks is better than performance on
each of the individual tasks (Kinsbourne, 1970), the supply
of attention is presumed to fluctuate but not to increase
indefinitely. In an experimental situation, fluctuation of
attention can be minimized by asking human subjects to give
their best effort while performing the task(s) (Friedman &
Poison, 1981). To avoid fatiguing subjects, adequate rest
breaks should be provided.

7
Review of the recent dual-task literature revealed at
least six studies pertaining to the shared/unshared
resource/resources theories of attention. Two articles
(Gladstones, Regan, & Lee, 1989; Pashler, 1992) with
differing interpretations and results offered support for
the single unshared resource theory of attention. One
article (Ballesteros, Manga, & Coello, 1989) upheld the
single shared resource theory of attention. The multiple
unshared resources theory of attention was strengthened by
two articles (Friedman, Poison, & Dafoe, 1988; Herdman &
Friedman, 1985) but weakened by another article (Pashler &
O'Brien, 1993). Finally, no studies directly supported or
refuted the multiple shared resources theory of attention.
A lack of evidence for this latter theory may reflect
difficulties developing and implementing a reasonable
methodology for adequate testing. Navon and Gopher (1979)
advocate numerous dual-task experiments with subtle changes
of isolated variables. All articles but Herdman and
Friedman (1985) will be reviewed in detail. This latter
article will be omitted; instead, more recent articles,
where each author is the first author, will be described
(Friedman, Poison, & Dafoe, 1988; Herdman, 1992).
Single Unshared Resource Theory
According to the single unshared resource theory of
attention (Welford, 1952; Broadbent, 1958), humans are
hypothesized to have a single resource for selective
processing of information. This resource cannot be divided

8
or shared across concurrent tasks; thus, dual-task
performance will always be worse than performance on a
single task.
Support for Welford's (1952) single channel theory has
been offered by Pashler (1992) . Although Welford's theory
can be considered an example of a single unshared resource
theory of attention, Pashler rejects this classification.
Instead of characterizing attention as a single mental
resource, Pashler suggested that it is composed of separate
mechanisms: one for facilitation of cognitive processing
for a specific source of sensory information (i.e.,
selective attention) and another for response selection
(i.e., intention).
In accordance with Welford (1952), Pashler (1992)
stated that a single mental mechanism exists for selecting
responses. This proposed mechanism can handle response
selection for only one task at a time. When presented with
concurrent tasks, response selection occurs for the primary
task. Upon completion of this process and initiation of
response production for the primary task, response selection
will commence for the secondary task. Impaired performance
in dual-task conditions was hypothesized to result from a
bottleneck in the response selection mechanism.
In Pashler's (1992) model, response selection occurs
after perception and prior to response production. Neither
perception nor response production are limited in

information capacity; therefore, more than one item can be
perceived and more than one response can be produced.
9
Pashler (1991) presented subjects with a concurrent
paradigm, where they were required to press a button to a
tone as well as report a briefly displayed letter. Reaction
time was measured in the tone task, while accuracy of oral
response was measured in the letter task. Because subjects
were able to quickly shift their attention in order to
accurately detect a letter while pressing a button to a
tone, Pashler maintained the distinction between selective
attention (i.e., facilitation of cognitive processing for a
specific source of sensory information) and response
selection (i.e., intention). Aside from concluding that
response selection (pressing a button) does not interfere
with selective attention (detecting a letter), Pashler did
not further address the relationship between selective
attention and response selection (i.e., intention).
Gladstones et al. (1989) claim support for a single
unshared resource theory of attention, despite obtaining
comparable performance during single-task and dual-task
conditions. Gladstones and colleagues studied the effects
of stimulus and response modality on the single- and dual-
task performance of "two forced-paced serial reaction time
tasks" (p. 1) where subjects were required to respond as
rapidly as possible to concurrent presentation of two
stimuli.

10
The stimuli were presented either visually or
auditorily. The visual stimulus was presentation of one of
three lights varying in color to either the left or right
side of space. The auditory stimulus was binaural
presentation of one of three tones varying in pitch. In
response to the visual stimuli, subjects responded either
manually or vocally. The manual response required subjects
to press one of three specified keys with either the left or
right hand. The vocal response required subjects to say
"a", "b", or "c". Subjects were administered all
combinations of these stimuli and responses in a single-task
and dual-task format.
Prior to actual performance on the experimental tasks,
ten subjects received extensive practice with each single-
and dual-task condition. Practice continued until the
shortest interstimulus interval (ISI) was determined,
allowing subjects to respond at a 93.94% accuracy level on
three or more successive trials. For single-task
conditions, the ISI was approximately 700 ms. For dual-task
conditions, the ISI was approximately 1400 ms. Practice and
test sessions were distributed over several weeks. Each
session lasted between 60 and 90 minutes. Total
participation required approximately eight hours. Nine
subjects were right-hand dominant, and one subject was left-
hand dominant.
Gladstones et al. (1989) measured performance accuracy.
They reported that single-task performance was not

11
significantly different from dual-task performance. They
interpreted this result based on an alternative
conceptualization of Welford's single channel theory (1952)
but they did not provide a rationale. According to
Gladstones et al., comparable single-task and dual-task
performance supports the single channel theory of
information processing (i.e., a single unshared resource
theory of attention). Many researchers (Allport et al.,
1972; Wickens, 1984) interpret such a finding as evidence
against the single channel theory and as support for a
multiple channel theory of information processing (e.g.,
multiple unshared or multiple shared attentional resources).
In addition, Gladstones et al. claimed that if dual-task
performance had exceeded single-task performance, then a
multiple channel theory would have been supported.
Gladstones et al. did not account for the numerous examples
in the literature of dual-task decrement, in comparison to
single-task performance.
Aspects of the methodology utilized by Gladstones et
al. (1989) may account for their finding. Subjects in this
study received extensive practice, yielding performance at
an optimal level and eliminating possible interference
effects that reflect the operation of underlying processes.
In addition, subjects were given twice as much time to
respond to stimuli in the dual-task condition than they were
allowed in the single-task condition. Finally, simultaneous
presentation of concurrent stimuli tends to not produce

12
differences between dual-task conditions; however, when
certain larger stimulus onset asynchronies are utilized,
differences are observed (Herdman, 1992).
Overall, the evidence provided by the recent dual-task
literature for the single unshared resource theory of
attention is not very strong.
Single Shared Resource Theory
The single shared resource theory of attention
(Kahneman, 1973; Moray, 1967; Norman & Bobrow, 1975)
proclaims that a single resource of attention can be shared
or divided among concurrent tasks. Impairments in selective
processing of information will only be observed when the
total demand for this resource exceeds the available supply.
Ballesteros et al. (1989) investigated the effects of
detecting nonmatching nonwords and nonmatching lines on
unilateral hand tapping. Sixteen subjects between the ages
of 20 and 23 years were selected for participation in this
study, based on their detection rate of nonwords and lines
differing from reference stimuli. Of the sixteen subjects,
eight were quick to identify the nonmatching stimuli. The
remaining eight subjects performed this task slowly. All
subjects were right-hand dominant.
In the single-task condition, subjects tapped as
quickly as possible with their right hand and then with
their left hand. In one of the dual-task conditions,
subjects tapped with one hand while they used the other hand
to point to the nonwords that differed from the reference

13
nonword. In a related dual-task condition, subjects tapped
one hand but pointed to the letter of the nonwords that made
it differ from the reference nonword. In another dual-task
condition, subjects tapped one hand while they used the
other hand to point to lines that differed in orientation
from the reference line. In the final dual-task condition
which relates to the previous condition, subjects tapped one
hand while they pointed to the part of the line causing it
to differ from the reference line. The number of taps as
well as the accuracy of detecting nonmatching nonwords and
nonmatching lines were collected over a 20 second period for
each dual-task condition. In addition, the number of taps
over a 20 second period were obtained for the single-task
condition with each hand.
Pertinent results from Ballesteros et al. (1989)
indicated a significant decline in hand-tapping when it was
paired with detection of the different nonwords; this effect
occurred only for the group of subjects who were fast to
detect nonmatching stimuli. Subjects who were slow to
detect different stimuli exhibited a significant decline in
hand-tapping when it was paired with detection of the
different lines (subject group by nonmatching task
interaction). In comparison to the single-task condition
(only hand-tapping), a significant reduction was observed
for right hand-tapping when it was paired with another task
(i.e., nonword and line detection tasks). Left hand-tapping
was comparable for the single- and dual-task conditions.

14
Significant differences between tapping hand and dual-task
performance with the nonword and line detection tasks were
not discovered.
Because performance decrement was identified in some
dual-task conditions in comparison to the single task
condition, Ballesteros et al. (1989) interpreted these
findings as support for Kahneman's (1973) limited
attentional resource theory. In accordance with a single
shared resource theory of attention, Ballesteros et al.
reported that impairments resulted after the demand for
attentional resources exceeded the available supply. They
explained the reduction of right hand-tapping performance
across the dual-task conditions as an indication of left-
hemispheric dominance for concurrent performance of a right-
handed motor task and these cognitive tasks (detection of
nonmatching nonwords and lines).
Methodological concerns may account for Ballesteros et
al. (1989) findings, which are difficult to explain. They
obtained a limited sampling of each single- and dual-task
condition; that is, only 20 seconds of behavior (one trial).
Future studies would benefit from the administration of more
than one trial to insure a more representative behavior
sample. Additionally, this experiment utilized the
detection of nonmatching "language" and "spatial" stimuli
for its primary task in the dual-task condition. These
elementary tasks may not have engaged the corresponding
hemispheres sufficiently to cause expected dual-task

15
decrements (i.e., reduction in left and right hand-tapping
performances when paired with detection of nonmatching
nonwords or lines for all subjects).
Multiple Unshared Resources Theory
According to the multiple unshared resources theory of
attention (Allport et al., 1972; Friedman & Poison, 1981;
Wickens, 1984), humans have multiple resources for selective
processing of particular information. Attention can be
shared between tasks that utilize a particular resource, but
not between resources.
Support for a multiple unshared resource theory of
attention has been provided by Friedman and her colleagues
(Friedman & Poison, 1981; Friedman, Poison, Dafoe, &
Gaskill, 1982; Herdman & Friedman, 1985) as well as by other
researchers (Hardyck, Chiarello, Dronkers, & Simpson, 1984;
Hellige & Wong, 1983). More specifically, these researchers
claim that independent processing resources exist for each
cerebral hemisphere. Processing resources can be shared
among tasks utilizing one hemisphere, but not between
hemispheres. When performing concurrent tasks, impairments
tend to result from tasks primarily using resources from the
same hemisphere in comparison to tasks using resources from
different hemispheres. Same hemisphere tasks reportedly
deplete available resources, causing impaired dual-task
performance in comparison to single-task performance.
Different hemisphere tasks reportedly have sufficient
resources for single-task and dual-task performances,

16
yielding comparable results. According to Friedman and
Poison (1981), two tasks share a common resource when
performance increases in the emphasized task and performance
decreases in the other task. If this performance trade-off
does not occur, then the two tasks presumably do not share a
common processing resource. This theory has been primarily
supported by evidence from pairs of perceptual or cognitive
tasks (e.g., reading aloud and remembering nonwords paired
with pressing a key indicating whether laterally presented
nonwords were the same or different; reading aloud and
remembering nonwords paired with remembering lateralized
tones) .
A recent study conducted by Friedman et al. (1988)
caused them to entertain the possibility that independent
processing resources may exist for cognitive and motor tasks
in addition to the independent resources existing for left
and right hemisphere tasks. Friedman et al. investigated
the effects of reading and remembering nonwords on
unilateral finger tapping. Eight right-handed male subjects
were selected for participation in this study, based on a
right-hand advantage for tapping and on a reading advantage
for nonwords presented to the right rather than the left¬
side of space.
In the single-task condition for nonwords, subjects
initially received a warning tone which was followed by a
fixation point at the center of a screen. The fixation
point remained present for 7 s, then it was replaced by

17
three five-letter nonwords (consonant-vowel-consonant-vowel-
consonant). The nonwords were displayed for 5 s. During
this interval, subjects were instructed to read the nonwords
aloud. Following this period, the nonwords were replaced by
the fixation point that remained present for 5 s.
Subsequently, a second tone sounded, signaling subjects to
recall the nonwords presented in this trial.
In the single-task condition for finger tapping,
subjects tapped as quickly as possible with the index finger
of one hand for 17 s. A tone signaled the beginning and
ending of this period. Tapping was assessed for the left
and right index finger.
In the dual-task condition, the nonword and finger¬
tapping tasks were combined. Upon hearing the tone,
subjects began tapping as rapidly as possible with one index
finger. Subjects kept their eyes focused on the central
fixation point, awaiting presentation of the three nonwords.
When the nonwords appeared on the screen, subjects read them
aloud. During subsequent presentation of the fixation
point, subjects presumably rehearsed the to-be-recalled
nonwords while focusing their eyes at the center of the
screen. Following another tone, subjects ceased finger¬
tapping and recalled the nonwords. Task emphasis was
manipulated in the dual-task condition. In one condition,
subjects were paid more money for their memory performance
(i.e., number of nonwords correctly recalled). In the other
dual-task condition, subjects were paid more money for their

18
tapping performance. Friedman et al. (1988) assumed that
subjects would devote more attentional resources to
performance of the task that would pay them substantially
more money.
Results revealed that subjects remembered more nonwords
when concurrently tapping with their left finger than with
their right finger. Regardless of finger used, subjects
remembered more nonwords when the nonword task was
emphasized than when the tapping task was emphasized.
Following correction for the significant difference in
finger tapping (i.e., more taps for the right than left
finger), results indicated that subjects significantly
reduced their rate of tapping for both fingers when they
concurrently read nonwords aloud in comparison to when they
fixated on a centrally located point. While reading
nonwords aloud and tapping, subjects' rate of tapping for
both fingers increased when the tapping task was emphasized
and then decreased when the nonword task was emphasized.
When concurrent rehearsal of nonwords and finger tapping was
compared to the other two dual-task conditions (i.e.,
fixation and tapping; reading and tapping), subjects
significantly reduced their rate of tapping with larger
decrements observed for the right finger. When task
emphasis was manipulated, a performance trade-off occurred
for the reading and tapping condition. Performance trade¬
offs did not occur for the fixation and tapping condition or
for the rehearsal and tapping condition.

19
Friedman et al. (1988) interpreted their findings from
the finger tapping and nonword reading condition as evidence
of left-hemisphere involvement in the coordination of
speaking and finger movements, accounting for the comparable
decrement in left and right finger tapping during concurrent
reading. These researchers also concluded that separate
resources are required for finger tapping and for rehearsal
of nonwords. If these behaviors shared a common resource,
then performance trade-offs would have resulted when one
task was emphasized over the other.
From the results of five dual-task experiments, Pashler
and O'Brien (1993) offered evidence against a multiple
unshared resource theory of attention and support for a
single unshared resource theory of response selection. One
pertinent experiment from this article (experiment 3) will
be described in detail.
In their third experiment, Pashler and O'Brien (1993)
studied the effects of reading nonwords on reaction time to
lateralized visual targets. This experiment lacked single¬
task conditions, utilizing only dual-task conditions. The
dual-task condition required subjects to keep their eyes
focused upon crossed lines at the center of a computer
monitor screen. For each trial, a six letter nonword
(consonant-vowel-consonant-consonant-vowel-consonant)
replaced the crossed lines. The nonword remained present
for 200 ms. After a stimulus onset asynchrony (SOA) of 50,
150, 500, or 1000 ms, a white disk was presented to a fixed

20
position in either the upper left, lower left, upper right,
or lower right quadrant of the computer screen. The disk
remained present for 100 ms. Twenty-four right-handed
subjects were instructed to read aloud each nonword and to
press one of four designated keys (one assigned to each
quadrant) when they detected the disk. Subjects responded
with a specified finger of the left hand to upper and lower
left-sided disks and with a specified finger of the right
hand to upper and lower right-sided disks. Reaction times
were recorded for both tasks. Subjects were instructed to
respond rapidly and accurately to the stimuli of each task.
Of the 24 subjects, 12 received a mixed presentation of
disks to the left and right sides of the computer screen
during dual-task performance. For the other 12 subjects,
disks were presented only to the left or only to the right
side of the screen. In this latter condition, side of disk
presentation alternated between dual-task blocks.
The primary finding from this experiment was a
significant increase in reaction times (i.e., slower
responses) for reading nonwords and for responding to disks
at the shorter SOA intervals. No significant differences in
reaction time were obtained between left- and right-sided
disks or between mixed or blocked presentation of the disks.
Thus, at longer SOA intervals, subjects read nonwords faster
and reacted faster to disks. Subjects responded comparably
to left- and right-sided targets while concurrently reading
nonwords.

21
According to Pashler and O'Brien (1993), results from
their third experiment reflect response selection
interference. Interference reportedly occurs because a
response to a second task can not happen until a response is
selected for the first task. Interference typically delays
responding to the second task. It may or may not affect
responding to the first task (Pashler & Johnston, 1989) .
Response selection interference is most likely observed at
shorter SOA intervals. This interference has been termed
the psychological refractory period (PRP) effect, after
Welford (1952) .
Because no significant differences were detected
between left- and right-handed reaction times to respective
left- and right-sided disks during concurrent nonword
reading, Pashler and O'Brien postulated that response
selection is a single mechanism operating within the brain.
If separate mechanisms existed for each hemisphere as
postulated by Friedman and Poison (1981) , then impaired
performance should have resulted for right-handed reaction
times to right-sided disks while reading nonwords (same
hemisphere tasks) in comparison to left-handed reaction
times to left-sided disks while reading nonwords (different
hemisphere tasks).
Results from the other four dual-task experiments in
Pashler and O'Brien (1993) corroborated their finding of
response selection interference. Briefly, the first
experiment measured the effects of orally responding "high"

22
or "low" to respective binaural tones on reaction time to
lateralized visual disks (this latter task was used in their
third experiment). The second experiment utilized the tasks
from the first experiment but the order of presentation was
reversed. The fourth experiment measured the effects of
reaction time to left-sided visual disks on reaction time to
right-sided visual disks. The fifth experiment measured the
effects of reaction time to left-sided visual disks on
reaction time to say whether two centrally presented words
rhymed or not (i.e., "rhyme" or "no rhyme"). The primary
findings from these four experiments were decreased reaction
times (i.e., faster responding) at longer SOA intervals for
the first task (experiments 2 and 5) and for the second task
(experiments 1, 2, 4, and 5). Unexpectedly, reaction times
were faster for the first task (experiments 1 and 2) and for
the second task (experiment 1), when disks were presented to
the right quadrants.
To account for findings from other studies that have
demonstrated exacerbation of dual-task interference when the
tasks were performed primarily by the same cerebral
hemisphere rather than different hemispheres, Pashler and
O'Brien (1993) began by noting that these studies tended not
to require selection of separate responses to dual-task
stimuli. According to Pashler and O'Brien, response
selection interference is most pronounced when subjects have
to select between at least two possible responses for each
stimulus. These investigators questioned whether response

23
selection caused the interference observed with same
hemisphere tasks. After expressing doubt, they concluded
that the source of the interference for same hemisphere
tasks was still unknown. The study would have benefited
from single-task conditions, in order to determine just how
much interference was occurring in the various dual-task
conditions.
Unfortunately, none of these information-processing
theories of attention (i.e., single unshared resource,
single shared resource, multiple unshared resources, or
multiple shared resources) accounts for all experimental
findings. There are supporting as well as conflicting data
for each theory (Kinsbourne, 1981). For example, impaired
performance on concurrent tasks relative to performance on
each individual task provides support for the single
unshared resource theory of attention (Kerr, 1973; Klapp,
1979; Noble, Trumbo, & Fowler, 1967; Peters, 1977). For
example, in the study conducted by Noble et al. (1967),
undergraduate college students exhibited significant
interference during concurrent performance of a visual
pursuit tracking task and an auditory number monitoring
task, in comparison to performance only on the pursuit
tracking task. However, the single unshared resource theory
of attention does not account for findings of comparable
performance on concurrent tasks as well as on each
individual task (Allport et al., 1972; Spelke, Hirst, &
Neisser, 1976). For example, in the study conducted by

24
Allport et al. (1972), five third-year undergraduate Music
students were able to shadow a taped verbal passage while
sight-reading and playing an unfamiliar piece of music. In
this study (Allport et al., 1972), dual-task performance was
comparable to their single-task performances. Nonetheless,
these theories have served as heuristics for further
exploration of how attention operates.
Automatic and Controlled Processing of Information
An alternative heuristic for how attention operates has
also been used (Cowan, 1988; Neisser, 1967; Posner & Snyder,
1975; Schneider & Shiffrin, 1977; Shiffrin & Schneider,
1977). The operation of attention varies according to the
type of information to-be-processed and whether or not this
information can be processed automatically. Humans are
hypothesized to have a central (i.e., single sharable)
attentional resource for controlled processing of selected
information. This central resource is voluntarily directed
by the individual for processing a limited amount of
information. According to Cowan (1988) , the focus of
attention is limited to approximately two or three items.
However, humans are also hypothesized to process some
information automatically. This information tends to be
well learned, and according to Cowan (1988) , the information
is processed automatically under the control of long-term
memory. Although automatic processing reportedly does not
require attentional resources from the central supply, it
seems likely that at least a very small amount of attention

25
would be required for adequate routine processing. In
addition, automatic processing is less limited by capacity
restrictions; therefore, often more than three items can be
processed automatically. According to Allport (1990), "the
attempt to apply the same dichotomy (automatic/controlled)
to the whole range of dual-task concurrency costs appears to
have been, for most practical purposes, abandoned" (p. 640).
Anatomy
Up to this point in time, the information-processing
heuristics have essentially ignored the necessary anatomy
for the operation of attention. Since Friedman and Poison
(1981) hypothesized separate attentional resources for each
cerebral hemisphere, investigation of the anatomy
responsible for dual-task performance has remained dormant.
A heuristic which accounts for the anatomy needed for
attention within a concurrent task paradigm may better
account for the findings from this particular literature.
While such heuristics are lacking in the dual-task
literature, they exist in the hemispatial neglect and the
neuropsychological literatures.
Based on studies with brain-impaired humans and animals
demonstrating neglect of the contralesional side of space
despite intact sensory or motoric abilities, Heilman,
Watson, and Valenstein (1985) and Mesulam (1990) proposed
neuroanatomical models for arousal, selective sensory
attention, and selective motor intention. According to
Heilman et al., arousal (i.e., general readiness for sensory

26
and motor processing) is produced by activity of the
mesencephalic reticular formation (MRF). The MRF affects
cortical processing of sensory information directly by
diffuse polysynaptic projections to areas of the cortex
(i.e., primary sensory cortex, unimodal sensory association
cortex, prefrontal cortex, superior temporal sulcus,
inferior parietal lobule, and posterior cingulate gyrus)
possibly through cholinergic pathways or indirectly by
projections to the nucleus reticularis of the thalamus. The
MRF indirectly influences the cortex by inhibiting the
nucleus reticularis, resulting in the facilitation of
sensory information flow from the thalamus to the primary
sensory cortex. Sensory information proceeds from the
primary sensory cortex to unimodal sensory association
cortices for further processing. From the unimodal sensory
association cortices, information may advance to the
multimodal sensory association cortices directly or
indirectly after processing by the prefrontal cortex and the
superior temporal sulcus. Arousal is maintained by
projections from the prefrontal cortex and superior temporal
sulcus to the MRF and or nucleus reticularis. The inferior
parietal lobule, prefrontal cortex, superior temporal
sulcus, and posterior cingulate gyrus have reciprocal
connections. The inferior parietal lobule receives
information about the individual's goals from the prefrontal
cortex, about the significance of the sensory information
and the individual's biological needs from the posterior

27
cingulate gyrus, and about the sensory stimulus from
specific neurons within the inferior parietal lobule (e.g.,
enhancement neurons), resulting in selective sensory
attention.
According to Heilman et al. (1985), selective motor
intention requires arousal, resulting from inhibition of the
nucleus reticularis by the MRF. Selective motor intention
(i.e., the facilitation of cognitive processing for
production of a motor response to a meaningful stimulus)
depends on projections from the centromedian
parafascicularis nuclear complex of the thalamus (CMPF) to
the dorsolateral prefrontal cortex to the nucleus
reticularis. This CMPF-prefrontal cortex-nucleus
reticularis system produces inhibition of the nucleus
reticularis, leading to a reduction of its inhibitory output
to the ventrolateral nucleus of the thalamus. Subsequently,
facilitation of motor preparedness occurs between the
ventrolateral thalamic nucleus and the motor and premotor
cortices. The dorsolateral prefrontal cortex receives
information about the individual's biological needs from the
anterior cingulate gyrus, and in turn, influences motor and
premotor cortices, resulting in selective motor intention.
The anterior cingulate gyrus has reciprocal connections with
the prefrontal cortex. Adjacent to the anterior cingulate,
the supplementary motor area projects to the basal ganglia
(Heilman, Watson, & Valenstein, 1993) which in turn project

28
to the ventrolateral and ventroanterior nuclei of the
thalamus.
Mesulam (1990) proposed a single network model for
spatially directed attention, incorporating neuroanatomy
necessary for arousal, selective sensory attention, and
selective motor intention. According to Mesulam, spatially
directed attention results from three main, reciprocally
connected cortical areas: dorsolateral posterior parietal
cortex, dorsolateral premotor-prefrontal cortex, and
cingulate gyrus. The dorsolateral posterior parietal cortex
along with associated areas (e.g., sensory association
cortex, superior temporal sulcus) are primary for selective
sensory attention, while the dorsolateral premotor-
prefrontal cortex and associated areas (e.g., superior
colliculus) are primary for selective motor intention. The
cingulate gyrus determines the significance of sensory or
motoric information. These three main neuroanatomic regions
are connected with the striatum and the pulvinar nucleus of
the thalamus. In addition, these main regions receive
projections from the brainstem and thalamic components of
the reticular activating system, providing arousal.
Subsequently, Posner and Peterson (1990) and Mirsky,
Anthony, Duncan, Ahearn, and Kellam (1991) proposed general
theories of attention along with corresponding anatomy.
Based on visual detection studies with brain-impaired and
neurologically normal humans and monkeys, Posner and
Peterson suggested the existence of two attention systems.

29
The posterior attention system controls covert orienting of
visual attention to select spatial locations (i.e.,
selective sensory attention), while the anterior system is
involved in attention to language and regulation of the
posterior attention system. The posterior attention system
is composed of the following anatomical areas: primary
visual cortex, posterior parietal lobe, superior colliculus
and or surrounding midbrain areas, and pulvinar of the
thalamus. According to Posner and Petersen, the posterior
parietal lobe disengages selective attention from its
current focus after receiving information from the primary
visual cortex, then the superior colliculus and or
surrounding midbrain areas move attention to the location of
interest, and the pulvinar engages the point of interest.
The primary component of the anterior attention system is
the anterior cingulate gyrus. Posner and Petersen purported
that the right cerebral hemisphere contains the necessary
anatomy for alertness (i.e., arousal), influencing the
posterior and anterior attention systems.
Mirsky et al. (1991) proposed four components of
attention (i.e., focus-execute, encode, shift, sustain),
based on principal components analyses of neuropsychological
data from neurological, psychiatric, and normal adults and
from normal children. Following these analyses, Mirsky and
his colleagues referred to the human and animal neurological
literature to identify likely anatomical structures that
could account for the proposed attention components.

30
According to Mirsky et al., focusing on the environment
(i.e., selective sensory attention) and executing responses
is controlled by the inferior parietal cortex and its
connections to the corpus striatum. The superior temporal
sulcus is also involved in the focus component of attention.
Encoding of information is managed by the hippocampus and
amygdala, while shifting selective attention is controlled
by the prefrontal cortex, medial frontal cortex, and
anterior cingulate gyrus. In addition to arousal,
sustaining selective attention is dependent upon the tectum,
mesopontine regions of the reticular formation, and midline
region and reticular nucleus of the thalamus.
Amongst these neuroanatomical models of attention
(Heilman et al., 1985; Mesulam, 1990; Mirsky et al., 1991;
Posner & Petersen, 1990), a number of commonalties exist.
These models tend to propose similar structures for arousal
(i.e., mesencephalic reticular formation and nucleus
reticularis of the thalamus), selective sensory attention
(i.e., inferior parietal lobule) and selective motor
intention (i.e., dorsolateral prefrontal cortex). In
addition, the cingulate gyrus is identified as an important
structure, influencing selective sensory attention and
selective motor intention. Most important, attention is not
purported to exist within only one brain structure. Rather,
attention is the result of a network of specific anatomical
areas and pathways activated by corresponding sensory
stimuli, motoric responses, and motivational factors.

31
It is proposed that the results of dual-task studies,
investigating how attention operates, would be explained
best by considering the interaction of activated
neuroanatomical structures and pathways. Such a proposal is
outlined in the Experiment and Hypotheses section of this
chapter. However, the viability of this or any other theory
concerning the operation of attention would be best tested
with studies that monitor brain activity in addition to
cognitive performance for subsequent correlation of results.
In addition to experiments recording event related
potentials during performance of dual-task paradigms,
functional neuroimaging studies with magnetic resonance
imaging (MRI), positron emission tomography (PET), and
single photon emission computed tomography (SPECT) offer
mediums for elucidating the relationship among attention,
cognitive functioning, and involved anatomy.
Language
Language has been defined as the "code whereby ideas
about the world are represented through a conventional
system of arbitrary signals for communication" (Bloom &
Lahey, 1978, p. 4). This code has been conceptualized as
consisting of three main components: phonology, semantics,
and syntax (Mesulam, 1990). Phonology is the process that
sequences individual phonemes (i.e., sounds) to form words.
Semantics is the process that associates meaningful concepts
with their corresponding symbolic and lexical

representations (i.e., words). Syntax is the process that
designates relationships between words (Nadeau, 1988) .
Anatomy
32
In the 1800s, investigators began studying brain-
injured patients in an attempt to discover areas of the
brain necessary for language. Broca (1964a/1861;
1964b/1861) provided some important evidence by describing
patients with impaired language production following a
common lesion in the third frontal convolution of the left
hemisphere. In 1874, Wernicke presented data associating a
lesion in the temporal-parietal cortex of the left
hemisphere with impaired language comprehension (Benson,
1985). Subsequently, these two regions of the left
hemisphere became known respectively as Broca's and
Wernicke's areas. These areas along with the
neuroanatomical connections between them were incorporated
into a model of how language functions within the left
hemisphere by Wernicke. In 1885, Lichtheim postulated a
model with two separate processing routes for speech
production: a phonological route and a semantic route.
In the 1965, Geschwind integrated past and then current
theories and studies of brain-injured humans demonstrating
impairments of language processing or speech production as
well as studies of brain-impaired animals, yielding a
neuroanatomical model of language. In order to read aloud a
written word, Geschwind proposed that written language is
initially processed by the primary visual cortex
♦

33
(Broadmann's area 17) then by the visual association
cortices (Broadmann's area 18 and 19) in each hemisphere.
Subsequently, visual information is transferred to the left
angular gyrus directly in the left hemisphere and indirectly
from the right hemisphere by way of the following two
pathways: (1) right visual association cortices to right
angular gyrus to left angular gyrus via the corpus callosum
and (2) right visual association cortices to left visual
association cortices via the corpus callosum to left angular
gyrus. The left angular gyrus transforms the visual word
form (i.e., written language) into the auditory word form
(i.e., spoken language) and vice versa. After visual-to-
auditory transformation, this information proceeds to
Broca's area via the arcuate fasciculus for motor
programming of subsequent speech. From Broca's area,
processing occurs in the primary motor cortices of the
inferior frontal lobes (i.e., Brodmann's area 4), resulting
in formation of actual movements of the face and throat and
subsequently in spoken language. According to Geschwind,
Wernicke's area is the association cortex for auditory
information in the left hemisphere. Damage to these areas
or their connections will tend to yield predictable patterns
of impairment, otherwise known as aphasia syndromes.
Subsequently, support has amassed from clinical-
pathological (Taylor, 1969) and carotid sodium amytal
studies (Wada & Rasmussen, 1960) as well as from cerebral
stimulation (Rasmussen & Milner, 1977) and blood flow

34
(Lassen, Ingvar, & Skinhoj, 1978) studies demonstrating the
dominance of the left hemisphere for primary language
functions in approximately 96 % of right-handed individuals
and 70 % of left-handed individuals (Rasmussen & Milner,
1977) .
Currently, the search continues to identify important
structures and pathways within the brain for phonological,
semantic, and syntactic aspects of language. In 1990,
Mesulam postulated a neuroanatomical model, involving two
main areas (i.e., Wernicke's and Broca's areas), to account
for these components of language. According to Mesulam,
Wernicke's area (i.e., posterior one-third of the left
superior temporal gyrus in Brodmann's area 22) along with
associated areas in the left temporal and parietal cortices
(i.e., Brodmann's areas 37, 39, and 40) are primarily
involved in processing of phonological, lexical (i.e.,
word), and semantic information. Within these anatomical
areas, information pertaining to sound, word, and meaning
relationships is stored, allowing transformation of auditory
information into visual word forms and vice versa as well as
access to semantics. Broca's area (i.e., peri-sylvian area
of the inferior gyrus in the frontal cortex, otherwise known
as Brodmann's area 44) and associated areas in the left
frontal cortex (i.e., Brodmann's area 6 in the pre-motor
cortex and Brodmann's areas 45, 47, and 12 in the prefrontal
cortex) are involved mainly in the processing of
articulatory and syntactic information. Within this region

35
of the left hemisphere, transformation of lexical
information into articulatory sequences occurs as well as
arrangement of words into sentences. Within Brodmann's area
6, the supplementary motor cortex is involved in planning
and initiation of speech. Brodmann's areas 12, 45, and 47
in the prefrontal cortex are involved in the retrieval of
words from superordinate categories. Mesulam's model
includes interconnections between the Wernicke's, Broca's,
and their associated areas, allowing for normal language
functioning.
Rapcsak, Rothi, and Heilman (1987) provided evidence
that separate routes exist for phonological and lexical
reading. They studied one patient who experienced a
cerebral hemorrhage, damaging the posterior portion of the
middle and inferior gyri of the left temporal cortex (i.e.,
Brodmann's areas 21 and 37) and underlying white matter.
This patient exhibited selective impairment of phonological
reading; thus, he was unable to read most nonwords.
However, he was able to read lexically the majority of words
with regular and irregular print-to-sound correspondence.
According to Rapcsak et al., the phonological reading route
involves the transfer of visual information from the ventral
visual association cortex to Wernicke's area via the middle
and inferior gyri and or underlying white matter of the left
temporal cortex. The patient's lesion in these connection
areas and pathways disrupted the phonological system. The
lexical reading route involves the transfer of visual

36
information from the ventral visual association cortex to
the angular gyrus and then to Wernicke's area, enabling the
patient to read irregular words.
Further support for the existence of separate
processing routes for language is offered by Coslett,
Roeltgen, Rothi, and Heilman (1987). These researchers
studied four patients with preserved repetition, impaired
comprehension, and fluent but semantically empty speech
(i.e., transcortical sensory aphasia), following different
areas of neuroanatomical damage (i.e., cortical atrophy and
symmetrically enlarged ventricles from a primary
degenerative dementia; left posterior parietal infarction;
bitemporal involvement from herpes simplex encephalitis; and
left basal ganglia and thalamic hemorrhage). Based on
results from assessment of language functioning (i.e.,
spontaneous speech, auditory comprehension, repetition,
naming, reading aloud, reading comprehension, lexical
decision making, and syntax), Coslett et al. concluded that
the following three processing components support repetition
and reading aloud: phonology without lexical (whole word)
access, semantics with lexical and syntactic access, and
lexical and syntactic access without semantics. Consistent
with an impairment in the mechanism for semantics despite
lexical and syntactic access, two of the patients exhibited
limited comprehension but they were able to read nonwords
because of an intact mechanism for phonology without lexical
access as well as read irregular words because of an intact

37
mechanism for lexical and syntactic access. Based on data
from two other patients, impairments of lexical, syntactic,
and semantic access were noted. One of the two patients
with complete assessment data exhibited difficulty reading
irregular words along with semantic and syntactic errors,
suggesting impairment of the mechanism for semantics with
lexical and syntactic access. However, this patient
demonstrated relative preservation in the ability to read
nonwords, suggesting an intact mechanism for phonology
without lexical access.
More recently, a case study has been reported that
identified the importance of Brodmann's area 37 (i.e., that
part of area 37 consisting of the posterior portion of the
left middle temporal gyrus) in the lexical-semantic system
(Raymer, Foundas, Maher, Greenwald, Morris, Rothi, &
Heilman, 1995). Following primary lesion of Brodmann's area
37, a patient developed significant word-finding problems
(anomia), despite relatively intact comprehension. More
specifically, the patient experienced impairments in oral
and written naming of pictures, oral naming to auditory
definition, writing to dictation, as well as oral reading of
real words and nonwords. Raymer et al. concluded that
Brodmann's area 37 appears fundamental in the provision of
access to lexical information within the lexical-semantic
route for language processing.
In support of Lichtheim's model (1885), McCarthy and
Warrington (1984) provide evidence that separate routes

38
exist for phonological (i.e., lexical in this case) and
semantic processing of information. They studied two
patients with impaired repetition and relatively preserved
spontaneous speech (i.e., conduction aphasia) and one
patient with the opposite pattern, that is, relatively
preserved repetition and impaired spontaneous speech
(transcortical motor aphasia). The repetition and speech
production of the two patients with conduction aphasia only
improved when semantic processing was emphasized, while the
repetition and speech production of the patient with
transcortical motor aphasia worsened under the same
conditions.
Based on findings from cerebral blood flow studies with
normal humans as well as cognitive studies with normal and
brain-impaired humans, Petersen, Fox, Posner, Mintun, and
Raichle (1989) proposed a neuroanatomical model for lexical
processing of written and spoken language. According to
Petersen et al., a written word is initially processed in
the left and right primary visual cortices. Subsequently,
information is transferred to the visual association areas
(extrastriate cortex) for lexical access. To read aloud a
written word, the information is transferred from the visual
association areas to the supplementary motor area, sylvian
cortex, and left premotor area in the frontal lobe for motor
programming and articulatory coding. Following motor
programming and articulatory coding, processing continues in
the primary motor cortex for actual motoric output (i.e.,

39
speech) of the written word. To produce a semantic
associate to a written word, information is transferred from
the visual association cortices to the left anterior
inferior frontal cortex for generation of semantic
associations to the written word. Subsequently, this
information is transferred to the supplementary motor area,
sylvian cortex, and left premotor area in the frontal cortex
for motor programming and articulatory coding. Further
processing occurs in the primary motor cortex, yielding
motoric output of the semantic associate. Petersen et al.
did not find activation in either Wernicke's area or the
angular gyrus, while normal subjects viewed, read, or
generated a semantic associate to written words contrary to
Geschwind's model. Steinmetz and Seitz (1991) suggested
that methodological procedures, employed by Petersen et al.
(i.e., intersubject averaging of positron emission
tomography scans), increased data variability, obscuring
likely activation of these areas.
To summarize the findings from the literature
pertaining to language functioning and corresponding
neuroanatomy within the left hemisphere, the posterior
cortices have been primarily associated with phonological,
lexical, and semantic processing. More specifically,
Wernicke's area appears important for phonological
processing. Brodmann's area 37 appears important for access
to lexical information within the lexical-semantic route for
language processing. The angular gyrus (Brodmann's area 39)

40
has been identified as a likely structure for the
transformation of visual word forms into auditory word forms
and vice versa (i.e., lexical processing and for access to
meaning (i.e., semantic processing). Reading can occur by
way of any of the three following processing routes:
phonological, lexical without access to semantics, lexical
with access to semantics. The frontal cortex in the left
hemisphere has been mainly associated with processes related
to output and syntax. More specifically, Broca's area has
been identified as a structure important in motor
programming for subsequent speech. The supplementary motor
area is hypothesized to be involved in the initiation and
planning of speech. The arcuate fasciculus connects
Wernicke's with Broca's area. Similar to models of
attention, language is proposed to be the result of a
network of specific anatomical areas and pathways.
Model of Recognition, Production, and Comprehension of
Written Words
Ellis and Young (1988) proposed a fairly comprehensive
model for the recognition and production of spoken and
written words that accounts for the findings from Rapcsak et
al. (1987), Coslett et al. (1987), Raymer et al. (1995),
McCarthy and Warrington (1984) as well as the results from
many other studies documenting similar dissociations within
the field of reading (e.g., Schwartz, Saffran, & Marin,
1980; Warrington & Shallice, 1979). Because the present
investigation will examine selective attention as it relates

41
to language at the lexical and semantic level with single
written words, only a subset of Ellis and Young's composite
model is presented in Figure 1-1. From this model, only the
components necessary for reading a familiar word aloud and
for producing a similar meaning or a highly associated word
(i.e., a semantic association) will be defined. In
addition, neuroanatomical structures and pathways proposed
to be important for these components, based on the above
literature review, will be included.
According to Ellis and Young (1988), the visual
analysis system identifies letters as letters and notes
their position within a written word (visual association
cortices; Brodmann's areas 18 and 19). This system also
begins to identify whether the letters form a familiar or an
unfamiliar word. The visual input lexicon contains the
representations of familiar words in their written form
(Brodmann's area 37; angular gyrus, Brodmann's area 39),
while the auditory input lexicon contains the
representations of familiar words in their heard form. The
meanings of words are represented in a distributed semantic
system (McCarthy & Warrington, 1990) with access by way of
the angular gyrus (Brodmann's area 39). The speech output
lexicon contains the pronunciations of familiar words
(angular gyrus, Brodmann's area 39). The phoneme level
activates the motor programs for the phonemes in words
(Broca's area and surrounding frontal cortex; Brodmann's
area 44, 45, 47, 12 and 6).

42
In order to read a familiar word aloud, the written
word enters the cognitive processing system from visual
sensation. Many of the word's physical properties are
preserved in a brief sensory store for up to several hundred
milliseconds (Cowan, 1988). Perceptual processing of the
word occurs next, within the visual analysis store. Because
the word is familiar, it is further processed by the visual
input lexicon. When the word is recognized as familiar, the
spoken form of the word can be retrieved from the speech
output lexicon. Once the correct pronunciation of the word
is obtained, then the phoneme store becomes activated for
subsequent motor programming of the word.
To produce a semantically associated word for a read
word, the written word receives sensory processing, then
perceptual processing within the visual analysis system.
Because the word is familiar, it activates the corresponding
entry in the visual input lexicon. The meaning of the
familiar written word is obtained within the semantic
system. In addition, synonyms or highly associated words
are coactivated by input from the semantic system to the
output lexicon and the most strongly activated associate can
be chosen for production. Correct pronunciation of the
semantic associate is triggered from the speech output
lexicon. Subsequently, the proper phoneme sequences are
activated for motor programming.
Based on Ellis and Young's (1988) model for the
recognition, comprehension, and naming of written words,

43
these two language tasks (reading a word aloud; producing a
semantic associate for a word that is read) presumably
require differing amounts of cognitive processing. After
sensation, reading a familiar word aloud reportedly requires
processing by four language components (visual analysis
store, visual input lexicon, speech output lexicon, phoneme
store). Producing a semantic association requires
processing by five language components (visual analysis
store, visual input lexicon, semantic system, speech output
lexicon, phoneme store), following sensory processing.
Therefore, it is proposed that producing a semantic
association requires more cognitive processing than reading
a word aloud.
The attentional demands of these two tasks (i.e.,
lexical processing with and without an emphasis on
semantics) are the subject of the current study. Because
task difficulty may influence performance on these tasks in
addition to or rather than the number of processing steps,
high and low frequency words will be used to decipher the
possible effects of these factors. Investigators have
demonstrated differences between high and low frequency
words when utilized in single-task and dual-task paradigms.
While reading a passage in a single-task paradigm, subjects
fixated longer on low frequency than high frequency words
(Just & Carpenter, 1980). In another single-task study
(Polich Sc Donchin, 1988) , subjects responded slower to low
frequency than to high frequency words when required to make

44
a lexical decision (i.e., deciding whether or not a word is
a real word). Additionally, these subjects exhibited a
longer P300 (event-related potential) latency and a reduced
P300 amplitude when making a lexical decision about low
frequency words, in comparison to high frequency words.
Polich and Donchin concluded that word frequency affects the
length of time spent searching the visual input lexicon for
the presented word. In dual-task paradigms, subjects
responded slower when low frequency words were paired with a
secondary task than when high frequency words were paired
with a secondary task (Becker, 1976; Herdman, 1992; Herdman
& Dobbs, 1989).
Selective Attention and Language
While theorists have postulated varied relationships
between vigilance and language (Glosser & Goodglass, 1990;
Luria, 1977), two consistent theories have been proposed
regarding selective attention and language (Nadeau &
Crosson, in press; Ojemann, 1983) in addition to Posner and
Petersen's theory (1990; see Anatomy in the Attention
section). Based on research from electrical stimulation
mapping studies (e.g., Ojemann, 1975; Ojemann, 1977),
Ojemann (1983) postulated two unique roles for the thalamus
within the hemisphere dominant for language (usually the
left). According to Ojemann, the left thalamus selectively
directs attention to language (a) by activating the relevant

45
areas of the brain for subsequent language processing (b) in
a simultaneous manner.
Nadeau and Crosson (in press) offered further support
for Ojemann's theory, while also expanding it. Following
examination of research on thalamic infarction, Nadeau and
Crosson proposed that the frontal lobe in the language
dominant hemisphere of the brain influences the nucleus
reticularis of thalamus via the inferior thalamic peduncle.
In turn, the nucleus reticularis influences the centromedian
nucleus of the thalamus, resulting in selective engagement
of cortical areas necessary for language processing (e.g.,
semantics) via diffuse connections of the centromedian
nucleus with various cortical regions. Meanwhile, the
frontal cortical-nucleus reticularis-centromedian system
reportedly holds other regions (i.e., those not necessary
for language) of the cortex in a state of relative
disengagement.
Nadeau and Crosson's (in press) theory suggests an
intrahemispheric mechanism for selective processing of
language, resulting from differential activation of the left
centromedian nucleus by the frontal lobe via the nucleus
reticularis. Posner and Petersen (1990) also proposed that
a frontal cortical structure (i.e., anterior cingulate
gyrus) is involved in attention to language as well as
regulation of the posterior attention system. While
Friedman and Poison (1981) concur that the left hemisphere
contains a mechanism and resources for selectively

46
processing language, they propose that the left hemisphere
hosts additional resources for selective processing of
information relevant to other left hemisphere functions
(e.g., motor control of the right hand). A similar left
intrahemisphere mechanism for directing selective attention
to information preferentially processed by the left
hemisphere has been considered by Petry, Crosson, Rothi,
Bauer, and Schauer (1994). Friedman and Poison differ from
this group of researchers with their view that the
attentional resources of the hemispheres can not be
differentially activated, despite inconsistent data from
functional neuroimaging studies (Binder, Rao, Hammeke,
Frost, Bandettini, Jesmanowicz, & Hyde, 1995; Demonet,
Chollet, Ramsay, Cardebat, Nespoulous, Wise, Rascol, &
Frackowiak, 1992; Petersen et al., 1989). Friedman and
Poison (1981) hypothesized that the left and right
hemispheres become equally activated for all information
processing even when one of the hemispheres participates at
a minimum level in the cognitive activity.
Based on results from a correlational study
investigating selective visual attention and language
functioning with neurologically normal and left-hemisphere
brain-damaged subjects, Petry et al. (1994) raised the
hypothesis that a left intrahemispheric mechanism with
associated resources exists for selective processing of left
hemisphere functions, such as language and detection of
right-sided visuospatial information. Relative to the

47
neurologically normal group, their left-hemisphere brain¬
damaged subjects exhibited a deficit in the ability to
direct selective attention to the right side of space in
order to detect visuospatial information.
According to Petry et al. (1994), the left-hemisphere
brain-damaged subjects did not exhibit impairments on a test
of visual neglect or on a test of visual vigilance, when
compared to the neurologically normal control group.
Additionally, for the left-hemisphere brain-damaged group,
only the deficit of re-directing selective attention to the
right side of space significantly correlated with more
severe impairments on measures of verbal fluency, auditory
comprehension, naming, and repetition.
Petry et al. (1994) essentially hypothesized a multiple
unshared resources theory of attention, where a mechanism
within each hemisphere selectively engages various resources
for a particular type of information processing. Resource
limitations exist within each processor (hemisphere). These
researchers considered possible effects of an injury to the
left intrahemisphere mechanism. They postulated that damage
to this mechanism may result in inefficient engagement of
resources for processing of information in the left
hemisphere. Inefficient processing may then exacerbate
impairments from damage already present in structures and
pathways necessary for the function. For example, disorders
of attention and language are commonly reported after injury
to left hemisphere. Petry et al. hypothesized that the

48
level of difficulty experienced by language disordered
patients may be in part determined by an inefficiency in the
selective engagement of needed cortical processes. While
impaired selective engagement may influence language
dysfunction, it was not purported to be the primary cause of
language difficulties. Petry et al. maintained that damage
to important areas and pathways involved in language
processing (e.g., Broca's area, Wernicke's area, and arcuate
fasciculus) was the primary cause of language dysfunction.
As an alternative to a general left intrahemispheric
mechanism for selective engagement of information
processors, Petry et al. (1994) also considered the possible
existence of a more refined attention mechanism. Instead of
a mechanism where attention resources are shared across all
left hemisphere processing tasks, additional unsharable
mechanisms may coexist for selective processing of
particular types of information within the left hemisphere.
For example, there may be separate attention mechanisms for
language processing and for processing right-sided
visuospatial information. The resources from these separate
mechanisms can not be shared. Thus, the mechanisms for
processing language and right-sided visuospatial information
may coexist rather than relate within the left hemisphere.
In an attempt to clarify whether language is subserved
by a general selective attention mechanism that also engages
other cognitive systems (i.e., right-sided visuospatial
information) or by a specific selective attention mechanism

that engages only language within the left hemisphere, the
current project will employ the dual-task technique.
49
Dual-Task Paradigm
The dual-task method consists of comparing concurrent
performance on two tasks to performance on each individual
task. Traditionally, this paradigm has been used to study
the operation of selective attention, leading to the
development of the previously reviewed theories of attention
(i.e., single unshared resource, single shared resource,
multiple unshared resources, multiple shared resources, and
automatic/controlled processing). More recently, this
methodology has been used to investigate the lateralization
of functions within the brain. However, Ojemann (1983)
suggests that the dual-task procedure more applicably
measures the lateralization and operation of attentional
mechanisms rather than the lateralization of cognitive
functions.
Assumptions
Regarding the operation of selective attention, a
variety of dual-task methodologies, such as dichotic
listening, visual half-field presentation, and pairing of a
manual task with a cognitive task, have been employed.
While performing two concurrent tasks, the allocation of
attention is manipulated by varying task priority or task
difficulty (Green & Vaid, 1986) . Subjects may be instructed
to focus their attention primarily on task A or B, or

50
equally on both tasks. When attention is primarily directed
to task A, results may then reflect the influence of task A
on task B. Typically, performance on task B will worsen
reflecting less attention to this task. When attention is
directed equally to both tasks, results then reflect the
bidirectional influence of each task. Additionally,
different levels of difficulty may be introduced for either
task A or B. It is generally presumed that more processing
resources are expended on a task with more focused
attention. For example, when task A receives more attention
than task B, typically performance on task B will decline.
It is also assumed that more attentional resources are
activated with increasingly difficult tasks. However, a
point is eventually reached when additional resources no
longer benefit an individual's performance, that is, when
the costs outweigh the benefits.
Because the current project will investigate whether
language is subserved by a general or a specific selective
attention mechanism within the left hemisphere, five
relevant studies (Herdman, 1992; Hiscock, Cheesman, Inch,
Chipuer, & Graff, 1989; Milner, Jeeves, Ratcliff, &
Cunnison, 1982; Posner, Early, Reiman, Pardo, & Dhawan,
1988; Posner, Inhoff, Friedrich, & Cohen, 1987) will be
reviewed. These studies were selected because they utilized
a language task in their methodology and because they were
representative of typical findings in the dual-task
literature. In comparison to single-task performance, dual-

51
task performance typically produces interference (Friedman
et al. 1988; Herdman, 1992; Hiscock et al., 1989; Milner et
al. , 1982; Posner et al., 1988; Posner et al., 1987). The
interference tends to be greater for same hemisphere tasks
(Milner et al. , 1982; Posner et al. , 1988) than for
different hemisphere tasks. The next most frequent finding
in this literature is no change in performance from the
single-task to the dual-task conditions (Gladstones et al. ,
1989; Pashler, 1992). Occasionally, concurrent performance
of same hemisphere tasks will yield enhancement in
comparison to the single-task performance (Hiscock et al.,
1989; Pasher & O'Brien, 1993). Overall, most studies report
a mixture of these types of findings; for example,
interference in one condition and no change in another
(Ballesteros et al., 1989; LaBarba, Bowers, Kingsberg, &
Freeman, 1987; Urbanczyk, Angel, & Kennelly, 1988). In
comparison to single-task performance, the following
variables tend to enable concurrent performance:
integration of the task into long-term memory, use of simple
stimuli and responses, dissimilar stimuli and responses for
tasks; and predictable presentation of task stimuli (Cohen,
1993; Hiscock, 1986).
Hiscock et al. (1989) investigated the effects of
reading aloud on a variety of unilateral finger tapping
tasks. Forty-eight right-handed subjects participated in
this experiment. In the single-task condition for reading,
subjects were instructed to read aloud, for 15 s, a summary

52
paragraph selected from an introductory psychology textbook.
Additionally, subjects were told to remember as much as
possible from the paragraph. Following the 15 s reading
period, subjects were asked to say three to five key words
reflecting the content of the paragraph.
In the single-task conditions for finger tapping,
subjects performed assorted tasks based on combinations of
the following variables: rate (speeded tapping vs.
consistent tapping), movement (repetitive tapping of one key
vs. alternating tapping between two keys), and hand used
(left vs. right). Thus, subjects received one trial (15 s)
of the following tasks: speeded-repetitive tapping,
speeded-alternating tapping, consistent-repetitive tapping,
and consistent-alternating tapping. This combination of
tasks was performed separately with the left hand and with
the right hand.
In the dual-task conditions for reading aloud and
finger tapping, the single-task condition for reading aloud
was paired with each combination of the single-task
conditions for finger tapping. Additionally, task emphasis
(reading vs. finger tapping) was manipulated, such that,
subjects received one trial (15 s) of each dual-task
condition where reading was the most important task as well
as one trial of each dual-task condition where finger
tapping was the most important task. Therefore, each dual-
task condition varied across four variables: rate,
movement, hand used, and task emphasis. An example of one

53
dual-task trial was speeded, repetitive, left-handed finger
tapping paired with reading aloud and remembering aspects of
the paragraph, where performance on the reading task was
emphasized.
Results from Hiscock et al. (1989) revealed that
reading aloud decreased the rate of speeded finger tapping
(7 %) but increased the rate of consistent finger tapping (3
%), regardless of task emphasized. In both conditions, the
right hand was significantly more affected than the left
hand; thus, when tapping rapidly right-handed tapping was
significantly reduced as compared to left-handed tapping,
and when tapping consistently right-handed tapping
significantly improved as compared to left-handed tapping.
Hiscock et al. interpreted this mixed finding of right-hand
interference (when reading and rapidly tapping) and of
right-hand facilitation (when reading and consistently
tapping) as evidence for the role of the left-hemisphere in
coordinating speech with right-hand movements in right-
handed individuals. Based on results from this study,
Hiscock et al. proposed that the left-hemisphere adjusts
right-hand movements in order to coordinate this activity
with speech.
Analysis of reading performance indicated a trend
toward faster reading and less errors in the single-task
conditions in comparison to the dual-task conditions when
reading was or was not emphasized. Hiscock et al. (1989)

54
concluded that the dual-task paradigm was a valid method for
the investigation of lateralized verbal processing.
Because Hiscock et al. (1989) compared such a large
number of dual-task conditions within subjects, the number
of trials per condition was constrained. The conclusions
from this study would be bolstered with replication as well
as with utilization of a design allowing for more than one
trial (15 s) in each dual-task condition.
Herdman (1992) investigated the effects of reading
words aloud as well as determining whether words were real
words or nonwords on reaction time to a tone discrimination
task. The methodology and results from Herdman's second
experiment will be described in detail. This second
experiment is a replication as well as an extension of the
first experiment listed in this article.
In the single-task condition for reading words aloud,
subjects were required to keep their eyes focused on a dot
that was located at the center of a computer monitor screen.
Subjects initiated a trial by pushing and holding a key with
the index finger of their preferred hand. After 500 ms, the
fixation dot was replaced by a high, medium, or low
frequency word, ranging from 4 to 6 letters. The words were
selected from Kucera and Francis (1967). Subjects were
instructed to read each word aloud as quickly as possible,
initiating removal of the word from the screen. Subjects
were given a maximum of 2 s to respond. Response times were
recorded.

55
In the single-task condition for determining whether
words were real words or nonwords (i.e., lexical decision
making), the procedure was the same as the one used in the
single-task condition for reading except for the following
differences: on half of the trials, the fixation dot was
replaced by a 4 to 6 letter nonword whereas on the other
half of the trials, the dot was replaced by a high, medium,
or low frequency 4 to 6 letter word. When subjects were
presented with a nonword, they responded aloud with
"nonword". When they received a real word, subjects said
"word". Because response times were recorded, subjects were
instructed to respond as quickly as possible.
In the single-task condition for the tone
discrimination task, subjects were instructed to keep their
eyes fixated on the central dot. Subjects started a trial
by pushing and holding a key with the index finger of their
preferred hand. After 500 ms, the fixation dot was replaced
by five asterisks, simulating the visual complexity of word
presentation in this position during the dual-task
conditions. Additionally, either a low or high pitch tone
was presented. When subjects received a low pitch tone
(distractor), they were instructed to continue holding the
key which they pushed to start the trial. When they
received a high pitch tone (probe), subjects were told to
remove their finger from the key as quickly as possible.
Reaction times were recorded. For distractor tones,
reaction times would be approximately 2 s (i.e., the maximum

56
amount of time allowed for a trial). Reaction times for
probe trials would be less than 2 s.
In one dual-task condition, reading words aloud was
paired with the tone discrimination task. In the other
dual-task condition, the lexical decision task was paired
with the tone discrimination task. For these dual-task
conditions, subjects were told to keep their eyes focused on
the central dot. Subjects initiated a trial by pushing and
holding a key with the index finger of their preferred hand.
After 500 ms, the fixation dot was replaced by a word
(reading task) or by either a word or a nonword (lexical
decision task). In addition, one of two tones was
presented. When subjects received a distractor tone, they
were instructed to respond to the letter string (i.e., read
it aloud or say either "word" or "nonword") while they
continued holding the key which started the trial. When
subjects received a probe tone, they were instructed to stop
performing the letter string task and to remove their finger
from the start key as rapidly as possible. On probe trials,
subjects did not provide a response for the reading task or
for the lexical decision task. This paradigm has been
referred to as the dual-task change paradigm because
subjects forfeit a response to the primary task in order to
respond only to the secondary task. The tone discrimination
task began 0, 84, or 167 ms, after the presentation of a
letter string (i.e., the primary task).

57
Primary task (reading and lexical decision) and
stimulus onset asynchrony (0, 84, and 167 ms) were between
subjects factors. Therefore, each subject was randomly
assigned to one of six dual-task conditions. Each of the
six dual-task conditions was performed by 16 subjects,- thus
a total of 96 subjects participated in this study. In
addition, these subjects performed the corresponding single¬
task conditions. For example, subjects assigned to reading
and 0 ms condition performed the single-task condition for
reading words aloud, the single-task condition for tone
discrimination and the dual-task condition for reading and
tone discrimination with a stimulus onset asynchrony (SOA)
of 0 ms between the tasks. Handedness of subjects was not
assessed.
Results from Herdman (1992) revealed significantly
slower responding to the probe tones during the tone
discrimination task when it was paired with the reading or
lexical decision tasks than when it was performed alone. In
addition, subjects took longer to respond to probe tones
paired with the lexical decision task in comparison to probe
tones paired with the reading task. Subjects also responded
slower to probe tones at later SOAs (84 and 167 ms) than to
probe tones presented simultaneously with a letter string (0
ms). Based on prior research demonstrating slower reaction
times to an auditory probe when it was paired with a low
frequency word in comparison to a high frequency word
(Becker, 1976; Herdman & Dobbs, 1989), Herdman (1992)

58
concentrated his analyses on the reaction times to probe
tones occurring with or after the presentation of high and
low frequency words. Results indicated that subjects took
longer to respond to probe tones paired with low frequency
words in comparison to probe tones paired with high
frequency words. Herdman concluded that "(a) lexical access
requires attentional resources and (b) more resources are
required to recognize low- as compared with high-frequency
words" (p. 466).
Milner et al. (1982) measured the effects of counting
backward as well as manually adjusting the orientation of
screws on reaction times to lateralized light flashes. In
the single-task condition, right-handed subjects were
required to keep their eyes continually focused on a
fixation spot appearing at the center of a computer monitor
screen. Following a brief warning tone, a small light flash
was randomly presented to a fixed location at the left or
right of the central fixation spot. Each light flash lasted
for 2 ms. Subjects were instructed to press a key with
either their left or right thumb whenever they detected a
light flash. On half of the trials, subjects responded with
their left thumb. On the other half of the trials, they
responded with their right thumb.
In one of the dual-task conditions utilized by Milner
et al. (1982), twelve right-handed subjects counted
backwards by 3, 4, or 6 while detecting light flashes.
Light flashes were presented only when subjects were in the

59
process of saying a number. In the other dual-task
condition, sixteen right-handed subjects adjusted the
orientation of screws to match the orientation of other
screws while detecting light flashes. Light flashes were
presented only when subjects were in the process of turning
a screw. In both dual-task conditions, an instruction to
focus on the central fixation spot replaced the warning
tone, prior to each trial.
Results from Milner et al. (1982) revealed a
significant increase in reaction times for each dual-task
condition in comparison to the single-task condition. When
the backwards counting task was paired with the light flash
detection task, larger reaction times were obtained to light
flashes appearing in the right visual field than in the left
visual field. When the manual orientation task was paired
with the light flash detection task, no differences existed
in the reaction times for the right and left visual fields.
This study replicated results obtained by Rizzolatti,
Bertoloni, and Buchtel (1979). According to Milner et al.,
the effect of the verbal task (i.e., slower responding to
right-sided light flashes) does not seem to be the result of
a "nonspecific cognitive overload" (p. 594) because the
manual orientation task did not also cause selectively
slower responses to right-sided light flashes.
Posner and his colleagues conducted two dual-task
experiments that utilized a task involving language and a
covert orienting of visual attention task (COVAT; Posner et

60
al., 1988; Posner et al., 1987). Before explaining the
dual-task experiments, the COVAT must be explained.
Covert Orienting of Visual Attention Task
The covert orienting of visual attention task (COVAT)
was developed by Posner in 1980. Since this time, it has
been used in an extensive number of studies with
neurologically normal subjects as well as brain-injured
patients. The task, which employs nonverbal symbols and
requires only a key-press response, yields a consistent
pattern of results with normal subjects (Posner, 1980;
Posner et al., 1988). For brain damaged patients, specific
patterns of impairment result following lesions of the left
or right hemisphere (Posner et al., 1984; Rafal & Posner,
1987) .
The COVAT requires subjects to keep their eyes focused
on a fixation point at the center of a computer monitor
screen ("+") and to press a key as soon as they see the
target ("*"). The target appears in a box either to the
left or to the right of the central fixation point. On a
majority of trials, subjects receive a cue (i.e., the
brightening of one of the two boxes) indicating where the
target is likely to appear. For most cued trials (i.e., 80
% of cued trials), the target appears in the box which has
brightened (valid trials), but for some cued trials (i.e.,
20 % of cued trials), the target appears in the box which
has not brightened (invalid trials). On other trials,

neither box is brightened before the target appears (no cue
trials; see Figure 1-2).
61
When all three trials are randomly intermixed within
blocks, neurologically normal subjects respond fastest to
valid trials, slowest to invalid trials, and intermediately
to no cue trials (Posner, 1980; Posner et al., 1988). The
advantage in reaction time for valid over invalid trials has
been termed the validity effect (Posner, Sandson, Dhawan, &
Shulman, 1989), and it has been attributed to the effects of
the cue. In addition to alerting subjects to an upcoming
target, the cue is a sensory stimulus that covertly directs
attention to a particular location. The cue affects
processing within 50 ms of onset (Posner & Cohen, 1984). If
the target subsequently appears at the cued location, then
processing is facilitated. If the target appears elsewhere,
then processing is inhibited. The effects of facilitation
and inhibition of processing occur 100 ms after the onset of
the cue even when the cue's accuracy is reduced to chance,
that is, when the target has a 50 % chance of appearing in
the box that brightened (Friedrich & Rader, 1990).
In accordance with instructions, subjects do not move
their eyes during this task because the most efficient
strategy is to keep the eyes centered (Posner, 1980; Posner
& Cohen, 1984). With their eyes centrally fixated, subjects
attend, covertly and selectively, to cued locations for
rapid target detection. Posner, Synder, and Davidson (1980)
have characterized selective visual attention as a spotlight

varying in size with task demands. The spotlight enhances
processing of the selected information.
62
Posner and his colleagues described three mental
operations involved in covert orienting of visual selective
attention (Posner & Rafal, 1987; Posner, Walker, Friedrich,
& Rafal, 1984; Rafal & Posner, 1987; Rafal, Posner,
Friedman, Inhoff, & Bernstein, 1988) . Covert orienting
involves the mental shifting of the spotlight (i.e.,
selective attention) to the source of interest. First,
selective attention 'disengages' from its current focus;
next attention 'moves' to the location of interest; and
finally attention 'engages' the point of interest.
Regarding performance on the COVAT, when the cue is
presented, subjects move selective attention covertly to the
cued location and engage attention in anticipation of the
upcoming target. If the target appears at this engaged
location (valid trials), then subjects tend to respond
quickly. However, if the target does not appear at this
engaged location (invalid trials), then subjects must
disengage attention, move it to the target location, and
engage the target, resulting in a slower response time. If
a cue is not presented (no cue trials), then subjects move
attention to the target and engage it at this location.
According to Posner and his collaborators, subjects do
not engage attention at the central fixation point; thus,
when they are presented with a cue or target, covert
orientation begins with movement of selective attention

63
rather than with disengagement. However, it appears that
some amount of engagement is present at the central fixation
point as well as at each possible target location. At the
fixation point, it is hypothesized that a small amount of
attention is engaged since subjects are instructed to keep
their eyes focused there. In addition, the most efficient
strategy for target detection entails keeping one's
attention centered at the beginning of each trial. At the
possible target locations, a small amount of attention is
engaged prior to the presentation of a cue or target
enabling detection of these stimuli.
Posner et al. (1987) investigated whether selective
attention to visuospatial information was managed by an
isolated resource or by a general resource that also
selectively attends to language. In addition to the COVAT,
Posner et al. used one of two tasks involving language for
the dual-task condition. One task required subjects to
count the number of auditorily presented words beginning
with a particular phoneme. The other task required subjects
to count backwards by one from an auditorily presented
three-digit number. The phoneme counting task was performed
silently, while the counting backward task was performed
aloud.
Eight neurologically normal subjects and nine patients
with parietal lesions performed the COVAT paired with the
phoneme counting task. Eight different neurologically
normal subjects and five patients from the parietal lesion

64
group performed the COVAT paired with the counting backwards
task. Before and after the dual-task condition, all
subjects completed the COVAT alone.
Posner et al. (1987) hypothesized that if visuospatial
information is processed by an isolated attentional
resource, then subjects should still benefit from the cue on
valid trials during the dual-task condition. However, a
general increase in reaction times would be anticipated for
the dual-task condition "due to interference with output or
reliance on some very general common resource" (p. 108). If
visuospatial information is processed primarily by a general
attentional resource, then subjects should no longer benefit
from the cue on valid trials during the dual-task condition.
A general increase in overall reaction times would also be
expected.
Because patients with lesions of the parietal lobe have
been shown to have difficulty re-directing attention to the
side of space contralateral to their lesion (Posner et al.,
1984; Posner et al., 1987), these patients were expected to
respond even slower to invalid trials with contralateral
targets during the dual-task condition. This deficit was
expected, if visuospatial information and language are
processed by a general attentional resource. If slower
response times do not result for these trials during the
dual-task condition, then "the attention system common to
language and spatial orienting is quite different from that
used by spatial orienting alone" (p. 109).

65
Regarding results for the neurologically normal
subjects, responses were slower during the dual-task
conditions than during the COVAT condition. When the
phoneme counting task was paired with the COVAT, subjects
continued to benefit from the cue on valid trials. When the
counting backwards task was paired with the COVAT, normal
subjects benefited less from the valid cues. Posner et al.
(1987) suggested that the counting backward task was more
difficult than the phoneme counting task, thus interfering
with orienting toward valid COVAT cues.
Performance of the parietal damaged patients varied
with the target-onset interval. When the target appeared
100 ms after the cue, patients did not benefit from the cue
on valid trials during the dual-task conditions. However,
at 500 or 1000 ms, the patients benefited from the valid
cues. Response times tended to be larger during the dual-
task conditions than the COVAT condition. The parietal
damaged patients did not exhibit extraordinarily slow
responding to the invalid trials with contralateral targets.
Posner et al. (1987) suggested that orienting toward valid
cues at short intervals (100 ms) was more difficult than
orienting toward valid cues at longer intervals (500 ms).
Posner et al. (1987) concluded that the "spatial
orienting system must share some operations with the two
secondary tasks, causing a delay in orienting when they are
sufficiently difficult" (p. 112). According to Posner et
al., the results suggest an interaction of two attention

66
systems: (a) an isolated system and set of resources for
selective processing of visuospatial information and (b) a
general system and set of resources for selective processing
of visuospatial information and language. The general set
of resources reportedly directs orienting to all types of
information, while the resources specific to visuospatial
information permit subjective report of this information.
Posner et al. hypothesized that the frontal lobes were
important in the general system for selective processing of
visuospatial information and language.
During the dual-task conditions in Posner et al.
(1987), it is difficult to know what the response times to
the COVAT reflect because presentation of the language tasks
was not controlled. While performing the COVAT, subjects
responded to an audiotape presenting stimuli for the
language tasks. The language stimuli were not coordinated
with the COVAT; therefore, the COVAT data in the dual-task
condition probably reflect multiple influences. If a COVAT
trial occurred prior to processing language stimuli, then
some of the results may reflect the interference of the
COVAT on language. If a language stimulus occurred prior to
processing the COVAT, then some of the results may reflect
the interference of language on the COVAT. Additionally,
some of the results probably reflect that lack of
interference between the COVAT and language.
Although Posner et al. (1987) reportedly wanted to
study selective attention, the vigilance component of

67
attention was likely influenced by including a large number
of trials (e.g., 100, 300) in each block in the various
conditions possibly inducing fatigue and reducing vigilance
in the later trials within each block. Surprisingly, Posner
et al. (1987) neglected to report whether the neurologically
normal subjects responded differently to the COVAT targets
appearing on the left and right side of space during the
dual-task conditions. While concurrently performing the
COVAT and a language task, differential processing demands
are made on the left and right cerebral hemispheres. The
left hemisphere primarily processes right-sided COVAT
targets as well as language, whereas the right hemisphere
primarily processes only left-sided COVAT targets. Because
of this difference in the amount of cerebral hemispheric
processing, slower reaction times would be expected for
right-sided COVAT targets, when compared to left-sided
targets, during a concurrent language task.
In a subsequent study, Posner et al. (1988) did examine
differential responding to left- and right-sided COVAT
targets during concurrent performance with a language task.
The language task required subjects to repeat aloud, with
minimal lagtime, material from an audiotaped book (i.e.,
"Lincoln"). Before and after completion of the COVAT alone,
20 normal subjects performed the COVAT paired with this
repetition task.
Results from Posner et al. (1988) revealed that
subjects responded slower to the 100 ms trials of the COVAT

68
during dual-task performance than during single-task
performance. In the single-task condition, subjects
responded comparably to left- and right-sided COVAT targets.
In addition, they responded faster to valid than to invalid
trials when the COVAT was performed alone, demonstrating the
validity effect. In the dual-task condition, Posner et al.
reported that subjects responded slower to invalid trials
with right-sided targets, after the no cue trials were
excluded from the dataset. During these particular trials,
subjects received a left-sided cue followed by a right-sided
target. Posner et al. interpreted this finding as evidence
of the effect of attention to language on visuospatial
orienting. Additionally, this latter dual-task finding was
similar, but less severe, to the pattern obtained by
schizophrenics performing the COVAT alone.
For slower responding to invalid trials with right¬
sided targets during the dual-task condition, an alternative
interpretation (Posner & Early, 1990) has been offered
instead of the one provided by Posner et al. (1988) .
Instead of subjects responding slower to invalid trials with
right-sided targets, alternatively subjects responded faster
to invalid trials with left-sided targets. The basic
finding was a significant difference between left- and
right-sided targets on invalid trials with faster reaction
times to left-sided targets and slower reaction times to
right-sided targets. Therefore, this finding of slower
responses to invalid trials with right-sided targets can be

69
interpreted as difficulty shifting attention from the left¬
sided cue to the right-sided target (Posner et al., 1988).
Alternatively, this same finding as well as the finding from
Petry et al. (1994) can be interpreted as limited response
(i.e., attraction of covert attention) to right-sided cues,
resulting in faster responses to left-sided targets on
invalid trials (Posner & Early, 1990) . When the difference
between valid and invalid trials is compared, comparable
differences are obtained for single-task performance with
left-sided targets and for single-task and dual-task
performance with right-sided targets. The difference in
reaction times for valid and invalid trials is reduced only
for dual-task performance with left-sided targets (i.e.,
absence of a validity effect). As a result, the
interpretation that limited response (i.e., attraction of
covert attention) to right-sided cues resulting in faster
responses to left-sided targets on invalid trials may be
more viable. However, subjects do not appear to display
slower reaction times to valid trials with right-sided cues
and targets. These subjects appear to benefit from right¬
sided cues, facilitating fast reaction times to subsequent
right-sided targets (valid trials with right-sided cues and
targets). Additionally, subjects respond comparably to
valid trials with right- and left-sided cues and targets.
In comparison to Posner et al. (1987), the study
conducted by Posner et al. (1988) is an improvement because
differential responding to left- and right-sided targets was

70
explored. However, Posner et al. (1988) still retained the
following two methodological flaws: (a) uncontrolled
presentation of the language task in relation to the COVAT
during the dual-task condition and (b) large number of
trials (i.e., 240) in each block of the various conditions.
When presentation of the language stimuli is not controlled
with regards to presentation of stimuli in the COVAT task,
the data from the COVAT in the dual-task condition likely
reflect multiple influences (i.e., interference of the COVAT
on language, interference of language on the COVAT, and lack
of interference between the COVAT and language). When a
large number of trials are administered, vigilance may be
reduced in the selective attention task.
In addition to Posner and his colleagues (Posner et al.
1988; Posner et al., 1987), Pashler and O'Brien (1993) as
well as Milner et al. (1982) measured reaction times to
lateralized targets during concurrent performance of a
language task. These latter two experiments differed from
the Posner et al. studies in that sensory cues were not
administered prior to the presentation of left- and right¬
sided targets. During dual-task performance, Pashler and
O'Brien found no significant differences in reaction times
to left- and right-sided targets. In contrast, Milner et
al. found significantly slower responses to right-sided
targets as compared to left-sided targets, during dual-task
performance. Pashler and O'Brien required subjects to read
nonwords while they also responded to one of four possible

71
lateralized targets. Milner et al. required subjects to
count backwards while they responded to one of two possible
lateralized targets. Posner et al. (1988) did not report
significant differences between left- and right-sided
targets on the uncued trials or on the valid trials, during
dual-task performance. However, a significant difference
between left- and right-sided targets was reported for
invalid trials during dual-task performance. Because the
cues utilized in the Posner et al. studies are sensory
(i.e., the temporary brightening of a likely location for
subsequent target presentation), the COVAT is a useful
paradigm for studying the effects of language processing on
visual selective attention. The methodology proposed for
the present study is most similar to the methodology
utilized by Posner et al. (1988), as the proposed study
paired a reading task and a semantic association task with
the COVAT while Posner et al. paired a text repetition
(shadowing) task with the COVAT.
The current project utilized a similar but improved
methodology to one used by Posner and his colleagues (Posner
et al., 1987; Posner et al., 1988). While investigating
whether a specific or a general selective attention
mechanism exists within the left hemisphere for processing
language, the present study controlled the presentation of
both tasks during the dual-task conditions. The language
tasks were presented prior to the COVAT on each trial, so
that, the effects of language on the COVAT would be

72
reflected in the dual-task COVAT data. In addition, the
effect of vigilance was reduced by decreasing the number of
trials in each block. The present study also examined
whether subjects responded differently to left- and right¬
sided COVAT targets, while they concurrently performed a
language task.
Experiment and Hypotheses
A dual-task paradigm was employed in order to
investigate whether a specific or a general selective
attention mechanism existed within the left hemisphere for
processing language. With regard to theories about the
operation of attention, the proposed study examined whether
a single or multiple resources of attention existed and
whether or not the resource(s) were shared between multiple
attentional resources and or cognitive functions. This main
question was assessed within the context of a proposed model
for selective processing of language and visuospatial
information based on assumptions about the anatomical system
needed to engage these cortical regions of the brain.
Experiment
In the current study, language was examined at the
lexical level with single written words with minimal or
maximal emphasis on semantic processing. Although all the
language tasks required lexical access (i.e., access to
words), one task emphasized semantics (i.e., producing

73
semantic associates) while the other task did not (i.e.,
reading familiar words). The following two language tasks
were administered: reading a familiar word, and producing a
similar meaning or a highly associated word. Selective
attention was examined at two levels within the present
study. At one level, the COVAT assessed selective attention
to visuospatial information, appearing to the left and right
of a central fixation point. At another level, selective
attention was examined during the dual-task condition; that
is, the effect of semantic and non-semantic lexical
processing on visual selective attention. Since the purpose
was to examine the effects of lexical or lexical-semantic
processing on visual selective attention, the language tasks
were emphasized as primary and were presented before the
visuospatial attention task (COVAT).
The study utilized neurologically normal subjects.
Prior to the dual-task condition, all subjects performed the
two language tasks and the COVAT alone. All subjects then
performed each of the two language tasks paired with the
COVAT. During the dual-task condition, single words
replaced the central fixation point while subjects then
performed the COVAT (see Figure 1-3). Accuracy of response
was recorded for the language tasks, while reaction time was
recorded for the COVAT. Subjects responded with their non¬
dominant left hand while performing the COVAT alone and
paired with a language task, in order to facilitate
comparison to other COVAT studies utilizing neurologically

normal adults and left-hemisphere brain damaged patients
(Petry et al., 1994).
74
To insure concurrent performance during the dual-task
conditions, the stimulus onset asynchronies (SOAs) between
presentation of the language task (i.e., single words to be
read aloud or single words for subsequent generation of a
semantic associate) and the COVAT (i.e., brightened box
attracting covert selective attention to the cued area and a
star signaling a key-press response) were determined based
on a review of the event-related potential literature.
Event-Related Potentials
Event-related potentials (ERPs) are changes in membrane
potential for a group of cells occurring before, during, or
after a physical or psychological event (Picton, 1988). To
summarize the results from a survey of relevant event-
related potential studies, exposure to a high contrast
pattern visual stimulus results in processing from the
peristriate cortex at 100 ms post-stimulus onset (Galaburda
& Livingstone, 1993; Vaughan & Gross, 1969). At this point,
it appears that the first output from the stimulus leaves
the occipital cortex for further processing in other
cortical areas. If the pattern stimulus is psychologically
significant, then the potentials appear to reflect such
influences. In the context of a visual selective attention
task, Rugg, Milner, Lines, & Phalp (1987) reported larger
occipital potentials during an attend than during an
unattend condition. These potentials occurred 20 ms later

than the ones recorded to pattern stimulation lacking
psychological significance (Galaburda & Livingstone, 1993).
75
Potentials recorded from the frontal cortex during a
visual selective attention task (Rugg et al., 1987) and from
the frontal and parietal cortices during a category priming
task (Boddy, 1981) yielded a similar significant finding.
During both tasks, an enlarged negative wave peaked around
130 and 145 ms. Rugg et al. interpreted this potential as
reflecting further cortical processing of the visual
stimuli. Boddy interpreted this similar potential as
reflecting selective attention to words associated with a
particular category prime. Thus, Boddy proposes an effect
of selective attention as well as early access to semantics
(i.e., further cortical processing).
From additional recordings of frontal and parietal
cortices, Rugg et al. (1987) reported enhanced negativity of
a negative wave peaking at 250 ms and of a positive wave at
350 ms during an attend rather than during an unattend
condition. These potentials were also interpreted as
reflecting further information processing (Hillyard & Munte,
1984; Picton, 1988). From additional recordings of the
frontal cortex in Boddy (1981), an enlarged positive wave
peaking at 216 ms was registered. This wave was interpreted
as reflecting effects of selective attention and early
access to the meanings of words.
Neville, Kutas, & Schmidt (1982) reported an enhanced
negative wave peaking at 409 ms from left frontal and

76
temporal cortices during unilateral and bilateral
presentation of vertically-oriented words. This potential
was proposed to reflect processes related to reading.
During the reading condition in Stuss, Sarazin, Leech, &
Picton (1983), two negative waves were recorded: One
peaking at 262 ms and the other at 421 ms.
Regarding presentation of visual stimuli in the present
experiment in order to insure concurrent task performance,
appropriate intervals between the language task and the
COVAT would be 100 ms and 250 ms; thus, following
computerized presentation of a word, the COVAT cue would
randomly begin after a 100 or 250 ms delay followed by the
COVAT target after the typically used 100 or 800 ms delay
(cued trials). Thus, on cued trials, the COVAT target
randomly appeared after a 200 ms, 350 ms, 900 ms, or 1050 ms
delay from the "start" of the language task in the dual-task
conditions (see Figure 1-4). On no cue trials, the COVAT
target randomly appeared after a 200 ms, 350 ms, 900 ms, or
a 1050 ms delay after word onset.
With a 100 ms delay between the presentation of a word
from the language tasks and the COVAT, the word would nearly
have completed processing within the occipital cortex when
the COVAT cue began. Thus, this 100 ms interval would
assess the effects of early single word reading or semantic
association on visual selective attention. With the 250 ms
delay, words would be in the midst of processing by cortical
areas other than the occipital cortex, when the COVAT cue

77
began. This COVAT cue would complete processing within the
occipital cortex at 370 ms. With the 900 ms or 1050 ms
intervals, primary cortical processing of the word would
have ceased, when the COVAT began.
Anatomy Proposed to be Primarily Involved in Selective
Attention and Subsequent Processing of Language and
Visuospatial Information
Based on a review of studies involving lesions of the
thalamus, Nadeau and Crosson (in press) described a system
within each hemisphere involving the frontal cortex, nucleus
reticularis, inferior thalamic peduncle (which connects the
frontal cortex with the nucleus reticularis), and
centromedian that selectively engages the specific cortical
areas necessary for information processing while maintaining
unneeded cortical areas in a state of relative
disengagement. With regard to language, the fronto-nucleus
reticularis-centromedian system in the language dominant
hemisphere (i.e., the left hemisphere for the majority of
right-handed individuals) differentially activates needed
areas for language processing while keeping other cortical
regions (i.e., those not necessary for language processing)
relatively disengaged. This left intrahemisphere system is
also proposed to activate other structures and pathways of
the brain that are needed for attention to other cognitive
activities, for example, detection of right-sided
visuospatial information.

78
The intrahemisphere system, proposed by Nadeau and
Crosson (in press), for selective engagement of attention
and corresponding anatomical structures and pathways for
cognitive processing can be considered an example of a
multiple resources theory of attentional operation, even
though it was not originally conceptualized in this manner.
As implied by their theory, separate systems of attentional
engagement are proposed for each hemisphere. Although
resources may be shared within a hemisphere, it will be
assumed that they cannot be shared between hemispheres;
thus, their proposal satisfies the conditions for a multiple
unshared (between hemispheres, not between tasks within a
single hemisphere) resources model of attention.
Alternatively, if these anatomical systems are not separate
but shared between tasks within a hemisphere, then dual-task
performance should be impaired relative to single-task
performance because single or multiple anatomical regions
would be overloaded within the left hemisphere.
With regard to the proposed experiment, the anatomical
systems for selective processing of language and right-sided
visuospatial information are purported to share common
anatomical structures and pathways, resulting in
demonstrable impairments during concurrent performance of
these tasks relative to single-task performance. In
addition to the shared use of the selective engagement
mechanism in the left hemisphere, the language tasks and the
right-sided cues and targets of the COVAT will share use of

79
the primary sensory and motor areas as well as unimodal and
multimodal cortical areas (i.e., occipital cortex, angular
gyrus, premotor cortex, and motor cortex). During dual-task
performance, it was hypothesized that complex processing and
responding required at the level of the left frontal cortex
overloads the selective engagement attentional system,
leading to impairment of language and right-sided COVAT
performance. In addition to a decrement in language
performance during dual-task conditions, impairment of only
right-sided COVAT cues and targets would support a general
system for attention within the left hemisphere where
attentional resources are shared among cognitive tasks
within this hemisphere but not between hemispheres. If the
anatomical systems for selective processing of written
language and visuospatial information are separate and not
shared within the left hemisphere, then dual-task
performance should be comparable to single-task performance
in the present study. This latter finding would also be
predicted by a multiple resources theory of attention where
all resources share attention among cognitive tasks.
If performance to left- and right-sided COVAT cues and
targets are equally impaired during dual-task performance in
addition to a decrement in language performance, then a
single resource rather than a multiple resources model of
attention would be bolstered. According to the single
resource theory of attention, dual-task performance is
always worse than single-task performance. It is

80
hypothesized that the performance deficits would interfere
with processing in both hemispheres regardless of whether
structures and pathways were primarily engaged in one
hemisphere over the other hemisphere. If the attentional
resource was not shared between cognitive tasks, then marked
impairments would occur for all dual-task combinations
regardless of the attentional demands inherent in each task
because of interference from rapid switching of attention
between tasks. If the resource was shared between cognitive
tasks, then dual-task impairments would be graded as based
on each task's demands for attention. As an example of
possible performance on the COVAT paired with the proposed
language tasks, more marked deficits would be expected in
response to left- and right-sided COVAT stimuli as well as
to language stimuli when the COVAT was paired with the
semantic association task in comparison to the reading task
if the single resource was shared. With a more attention
demanding task, like semantic association, paired with the
COVAT, more deficits would be expected because more
interference is hypothesized in order to achieve successful
performance of both tasks. Less attentional interference is
hypothesized for the reading task when it is performed
concurrently with the COVAT, therefore, less impairment of
responses to left- and right-sided COVAT stimuli and to
language stimuli would be expected, in comparison to dual¬
task performance of the COVAT with the semantic association
task.

81
Hypotheses
Based on the proposed relationship between attention
and language as well as findings from the dual-task
literature (particularly Posner et al., 1988), a general
left intrahemispheric mechanism for engagement of attention
and subsequent cognitive processing is proposed. This
mechanism can be conceptualized as a multiple unshared
resources theory of attention where resources are shared
among cognitive tasks executed within a particular
hemisphere but not between hemispheres. Given the above
conceptual framework for selective attention, the following
hypotheses were proposed:
1. Dual-task performance would show effects of
interference; that is, slower reaction times to COVAT
targets and increased language errors (mispronunciation on
reading task, incorrect answer or no response on semantic
association task).
2. More specifically, slower reaction times would be
anticipated for invalid COVAT trials with right-sided
targets during dual-task performance. In addition, subjects
would respond significantly slower to invalid trials as
compared to valid trials with right-sided targets,
demonstrating the validity effect.
3. Faster reaction times would be expected for invalid
COVAT trials with left-sided targets during dual-task
performance. Additionally, a validity effect would not be
anticipated for left-sided targets during dual-task

performance; thus, no significant difference in reaction
times for valid and invalid trials with left-sided targets.
82
4. Because the semantic association task was
hypothesized to require more processing than the reading
task, more interference would be expected when the COVAT was
paired with this task than with the reading task; thus, the
pattern of responding identified in (2) and (3) would be
more pronounced. Within each dual-task condition, subjects
would respond slower to low frequency words than to high
frequency words. A significant difference in reaction time
would be anticipated between low frequency words of the
semantic association-COVAT condition and high frequency
words of the reading-COVAT condition.
5. Although more language errors were expected during
the dual-task conditions in comparison to the single-task
conditions, this result would not be significant, only a
trend (Herdman, 1992; Hiscock et al., 1989). More errors
would be anticipated for the semantic association task than
for the reading task. In addition, subjects would be
expected to make more errors with low frequency rather than
high frequency words.

Figure 1-1. Model for the recognition, production, and
comprehension of written words, based on
Ellis and Young (1988).

34
Heard Word Written Word
i
Speech

Figure 1-2. Schematic of the covert orienting of visual
attention task.

Valid Trial
Fixation
Cue
Target
Fixation
Cue
Target
Fixation
Target
+
+
Invalid Trial
+
No Cue Trial
+

Figure 1-3. Schematic of dual-task performance with the
covert orienting of visual attention task
and a language task.

Valid Trial
Fixation
+
Language Task
WORD
COVAT Cue
WORD
COVAT Target
WORD
*
Invalid Trial
Fixation
+
Language Task
WORD
COVAT Cue
WORD
COVAT Target
WORD
*
No Cue Trial
Fixation
+
Language Task
WORD
COVAT Target
WORD
*

Figure 1-4. Stimulus onset asynchronies for dual-task
performance of the covert orienting of
visual attention task and a language task.

90
Valid Trial
Fixation
+
Language Task
WORD
COVAT Cue
WORD
COVAT Target
WORD
*
I
Invalid Trial
Fixation
+
Language Task
WORD
COVAT Cue
WORD
COVAT Target
WORD
*
No Cue Trial
Fixation
+
Language Task
WORD
COVAT Target
WORD
*
Time
1000 ms
100/250 ms
100/800 ms
500/2000 ms
1000 ms
100/250 ms
100/800 ms
500/2000 ms
1000 ms
200/350 ms
900/1050 ms
500/2000 ms

CHAPTER 2
MATERIALS AND METHODS
Subiects
Potential subjects from introductory psychology classes
at the University of Florida and Santa Fe Community College
were screened with a structured interview (see Appendix A)
and with the six primary items from the Briggs-Nebes
Modification of the Annett Handedness Questionnaire (Annett,
1967; Briggs & Nebes, 1975; see Appendix B). Of the 65
subjects screened, 36 were excluded because they did not
meet all the proposed criteria necessary for participation.
Subjects were excluded: (a) If they were not native English
speakers; (b) if they had a history of brain infection or
tumor; (c) if they were unconsciousness for more than 5
minutes following a single incident of brain injury or if
they had experienced more than one incident of brain injury;
(d) they reported changes in their cognition or behavior
following a high fever; (e) if they had a history of
learning disability, long-term or severe psychopathology,
attention-deficit hyperactivity disorder, or seizures; (f)
if drugs or alcohol caused problems for them in
relationships, at school or at work, resulted in missing
work or class on more than one occasion, or led to the
receipt of a "driving under the influence" charge; (g) if
91

92
receipt of a "driving under the influence" charge; (g) if
they had a history of language or speech disorder; (h) if
they did not have normal or corrected-to-normal vision in
both eyes; or (i) if they did not sleep at least four hours
during the night prior to the day of the experiment. On the
Briggs-Nebes Modification of the Annett Handedness
Questionnaire, subjects were excluded if they obtained a
score below 5, indicating either left-hand dominance or
mixed-handedness. Following screening, 29 right-handed,
native English speaking, neurologically normal
undergraduates voluntarily participated in order to fulfill
a class requirement or to receive extra-credit in class.
Of the 29 subjects, 14 were obtained from the
University of Florida while 15 were obtained from Santa Fe
Community College. Twenty females and nine males
participated in the present study. The mean age of subjects
was 23.1 (SD = 5.3), while the mean number of years of
education was 13.6 (SD = 1.2).
Hand Preference
Subjects' hand preference was determined by their
responses to the six 'primary' items from Briggs-Nebes
Modification of the Annett Handedness Questionnaire (Annett,
1967; Briggs & Nebes, 1975; see Appendix B). For each
activity, subjects indicated on a five-point scale from
'always left' to 'always right' which hand was used. Values

93
were assigned to each response, ranging from -2 (always
left) to +2 (always right). The total score was the sum of
the values for each question. Total scores could range from
-12 to +12. Subjects with scores between -12 and -5 were
considered left-hand dominant. Subjects with scores between
-4 and 4 demonstrated mixed-handedness, while subjects with
scores between 5 and 12 were right-handed. Subjects scoring
less than 5 were excluded from the study. The mean score
for subjects was 10.5 (SD = 1.9).
Apparatus
Covert Orienting of Visual Attention Task
The covert orienting of visual attention task (COVAT)
was performed on an IBM Personal Computer AT with a
Panasonic Panasync C1381 color monitor in a moderately lit
room. Subjects were seated approximately 61 cm in front of
the computer monitor screen.
Throughout performance on this task, a green cross and
two dark rectangles bordered in green remained present on
the computer screen. The green cross (0.2 X 0.2 cm) was
located at the center of the screen, while one dark
rectangle bordered in green (1.5 X 2.0 cm) was located to
the left and right of the cross. The cross and the
rectangles were presented at the same horizontal level on
the dark background of the computer screen. The two
rectangles were separated by 13 cm and were approximately

94
centered on the screen (8 cm from the top, 11.5 cm from the
bottom, and 5 cm from each side of the screen to the outer
edge of the left and right rectangles). The left and right
rectangles were 9 degrees from the centered cross. While
performing the COVAT, subjects were instructed to keep their
eyes focused on the cross (see Appendix C for complete task
instructions given to subjects).
For each trial, the target stimulus was a green
asterisk (0.3 X 0.3 cm). The asterisk was presented
randomly 100 or 800 ms after the start of a trial, inside
the center of the left or right rectangle. For 75 % of the
trials, a cue was presented. The cue was the brightening of
the border of one of the two rectangles, indicating where
the asterisk would likely appear as well as covertly
attracting selective attention to this cued location. The
cue was 67 % accurate,- therefore, when a rectangle was cued,
there was a 67 percent chance that the asterisk would appear
inside this cued rectangle (valid trial) and a 33 percent
chance that it would appear inside the uncued rectangle
(invalid trial). The cue remained present until the end of
the trial (i.e., when the subject responded to the target or
for a maximum of 5000 ms). For 25 % of the trials, a cue
was not presented (no cue trial). On no cue trials, there
was a 50 percent chance that the target would appear inside
either the left or right rectangle (see Figure 2-1).

95
Across all trials, the asterisk was presented an equal
number of times at both cue-to-target intervals (100 ms, 800
ms) and inside the left and right rectangle. The asterisk
remained within the left or right rectangle until subjects
responded by pressing the space bar key with their left hand
or for a maximum of 5000 ms. Subjects responded as quickly
as possible to the asterisk by pressing the space bar on the
computer key board. Reaction time was recorded. The
intertrial interval was 1000 ms.
Eight practice trials and 96 test trials were
administered. The test trials were divided into two blocks
with each block containing 48 trials. Upon completion of a
block, subjects received a 60 s rest period. Subjects
required approximately 3 minutes to complete two blocks of
the COVAT, excluding the time allotted for their rest
period.
Language Tasks
Two language tasks (reading a familiar word and
producing a similar meaning or an associated word) were
presented on an IBM Personal Computer AT with a Panasonic
Panasync C1381 color monitor in a moderately lit room.
Subjects were seated approximately 61 cm in front of the
computer monitor screen.
For each language task, a trial began with the
presentation of a green cross (0.2 X 0.2 cm) to the center
of the dark computer monitor screen. While performing the

96
language tasks, subjects were instructed to keep their eyes
focused on the central fixation cross (see Appendices D and
E for complete task instructions given to subjects). After
a 1000 ms delay, a single word replaced the cross (see
Figure 2-2). The word was always a noun centered
horizontally in upper-case, green letters. Each letter was
0.5 cm in height and approximately 0.3 cm in width. The
nouns ranged in length from 4 letters (1.3 cm) to 9 letters
(3 cm).
In order to minimize activation of the right cerebral
hemisphere, the nouns were selected on the basis of ratings
for low-to-moderate imageability and low-to-moderate
concreteness; therefore, the top third of high imageability
and high concreteness nouns were excluded (Benjafield &
Muckenheim, 1989; Friendly, Franklin, Hoffman, & Rubin,
1982; Gilhooly & Logie, 1980; Paivio, Yuille, & Madigan,
1968; Toglia & Battig, 1978). These nouns occurred either
at a low (< 20 occurrences in approximately 1 million words)
or high (> 50 occurrences in approximately 1 million words)
frequency range within the English language (Francis &
Kucera, 1982). Based on a judgment made by the
experimenter, the selected nouns were words that would be
most likely familiar to undergraduate college students.
Additionally, nouns were selected based on the existence of
a similar meaning word or an associated word that could be
called readily to the experimenter's mind (see Appendices F

97
and G for low and high frequency words with low-to-moderate
ratings in concreteness and imageability utilized in the
reading and semantic association tasks).
Because of a limited number of words meeting the above
criteria, the same set of words was used for the reading and
semantic association tasks. Half of the words occurred at a
low frequency range, while the other half of the words
occurred at a high frequency range. The average number of
letters presented in the low and high frequency word groups
was seven.
During the reading task, subjects read the words aloud
quickly and accurately. The words were presented in a
random order. Each word remained visible on the monitor
screen for 1500 ms.
During the semantic association task, subjects said
aloud the first word that came to mind that meant the same
thing or that was strongly associated to the presented word
for most people. Subjects were instructed to say this word
aloud quickly and accurately. If they were unable to
generate a synonym or an associated word for a presented
word, subjects were told to say "pass." However, they were
instructed to not pass too often.
Because the utilized computer program for the semantic
associate task did not record the order of randomly
presented words, three random word orders were created by
the experimenter to facilitate the subsequent evaluation of

98
subjects' responses. One of these three word orders was
randomly chosen and then presented to each subject. During
the semantic associate task, each word remained visible on
the computer screen for 3500 ms.
For the reading and semantic association tasks, words
were not exposed for equivalent time intervals. In the
reading task, words were presented for 1500 ms, while they
were presented for 3500 ms in the semantic association task.
This difference in exposure duration was necessary in order
to equate for the time period between completion of each
task (i.e., reading a word aloud and generating a similar
meaning or an associated word) and the beginning of the next
trial. Following completion of each task, subjects
typically had 1000 ms prior to start of the next trial which
began with the presentation of the fixation point.
For each language task, subjects were administered
eight practice trials followed by 48 test trials. Their
oral responses were recorded on audiotape as well as written
down by the experimenter. Subjects required 2 minutes to
complete 48 test trials of the reading task, while requiring
approximately 4 minutes to perform 48 trials of the semantic
association task.
Covert Orienting of Visual Attention Task Paired with
Language Tasks
The COVAT was performed concurrently with each of the
two language tasks (i.e., reading a familiar word and
producing a similar meaning word or an associated word).

99
The dual-task conditions were presented on an IBM Personal
Computer AT with a Panasonic Panasync C1381 color monitor in
a moderately lit room. Subjects were seated approximately
61 cm in front of the computer monitor screen.
With a few exceptions, the COVAT was performed as
previously described. Throughout concurrent performance,
only the two rectangles were continuously present on the
computer monitor screen. Instead of a fixed green cross at
the center of the screen, the cross now appeared for only
1000 ms during the intertrial interval. A dual-task trial
began with the cross being replaced by one noun centered and
printed horizontally in upper-case, green letters. The
nouns ranged in length from 4 letters to 9 letters. The
dimensions of the COVAT and language stimuli (i.e., the size
and arrangement of the cross, rectangles, asterisk, and
words on the computer screen) were identical for single-task
and dual-task performances of the COVAT and the language
tasks. Throughout each dual-task trial, subjects were
instructed to keep their eyes focused at the center of the
computer screen, initially upon the cross and then upon the
noun (see Appendices H and I for complete task instructions
given to subjects).
Because a minimum of 392 nouns were required for dual-
task performance (384 test words and 8 practice words),
nouns were selected on the basis of ratings for low-to-
moderate as well as high imageability and low-to-moderate as

100
well as high concreteness (Benjafield & Muckenheim, 1989;
Friendly et al., 1982; Gilhooly & Logie, 1980; Paivio et
al. , 1968; Toglia & Battig, 1978). These nouns occurred
either at a low (< 20 occurrences in approximately 1 million
words), medium (> 21 and <49 occurrences in approximately 1
million words), or high (> 50 occurrences in approximately 1
million words) frequency range within the English language
(Francis & Kucera, 1982). The selected nouns were words
that would be most likely familiar to undergraduate college
students, based on a judgment made by the experimenter.
Additionally, nouns were selected based on the existence of
a similar meaning word or an associated word that could be
called readily to the experimenter's mind. Nouns utilized
in single-task performance of the reading and semantic
association tasks were excluded from use in dual-task
performance of the reading and semantic association tasks
paired separately with the COVAT.
From this set of chosen words, a limited number of low
(72) and high (72) frequency nouns with low-to-moderate
ratings in imageability and concreteness were paired with
particular trials of the COVAT during dual-task performance.
These trials were selected because they were primary in
addressing the experimenter's a-priori hypotheses, as the
COVAT target appearing at 100 ms after COVAT trial onset
would occur during processing of the displayed noun whereas
the COVAT target appearing at 800 ms would have occurred

101
after the majority of language processing (see Event-Related
Potentials in the Experiment and Hypotheses section).
Therefore, an equal number of low (72) and high (72)
frequency nouns with low-to-moderate ratings in imageability
and concreteness were paired with the following COVAT
trials: half of the valid trials as well as all of the
invalid and no cue trials occurring at the 100 ms COVAT
target interval. This pairing yielded an equivalent number
of valid, invalid, and no cue trials at the 100 ms COVAT
target interval for subsequent analyses. The remaining
nouns (i.e., medium frequency words with low-to-moderate
ratings in imageability and concreteness,- low, medium, and
high frequency words with high ratings in imageability and
concreteness) were paired with the remaining COVAT trials:
half of the valid trials at the 100 ms COVAT target interval
as well as all of the valid, invalid, and no cue trials at
the 800 ms COVAT target interval. Nouns of differing
lengths were distributed evenly across trial types (i.e.,
valid, invalid, and no cue trials) and target intervals.
The average number of letters presented in the groups of low
and high frequency nouns with low-to-moderate ratings in
imageability and concreteness was six. The same set of
words was used for the reading task paired with the COVAT
and for the semantic associate task paired with the COVAT
(see Appendices J and K for low and high frequency words
with low-to-moderate ratings in concreteness and

102
imageability utilized in the reading and semantic
association tasks paired separately with the COVAT).
Following computerized presentation of a noun on cued
trials, the COVAT cue (i.e., the brightening of the border
of one of the two stationary rectangles) occurred randomly
after a 100 ms or 250 ms delay. The cue was subsequently
followed by the presentation of the COVAT target (i.e., a
green asterisk) after a 100 ms or 800 ms delay (see Figure
1-4). Thus, on cued trials, the COVAT target randomly
appeared after a 200, 350, 900, or 1050 ms delay following
the presentation of a word at the beginning of a dual-task
trial. On no cue trials, the COVAT target randomly appeared
after a 200, 350, 900, or a 1050 ms delay following
presentation of a noun.
Across all trials, the COVAT target was presented an
equal number of times at all delay intervals (200, 350, 900,
and 1050 ms) and inside the left and right rectangles. The
asterisk remained present within the left or right rectangle
until subjects responded by pressing the space bar key with
their left hand or for a maximum of 5000 ms. Subsequently,
only the COVAT target was removed from the computer monitor
screen, leaving the noun visible for an additional 500 ms in
the reading-COVAT condition and for an extra 2000 ms in the
semantic association-COVAT condition. In order to equate
for the time period between completion of each dual-task
condition (i.e., reading a word aloud and generating a

103
similar meaning or an associated word) and the beginning of
the next trial, nouns were not exposed for equivalent time
intervals. Following completion of each dual-task
condition, subjects typically had 1000 ms prior to start of
the next trial.
During the dual-task conditions (i.e., the reading task
paired with the COVAT and the semantic association task
paired with the COVAT), each word and COVAT trial pairing
was presented in a random order. Subjects were told to
respond as quickly and as accurately as possible to both the
words and the subsequent asterisks, but their performance on
the language tasks (i.e., reading each word aloud, or saying
one similar meaning or associated word aloud) was most
important during the concurrent conditions (Fisk, Derrick, &
Schneider, 1986-87; Hiscock et al., 1989). This last dual¬
task instruction designated the language task as the primary
task and the COVAT as the secondary task for subjects,
enabling examination of the effects of the language task on
visual selective attention (i.e., the COVAT). In addition,
subjects were instructed to avoid delaying any of their
responses or saying 'pass' too often.
Oral responses to the language tasks were recorded on
audiotape as well as written down by the experimenter.
Reaction times to the COVAT targets were collected by the
computer.

104
For each dual-task condition, subjects were
administered eight practice trials followed by 384 test
trials. The test trials were divided into six blocks with
each block containing 64 trials. Upon completion of a
block, subjects received a 60 s rest period. Subjects
required approximately 18 minutes to complete six blocks of
the reading task paired with the COVAT and approximately 30
minutes to complete six blocks of the semantic association
task paired with the COVAT.
Procedure
After informed consent was obtained, subjects
individually received the structured interview (see Appendix
A) and the six 'primary' items from the Briggs-Nebes
Modification of the Annett Handedness Questionnaire (see
Appendix B). Each subject who met the criteria for
participation was randomly assigned to one of six groups for
the purpose of counterbalancing the order of presentation of
the single task conditions (see Table 2-1). Each subject
was also randomly assigned to one of two groups for the
purpose of counterbalancing the order of presentation of the
dual-task conditions (see Table 2-2).
All subjects received the three single-task conditions
(i.e., COVAT, Reading task, Semantic Association task),
prior to the administration of the two dual-task conditions
(i.e., COVAT and Reading task, COVAT and Semantic

105
Association task). They were tested individually in each of
these conditions. Following completion of the testing
conditions, each subject reviewed a list of low and high
frequency words with low-to-moderate ratings in imageability
and concreteness that were presented in the single-task
reading and semantic association conditions or in the dual-
task 100 ms COVAT target interval conditions. Subjects
indicated whether each word was familiar or unfamiliar to
them. Unfamiliarity was defined as "no known exposure to
the word prior to presentation of it during this study." In
addition, subjects completed a post-experimental
questionnaire where they rated task difficulty on a 7-point
scale with 1 indicating that the task was "very easy" and 7
indicating that the task was "very difficult" (see Appendix
L). All subjects were debriefed.

106
Table 2-1. Counterbalanced Order of Single-Task
Presentation.
Group Single-Tasks
1
(1)
COVAT
(2)
Reading
(3)
Semantic
Association
2
(1)
COVAT
(2)
Semantic
Association
(3)
Reading
3
(1)
Reading
(2)
COVAT
(3)
Semantic
Association
4
(1)
Reading
(2)
Semantic
Association
(3)
COVAT
5
(1)
Semantic
Association
(2)
COVAT
(3)
Reading
6
(1)
Semantic
Association
(2)
Reading
(3)
COVAT

107
Table 2-2. Counterbalanced Order of Dual-Task Presentation.
Group Dual-Tasks
1
(1)
Reading and COVAT
(2)
Semantic Association
and
COVAT
2
(1)
Semantic Association
and
COVAT
(2)
Reading and COVAT

Figure 2-1. Stimulus onset asynchronies for the covert
orienting of visual attention task.

109
Valid Trial
Time
Fixation
+
Cue
+
Target
+
*
Invalid Trial
Fixation
+
Cue
+
Target
+
*
No Cue Trial
Fixation
+
Target
+
*
1000 ms
100/800 ms
1000 ms
100/800 mi
1100/
1800 ms

Figure 2-2. Schematic of the language tasks: Reading
and generation of semantic associations.

Reading
Time
Fixation
+
1000 ms
Language Task
WORD
1500 ms
Semantic Association
Fixation
Time
1000 ms
Language Task
WORD
3500 ms

CHAPTER 3
RESULTS
Statistical Analyses
The data obtained from the single- and dual-task
conditions were analyzed with a repeated measures analysis
of variance (ANOVA). In each ANOVA, the Huynh and Feldt
epsilon was used to determine whether the sphericity
assumption was met for each main effect and interaction. If
the Huynh and Feldt epsilon equaled 1, then sphericity was
met and the ANOVA was used (Stevens, 1990) . However, if the
Huynh and Feldt epsilon was less than 1, then the sphericity
assumption for the repeated measures main effect or
interaction was violated, and a multivariate analysis of
variance (MANOVA) was substituted (Stevens, 1990). If the
sphericity assumption was met, then the Tukey multiple
comparison procedure was employed to maintain the overall
type I error rate at 0.05 for each set of a posteriori tests
(Kirk, 1968). If the sphericity assumption was violated,
then the Bonferroni multiple comparison procedure was
substituted for the Tukey procedure (Stevens, 1990) .
112

113
Covert Orienting of Visual Attention Task Alone and Paired
with Language Tasks
All reaction times less than 150 ms were eliminated
from the data in the covert orienting of visual attention
task (COVAT) in the single- and dual-task conditions.
Removal of these reaction times were an attempt to reduce
error variance, resulting from accidental responding. Less
than 1 % of all trials were excluded. More specifically,
the mean proportion of eliminated trials were as follows:
0.4 % (SD = 1 %) from the COVAT alone, 0.3 % (SD = 0.6 %)
from the reading-COVAT task, and 0.1 % (SD = 0.4 %) from the
semantic association-COVAT condition. Because sphericity
was violated (Huynh-Feldt Epsilon = 0.73), a repeated
measures MANOVA with task (COVAT, reading-COVAT, semantic
association-COVAT) as a within-subjects factor was
conducted. A significant main effect was obtained F(2, 27)
= 4.26, p = .025. Subjects committed more false positive
errors during the reading-COVAT task, in comparison to the
semantic association-COVAT condition. There were no
significant differences between the COVAT and reading-COVAT
condition or between the COVAT and semantic association-
COVAT conditions for overall proportion of false positive
errors (see Table 3-1). The lack of a significant
difference between the COVAT and the semantic association-
COVAT conditions is related to the larger error term for the
COVAT.
Although reaction times greater than 3000 ms are often
removed from the data in an attempt to reduce error variance

114
resulting from accidental nonresponding on the COVAT, these
response times were included in the present study for the
following reasons: (a) It was unlikely that neurologically
normal adults would commit nonresponding errors and (b)
larger reaction times are reflective of interference
effects.
Because a limited number of low and high frequency
nouns with low-to-moderate ratings in imageability and
concreteness were paired with only the COVAT trials that had
a 100 ms delay between COVAT trial onset and the appearance
of the COVAT target, only the median reaction times from the
100 ms COVAT trials were analyzed in the single- and dual-
task COVAT conditions. The 800 ms COVAT target interval
trials were not analyzed, as was often the case in similar
studies (Posner et al., 1984; Posner et al., 1988).
COVAT Alone. For the 100 ms delay between COVAT trial
onset and the appearance of the COVAT target (i.e., the
COVAT target delay) in the single-task condition (COVAT
alone), the median reaction time was calculated for each
subject on all combinations of the following factor levels:
Trial type (valid, invalid, no cue) and target side (left,
right).
A repeated measures ANOVA with trial type and target
side as within subjects factors yielded a significant main
effect for trial type, F(2, 56) = 18.40, p = .000. Subjects
responded significantly faster to valid than to invalid
trials. Although subjects responded intermediately to no

115
cue trials, no significant differences were detected between
valid and no cue trials or between invalid and no trials
(see Table 3-2). The trial type by target side interaction
and the main effect for target side were not significant.
COVAT Paired with Language Tasks. For the 100 ms COVAT
target delay in the dual-task conditions (COVAT paired
separately with the reading task and the semantic
association task), the median reaction time was computed for
each subject on all combinations of the following factor
levels: Trial type (valid, invalid, no cue), target side
(left, right), delay between the start of each language task
and the COVAT (100, 250 ms) , and frequency of concurrent
word (low, high).
In dual-task conditions, the median reaction times were
calculated from all presented trials, that is, from trials
that utilized familiar as well as unfamiliar words (as rated
by subjects at the end of the experiment). The inclusion of
reaction times with unfamiliar words on dual-task trials was
based on a preliminary analysis using a paired difference t-
test, with a sample of subjects (n = 5). No significant
difference was found between median reaction times with and
without unfamiliar words in the reading-COVAT condition, t
(4) = 1.6, p > .05 (two-tailed), or in the semantic
association-COVAT condition, t (4) = . 57, p > .05 (two-
tailed) .
Two separate ANOVAs were conducted, one for each delay
between appearance of the word and onset of the COVAT trial

116
(100 ms, 250 ms). Since all conditions were given to all
subjects, all factors in both ANOVAs were repeated measures.
For the task factor in each ANOVA, COVAT alone was included
for the purposes of comparison to the dual-task conditions.
Thus, there were five conditions under the task factor for
each ANOVA: (a) COVAT alone, (b) reading-COVAT with low
frequency words, (c) reading-COVAT with high frequency
words, (d) semantic association-COVAT with low frequency
words, and (e) semantic association-COVAT with high
frequency words. In addition to the task factor, each ANOVA
had a trial type factor (valid, invalid, no cue), and a
target side factor (left, right).
100 ms Word-COVAT Delay
In the task by trial type by target side ANOVA at the
100 ms word-COVAT delay, a significant main effect was
obtained for trial type, F (2, 56) = 5.39, p = .007.
Because of a sphericity violation (Huynh-Feldt epsilon =
0.28), the MANOVA was substituted for the task main effect
which was significant, F (4, 25) = 15.25, p = .000. As
shown in Figure 3-1, subjects responded fastest to COVAT
targets in the COVAT alone condition, intermediate to
targets in the reading-COVAT condition with high frequency
words, slower to targets in the reading-COVAT condition with
low frequency words, and considerably slower to targets in
the semantic association-COVAT conditions with low or high
frequency words. There was no significant difference in
reaction time between the semantic association-COVAT task

117
with low frequency words and the semantic association-COVAT
task with high frequency words; however, significant
differences were obtained for all other comparisons between
tasks (see Table 3-3). Subjects responded fastest to valid
trials in comparison to invalid or no cue trials. Invalid
and no cue trials were not significantly different (see
Table 3-4). The main effect for target side and all
interactions failed to reach significance.
From the above analyses, the most striking finding is
that subjects responded substantially slowest to the
semantic association-COVAT conditions, in comparison to the
COVAT and reading-COVAT conditions.
250 ms Word-COVAT Delay
At the 250 ms delay between the start of the language
tasks and the COVAT, a task by trial type by target side
ANOVA was conducted. Because of sphericity violations, the
task by target side interaction (Huynh Feldt epsilon =
0.58), F(4, 25) = 3.50, p = 0.021, and the main effect for
task (Huynh Feldt epsilon = .28), F(4, 25) = 17.25, p =
0.000, were significant based on findings from the
substituted MANOVA. In response to left-sided COVAT
targets, subjects responded fastest in the COVAT alone
condition and in the reading-COVAT condition with high
frequency words, next-to-fastest in the reading-COVAT
condition with low frequency words, slowest in the semantic
association-COVAT condition with high frequency words, and
next-to-slowest in the semantic association-COVAT condition

118
with low frequency words (see Figure 3-2). For left-sided
targets, there were no significant differences in reaction
times between the COVAT and the reading-COVAT task with high
frequency words or between the semantic association-COVAT
conditions with high and low frequency words; however,
significant differences were obtained for all other
comparisons between tasks. In response to right-sided COVAT
targets, task results were similar to findings with left¬
sided targets. Therefore, there were no significant
differences in response times between the COVAT and reading-
COVAT condition with high frequency words or between the
semantic association-COVAT conditions with high and low
frequency words. All other comparisons between tasks were
significant for right-sided targets. Significant
differences were not detected between left- and right-sided
targets for any of the five task conditions (see Tables 3-5
and 3-6). The following interactions were not significant:
Task by trial type by target side, task by trial type, and
trial type by target side. The main effects for trial type
and target side also failed to reach significance.
Similar to results from the 100 ms word-COVAT delay,
the most dramatic finding is that subjects responded
markedly slower to the semantic association-COVAT
conditions, as compared to the COVAT and reading-COVAT
conditions.
For both word-COVAT delays (100, 250 ms), the standard
deviations for the semantic association-COVAT conditions

119
with low and high frequency words were substantially large
in comparison to the other COVAT conditions (see Tables 3-3
and 3-5). A test of homogeneity of error variances (Kirk,
1968) revealed violations of this assumption at the 100 ms
word-COVAT delay, Fmax = 101.616, p < .05, and at the 250 ms
word-COVAT delay, Fmax = 88.407, p < .05. As compared to the
standard deviations for the COVAT task alone, the standard
deviations for the semantic association-COVAT conditions
were approximately seven times as large. The standard
deviations for the reading-COVAT conditions with low and
high frequency words were about twice as large as the
standard deviations for the COVAT task. Because the
exceptionally large error variances in the semantic
association tasks could obscure the trial type by target
side by task interactions which were hypothesized, it was
necessary to explore both the nature of this phenomenon and
means for reducing it. Relative frequency histograms
depicting the average reaction time achieved by each subject
for the COVAT, reading-COVAT, and semantic association-COVAT
conditions (across trial type, target side, word frequency,
and word-COVAT delay) were constructed, in order to
investigate the large error variance in the semantic
association-COVAT conditions. As shown in Figures 3-3 and
3-4, the mean reaction times for the COVAT and reading-COVAT
task were distributed around one central point, while the
mean reaction times for the semantic association-COVAT tasks
were distributed around two main sets of points. Based on

120
the mean reaction times for the COVAT, reading-COVAT task,
and semantic association-COVAT task, 9 of the 29 subjects
responded markedly slower to the semantic association-COVAT
task enlarging the error variance for this task, despite
responding comparably to the majority of the subject sample
on the COVAT and reading-COVAT task.
To reduce the disproportionately large error variance
in the semantic association-COVAT conditions, an index that
equated for general response time in each condition with the
no cue trials was computed for every subject. The median
reaction time index for the valid trials was ((Valid - No
Cue) / No Cue), while the index for the invalid trials was
((Invalid - No Cue) / No Cue). It should be noted that use
of this index to control for the large variance in the
semantic association tasks is primarily a way of exploring
the relationship between valid and invalid trials by side in
different task conditions. Since the index equalizes
conditions for baseline response levels (i.e., for the no
cue trials), the main effect for task should no longer be
significant. Further, comparisons for no cue trials alone
are lost.
After transforming the data with the indices at the 100
ms word-COVAT delay, the standard deviation for the semantic
association-COVAT conditions with low and high frequency
words was comparable to the standard deviation for the
reading-COVAT conditions with low and high frequency words,
that is, approximately twice as large as the standard

121
deviation for the COVAT alone. In addition, Fmax was
substantially reduced (8.377), but the assumption of
homogeneity of error variances was still violated, p < .05.
At the 250 ms word-COVAT delay, the data transformed by the
indices produced a standard deviation for the semantic
association-COVAT condition with low and high frequency
words about twice as large as the one for the COVAT alone
condition. In addition to reducing the standard deviation
for the semantic association-COVAT conditions, the indices
reduced the standard deviation for the reading-COVAT
conditions with low and high frequency words from twice as
large as the COVAT alone standard deviation to one-and-a-
half times as large. A decrease was also noted for Fmax
(16.439), but the assumption of homogeneity of error
variances was still violated, p < .05.
Transformed Data: 100 ms Word-COVAT Delay
A task (COVAT, reading-COVAT with low frequency words,
reading-COVAT with high frequency words, semantic
association-COVAT with low frequency words, semantic
association-COVAT with high frequency words) by trial type
(valid, invalid) by target side (left, right) repeated
measures ANOVA was conducted on the data transformed by
above indices at the 100 ms word-COVAT delay. The main
effect for trial type was significant, F(l, 28) = 23.53, p =
.000. Because sphericity was violated, a MANOVA was
substituted for the task by trial type interaction which was
significant, F(4, 25) = 3.23, p = .029. After equating for

122
general response time with the indices, subjects responded
significantly faster to valid in comparison to invalid
trials for only the COVAT alone condition (see Figure 3-5).
There were no significant differences between trial types
(valid v. invalid) for the reading-COVAT or semantic
association-COVAT conditions with either low or high
frequency words. When response times for each task were
compared with regard to trial type, no significant
differences were detected among valid trials for the five
task conditions or among invalid trials for the five
conditions (see Tables 3-7 and 3-8). The following
interactions failed to reach significance: Task by trial
type by target side, task by target side, and trial type by
target side. The main effects for task and target side were
not significant.
Transformed Data: 250 ms Word-COVAT Delay
At the 250 ms word-COVAT delay, a task by trial type by
target side repeated measures ANOVA with the indices data
yielded a main effect for trial type, F(l, 28) = 12.97, p =
.001. When the MANOVA was substituted because of sphericity
violations, a significant main effect for task (Huynh-Feldt
epsilon = 0.71), F(4 ,25) = 3.39, p = .024 and a significant
task by trial type interaction (Huynh-Feldt epsilon = 0.84),
F(4, 25) = 3.25, p = .028 were obtained. As depicted in
Figure 3-6, subjects responded significantly faster to valid
in comparison to invalid COVAT targets in the COVAT alone
condition and in the reading-COVAT condition with low

123
frequency words. Reaction times to valid and invalid trials
were not significantly different from each other in the
reading-COVAT condition with high frequency words or in the
semantic association-COVAT conditions with either low or
high frequency words. When response times for valid trials
were compared across the five conditions, significant
differences were detected between the semantic association-
COVAT condition with low frequency words and the COVAT alone
condition and between semantic association-COVAT condition
with low frequency words and the reading-COVAT condition
with high frequency words. Significant differences were not
obtained between any other task comparison for valid trials.
For invalid trials, subjects did not respond significantly
different across the five task conditions (see Tables 3-9
and 3-10). The following interactions were not significant:
Task by trial type by target side, task by target side, and
trial type by target side. The main effect for target side
failed to reach significance.
Language Tasks
For each performance of the language tasks (reading
alone, production of semantic associations alone, reading
paired with the COVAT at the 100 ms and at the 250 ms word-
COVAT delay, production of semantic associations paired with
the COVAT at the 100 ms and at the 250 ms word-COVAT delay),
an error was scored for each incorrect response or lack of
response to low or high frequency target words. More

124
specifically, the following is a list of possible errors for
the low and high frequency words in the reading alone and
reading-COVAT conditions: (a) mispronunciation of an
initial syllable followed by correct pronunciation of the
word, (b) mispronunciation of an initial syllable followed
by incorrect pronunciation of the word, (c) mispronunciation
of an entire word followed by correct pronunciation of the
word, (d) mispronunciation of an entire word followed by a
subsequent mispronunciation of the word, (e) single
mispronunciation of the entire word, (f) correct
pronunciation of an initial syllable followed by correct
pronunciation of the word (i.e., faltering speech), (g)
correct pronunciation of an initial syllable followed by
incorrect pronunciation of the word, (h) subject said "pass"
because he or she could not formulate a response to a
presented word, (i) subject did not respond to a word, and
(j) the subject's response was unscorable.
In addition to the possible errors listed in the
single- and dual-task reading conditions for various ways of
mispronouncing a response or not responding, the following
is a list of possible errors for low and high frequency
words in the semantic association alone and paired with the
COVAT conditions: (a) association with no obvious
connection to a presented word, (b) correct association to
an incorrect homophonic word (e.g., saying "animal" for
"dear" or saying "climb" for "latter"), (c) correct
pronunciation of a presented word followed by a correct

125
association, (d) correct pronunciation of a presented word
followed by an incorrect association with no obvious
connection, and (e) correct pronunciation of a presented
word followed by a correct association to an incorrect but
related word.
Specific Types of Language Errors
For each subject, the proportion of each error type for
the low and high frequency words in the reading, semantic
association, reading-COVAT (ignoring word-COVAT delays), and
semantic association-COVAT (ignoring word-COVAT delays)
conditions was calculated by dividing the total number of
errors by the number of target trials. The proportion of
errors was obtained in order to equate for the different
number of target trials used in the single-task (24 low and
24 high frequency trials) and dual-task (72 low and 72 high
frequency trials) conditions.
Regarding the reading alone and reading-COVAT
conditions, subjects did not make any errors in response to
high frequency words. In response to low frequency words,
subjects mispronounced the entire word on 2 % of these
trials in the reading alone condition and on 3 % of these
trials in the reading-COVAT condition. Because other types
of errors were committed rarely during the reading alone and
reading-COVAT conditions, the mean proportion of errors for
the remaining categories was 0 %.
In response to low and high frequency words during the
semantic association only and semantic association-COVAT

126
conditions, the most frequent type of error made by subjects
was saying "pass" because he or she could not generate a
similar meaning or an associated word to the target word.
During the semantic association task, subjects passed on 14
% of low frequency trials and on 16 % of high frequency
trials. During the semantic association-COVAT condition,
subjects passed on 12 % of low frequency trials and 13 % of
high frequency trials. In addition to the pass errors made
during the semantic association only condition, subjects (a)
produced associations with no obvious connections to the
presented word on 4 % of low frequency trials and on 1 % of
high frequency trials, (b) did not respond on 1% of low and
on 2 % of high frequency trials, and (c) correctly
pronounced the initial syllable followed by incorrect
pronunciation of a correct association on 1 % of low and on
1 % of high frequency trials. During the semantic
association task, 2 % of the high frequency responses were
unscorable.
In addition to the pass errors made during the semantic
association-COVAT condition, subjects generated associations
with no obvious connections to the presented word on 3 % of
low frequency trials and 1 % of high frequency trials.
Subjects also responded with a correct association to an
incorrect homophonic word on 1 % of semantic association-
COVAT trials with low frequency words. Because other types
of errors were committed rarely during the semantic
association and semantic association-COVAT conditions, the

127
mean proportion of errors for the remaining categories was 0
o
o .
Overall Language Errors
The proportion of overall language errors was computed
for low and high frequency words in the following
conditions: (a) reading, (b) semantic association, (c)
reading-COVAT at the 100 ms word-COVAT delay, (d) reading-
COVAT at the 250 ms word-COVAT delay, (e) semantic
association-COVAT at the 100 ms word-COVAT delay, and (f)
semantic association-COVAT at the 250 ms word-COVAT delay.
By dividing the total number of errors by the number of
target trials, the proportion of errors equated for the
different number of target trials used in the single-task
(24 low and 24 high frequency trials) and dual-task (36 low
and 36 high frequency trials) conditions.
For each delay (100, 250 ms) between the start of a
language task and the COVAT, the overall proportion of
language errors was analyzed by a repeated measures ANOVA
with task (Reading, Semantic Association, Reading-COVAT,
Semantic Association-COVAT) and frequency (low, high) as the
within-subjects factors.
100 ms Word-COVAT Delay. At the 100 ms word-COVAT
delay, a MANOVA was substituted for the task main effect
because sphericity was violated (Huynh-Feldt epsilon =
0.56). The main effect for task was significant, F(3, 25) =
33.64, p = 0.000. As shown in Figure 3-7, subject made less
language errors during the reading and reading-COVAT

128
conditions in comparison to the semantic association
conditions with and without the COVAT. Significant
differences were not detected between the reading alone and
reading-COVAT conditions or between the semantic association
task and the semantic association-COVAT condition (see Table
3-11). The task by frequency interaction and the main
effect for frequency failed to reach significance.
250 ms Word-COVAT Delay. A task by frequency repeated
measures ANOVA for overall language errors at the 250 ms
word-COVAT delay was conducted. Because of sphericity
violations, the MANOVA was substituted for the task by
frequency interaction (Huynh-Feldt epsilon = 0.71) and for
the task main effect (Huynh-Feldt epsilon = 0.66) . A
significant task by frequency interaction, F(3, 25) = 3.11,
p = 0.044, and main effect for task, F (3, 25) = 38.66, p =
0.000, were obtained. In responding to low frequency words,
subjects made significantly less errors during the reading
and reading-COVAT conditions in comparison to the semantic
association and semantic association-COVAT conditions (see
Figure 3-7). Significant differences were not obtained
between the reading and reading-COVAT conditions or between
semantic association and semantic association-COVAT
conditions for low frequency words. For high frequency
words, subjects made the least amount of errors in the
reading and reading-COVAT conditions, the most in the
semantic association condition, and an intermediate amount
of errors in the semantic association-COVAT condition.

129
Aside from no significant difference between the reading and
reading-COVAT conditions, all task comparisons were
significant for high frequency words. When language errors
to low and high frequency words were compared within the
four task conditions, a significant difference was obtained
for only the reading and the reading-COVAT conditions at the
250 ms word-COVAT delay. Subjects made less language errors
to high than to low frequency words during the reading alone
and the reading-COVAT conditions. Significant differences
between low and high frequency trials were not detected for
the semantic association and the semantic association-COVAT
conditions (see Tables 3-12 and 3-13). The main effect for
frequency was not significant.
Language Task Order
To investigate the effect of counterbalancing the order
of presentation of the language tasks on the proportion of
overall language errors, separate repeated measures ANOVAs
were conducted for each single-task condition (reading,
semantic association) with order (reading then semantic
association, semantic association then reading) as the
between subjects factor and word frequency (low, high) as
the within subjects factor. For the reading only condition,
a significant order by word frequency interaction was
detected, F(l, 27) = 4.32, p = 0.047. In addition,
significant main effects were obtained for order, F(l, 27) =
5.00, p = 0.034, and for word frequency, F (1, 27) = 14.10,
p = 0.001. Subjects in the group that received the reading

130
condition prior to the semantic association condition made
significantly more errors to low frequency words than to
high frequency words. There was no significant difference
between the overall proportion of errors committed to low
and high frequency words for the other subject group
(semantic association then reading). In response to low
frequency words, subjects who read then generated semantic
associations made significantly more reading errors than
subjects who generated semantic associations then read. In
response to high frequency words, there was no significant
difference between the subject groups that received
different orders of single-task presentation (see Tables 3-
14 and 3-15).
For the semantic association condition, no significant
differences were obtained; thus, the order by word frequency
interaction and the main effects for order and word
frequency failed to reach significance (see Table 3-15).
The effect of counterbalancing the order of
presentation of the language tasks on the proportion of
overall language errors was also examined in the dual-task
conditions for each word-COVAT delay (100, 250 ms).
Separate repeated measures ANOVAs were conducted for each
dual-task condition (reading-COVAT, semantic association-
COVAT) at each word-COVAT delay (100, 250 ms) with order
(reading-COVAT then semantic association-COVAT, semantic
association-COVAT then reading-COVAT) as the between
subjects factor and word frequency (low, high) as the within

131
subjects factor. For the reading-COVAT conditions, the main
effect for frequency was significant at the 100 ms word-
COVAT delay, F(l, 27) = 8.77, p = 0.006, and at the 250 ms
word-COVAT delay, F(l, 27) =29.72, p = 0.000. At both
delays, subjects made significantly more language errors
when they responded to low than to high frequency words.
The order by word frequency interaction and the main effect
for order were not significant at the 100 or the 250 ms
word-COVAT delays (see Table 3-16) .
For the semantic association-COVAT condition, no
significant differences were obtained at either the 100 or
the 250 ms COVAT-delays; thus, the order by word frequency
interaction and the main effects for order and word
frequency failed to reach significance (see Table 3-16).
These dual-task results suggest that the order of task
presentation did not make a significant difference in the
overall proportion of language errors committed in either
the reading-COVAT or the semantic association-COVAT
conditions at the 100 or 250 ms word-COVAT delays.
Word Familiarity
For each subject, the proportion of unfamiliar low and
high frequency words with low-to-moderate ratings in
imageability and concreteness was calculated for the reading
and semantic association conditions and for the reading-
COVAT and semantic association-COVAT conditions (ignoring
word-COVAT delays). By dividing the total number of
unfamiliar words (as rated by each subject at the end of the

132
experiment) by the number of target words, the proportion of
unfamiliar words equated for the different number of target
words used in the single-task (24 low and 24 high frequency
trials) and dual-task (72 low and 72 high frequency trials)
conditions.
A repeated measures ANOVA with task (single-task, dual¬
task) and word frequency (low, high) as within subjects
factors was conducted on the proportion of unfamiliar words.
A frequency main effect was obtained, F(l, 28) = 33.73, p =
.000. In comparison to high frequency words in the single-
and dual-task conditions, subjects rated significantly more
low frequency words as unfamiliar. Subjects were unfamiliar
with 3.3 % of the low frequency words used in the single¬
task language conditions and unfamiliar with 2.5 % of the
low frequency words utilized in the dual-task language
conditions. In the single- and dual-task conditions,
subjects were familiar with all of the high frequency words.
The task by frequency interaction and the main effect of
task failed to reach significance.
Task Difficulty
The mean ratings of task difficulty by subjects were
analyzed with a Wilcoxon Matched-Pairs Signed-Ranks test
with task (COVAT, reading, semantic association, reading-
COVAT, semantic association-COVAT) as the within subjects
factor. As shown in Figure 3-8, subjects rated the COVAT
and reading task as the easiest tasks, the reading-COVAT

133
condition as the next-to-easiest task, the semantic
association-COVAT condition as the hardest task, and the
semantic association condition as the next-to-hardest task.
There was no significant difference in mean ratings of task
difficulty between the COVAT and reading conditions;
however, significant differences were obtained for all other
comparisons between tasks (see Table 3-17).
Slow Responders During the Semantic Association-COVAT
Condition
Because 9 of the 29 subjects responded markedly slower
to the semantic association-COVAT condition despite
responding comparably to the majority of the subject sample
during the COVAT and reading-COVAT conditions (see Figures
3-3 and 3-4), the following analyses were conducted to
identify any factors that could account for this difference
between these subgroups (slow and faster semantic
association-COVAT responders). For six randomly chosen
subjects from each subgroup (slow and faster responders),
the language strategy employed during the semantic
association-COVAT condition was investigated. For these
twelve subjects as a group, the proportion of responses that
were synonyms or semantic associations was calculated.
Based on the result of a large-sample confidence interval
(Agresti & Finlay, 1986), there was no significant
difference between the type of strategy used by the two
subgroups. Both slow and faster responders during the

134
semantic association-COVAT condition tended to generate
synonyms to the presented words rather than semantic
associations (see Table 3-18) . More specifically, 71 % of
responses produced by slow responders were synonyms (29 %
were semantic associations), and 74 % of responses given by
faster responders were synonyms (26 % were semantic
associations).
Finally, all of the subjects in the slow and in the
faster semantic association-COVAT subgroups were compared
with repeated measures ANOVAs for (a) the proportion of
false positive errors to COVAT targets (see Table 3-19), (b)
the proportion of overall language errors during the single-
and dual-task conditions (see Table 3-20), and (c) the
proportion of unfamiliar words (see Table 3-21).
Additionally, the subjects in these subgroups were compared
with ANOVAs for ratings of task difficulty in the single-
and dual-task conditions (see Table 3-22) . There were no
significant differences between the subjects in the slow and
faster (responding) subgroups on any of these measures.

135
Table 3-1. False Positive Errors: Statistics for the
Main Effect of Task.
Task
Comparison
F DF p
COVAT v. Read-COVAT
COVAT v. Sem-COVAT
Read-COVAT v. Sem-COVAT
0.06
1,
28
.806
2.84
1,
28
.103
7.30
1,
28
.012 *
* Bonferroni method of multiple comparisons requires p <
.017 in order to achieve a .05 level of significance for the
entire set of comparisons (.05 overall level of significance
/ 3 comparisons = .017).

136
Table 3-2.
COVAT Alone: Statistics
of Trial Type.
for the Main Effect
Trial Type
M *
SD
Valid
379.32
70.06
No Cue
400.46
61.95
Invalid
424.63
65.06
* Reaction time
Tukey HSD = 25.42 for p < .05

137
Table 3-3. 100 ms Word-COVAT Delay: Statistics for the
Main Effect of Task.
Task
M *
SD
COVAT alone
401.47
61.53
Read-COVAT, Hi Freq
469.80
93.52
Read-COVAT, Lo Freq
529.37
116.57
Sem-COVAT, Hi Freq
973.85
437.99
Sem-COVAT, Lo Freq
922.61
379.487
* Reaction time
Task Comparison
F
DF
P
COVAT v.
Read-COVAT, Lo
48.02
1,
28
.000*
COVAT v.
Read-COVAT, Hi
19.51
1,
28
.000*
COVAT v.
Sem-COVAT, Lo
52.89
1,
28
.000*
COVAT v.
Sem-COVAT, Hi
47.97
1,
28
.000*
Read-COV,
Lo v. Read-COV,
Hi
33.53
1,
28
.000*
Read-COV,
Lo v. Sem-COV,
Lo
39.55
1,
28
.000*
Read-COV,
Lo v. Sem-COV,
Hi
36.27
1,
28
.000*
Read-COV,
Hi v. Sem-COV,
Lo
46.34
1,
28
. 000*
Read-COV,
Hi v. Sem-COV,
Hi
41.62
1,
28
.000*
Sem-COV,
Lo v. Sem-COV, Hi
6.91
1,
28
.014
* Bonferroni (.05 overall level of significance / 10
comparisons), p < .005

138
Table 3-4. 100 ms Word-COVAT Delay: Statistics for the
Main Effect of Trial Type.
Trial Type
M *
SD
Valid
636.76
177.65
No Cue
667.57
189.18
Invalid
673.93
198.85
* Reaction time
Tukey HSD = 29.11 for p < .05

139
Table 3-5. 250 ms Word-COVAT Delay: Descriptive Statistics
for the Task by Target Side Interaction.
Task
Target Side
M *
SD
COVAT
Left
405.31
60.66
Read-COVAT,
Hi
Left
415.63
76.92
Read-COVAT,
Lo
Left
456.81
95.41
Sem-COVAT,
Hi
Left
863.83
413.30
Sem-COVAT,
Lo
Left
803.85
418.96
COVAT
Right
397.63
65.21
Read-COVAT,
Hi
Right
422.56
76.87
Read-COVAT,
Lo
Right
474.35
98.09
Sera-COVAT,
Hi
Right
841.45
369.70
Sem-COVAT,
Lo
Right
870.33
364.14
* Reaction time

140
Table 3-6. 250 ms Word-COVAT Delay: Statistics
Task by Target Side Interaction.
for
the
Task Comparison
Side
F
DF
P
COV v. Read-COV,
Lo
Left
14.89
1,
28
.001*
COV v. Read-COV,
Hi
Left
0.69
1,
28
.412
COV v. Sem-COV,
Lo
Left
26.31
1,
28
.000*
COV v. Sem-COV,
Hi
Left
34.33
1,
28
.000*
Read-COV, Lo v.
Read-COV
Hi
Left
21.50
1,
28
.000*
Read-COV, Lo v.
Sem-COV,
Lo
Left
22.70
1,
28
.000*
Read-COV, Lo v.
Sem-COV,
Hi
Left
30.45
1,
28
.000*
Read-COV, Hi v.
Sem-COV,
Lo
Left
28.25
1,
28
.000*
Read-COV, Hi v.
Sem-COV,
Hi
Left
36.27
1,
28
.000*
Sem-COV, Lo v. Sem-COV,
Hi
Left
3.39
1,
28
.076
COV v. Read-COV,
Lo
Right
28.50
1,
28
.000*
COV v. Read-COV,
Hi
Right
4.69
1,
28
.039
COV v. Sem-COV,
Lo
Right
47.52
1,
28
.000*
COV v. Sem-COV,
Hi
Right
39.62
1,
28
.000*
Read-COV, Lo v.
Read-COV, Hi
Right
25.58
1,
28
.000*
Read-COV, Lo v.
Sem-COV,
Lo
Right
37.56
1,
28
.000*
Read-COV, Lo v.
Sem-COV,
Hi
Right
29.68
1,
28
.000*
Read-COV, Hi v.
Sem-COV,
Lo
Right
49.61
1,
28
.000*
Read-COV, Hi v.
Sem-COV,
Hi
Right
39.90
1,
28
.000*
Sem-COV, Lo v. Sem-COV,
Hi
Right
2.30
1,
28
. 140
* Bonferroni (.05 overall level of significance / 25
comparisons), p < .002

141
Table 3-6--continued.
Side
Comparison
Task
F
DF
P
Left
V.
Right
COVAT alone
2.39
1, 28
.134
Left
V.
Right
Read-COV, Lo Freq
3.29
1, 28
.080
Left
v.
Right
Read-COV, Hi Freq
0.70
1, 28
.409
Left
v.
Right
Sem-COV, Lo Freq
4.80
1, 28
.037
Left
v.
Right
Sem-COV, Hi Freq
1.25
1 ,28
.273
* Bonferroni (.05 overall level of significance / 25
comparisons), p < .002

142
Table 3-7. Transformed Data at the 100 ms Word-COVAT Delay:
Descriptive Statistics for the Task by Trial
Type Interaction.
Task
Trial Type
M *
SD
COVAT
Valid
- . 047
.098
Read-COVAT, Hi
Valid
-0.27
.127
Read-COVAT, Lo
Valid
- . 042
.112
Sem-COVAT, Hi
Valid
- . Oil
.200
Sem-COVAT, Lo
Valid
- . Oil
. 155
COVAT
Invalid
. 071
.103
Read-COVAT, Hi
Invalid
.031
.103
Read-COVAT, Lo
Invalid
- .007
. 112
Sem-COVAT, Hi
Invalid
.036
.209
Sem-COVAT, Lo
Invalid
.032
.167
* Index score

143
Table 3-8. Transformed Data at the 100 ms Word-COVAT Delay:
Statistics for Task by Trial Type Interaction.
Task Comparison
Trial
F
DF
P
COV v. Read-COV,
Lo
Valid
0.03
1,
28
.861
COV v. Read-COV,
Hi
Valid
0.43
1,
28
.518
COV v. Sem-COV,
Lo
Valid
1.50
1,
28
.230
COV v. Sem-COV,
Hi
Valid
0.62
1,
28
.438
Read-COV,
Lo v.
Read-COV,
Hi
Valid
0.29
1,
28
.592
Read-COV,
Lo v.
Sem-COV,
Lo
Valid
0.84
1,
28
.366
Read-COV,
Lo v.
Sem-COV,
Hi
Valid
0.88
1,
28
.355
Read-COV,
Hi v.
Sem-COV,
Lo
Valid
0.23
1,
28
.635
Read-COV,
Hi v.
Sem-COV,
Hi
Valid
0.12
1,
28
.730
Sem-COV,
Lo v. Sem-COV, Hi
Valid
0.00
1,
28
.985
COV v. Read-COV,
Lo
Invalid
9.51
1,
28
.005
COV v. Read-COV,
Hi
Invalid
1.84
1,
28
.186
COV v. Sem-COV,
Lo
Invalid
1.26
1,
28
.270
COV v. Sem-COV,
Hi
Invalid
0.58
1,
28
.452
Read-COV,
Lo v.
Read-COV,
Hi
Invalid
1.76
1,
28
.195
Read-COV,
Lo v.
Sem-COV,
Lo
Invalid
1.13
1,
28
.297
Read-COV,
Lo v.
Sem-COV,
Hi
Invalid
0.90
1,
28
.352
Read-COV,
Hi v.
Sem-COV,
Lo
Invalid
0.00
1,
28
.986
Read-COV,
Hi v.
Sem-COV,
Hi
Invalid
0.01
1,
28
.920
Sem-COV,
Lo v. Sem-COV, Hi
Invalid
0.01
1,
28
.932
* Bonferroni (.05 overall level of significance / 25
comparisons), p < .002

144
Table 3-8--continued.
Trial Type
Comparison
Task
F
DF
P
Valid
v.
Invalid
COVAT alone
36.22
1,
28
.000*
Valid
v.
Invalid
Read-COV, Lo Frq
2.11
1,
28
.157
Valid
v.
Invalid
Read-COV, Hi Frq
10.20
1,
28
.003
Valid
v.
Invalid
Sem-COV, Lo Frq
2.98
1,
28
.095
Valid
v.
Invalid
Sem-COV, Hi Frq
1.54
1 ,
28
.225
* Bonferroni (.05 overall level of significance / 25
comparisons), p < .002

145
Table 3-9. Transformed Data at the 250 ms Word-COVAT Delay:
Descriptive Statistics for the Task by Trial
Type Interaction.
Task
Trial Type
M *
SD
COVAT
Valid
- . 047
.098
Read-COVAT, Hi
Valid
- .023
.090
Read-COVAT, Lo
Valid
- .019
.167
Sem-COVAT, Hi
Valid
.039
.155
Sem-COVAT, Lo
Valid
.156
.261
COVAT
Invalid
. 071
.103
Read-COVAT, Hi
Invalid
.048
.103
Read-COVAT, Lo
Invalid
. 116
.143
Sem-COVAT, Hi
Invalid
.011
.192
Sem-COVAT, Lo
Invalid
. 143
.250
* Index score

146
Table 3-10. Transformed Data at the 250 ms Word-COVAT Delay:
Statistics for Task by Trial Type Interaction.
Task Comparison
Trial
F
DF
P
COV v. Read-COV,
Lo
Valid
0.78
1,
28
.386
COV v. Read-COV,
Hi
Valid
0.91
1,
28
.349
COV v. Sem-COV,
Lo
Valid
12.66
1,
28
. 001*
COV v. Sem-COV,
Hi
Valid
6.12
1,
28
.020
Read-COV,
Lo v.
Read-COV,
Hi
Valid
0.01
1,
28
. 914
Read-COV,
Lo v.
Sem-COV,
Lo
Valid
7.60
1,
28
.010
Read-COV,
Lo v.
Sem-COV,
Hi
Valid
2.16
1,
28
.153
Read-COV,
Hi v.
Sem-COV,
Lo
Valid
13.83
1,
28
.001*
Read-COV,
Hi v.
Sem-COV,
Hi
Valid
4.71
1,
28
.039
Sem-COV,
Lo v. Sem-COV, Hi
Valid
4.80
1,
28
.037
COV v. Read-COV,
Lo
Invalid
1.72
1,
28
.200
COV v. Read-COV,
Hi
Invalid
0.55
1,
28
.463
COV v. Sem-COV,
Lo
Invalid
1.88
1,
28
. 181
COV v. Sem-COV,
Hi
Invalid
1.63
1,
28
.212
Read-COV,
Lo v.
Read-COV,
Hi
Invalid
4.54
1,
28
.042
Read-COV,
Lo v.
Sem-COV,
Lo
Invalid
0.33
1,
28
.569
Read-COV,
Lo v.
Sem-COV,
Hi
Invalid
6.77
1,
28
.015
Read-COV,
Hi v.
Sem-COV,
Lo
Invalid
4.18
1,
28
.050
Read-COV,
Hi v.
Sem-COV,
Hi
Invalid
0.99
1,
28
.328
Sem-COV,
Lo v. Sem-COV, Hi
Invalid
7.01
1,
28
.013
* Bonferroni (.05 overall level of significance / 25
comparisons), p < .002

147
Table 3-10--continued.
Trial Type
Comparison
Task
F
DF
P
Valid
V.
Invalid
COVAT alone
36.22
1, 28
.000*
Valid
V.
Invalid
Read-COV, Lo Frq
18.79
1, 28
.000*
Valid
v.
Invalid
Read-COV, Hi Frq
9.76
1, 28
.004
Valid
v.
Invalid
Sem-COV, Lo Frq
0.06
1, 28
.807
Valid
V.
Invalid
Sem-COV, Hi Frq
0.53
1 ,28
.471
* Bonferroni (.05 overall level of significance / 25
comparisons), p < .002

148
Table 3-11. Overall Language Errors at the 100 ms Word-
COVAT Delay: Statistics for the Task Main
Effect.
Task
M *
SD
Reading
.033
. 044
Semantic
.385
. 197
Reading-COVAT
.043
.038
S eman tic-COVAT
.321
. 171
* Proportion of language errors.
Task Comparison
F
DF
P
Reading v. Semantic
97.72
1,
27
.000*
Reading v. Reading-COVAT
1.02
1,
28
.321
Reading v. Semantic-COVAT
80.99
1,
27
.000*
Semantic v. Reading-COVAT
72.68
1,
27
.000*
Semantic v. Semantic-COVAT
6.31
1,
27
.018
Reading-COVAT v. Semantic-COVAT
66.16
1,
27
.000*
* Bonferroni (.05 overall level of significance / 6
comparisons), p < .008

149
Table 3-12. Overall Language Errors at the 250 ms Word-
COVAT Delay: Descriptive Statistics for the
Task by Frequency Interaction.
Task
Word
Frequency
M *
SD
Reading
Low
.029
. 039
Semantic
Low
. 177
. Ill
Reading-COVAT
Low
. 047
.043
Semantic-COVAT
Low
. 176
.087
Reading
High
.004
. 013
Semantic
High
.208
. 121
Reading-COVAT
High
.008
.015
S eman tic-COVAT
High
.142
.084
★
Proportion of language errors.

150
Table 3-13. Overall Language Errors at the 250 ms Word-
COVAT Delay: Statistics for the Task
by Frequency Interaction.
Word
Task Comparison
Freq.
F
DF
P
Reading v.
Semantic
Low
59.40
1,
27
.000*
Reading v.
Reading-COVAT
Low
3.23
1,
28
.083
Reading v.
S emantic-COVAT
Low
78.35
1,
27
. 000*
Semantic v.
Reading-COVAT
Low
48.30
1,
27
. 000*
Semantic v.
S emantic-COVAT
Low
0.01
1,
27
. 941
Reading-COV v. Semantic-COV
Low
63.48
1,
27
. 000*
Reading v.
Semantic
High
79.84
1,
27
. 000*
Reading v.
Reading-COVAT
High
0.72
1,
28
.402
Reading v.
Semantic-COVAT
High
80.18
1,
27
.000*
Semantic v.
Reading-COVAT
High
75.32
1,
27
.000*
Semantic v.
Semantic-COVAT
High
12.04
1,
27
.002*
Reading-COV v. Semantic-COV
High
64.49
1,
27
.000*
* Bonferroni (.05 overall level of significance / 16
comparisons), p < .003

Table 3-13--continued.
Word Frequency
Comparison
Task
F
DF
P
Low v. High
Reading
12.15
1, 28
.002*
Low v. High
Semantic
1.83
1, 27
.187
Low v. High
Reading-COVAT
30.82
1, 28
.000*
Low v. High
Semantic-COVAT
4.31
1 ,27
.048
* Bonferroni (.05 overall level of significance / 16
comparisons), p < .003

152
Table 3-14. Language Task Order: Statistics for the Task
Order by Word Frequency Interaction for the
Reading Only Condition.
Task, Frequency
Task Order
M *
SD
Reading,
Low
Read-Sem
.045
.045
Reading,
Low
Sem-Read
. 014
.026
Reading,
High
Read-Sem
.006
.015
Reading,
High
Sem-Read
.003
.011
* Proportion of language errors.
Tukey HSD for Reading = .018 for p < .05

153
Table 3-15. Language Task Order: Descriptive Statistics
for the Semantic Association Condition.
Task, Frequency
Task Order
M *
SD
Semantic,
Low
Read-Sem
.170
.122
Semantic,
Low
Sem-Read
.185
. 104
Semantic,
High
Read-Sem
.193
.126
Semantic,
High
Sem-Read
.223
.117
* Proportion of language errors.

154
Table 3-16. Language Task Order: Descriptive Statistics
for the Dual-Task Conditions.
Task, Frequency Task Order M * SD
Read-COV-lOO, Low
Read-COV-lOO, Low
Read-COV-lOO, High
Read-COV-lOO, High
Sem-COV-lOO, Low
Sem-COV-lOO, Low
Sem-COV-lOO, High
Sem-COV-lOO, High
Read-COV-250, Low
Read-COV-250, Low
Read-COV-250, High
Read-COV-250, High
Sem-COV-250, Low
Sem-COV-250, Low
Sem-COV-250, High
Sem-COV-250, High
ReadCOV-SemCOV
SemCOV-ReadCOV
ReadCOV-SemCOV
SemCOV-ReadCOV
ReadCOV-SemCOV
SemCOV-ReadCOV
ReadCOV-S emCOV
SemCOV-ReadCOV
ReadCOV-SemCOV
SemCOV-ReadCOV
ReadCOV-SemCOV
SemCOV-ReadCOV
ReadCOV-SemCOV
SemCOV-ReadCOV
ReadCOV-SemCOV
SemCOV-ReadCOV
.037
.033
. 024
.022
.019
.027
.006
.012
. 141
.091
.182
.092
. 155
.090
.165
.123
.052
.051
. 042
.030
.013
.018
.002
.007
. 147
. 087
.204
.078
.117
.069
.167
.092
★
Proportion of language errors.

155
Table 3-17. Task Difficulty: Statistics for the Single-
and Dual-Task Conditions.
Task
M *
SD
COVAT only
1.11
0.315
Reading only
1.18
0.390
Semantic only
3.29
0.976
Reading-COVAT
2.29
1.117
Semantic-COVAT
4.27
1.456
* Level of difficulty
(l=very easy,
7=very difficult).
Task Comparison
Z
P
COVAT v.
Reading
- .734
.463
COVAT v.
Semantic
-4.541
.000 *
COVAT v.
Read-COVAT
-3.847
.000 *
COVAT v.
Sem-COVAT
-4.541
.000 *
Reading
v. Semantic
-4.623
.000 *
Reading
v. Read-COVAT
-3.920
.000 *
Reading
v. Sem-COVAT
-4.623
.000 *
Semantic
v. Read-COVAT
-3.283
.001 *
Semantic
v. Sem-COVAT
-3.603
.000 *
Read-COVAT v. Sem-COVAT
-4.433
.000 *
* Bonferroni (.05 overall
level of significance / 10
comparisons), P < .005

156
Table 3-18. Slow and Faster Responders During the Semantic
Association-COVAT Condition: Descriptive
Statistics for Response Strategies.
Type of Responder
Response
Strategy *
Synonym
Semantic Association
Slow
. 80
.20
Slow
.74
.26
Slow
.74
.26
Slow
.71
.29
Slow
.71
.29
Slow
.53
.47
Faster
. 82
.18
Faster
.87
. 13
Faster
.65
.35
Faster
.62
.38
Faster
. 85
.15
Faster
.65
.35
★
Proportion of overall responses.

157
Table 3-19. Slow and Faster Responders During the Semantic
Association-COVAT Condition: Descriptive
Statistics for False Positive Errors.
Task
Type of Responder
M *
SD
COVAT
Slow
.002
.007
Reading-COVAT
Slow
.004
.007
S emantic-COVAT
Slow
.000
.000
COVAT
Faster
.004
.013
Reading-COVAT
Faster
.003
.006
Semantic-COVAT
Faster
.001
.005
* Proportion of false positive errors.

158
Table 3-20. Slow and Faster Responders During the Semantic
Association-COVAT Condition: Descriptive
Statistics for Language Errors.
Task, Frequency
Type of Responder
M *
SD
Reading, Low
Slow
. 019
.030
Reading, High
Slow
.009
.019
Semantic, Low
Slow
.130
.092
Semantic, High
Slow
.180
.091
Read-COV-100, Low
Slow
.031
.029
Read-COV-100, High
Slow
.015
.028
Sem-COV-100, Low
Slow
.163
.095
Sem-COV-100, High
Slow
. 142
.098
Read-COV-250, Low
Slow
.031
.026
Read-COV-250, High
Slow
.000
.000
Sem-COV-250, Low
Slow
.151
.096
Sem-COV-250, High
Slow
. 142
.085
Reading, Low
Faster
.033
.042
Reading, High
Faster
.002
.009
Semantic, Low
Faster
.200
.115
Semantic, High
Faster
.222
.132
Read-COVAT-100, Low
Faster
.031
. 028
Read-COVAT-100, High
Faster
. Oil
.019
* Proportion of overall language errors.

159
Table 3-20--continued.
Task, Frequency
Type of Responder
M *
SD
Sem-COVAT-100, Low
Faster
.161
.094
Sem-COVAT-100, High
Faster
.168
. Ill
Read-COVAT-250, Low
Faster
.054
.046
Read-COVAT-250, High
Faster
.011
.017
Sem-COVAT-250, Low
Faster
.187
.082
Sem-COVAT-250, High
Faster
.142
.085
* Proportion of overall language errors.

160
Table 3-21. Slow and Faster Responders During the Semantic
Association-COVAT Condition: Descriptive
Statistics for Word Familiarity.
Task, Word Frequency
Type of Responder
M *
SD
Single-task, Low
Slow
. 019
.030
Single-task, High
Slow
. 000
.000
Dual-task, Low
Slow
.029
.040
Dual-task, High
Slow
.000
.000
Single-task, Low
Faster
. 040
.029
Single-task, High
Faster
.000
.000
Dual-task, Low
Faster
.019
.023
Dual-task, High
Faster
. 000
.000
* Proportion of unfamiliar words.

161
Table 3-22. Slow and Faster Responders During the Semantic
Association-COVAT Condition: Descriptive
Statistics for Task Difficulty.
Task
Type of Responder
M *
COVAT
Slow
1.22
Reading
Slow
1.22
Semantic
Slow
3.11
Reading-COVAT
Slow
2.22
Semantic-COVAT
Slow
3.89
COVAT
Faster
1.05
Reading
Faster
1.16
Semantic
Faster
3.37
Reading-COVAT
Faster
2.32
S emantic-COVAT
Faster
4.45
* Level of difficulty (l=very easy, 7=very difficult).

Figure 3-1. Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 100 ms delay between
language task and onset of the COVAT
(C=COVAT; RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 100=100 ms delay
between language task and onset of the
COVAT).

MEAN REACTION TIME (MS)
163
100 ms Delay between Language Tasks & COVAT
-*• C-Rt-100
-o RC-Lo-Rt
RC-Hi-Rt
-a- SC-Lo-Rt
-*â–  SC-Hi-Rt
-**â–  C-Lt-100
RC-Lo-Lt
RC-Hi-Lt
-*• SC-Lo-Lt
SC-Hi-Lt
TRIAL TYPE

Figure 3-2. Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 250 ms delay between
language task and onset of the COVAT
(C=C0VAT; RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 250=250 ms delay
between language task and onset of the
COVAT).

MEAN REACTION TIME (MS)
165
250 ms Delay between Language Tasks & COVAT
C-Rt-250
RC-Lo-Rt
RC-Hi-Rt
SC-Lo-Rt
SC-Hi-Rt
C-Lt-250
RC-Lo-Lt
RC-Hi-Lt
SC-Lo-Lt
SC-Hi-Lt
TRIAL TYPE

Figure 3-3. Relative frequency histograms for the mean
reaction time of the covert orienting of
visual attention task (COVAT) and
Reading-COVAT condition.

167
COVERT ORIENTING OF VISUAL ATTENTION TASK (COVAT)
Subject Mean RT
Count
Midpoint
8
325.00
o*********
7
375.00
O'k’k'k'k’k'k'k'kic
8
425.00
©★★★★★★★★★
3
475.00
O*********
3
525.00
O * ★ * ★ ★ . **★
0
575.00
O
★ ★★★★★★★★★★★ .
★★★★★★★★★★★★★
★★★★★★★★★★★★★
* ★ ★ * ★ ★
★★★★★★
★★★★★★★★★★★★★★★★★★
★★★★★★★★★★★★★
★★★★★★★★★★★★★★★★★★
I....+....I....+....I....+....I....+....I
0 2 4 6 8
Histogram
frequency
+
. I
10
READING-COVAT
Subject Mean RT
Count
Midpoint
3
325.00
o ★ * ★ * ★
5
375.00
o ★ ★ ★ ★ ★
5
425.00
o ★ ★ ★ ★ ★
6
475.00
O * * * * *
5
525.00
o ★ ★ ★ ★ ★
3
575.00
o ★ * ★ ★ ★
1
625.00
o ★ ★ ★ ★ ★
0
675.00
o
1
725.00
O . * * ★ ★
0
775.00
+
OHO
★★★★★★
★★★★★★★
.1...I...I...I
2 4 6 8
Histogram frequency
+
. I
10

Figure 3-4. Relative frequency histogram for the mean
reaction time of the Semantic Association-
COVAT condition.

169
SEMANTIC ASSOCIATION-COVAT
Subject Mean RT
Count
Midpoint
0
325.00
O
0
375.00
0
0
425.00
o
1
475.00
o ★ . ★★
2
525.00
O ★★★★★★★★ .
5
575.00
2
625.00
O'ic'kirieie'k'k'k'k'k'k • ★★★★★★★★
2
675.00
. ***★★★★
3
725.00
o★★★★★★★★★★★★★ • ★*★★★★★★★★★★★★★★
2
775.00
o★★★★★★★★★★★★★ .★★★★★★
1
825.00
1
875.00
Oicic'k'kie'kic'k'kie
0
925.00
o
1
975.00
o★★★★★★★★★★
0
1025.00
o
0
1075.00
0
0
1125.00
o
1
1175.00
O-kieie'kicic’kic'kic
1
1225.00
o★★★★★★★★★ •
0
1275.00
O
4
1325.00
o★★★★★★★.
0
1375.00
o
1
1425.00
. ★★★★
0
1475.00
o
0
1525.00
o
1
1575.00
o★★ . ★★★★★★★
0
1625.00
o
0
1675.00
o
0
1725.00
o
0
1775.00
o
0
1825.00
o
0
1875.00
o
0
1925.00
0
1
1975.00
O'kiricieieicicic'kic
I.... + ....I.... + ....I.... + ....I.... + ....I.... + ....I
0 1 2 3 4 5
Histogram frequency

Figure 3-5. Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 100 ms delay between
language task and onset of the COVAT,
after equating for general response time
in each condition with no cue trials
(C=C0VAT; RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 100=100 ms delay
between language task and onset of the
COVAT).

-NC)/NC
171
ransformed Data: 100 ms Delay between Language Tasks & COVAT
-*• C-Rt-100
-o RC-Lo-Rt
-o- RC-Hi-Rt
-a- SC-Lo-Rt
SC-Hi-Rt
-*â–  C-Lt-100
RC-Lo-Lt
-- RC-Hi-Lt
SC-Lo-Lt
SC-Hi-Lt
TRIAL TYPE

Figure 3-6. Covert orienting of visual attention task
(COVAT) alone and paired with the language
tasks at the 250 ms delay between
language task and onset of the COVAT,
after equating for general response time
in each condition with no cue trials
(C=COVAT; RC-Lo=Reading-COVAT condition with
low frequency words; RC-Hi=Reading-COVAT
condition with high frequency words;
SC-Lo=Semantic association-COVAT condition
with low frequency words; SC-Hi=Semantic
association-COVAT condition with high
frequency words; Rt=Targets presented in
the right visual field; Lt=Targets presented
in the left visual field; 250=250 ms delay
between language task and onset of the
COVAT).

-NC)/NC
173
Transformed Data: 250 ms Delay between Language Tasks & COVAT
0.30
0.25
0.20
0.15
0.10
0.05
0.00
-0.05
-0.10
VALID INVALID
-*â–  C-Rt-250
-a- RC-Lo-Rt
-*â–  RC-Hi-Rt
-a- SC-Lo-Rt
-*â–  SC-Hi-Rt
C-Lt-250
RC-Lo-Lt
RC-Hi-Lt
-*â–  SC-Lo-Lt
-*â–  SC-Hi-Lt
TRIAL TYPE

Figure 3-7. Language errors for single- and dual-task
conditions (Semantic Only=Semantic
association task; COV&Sem=Semantic
association-COVAT condition; Reading only=
Reading task; COV&Read=Reading-COVAT
condition; 100=100ms delay between language
task and onset of the COVAT; 250=250 ms
delay between language task and onset of
the COVAT).

175
Language Errors for Single- & Dual-Task Conditions
cn
x
o
oc
DC
LU
LU
O
<
D
0
z
<
-I
LL
O
sp
0s
Semantic Only
COV&Sem-100
COV&Sem-250
Reading Only
COV& Read-100
COV&Read-250
WORD FREQUENCY

Figure 3-8. Task difficulty ratings (COVAT only=Covert
orienting of visual attention task; Reading
Only=Reading task; Semantic Only=Semantic
association task; COV&Reading=Reading-COVAT
condition; COV&Semantic=Semantic association-
COVAT condition).

LEVEL OF DIFFICULTY
177
Task Difficulty, based on Subjects' Ratings
â–  COVAT Only
0 Reading Only
H Semantic Only
02 COV&Reading
â–¡ COV&Semantic
TASK

CHAPTER 4
DISCUSSION AND CONCLUSIONS
The results from the covert orienting of visual
attention task and from the language tasks (reading familiar
words, producing similar meaning or associated words) will
be evaluated and interpreted with respect to the original
hypotheses of the study and to data reported by other
researchers in the field.
Covert Orienting of Visual Attention Task
Similar to prior research conducted on the covert
orienting of visual attention task (COVAT) with
neurologically normal subjects (Petry et al., 1994; Posner,
1980; Posner et al., 1987; Posner et al., 1988), subjects in
the present study responded significantly faster to valid
than to invalid trials demonstrating what has been termed
the "validity effect" (Posner et al., 1989). As a result of
selective attention to the COVAT cue, performance was
facilitated on valid trials and inhibited on invalid trials
when the COVAT target appeared 100 ms after cue onset.
Additionally, subjects performed comparably when the COVAT
target appeared on the left or right side of space.
178

Covert Orienting of Visual Attention Task Paired with
Language Tasks
In accordance with predicted results and previous
179
research (Posner et al., 1987; Posner et al., 1988),
subjects demonstrated effects of interference on the COVAT
during all conditions of dual-task performance. Although
the interference effects were apparent at both word-COVAT
delays (100, 250 ms), they were most pervasive at the 100 ms
word-COVAT delay. The data from the 100 ms word-COVAT delay
are believed to represent the effects of early lexical
access with and without an emphasis on semantics on visual
selective attention while the data from the 250 ms delay
represent the effects of lexical semantics and non-semantics
in the midst of processing on visual selective attention.
100 ms Word-COVAT Delay
When the COVAT began 100 ms after the start of the
language tasks, subjects responded significantly slower to
the COVAT target in all dual-task conditions (reading-COVAT
with high frequency words, reading-COVAT with low frequency
words, semantic association-COVAT with high frequency words,
semantic association-COVAT with low frequency words) in
comparison to the COVAT alone condition (see Figure 3-1).
The degree of interference on the COVAT varied according to
the proposed demands for attention and subsequent cognitive
processing needed for the language tasks. As proposed,
subjects responded slowest to the semantic association-COVAT
conditions which required the most attention for successful

180
task completion. They responded intermediately to the
reading-COVAT conditions and fastest to the COVAT alone.
In contrast to Posner and Petersen's (1990) hypothesis
that lexical processing may be so automatic as to not
require attention, subjects in the present study responded
significantly slower during the reading-COVAT condition in
comparison to the COVAT alone condition suggesting that
attention is required during lexical processing. Based on
slower responding to a tone discrimination task when it was
paired with a reading task than when it was performed alone,
Herdman (1992) also concluded that lexical processing
requires attention, even for experienced adult readers.
Although subjects were predicted to respond slowest to
COVAT targets during the semantic association-COVAT
conditions, it was not anticipated that they would react
markedly slower (i.e., approximately three times as slow) as
compared to the COVAT condition. Based on this finding, it
is believed that the semantic association-COVAT conditions
with low and high frequency words required substantially
more attention and cognitive processing than originally
estimated.
The relationship between the degree of attention for
cognitive processing and severity of dual-task COVAT
impairment was bolstered by the effect of word frequency.
As reported in the literature, subjects tend to respond
slower to low frequency than to high frequency words while

181
reading or making lexical decisions during a dual-task
paradigm (Herdman, 1992; Herdman & Dobbs, 1989). The
present study predicted that word frequency would exert its
influence within each level of overall responding for the
dual-tasks conditions, such that, subjects would respond
fastest to the reading-COVAT condition with high frequency
words, next-to-fastest to the reading-COVAT condition with
low frequency words, slowest to the semantic association-
COVAT condition with low frequency words, and next-to-
slowest to the semantic association-COVAT with high
frequency words. As hypothesized, subjects responded
consistently slower to COVAT targets when they were reading
low frequency words in comparison to high frequency words at
the 100 ms word-COVAT delay. Inconsistent with prior
predictions, they did not respond slower to low frequency
than to high frequency words during the semantic
association-COVAT conditions; instead, they responded
comparably. Because the overall level of reaction times to
COVAT targets during the semantic association-COVAT
condition was markedly elevated (i.e., slow) in comparison
to the reading-COVAT and COVAT conditions, it is believed
that the high demands for attention and subsequent cognitive
processing eliminated the effects of word frequency.
Additional support for interference effects on visual
selective attention during early lexical access comes from
the transformed data at the 100 ms word-COVAT delay. After

182
equating for baseline response levels in each condition with
the no cue trials, subjects exhibited the "validity effect"
but only in the COVAT alone condition (see Figure 3-5).
When subjects performed the single-task COVAT condition,
they were able to selectively attend to left- and right¬
sided COVAT cues resulting in faster responses to valid
trials and slower responses to invalid trials. However,
when subjects performed a reading or semantic association
task in addition to the COVAT, they were unable to
selectively attend to either left- or right-sided COVAT cues
resulting in comparable responses to valid and invalid
trials. As predicted based on findings from Posner (1988),
subjects did not exhibit a validity effect for left-sided
COVAT targets during any of the dual-task conditions.
Inconsistent with prior predictions and previous research
(Posner, 1988), subjects did not demonstrate a validity
effect for right-sided COVAT targets either.
Because the left hemisphere is dominant for language
and for processing of right-sided information and was
hypothesized to possess an intrahemispheric system for
selective engagement of attention where engagement resources
were shared between tasks executed within the hemisphere, it
was anticipated that resource overload would interfere
primarily with right-sided COVAT cues and targets leading to
particularly slow responses to invalid trials with right¬
sided COVAT targets in addition to faster responding to

183
invalid trials with left-sided COVAT targets. During
invalid trials with the selective attentional COVAT cues
appearing on the left side of space and subsequent targets
appearing on the right, subjects were expected to respond
significantly slower to these trials because of reduced
attentional resources in the left hemisphere for detection
of these targets. Subjects were expected to respond faster
to invalid trials with left-sided targets, than to invalid
trials with right-sided targets, because of reduced
attentional resources in the left hemisphere for detection
of right-sided cues. Because subjects did not exhibit a
validity effect for left- or right-sided targets, the data
support interference effects from a single resource theory
of attention where the mechanism for engagement of attention
operates on visuospatial information occurring in both
visual fields as well as on lexical information, rather than
the proposed multiple resources theory of attention.
As proposed, the multiple resources theory of attention
would have been supported if subjects demonstrated selective
impairment of right-sided performance on the COVAT (i.e., a
right-sided validity effect because of significantly slower
reaction times to invalid trials with right-sided targets
and lack of a left-sided validity effect). The left
intrahemispheric mechanism involving the frontal cortex,
nucleus reticularis, inferior thalamic peduncle, and
centromedian, as proposed by Nadeau and Crosson (in press),

184
was the system postulated to explain differential dual-task
interference effects on the COVAT. Since the interference
was more pervasive as it affected both left- and right-sided
targets, it is possible that this mechanism within the
dominant left hemisphere engages attention to left- and
right-sided visuospatial information particularly when it is
engaging attention to language. However, it is also
possible that lexical processing required marked engagement
of attention interfering with both left- and right-sided
COVAT cues and targets despite primary engagement within the
left hemisphere.
Because interference effects were graded across the
COVAT conditions (i.e., more pronounced during the semantic
association-COVAT condition than during the reading-COVAT
condition), a single resource theory of attention where
attention is shared among concurrent tasks was strengthened.
If marked interference occurred for all dual-task conditions
regardless of the attention demands inherent in each
condition, then a single resource theory of attention where
attention was not shared, but switched rapidly among
concurrent tasks, would have been bolstered.
Similar to results from the present study, Friedman et
al. (1988) reported comparable interference in finger
tapping with the left and right hand, during concurrent
reading. Pashler and O'Brien (1993) also reported no

185
significant differences in reaction times between left- and
right-sided targets while concurrently reading nonwords.
In contrast to these findings of equivalent
interference in left- and right-sided responding during
dual-task performance, Ballesteros et al. (1989), Milner et
al. (1982), and Posner et al. (1988) reported selective
interference with right-sided responses as compared to left¬
sided responses during dual-task performance. Ballesteros
et al. found that subjects tapped slower with their right-
than with their left- hand when it was paired with detection
of nonmatching nonwords or nonmatching lines. Milner found
that subjects responded significantly slower to right-sided
targets as compared to left-sided targets, while they
counted backwards. Posner et al. (1988) found a validity
effect for only right-sided targets while subjects performed
the COVAT paired with text repetition (shadowing) of
auditory material.
Based on the above findings, it appears that left- and
right-sided responses are affected in a similar manner
during concurrent reading of either real words or nonwords.
Attention to reading tends to yield comparable decrement in
left- and right-sided responding during performance of a
concurrent task. It appears that lexical processing of
single visually presented words is more demanding of
attention than lexical processing of auditorily presented
words within a context (i.e., within a sentence and a

story), resulting in interference effects for left- and
right- responses of a concurrent task.
250 ms Word-COVAT Delay
186
At the 250 ms word-COVAT delay, subjects responded
significantly slower to the COVAT target in all dual-task
conditions (reading-COVAT with low frequency words, semantic
association-COVAT with high frequency words, semantic
association-COVAT with low frequency words) with the
exception of the reading-COVAT condition with high frequency
words in comparison to the COVAT alone condition (see Figure
3-2). Similar to findings at the 100 ms word-COVAT delay,
the degree of interference on the COVAT varied according to
the proposed demands for attention and subsequent cognitive
processing necessary for the language tasks. Subjects
responded slowest to the semantic association-COVAT
conditions which required the most attention for successful
task completion. They responded intermediately to the
reading-COVAT condition with low frequency words and fastest
to the conditions requiring the least amount of attention
and cognitive processing: the COVAT alone and reading-COVAT
condition with high frequency words.
Consistent with results obtained at the 100 ms word-
COVAT delay, the mean reaction time difference between the
semantic association-COVAT and COVAT conditions was about
three times as large as the difference between the reading-
COVAT and COVAT conditions. Substantial slowing to COVAT

187
targets during the semantic association-COVAT conditions is
believed to reflect reduced attentional resources for
processing of COVAT targets because of large demands for
attention and cognitive processing while in the midst of a
lexical-semantic task.
Similar to findings for word frequency at the 100 ms
word-COVAT delay and from previous research (Herdman, 1992;
Herdman & Dobbs, 1989), subjects responded faster to COVAT
targets when they were reading high frequency words than
when they were reading low frequency words at the 250 ms
word-COVAT delay. Subjects did not demonstrate any
significant differences in reaction times to low or high
frequency words during the semantic association-COVAT
conditions. The absence of a word frequency effect on COVAT
targets during the semantic association-COVAT conditions is
believed to reflect the dominance of attentional demands for
task execution over subtler differences in attentional
demands for responding to words at different frequencies.
Interference effects on visual selective attention
while in the midst of lexical access were also apparent in
the transformed data which equated for the baseline level of
response in each condition. Consistent with findings from
the 100 ms word-COVAT delay, subjects demonstrated a
"validity effect" for the COVAT condition at the 250 ms
word-COVAT delay. In addition, they exhibited a validity
effect in the reading-COVAT condition with low frequency

188
words (see Figure 3-6). Therefore, subjects were able to
selectively attend to left- and right-sided COVAT cues when
they performed the COVAT alone or concurrently with reading
low frequency words, resulting in faster responses to valid
trials and slower responses to invalid trials. However,
when subjects read high frequency words or generated
semantic associations to low or high frequency words while
concurrently detecting COVAT targets, they were unable to
selectively attend to either left- or right-sided COVAT cues
resulting in comparable responses to valid and invalid
trials.
Although interference effects were obtained for both
low and high frequency words during the reading-COVAT
condition at the 250 ms word-COVAT delay, interference
occurred differentially. When the data were not equated for
baseline response level, subjects demonstrated interference
by responding significantly slower to the reading-COVAT
condition with low frequency words in comparison to the
COVAT condition. No interference was exhibited in the
reading-COVAT condition with high frequency words, as
subjects responded comparably to the COVAT condition. When
the data were transformed and equated for baseline response
level, subjects then demonstrated interference with a lack
of validity effect to left- and right-sided targets in the
reading-COVAT condition with high frequency words. They no
longer exhibited interference with low frequency words

189
during the reading-COVAT condition, as they demonstrated a
validity effect indicating selective attention to COVAT
cues. In contrast to the 100 ms word-COVAT delay where
interference was observed whether or not the reading-COVAT
data were transformed, selective interference effects were
obtained at the 250 ms word-COVAT delay. This dissociation
between level of performance effects for reading low
frequency words but absence of validity effects for high
frequency words suggest that level of performance effects
may be caused by a different mechanism than the loss of
validity effects.
In addition, there were pervasive effects of
interference in the semantic association-COVAT conditions
with low and high frequency word at the 100 ms and 250 ms
word-COVAT delays, whether or not the data were transformed.
Selective interference effects on the COVAT while reading
low and high frequency words may be accounted for by the
following reasons. First, in contrast to the 100 ms word-
COVAT delay, primary engagement of attention for lexical
processing may have been close to ceasing at the 250 ms
word-COVAT delay as the target would have actually appeared
350 ms after the onset of the word to be read (see Figure 1-
4). According to Just and Carpenter (1980), the average
college student reads approximately 200 words per minute
when reading scientific texts which translates to one word
about every 300 ms. In addition, the differential effects

190
may be due to interruption at different points in the
processing sequence. Because high frequency words tend to
be recognized more quickly than low frequency words, it is
likely that processing of high frequency words by the visual
input lexicon after a 250 ms word-COVAT delay was complete
by the time the COVAT target appeared. However, processing
by the phonological output lexicon (or other mechanisms
downstream from the visual input lexicon) may still have
been active when the target appeared. If so, the loss of
the validity effect for high frequency words may reflect
interference related to intentional rather than purely
attentional processes. By the same token, the low frequency
words might still be in a stage of processing by the visual
input lexicon, indicating that the slowing of competing
responses reflects attentional factors related to processing
by the visual input lexicon. Finally, selective
interference effects may be more likely to occur in a dual-
task condition that required less engagement of attention
(reading-COVAT), while pervasive interference may be likely
exhibited in a more attention demanding condition (semantic
association-COVAT).
Despite equating for overall level of response in each
condition, a significant difference was detected between the
following tasks when responding to valid COVAT trials: (a)
COVAT and semantic association-COVAT with low frequency
words and (b) reading-COVAT with high frequency words and

191
semantic association-COVAT with low frequency words.
Subjects responded significantly faster to valid trials
during the COVAT and reading-COVAT condition with high
frequency words in comparison to the semantic association-
COVAT condition with low frequency words.
Language Tasks
Inconsistent with predicted results, subjects did not
demonstrate effects of interference on the language tasks
during dual-task performance. As compared to single-task
language performance, subjects did not commit a
significantly larger proportion of errors during the dual¬
task conditions at either the 100 or 250 ms word-COVAT
delays (see Figure 3-7). When the COVAT began 100 or 250 ms
after the start of the language tasks, subjects made
slightly more language errors during the reading-COVAT
condition in comparison to the reading alone conditions.
However, this difference failed to reach significance.
Although subjects committed more errors during the semantic
association condition as compared to the semantic
association-COVAT conditions at each word-COVAT delay, they
exhibited only the following significant difference: In
response to high frequency words, subjects made
significantly more language errors during the semantic
association condition than during the semantic association-
COVAT condition at the 250 ms word-COVAT delay. These

192
results are consistent with dual-task findings from the
Friedman et al. (1988) study where subjects performed better
on a language task when it was emphasized than when it was
not emphasized. Therefore, engagement of attentional
resources were preferential for the most important (i.e.,
primary) task, accounting for a general lack of interference
effects between single- and dual-task language processing.
In accordance with predictions, subjects made
significantly less language errors during the reading and
reading-COVAT conditions in comparison to the semantic
association conditions with and without the COVAT during
each word-COVAT delay (see Figure 3-7). During the reading
and reading-COVAT conditions, errors consisted primarily of
mispronunciations of the entire word. During the semantic
association and semantic association-COVAT conditions, the
most frequent type of error was "passing", which indicated
that subjects could not generate a similar meaning or an
associated word to the target word. In addition to pass
errors during the semantic association conditions with and
without the COVAT, subjects made the following types of
errors to a lesser extent: (a) associations with no obvious
connections to the presented word, (b) did not respond, (c)
correctly pronounced the initial syllable followed by
incorrect pronunciation of a correct association, and (d)
correct association to an incorrect homophonic word.

193
As predicted, subjects committed less language errors
with high frequency words in comparison to low frequency
words for the reading alone condition and for the reading-
COVAT condition at the 250 ms word-COVAT delay. In contrast
to predicted findings, subjects did not make significantly
less errors to high than to low frequency words in the
following conditions: reading-COVAT at the 100 ms word-
COVAT delay, semantic association only, and semantic
association-COVAT at the 100 and 250 ms delays. However,
trends in the predicted direction were observed for the
reading-COVAT condition at 100 ms word-COVAT delay and for
the semantic association condition at the 250 ms word-COVAT
delay. Subjects made a comparable proportion of language
errors to low and high frequency words during the semantic
association-COVAT condition at the 100 ms word-COVAT delay.
Although not significant, they made moderately more errors
in response to high frequency than to low frequency words
during the semantic association condition.
In contrast to findings from the present study, Herdman
(1992) did not report any significant effects of word
frequency (low, high) or task (reading single words, making
lexical decisions) on the proportion of language errors
within the single-task conditions (reading single words,
making lexical decisions) or within the dual-task conditions
(reading single words paired with tone discrimination,
making lexical decisions paired with tone discrimination).

194
Although Herdman reported an increase in the proportion of
errors during dual-task performance as compared to single¬
task performance, he did not state whether or not this
difference was significant.
Language Task Order
Overall, the order of presentation of the language
tasks did not have a significant influence on the mean
proportion of language errors in the single- and dual-task
conditions. Although subjects who read then generated
semantic associations tended to make more reading errors
than subjects who generated semantic associations then read,
this difference was significant only for low frequency words
in the reading only condition. Subjects who generated
semantic associations then read tended to produce more
errors in the semantic association condition than subjects
who read then generated semantic associations, but these
differences were not significant in the single- or dual-task
conditions.
Word Familiarity
In the single-task and dual-task conditions, subjects
were familiar with the majority of presented words. More
specifically, they were familiar with all of the high
frequency words and with approximately 97 % of the low
frequency words presented in the single- and dual-task
conditions. Because the majority of the words used in this
study were familiar, the assumption that subjects tended to

195
access words lexically by way of the visual input lexicon
rather than by way of grapheme-phoneme conversion mechanism
appeared justified as proposed by Ellis and Young (1988).
Based on Ellis and Young's theory, skilled readers only read
unfamiliar words by way of the grapheme-phoneme conversion
mechanism.
Task Difficulty
Subjects' ratings of task difficulty are consistent
with the proposed demands for attention and subsequent
cognitive processing needed for the tasks. With regard to
the visual selective attention tasks, subjects rated the
COVAT as the easiest task, the semantic association-COVAT
condition as the hardest task, and the reading-COVAT
condition as a task of intermediate difficulty (see Figure
3-8). Regarding the tasks involving lexical processing,
subjects rated the reading only condition as the easiest
task, the reading-COVAT condition as the next-to-easiest
task, the semantic association-COVAT condition as the
hardest task, and the semantic association alone condition
as the next-to-hardest task. Although subjects' ratings of
task difficulty mirrored performance on the visual selective
attention tasks (i.e., more COVAT interference with higher
ratings of task difficulty), their ratings did not reflect
performance on the language tasks.

196
Overall, subjects rated the COVAT and the reading task
as the easiest tasks, the reading-COVAT condition as the
next-to-easiest, the semantic association-COVAT condition as
the hardest task, and the semantic association condition as
the next-to-hardest task.
Slow Responders During the Semantic Association-COVAT
Condition
Although 9 of 29 subjects responded markedly slower to
COVAT targets during the semantic association-COVAT
condition despite responding comparably to the majority of
the subjects during the COVAT and reading-COVAT conditions
(see Figures 3-3 and 3-4) , no significant differences were
detected between this subgroup and the rest of the subjects
on the following factors: (a) proportion of false positive
errors to the COVAT targets in the single- and dual-task
conditions, (b) type of language strategy used during the
semantic association-COVAT condition (i.e., generation of
synonyms versus semantic associates), (c) overall proportion
of language errors in the single- and dual-task conditions,
(d) proportion of unfamiliar words in the single- and dual-
task conditions, and (e) task difficulty ratings in the
single- and dual-task conditions. It is difficult to
determine the reasons why this subgroup of subjects
responded slowly to the COVAT targets during the semantic
association-COVAT condition. The following subject
characteristics have been speculated: (a) less rich

197
vocabulary, (b) anxiety, (c) perfectionism, (d) oppositional
because they did not respond to both tasks as rapidly as
possible, and (e) adaptive response strategy because they
required additional attention and processing time for the
semantic association task. It is proposed that some
combination of these factors likely acted at different
points throughout testing; for example, subjects were
possibly more anxious at the beginning of the experiment
than at the end, resulting in slower responding. However,
the most promising reason is that the subjects required
additional attention and processing time for successful
completion of the primary language task, resulting in slowed
responses to the COVAT. Therefore, their response strategy
was adaptive because the word remained on the computer
screen for a longer period of time.
In view of the present discussion, the results of this
study suggest that lexical processing of familiar words,
especially with an emphasis on semantics, shares a common
selective attentional resource with covert orienting to
visuospatial information. In comparison to single-task
performance, subjects demonstrated effects of interference
on the covert orienting to visual attentional task (COVAT)
while they concurrently read or generated semantic
associations to single words. In addition to responding
slower to the COVAT targets during dual-task as compared to
single-task performance, subjects generally did not

198
demonstrate a "validity effect" (Posner et al., 1989)
reflecting reduced influence of cues on target detection.
Interference effects (i.e., slower response times and lack
of a validity effect) were present at the beginning as well
as in the midst of lexical access with and without an
emphasis on semantics; however, interference on the COVAT
was most pervasive at the beginning of lexical processing
(i.e., at 100 ms word-COVAT delay).
The degree of interference on the COVAT varied
according to the proposed demands for attention and
subsequent cognitive processing needed for the language
tasks. Subjects responded slowest to the semantic
association-COVAT condition, intermediately to the reading-
COVAT conditions, and fastest to the COVAT alone. As
suggested by these results, lexical processing of familiar
words with an emphasis on semantics required much higher
demands for attention than lexical processing without an
emphasis on semantics. Based on findings of select
impairments of semantics (e.g., a modality specific naming
deficit for living things) following various brain lesions,
the semantic systems appears to be distributed throughout
the cortex (McCarthy & Warrington, 1990) and accessed by way
of the angular gyrus. The findings from the present study
support greater attentional demands to search and coordinate
a distributed semantic system in comparison to the visual
input lexicon which appears to be more localized (Brodmann's

199
areas 37 and 39). However, lexical processing with and
without an emphasis on semantics appears to require
sufficient attentional resources as was demonstrated by-
interference effects to both left- and right-sided cues and
targets in the COVAT.
Future Research
To bolster conclusions from the present study, a
replication experiment is recommended with one important
addition. Aside from recording actual responses to the
language tasks (i.e., words read and semantic associations
generated), verbal response latency should also be recorded
by a voice-activated relay. In addition to providing
another measure of attention and cognitive processing
demands for the language tasks, response latency to the
language stimuli and the COVAT would provide adequate
information for subsequent investigation of the strategy
employed by subjects to accomplish dual-task responding.
With response latency from both tasks during single-task and
concurrent performance, the proportion of language responses
occurring before, during, and after the key press response
to the COVAT during the dual-task conditions could be
computed and relationships examined by correlation of the
response times for the language tasks and the COVAT.
Without the response latencies from the language tasks, it
was too difficult to determine the sequencing of subjects'

200
responses during the dual-task conditions. Especially
during the reading-COVAT condition where subjects responded
faster to both the language and COVAT stimuli, determination
of response sequence was unreliable based solely on tape-
recorded responses in which both the verbal and the COVAT
response could be heard. However, given findings from
Marsden (1987) where subjects sometimes completed one motor
act prior to another and sometimes performed them
concurrently despite instructions for either simultaneous or
sequential performance, it is hypothesized that similar
results would be discovered for concurrent performance of
the language tasks and the COVAT. Therefore, similar to
Marsden, subjects would be expected to exhibit a varied
response pattern during dual-performance, responding to one
task occasionally before, during, and after responding to
another task.
found no correlation between response times of simple motor
acts (unilateral elbow flexion and hand squeeze) performed
simultaneously or sequentially in normal individuals, it is
hypothesized that similar results would be discovered
between the response times of the language tasks and the
COVAT.
Following replication of the current study, the same
design should be utilized with one further change. The
COVAT should become the primary task and presented first
during the dual-task conditions, instead of the language

201
tasks as was the case in the present experiment. With the
COVAT as the primary task and attention primarily directed
to the completion of this task, results should reflect the
influence of visual selective attention on lexical
processing. It is unclear if significant differences would
be predicted between single-task and dual-task performance
on the COVAT. However, subjects would be expected to make
significantly more language errors during dual-task
performance than during single-task performance. More
specifically, subjects would make more errors during the
COVAT-semantic association condition than during the
semantic association condition alone as well as more errors
during the COVAT-reading condition than during the reading
condition alone. Based on findings from the present study,
subjects would continue to commit more errors during the
semantic association conditions with and without the COVAT
than during the reading conditions with and without the
COVAT. Similar to commitment of language errors, subjects
would be expected to demonstrate graded response latencies
to the language stimuli during single-task and dual-task
conditions. Therefore, subjects would respond slowest to
words during the COVAT-semantic association condition, next-
to-slowest during the semantic association condition,
fastest to the reading condition, and next-to-fastest during
the COVAT-reading condition.

202
After both the COVAT and the language tasks have acted
as the primary task in this paradigm, substitution of a less
difficult language task with an emphasis on semantics is
recommended. Instead of generating synonyms or semantic
associations, subject can complete a lexical decision task.
Variations of a lexical decision task have been described in
the literature (Becker, 1976; Boddy, 1981; Herdman, 1992);
for example, deciding whether presented letters constitute a
word or nonword or whether the presented word is an animal.
Based on results from Herdman (1992), a lexical decision
task was more attention demanding than a single word reading
task, but it was not markedly more demanding than the
reading task as was the semantic association task employed
in the current study.
After substituting different language tasks for the
ones used in the present experiment, the relationship
between visual selective attention and other cognitive
functions can be explored within this dual-task paradigm.
As was previously emphasized, the presentation of stimuli
should be fixed (i.e., task A occurs then task B occurs) to
facilitate interpretation of results (i.e., the effects of
task A on task B). In addition, the vigilance component
should continue to be reduced by using moderate number of
trials and frequent rest breaks.
In addition to exploring the relationship between
visual selective attention and various cognitive functions

203
with neurologically normal individuals, this paradigm can be
employed with individuals who have a history of brain injury
(Posner et al., 1987).
To further investigate the anatomy involved in visual
selective attention and lexical processing, the dual-task
paradigm could be employed in a functional neuroimaging
study. With this additional information, the location of
structures and pathways involved in the single resource
theory of attention may be determined.

APPENDIX A
AAL SCREENING QUESTIONNAIRE
Name Date/Time /
Sex Handedness Phone # College
1) What is your native language?
2) What is your D.O.B.?
3) What was the highest grade you completed in school?
4) Do you remember having difficulty with your school work
(e.g., problems learning to read, calculate; special class;
speech problems)?
5) Have you had a high fever?
6) Have you ever been unconscious after hitting your head or
having an accident?
7) Have you ever had a seizure?
8) Have you ever been told that you have a tumor?
9) Have you had an infectious disease of the brain?
10) Have you been hospitalized?
-if yes, when and why?
11) Have you received treatment for any psychiatric
problems?
12) What medications are you currently taking?
13) Has taking medication ever caused a problem for you
(e.g., relationship, school, work)?
204

205
14) Do you drink alcohol?
-if yes, how much? how often?
15) Has drinking alcohol ever caused a problem for you
(e.g., relationship, school, work)?
-if yes, when? how much & how often did you drink?
16) Have you ever missed word or class because of drinking?
-if yes, how often? when?
17) Have you ever received a D.U.I.?
18) Do you use other drugs (e.g., marijuana, cocaine)?
-if yes, when? how much & how often?
19) Has taking drugs ever caused a problem for you (e.g.,
relationship, school, work)?
-if yes, when? how much & how often?
20) Have you ever missed work or class because of drugs?
-if yes when? how often & how much?
21) Is your vision restricted, meaning that you have
difficulty seeing things clearly or that you have blindspots
where nothing can be seen?
22) Do you wear glasses?
23) How many hours did you sleep last night?
24) How many hours do you typically sleep each night?

APPENDIX B
BRIGGS-NEBES MODIFICATION OF THE ANNETT HANDEDNESS
QUESTIONNAIRE
Subject # Date/Time
Indicate hand preference: 1 = Always Left
2 = Usually Left
3 = No Preference
4 = Usually Right
5 = Always Right
1) To write a letter legibly?
2) To throw a ball to hit a target?
3) To play a game requiring the use of a racquet?
4) To hold a match when striking it?
5) To hammer a nail into wood?
6) To hold a toothbrush while cleaning teeth?
Are any of your (biological) relatives left-handed?
If yes, who (parent, sibling, grandparent)?
Did you ever switch your handedness preference?
If yes, when and how?
206

APPENDIX C
INSTRUCTIONS FOR COVAT
This is an experiment that measures response time.
Focus on the cross that appears in the middle of the screen
and not on the two boxes. Some time after the cross
appears, a star will appear in one of the two boxes. As
soon as the STAR appears in a box, press the SPACE BAR with
your LEFT hand. Respond ONLY to the star and to nothing
else.
Press the space bar with your left hand to start the
experiment.
207

APPENDIX D
INSTRUCTIONS FOR THE READING TASK
Focus on the cross that appears in the middle of the
screen. Some time after the cross appears, a word will
appear replacing the cross. As soon as the WORD appears,
read it aloud quickly and accurately.
Most of the words will be familiar to you; however,
some may be unfamiliar. No one is expected to know every
word. Just do your best in reading each word aloud.
Press the space bar with your left hand to start the
experiment.
208

APPENDIX E
INSTRUCTIONS FOR THE SEMANTIC ASSOCIATION TASK
Focus on the cross that appears in the middle of the
screen. Some time after the cross appears, a word will
appear replacing the cross. As soon as the WORD appears,
say aloud the first word that comes to mind that means the
same thing or that is strongly associated to it for most
people. Say this word quickly and accurately.
For example, if you saw the word, MONEY, you could say
'cash' or 'dime' or 'dollar'. But, don't say something
related to a personal association, such as, 'Chilis' (a
place where you worked for money).
Do not read the presented words aloud; just say one
similar meaning word or associated word aloud.
Most of the words will be familiar to you,- however,
some may be unfamiliar. No one is expected to know every
word. If you are presented with an unfamiliar word or a
familiar word and you have difficulty coming-up with a
similar meaning or an associated word, say "pass" but do not
pass too often. It is better to say a vague association, to
the presented word, than to say "pass."
Try not to say anything other than the similar meaning
word, an associated word, or pass during this task.
209

210
Press the space bar with your left hand to start the
experiment.

APPENDIX F
LOW FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS IN
CONCRETENESS AND IMAGEABILITY USED IN THE READING AND
SEMANTIC ASSOCIATION TASKS
APPLIANCE
INTELLECT
APTITUDE
JEALOUSY
ATHLETICS
MASTERY
BLOOM
MONSOON
CHEMISTRY
MOSQUE
DECREE
NONSENSE
DERELICT
NUTRIENT
DISCORD
PASTE
FAREWELL
PERFORMER
HAZARD
POLKA
HEAP
SORROW
INFECTION
VOCATION
211

APPENDIX G
HIGH FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS IN
CONCRETENESS AND IMAGEABILITY USED IN THE READING AND
SEMANTIC ASSOCIATION TASKS
AMOUNT
LANGUAGE
ANSWER
MARRIAGE
CAPACITY
MEMORY
CENTER
OPINION
CHAIN
SISTER
COMMITTEE
SITUATION
CONCEPT
SUBJECT
CRISIS
SURPRISE
EXISTENCE
TASK
INSTANCE
TRADITION
INTERVIEW
VICTORY
KNOWLEDGE
WEAKNESS
212

APPENDIX H
INSTRUCTIONS FOR THE COVAT PAIRED WITH THE READING TASK
This is an experiment that measures response time.
Focus on the cross that appears in the middle of the screen
and not on the two boxes. Some time after the cross
appears, a word will appear replacing the cross. As soon as
the WORD appears, read it aloud quickly and accurately.
Some time after the word appears, a star will appear in
one of the two boxes. As soon as the STAR appears in a box,
press the SPACE BAR with your LEFT hand.
Respond as quickly and accurately as possible to both
the words and the stars but reading the words aloud will be
most important.
Most of the words will be familiar to you; however,
some may be unfamiliar. No one is expected to know every
word. Just do your best in reading each word aloud.
Do not delay any of your responses. As soon as you see
a WORD, read it aloud. As soon as you see the STAR, press
the space bar with your LEFT hand. Sometimes you may press
the space bar, while you are reading a word. Other times
you may press the space bar, before or after you have read a
word.
Press the space bar with your left hand to start the
experiment.
213

APPENDIX I
INSTRUCTIONS FOR THE COVAT PAIRED WITH THE SEMANTIC
ASSOCIATION TASK
This is an experiment that measures response time.
Focus on the cross that appears in the middle of the screen
and not on the two boxes. Some time after the cross
appears, a word will appear replacing the cross. As soon as
the WORD appears, say aloud the first word that comes to
mind that means the same thing or that is strongly
associated to it for most people. Say this word quickly and
accurately. You do not need to read the presented words
aloud; just say one similar meaning word or associated word
aloud.
Some time after the word appears, a star will appear in
one of the two boxes. As soon as the STAR appears in a box,
press the SPACE BAR with your LEFT hand.
Respond as quickly and accurately as possible to both
the words and the stars but saying aloud similar meaning or
associated words will be most important.
Most of the words will be familiar to you; however,
some may be unfamiliar. No one is expected to know every
word. If you are presented with an unfamiliar word or a
familiar word and you have difficulty coming-up with a
similar meaning or an associated word, say "pass" but do not
214

215
pass too often. It is better to say a vague association, to
the presented word, than to say "pass."
Try not to say anything other than the similar meaning
word, an associated word, or pass during this task.
Do not delay any of your responses. As soon as you see
a WORD, say a similar meaning word or a strongly associated
word aloud. As soon as you see the STAR, press the space
bar with your LEFT hand. Sometimes you may press the space
bar, while you are saying a similar meaning or strongly
associated word. Other times you may press the space bar,
before or after you have said a similar meaning or strongly
associated word.
Press the space bar with your left hand to start the
experiment.

APPENDIX J
LOW FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS IN
CONCRETENESS AND IMAGEABILITY USED IN THE READING AND
SEMANTIC ASSOCIATION TASKS WHEN PAIRED WITH THE COVAT
ACCORD
DEMON
ACHE
DISGUISE
AGONY
DISTRESS
ALTITUDE
EDUCATOR
AMATEUR
ETERNITY
APEX
FALLACY
ARBOR
FINISH
AUDITION
FINITE
BLAME
FORECAST
BLUNDER
FRAUD
BRIEF
GENDER
BRUTE
GIST
BUFFOON
GOSPEL
CALCULUS
GRAMMAR
DEAR
HALF
DECEIT
HINT
DEITY
>
HONESTY
DELAY
IDLENESS
216

217
APPENDIX J-
-continued
JARGON
PRODUCE
KINDNESS
PROTOCOL
LAST
RARITY
LATTER
REAR
MADNESS
RECALL
MALADY
REMEDY
MENACE
REPLY
MILITARY
RETREAT
MODERN
REWARD
MOISTURE
RIDDLE
MORTAL
ROTATION
NEARNESS
RUMOR
NICETY
SADNESS
OATH
SICKNESS
OUTSET
SUFFIX
PACT
TOLL
PEER
UNREST
PREFIX
WORTH

APPENDIX K
HIGH FREQUENCY WORDS WITH LOW-TO-MODERATE RATINGS IN
CONCRETENESS AND IMAGEABILITY USED IN THE READING AND
SEMANTIC ASSOCIATION TASKS WHEN PAIRED WITH THE COVAT
ADDITION
DUTY
ADVICE
EFFORT
AGENCY
ERROR
AREA
FACT
ATTEMPT
FACTOR
BASE
FATHER
BELIEF
FEAR
BUSINESS
FEELING
CAREER
FUNCTION
CHANCE
GRADE
COMPANY
HELP
CONCERN
IDEA
COST
IMAGE
COURSE
INDUSTRY
CULTURE
MANNER
DECISION
MEETING
DEGREE
MIND
DIVISION
MOMENT
218

219
APPENDIX K-
-continued
NATION
REPORT
NOTE
REST
NOTION
RESULT
ORIGIN
SALARY
PART
SCIENCE
PEACE
SOUND
PHRASE
SOLUTION
PIECE
STATUS
PORTION
SUPPLY
POSITION
SYMBOL
PRESSURE
TALENT
PROBLEM
THEORY
PROPERTY
THREAT
REACTION
TREND
READING
TROUBLE
REASON
VISION
RELIGION
VOLUME
REMARK
WELFARE

APPENDIX L
POST-EXPERIMENTAL QUESTIONNAIRE
Subject # Date/Time
1) Please rate each task on the following scale.
STAR:
1 2 3 4 5
very easy
6 7
very difficult
READING:
1 2 3 4 5
very easy
6 7
very difficult
SEMANTIC ASSOCIATION:
1 2 3 4 5
very easy
6 7
very difficult
STAR + READING:
1 2 3 4 5
very easy
6 7
very difficult
STAR + SEMANTIC ASSOCIATION:
1 2 3 4 5
very easy
6 7
very difficult
2) How did you go about doing two tasks at once? What
strategy did you use?
Other Comments:
220

REFERENCES
Agresti, A., & Finlay, B. (1986). Statistical methods for
the social sciences (2nd ed.). San Francisco, CA: Dellen.
Allport, A. (1990). Visual attention. In M. I. Posner (Ed.),
Foundations of cognitive science (pp. 631-682).
Cambridge, MA: MIT Press.
Allport, D. A., Antonis, B., & Reynolds, P. (1972). On the
division of attention: A disproof of the single channel
hypothesis. Quarterly Journal of Experimental Psychology.
24, 225-235.
Annett, M. (1967). The binomial distribution of right,
mixed, and left handedness. Quarterly Journal of
Experimental Psychology. 19., 327-333.
Ballesteros, S., Manga, D., & Coello, T. (1989). Attentional
resources in dual-task performance. Bulletin of the
Psvchonomic Society. 27., 425-428.
Becker, C. A. (1976). Allocation of attention during visual
word recognition. Journal of Experimental Psychology:
Human Perception and Performance. 2, 556-566.
Benjafield, J., & Muckenheim, R. (1982). Dates of entry and
measures of imagery, concreteness, goodness, and
familiarity for 1046 words sampled from the Oxford
English Dictionary. Behavior Research Methods.
Instruments. & Computers. 21, 31-52.
Benson, D. F. (1985). Aphasia. In K. M. Heilman & E.
Valenstein (Eds.), Clinical neuropsychology (pp. 17-47).
New York: Oxford University Press.
Binder, J. R., Rao, S. M., Hammeke, T. A., Frost, J. A.,
Bandettini, P. A., Jesmanowicz, A., & Hyde, J. S. (1995).
Lateralized human brain language systems demonstrated by
task subtraction functional magnetic resonance imaging.
Archives of Neurology. 52., 593-601.
Bloom, L., & Lahey, M. (1978). Language development and
language disorders. New York: John Wiley and Sons.
221

222
Boddy, J. (1981). Evoked potentials and the dynamics of
language processing. Biological Psychology. 13. 125-140.
Briggs, G. G., & Nebes, R. D. (1975). Patterns of hand
preference in a student population. Cortex. 11. 230-238.
Broadbent, D. E. (1958). Perception and communication. New
York: Pergamon.
Broca, P. (1964a). Loss of speech, chronic softening and
partial destruction of the left anterior lobe of the
brain. Journal of Neurosurgery. 21. 426-427. (Original
work published 1861)
Broca, P. (1964b). New observation of aphemia produced by a
lesion of the posterior half of the second and third
frontal convolutions. Journal of Neurosurgery. 21. 427-
431. (Original work published 1861)
Cohen, R. A. (1993) . The neuropsychology of attention. New
York: Plenum Press.
Coslett, H. B., Roeltgen, D. P., Gonzalez Rothi, L., &
Heilman, K. M. (1987). Transcortical sensory aphasia:
Evidence for subtypes. Brain and Language. 32. 362-378.
Cowan, N. (1988). Evolving conceptions of memory storage,
selective attention, and their mutual constraints within
the human information-processing system. Psychological
Bulletin. 104(2), 163-191.
Demonet, J. F., Choilet, F., Ramsay, S., Cardebat, D.,
Nespoulous, J. L., Wise, R., Rascol, A., & Frackowiak, R.
(1992). The anatomy of phonological and semantic
processing in normal subjects. Brain. 115. 1753-1768.
Ellis, A. VI., Sc Young, A. W. (1988) . Human cognitive
neuropsychology. Hillsdale, NJ: Lawrence Erlbaum
Associates.
Fisk, A. D., Derrick, W. L., & Schneider, W. (1986-87). A
methodological assessment and evaluation of dual-task
paradigms. Current Psychological Research & Reviews.
5(4), 315-327.
Francis, W. N., & Kucera H. (1982). Frequency analysis of
English usage: Lexicon and grammar. Boston: Houghton
Mifflin.

223
Friedman, A., & Poison, M. C. (1981). Hemispheres as
independent resource systems: Limited-capacity processing
and cerebral specialization. Journal of Experimental
Psychology: Human Perception and Performance. 7(5), 1031-
1058 .
Friedman, A., Poison, M. C., & Dafoe, C. G. (1988). Dividing
attention between the hands and the head: Performance
trade-offs between rapid finger tapping and verbal
memory. Journal of Experimental Psychology: Human
Perception and Performance. 14, 60-68.
Friedman, A., Poison, M. C., Dafoe, C. G., & Gaskill, S.
(1982). Dividing attention within and between
hemispheres: Testing a multiple resources approach to
limited-capacity information processing. Journal of
Experimental Psychology: Human Perception and
Performance. 8., 625-650.
Friedrich, F., & Rader, S. (1990). Reflexive and voluntary
orienting of visual attention: Effects of cue type and
cue validity. Paper presented at the conference on Recent
Advances in the Analysis of Attention, Eugene, OR.
Friendly, M., Franklin, P. E., Hoffman, D., & Rubin, D. C.
(1982) . The Toronto Word Pool: Norms for imagery,
concreteness, orthographic variables, and grammatical
usage for 1080 words. Behavior Research Methods &
Instrumentation. 14, 375-399.
Galaburda, A., & Livingstone, M. (1993). Evidence for a
magnocellular defect in developmental dyslexia. Annals of
the New York Academy of Sciences. 682. 70-82.
Geschwind, N. (1965) . Disconnexion syndromes in animals and
man. Brain. 88. 237-294; 585-644.
Gilhooly, K. J., & Logie, R. H. (1980). Age-of-acquisition,
imagery, concreteness, familiarity, and ambiguity
measures for 1944 words. Behavior Research Methods &
Instrumentation. 12., 395-427.
Gladstones, W. H., Regan, M. A., & Lee, R. B. (1989).
Division of attention: The single-channel hypothesis
revisited. Quarterly Journal of Experimental Psychology.
41A. 1-17.

224
Glosser, G., & Goodglass, H. (1990). Disorders in executive
control functions among aphasic and other brain-damaged
patients. Journal of Clinical and Experimental
Neuropsychology. 12(4). 485-501.
Green, A., & Vaid, J. (1986). Methodological issues in the
use of concurrent activities paradigm. Brain and
Cognition. 5, 465-476.
Hardyck, C., Chiarello, C., Dronkers, N., & Simpson, G. V.
(1984, June). Orienting attention in visual fields. Paper
presented at the 7th International Neuropsychology
Congree, Aachen, Germany.
Heilman, K. M., Bowers, D., Valenstein, E., & Watson, R. T.
(1987). Hemispace and hemispatial neglect. In M.
Jeannerod (Ed.), Neurophysiological and
neuropsychological aspects of spatial neglect (pp. 115-
150). Holland: Elsevier Science.
Heilman, K. M., Watson, R. T., & Valenstein, E. (1985).
Neglect and related disorders. In K. M. Heilman & E.
Valenstein (Eds.), Clinical neuropsychology (pp. 243-
293). New York: Oxford University Press.
Heilman, K. M., Watson, R. T., & Valenstein, E. (1993).
Neglect and related disorders. In K. M. Heilman & E.
Valenstein (Eds.), Clinical neuropsychology (pp. 279-
336). New York: Oxford University Press.
Hellige, J. B., & Wong, T. M. (1983). Hemispheric-specific
interference in dichotic listening: Task variables and
individual differences. Journal of Experimental
Psychology: General. 122. 218-239.
Herdman, C. M. (1992). Attentional resource demands of
visual word recognition in naming and lexical decisions.
Journal of Experimental Psychology: Human Perception and
Performance. 18. 460-470.
Herdman, C. M., & Dobbs, A. R. (1989). Attentional demands
of visual word recognition. Journal of Experimental
Psychology: Human Perception and Performance. 15, 124-
132 .
Herdman, C. M., & Friedman, A. (1985) . Multiple resources in
divided attention: A cross-modal test of the independence
of hemispheric resources. Journal of Experimental
Psychology: Human Perception and Performance. 11, 40-49.

225
Hillyard, S. A., & Munte, T. F. (1984). Selective attention
to color and location: An analysis with event-related
brain potentials. Perception and Psychophysics. 36. 185-
198 .
Hiscock, M. (1986). Lateral eye movements and dual-task
performance. In H. J. Hannay (Ed.), Experimental
technicrues in human neuropsychology (pp. 264-308) . New
York: Oxford University Press.
Hiscock, M., Cheesman, J., Inch, R., Chipuer, H. M., &
Graff, L. A. (1989). Rate and variability of finger
tapping as measures of lateralized concurrent task
effects. Brain and Cognition. 10, 87-104.
James, W. (1890) . The principles of psychology. New York:
Holt.
Just, M. A., Sc Carpenter, P. A. (1980) . A theory of reading:
From eye fixations to comprehension. Psychological
Review. 87(4), 329-354.
Kahneman, D. (1973). Attention and effort. Englewood, NJ:
Prentice-Hall.
Kerr, B. (1973) . Processing demands during mental
operations. Memory and Cognition. 1, 401-412.
Kinchla, R. A. (1980). The measurement of attention. In R.
S. Nickerson (Ed.), Proceedings of the eighth
international symposium on attention and performance (pp.
213-237). Hillsdale, NJ: Lawrence Erlbaum Associates.
Kinsbourne, M. (1970). A model for the mechanism of
unilateral neglect of space. Transactions of the American
Neurological Association. 95. 143-146.
Kirk, R. E. (1968) . Experimental design: Procedures for the
behavioral sciences. Belmont, CA: Brooks-Cole.
Klapp, S. T. (1979). Doing two things at once: The role of
temporal compatibility. Memory and Cognition. 5., 375-381.
Kucera, H., & Francis, W. N. (1967). Computational analysis
of present-dav American English. Providence, RI: Brown
University Press.
LaBarba, R. C., Bowers, C. A., Kingsberg, S. A., & Freeman,
G. (1987) . The effects of concurrent vocalization on foot
and hand motor performance: A test of the functional
distance hypothesis. Cortex. 23., 301-308.

226
Lassen, N. A., Ingvar, D. H., & Skinhoj, E. (1978). Brain
function and blood flow. Scientific American. 239. 62-71.
Lichtheim, L. (1885). On aphasia. Brain. 1_, 433-484.
Luria, A. R. (1977). On quasi-aphasic speech disturbances in
lesions of the deep structures of the brain. Brain and
Language, 4, 432-459.
Marsden, C. D. (1987). What do the basal ganglia tell
premotor cortical areas? CIBA Foundation Symposium. 132.
282-300.
McCarthy, R., & Warrington, E. K. (1984). A two-route model
of speech production: Evidence from aphasia. Brain. 107.
463-485.
McCarthy, R., & Warrington, E. K. (1990). Cognitive
neuropsychology: A clinical introduction. New York:
Academic Press.
Mesulam, M. M. (1990). Large-scale neurocognitive networks
and distributed processing for attention, language, and
memory. Annals of Neurology. 2.8(5) , 597-613.
Milner, A. D., Jeeves, M. A., Ratcliff, P. J., & Cunnison,
J. (1982). Interference effects of verbal and spatial
tasks on simple visual reaction time. Neuropsychologia.
20(5), 591-595.
Mirsky, A. F., Anthony, B. J., Duncan, C. C., Ahearn, M. B.,
Sc Kellam, S. G. (1991) . Analysis of the elements of
attention: A neuropsychological approach. Neuropsychology
Review. 2(2). 109-145.
Moray, N. (1967). Where is capacity limited? A survey and a
model. Acta Psvchologia. 27. 84-92.
Moruzzi, G., & Magoun, H. W. (1949). Brainstem reticular
formation and activation EEG. EEG and Clinical
Neuropsychology. 1, 455-473.
Nadeau, S. E. (1988). Impaired grammar with normal fluency
and phonology. Brain. Ill. 1111-1137.
Nadeau, S. E., & Crosson, B. (in press). Subcortical
aphasia. Brain and Language.

227
Navon, D. (1985). Attention division or attention sharing?
In M. I. Posner & S. M. Marin (Eds.), Proceedings of the
tenth international symposium on attention and
performance: Control of language processes (pp. 133-146).
Hillsdale, NJ: Lawrence Erlbaum Associates.
Navon, D., & Gopher, D. (1979). On the economy of the human¬
processing system. Psychological Review. 86.(3), 214-255.
Neisser, U. (1967). Cognitive psychology. New York:
Appleton-Century-Crofts.
Neville, H. J., Kutas, M., & Schmidt, A. (1982). Event-
related potential studies of cerebral specialization
during reading: Studies of normal adults. Brain and
Language. 16, 300-315.
Noble, M., Trumbo, D. A., & Fowler, F. (1967). Further
evidence of secondary task interference in tracking.
Journal of Experimental Psychology. 73. 146-149.
Norman, D. A., & Bobrow, D. J. (1975) . On data-limited and
resource-limited processes. Cognitive Psychology. 7, 44-
64 .
Ojemann, G. A. (1975). Language and the thalamus: Object
naming and recall during and after thalamic stimulation.
Brain and Language. 2, 101-120.
Ojemann, G. A. (1977). Asymmetric function of the thalamus
in man. Annals of the New York Academy of Sciences, 299.
380-396.
Ojemann, G. A. (1983). The intrahemispheric organization of
human language, derived with electrical stimulation.
Trends in Neurosciences, 6(5). 184-189.
Paivio, A., Yuille, J. C., & Madigan, S. A. (1968).
Concreteness, imagery, and meaningfulness values for 925
nouns. Journal of Experimental Psychology. 76.(1), 1-25.
Pardo, J. V., Fox, P. T., & Raichle, M. E. (1991).
Localization of a human system for sustained attention by
positron emission tomography. Nature, 349. 61-64.
Pashler, H. (1991). Shifting visual attention and selecting
motor responses: Distinct attentional mechanisms. Journal
of Experimental Psychology: Human Perception and
Performance. 17, 1023-1040.

228
Pashler, H. (1992). Attentional limitations in doing two
tasks at the same time. Current Directions in
Psychological Science. 1, 44-48.
Pashler, H.( & Johnston, J. C. (1989). Chronometric evidence
for central postponement in temporally overlapping tasks.
Quarterly Journal of Experimental Psychology. 41A. 19-45.
Pashler, H., & O'Brien, S. (1993). Dual-task interference
and the cerebral hemispheres. Journal of Experimental
Psychology: Human Perception and Performance. 19. 315-
330 .
Peters, M. (1977). Simultaneous performance of two motor
activities: The factor of timing. Neuropsvchologia. 15,
461-465 .
Petersen, S. E., Fox, P. T., Posner, M. I., Mintun, M., &
Raichle, M. E. (1989). Positron emission tomographic
studies of the processing of single words. Journal of
Cognitive Neuroscience. 1(2), 153-170.
Petry, M. C., Crosson, B., Gonzalez Rothi, L. G., Bauer, R.
M., & Schauer, C. A. (1994). Selective attention and
aphasia in adults: Preliminary findings.
Neuropsychologia. 32, 1397-1408.
Picton, T. W. (Ed.). (1988). Handbook of
electroencephalography and clinical neurophysiology (Vol.
3). Amsterdam: Elsevier Science.
Polich, J., Sc Donchin, E. (1988) . P300 and the word
frequency effect. Electroencephalography and Clinical
Neurophysiology. 70, 33-45.
Posner, M. I. (1980). Orienting of attention. Quarterly
Journal of Experimental Psychology. 32., 3-5.
Posner, M. I., & Boies, S. W. (1971). Components of
attention. Psychological Review. 78. 391-408.
Posner, M. I., & Cohen, Y. (1984). Components of visual
orienting. In H. Bouma & D. Bowhuis (Eds.), Attention and
performance X (pp. 531-556). Hillsdale, NJ: Lawrence
Erlbaum.
Posner, M. I., Early, T. S., Reiman, E., Pardo, P. J., &
Dhawan, M. (1988). Asymmetries in hemispheric control of
attention in schizophrenia. Archives of General
Psychiatry. 45, 814-821.

229
Posner, M. I., & Early, T. S. (1990) . In reply to "What is
left of attention in schizophrenia?" Archives of General
Psychiatry. 47., 394-395.
Posner, M. I., Inhoff, A. W., Friedrich, F. J., & Cohen, A.
(1987). Isolating attentional systems: A cognitive-
anatomical analysis. Psychobiology. 15(2), 107-121.
Posner, M. I., & Petersen, S. E. (1990) . The attention
system of the human brain. Annual Review of Neuroscience.
13, 25-42.
Posner, M. I., & Rafal, R. D. (1987) . Cognitive theories of
attention and the rehabilitation of attentional deficits.
In M. J. Meier, A. L. Benton, & L. Diller (Eds.),
Neuropsychological rehabilitation (pp. 182-201). New
York: The Guilford Press.
Posner, M. I., Sandson, J., Dhawan, M., & Shulman, G. L.
(1989). Is word recognition automatic? A cognitive-
anatomical approach. Journal of Cognitive Neuroscience.
1(1), 50-60.
Posner, M. I., & Synder, C. R. R. (1975). Attention and
cognitive control. In R. L. Solso (Ed.), Information
processing and cognition: The loyola symposium (pp. 55-
85). Hillsdale, NJ: Erlbaum.
Posner, M. I., Snyder, C. R. R., & Davidson, B. J. (1980).
Attention and the detection of signals. Journal of
Experimental Psychology: General. 109(2), 160-174.
Posner, M. I., Walker, J. A., Friedrich, F. J., & Rafal, R.
D. (1984). Effects of parietal injury on covert orienting
of attention. Journal of Neuroscience. 4(7), 1863-1874.
Posner, M. I., Walker, J. A., Friedrich, F. J., & Rafal, R.
D. (1987). How do the parietal lobes direct covert
attention? Neuropsvchologia. 25(1A), 135-145.
Rafal, R. D., & Posner, M. I. (1987). Deficits in human
visual spatial attention following thalamic lesions.
Proceedings of the National Academy of Sciences. 84.,
7349-7353.
Rafal, R. D., Posner, M. I., Friedman, J. H., Inhoff, A. W.,
& Bernstein, E. (1988). Orienting of visual attention in
progressive supranuclear palsy. Brain. Ill. 267-280.

230
Raymer, A. M.f Foundas, A., Maher, L. M., Greenwald, M. R.,
Morris, M., Rothi, L. J. G., & Heilman, K. M. (1995).
Cognitive neuropsychological analysis and neuroanatomic
correlates in a case of acute anomia. Unpublished
manuscript.
Rapcsak, S. Z., Gonzalez Rothi, L. J., & Heilman, K. M.
(1987). Phonological alexia with optic and tactile
anomia: A neuropsychological and anatomical study. Brain
and Language. 31. 109-121.
Rasmussen, T., & Milner, B. (1977) . The role of early left
brain injury in determining lateralization of cerebral
speech functions. Annals of the New York Academy of
Sciences. 299. 355-369.
Rugg, M. D.( Milner, A. D., Lines, C. R., & Phalp, R.
(1987). Modulation of visual event-related potentials by
spatial and non-spatial visual selective attention.
Neuropsychologia. 25, 85-96.
Schneider, W.( & Shiffrin, R. M. (1977). Controlled and
automatic human information processing: I. Detection,
search, and attention. Psychological Review. 84, 1-66.
Schwartz, M. F., Saffran, E. M., & Marin, O. S. M. (1980).
Fractionating the reading process in dementia: Evidence
for word-specific print-to-sound associations. In M.
Coltheart, K. E. Patterson, & J. C. Marshall (Eds.), Deep
dyslexia. London: Routledge and Kegan Paul.
Shiffrin, R. M., & Schneider, W. (1977). Controlled and
automatic human information processing: II. Perceptual
learning, automatic attending, and a general theory.
Psychological Review. 84., 127-190.
Spelke, E., Hirst, W., & Neisser, U. (1976). Skills of
divided attention. Cognition. 4, 215-230.
Stevens, J. (1990) . Intermediate statistics: A modern
approach. Hillsdale, NJ: Lawrence Erlbaum Associates.
Steinmetz, H., & Seitz, R. J. (1991). Functional anatomy of
language processing: Neuroimaging and the problem of
individual variability. Neuropsychologia. 29, 1149-1161.
Stuss, D. T., Sarazin, F. F., Leech, E. E., & Picton, T. W.
(1983). Event-related potentials during naming and mental
rotation. Electroencephalography and Clinical
Neurophysiology. 56. 133-146.

231
Taylor, L. B. (1969). Localisation of cerebral lesions by
psychological testing. Clinical Neurology. 16., 269-287.
Toglia, M. P., Sc Battig, W. F. (1978) . Handbook of semantic
word norms. Hillsdale, NJ: Lawrence Erlbaum Associates.
Urbanczyk, S. A., Angel, C., & Kennelly, K. J. (1988).
Hemispheric activation increases positive manifold for
lateralized cognitive tasks: An extension of Stankov's
hypothesis. Brain and Cognition, 8, 206-226.
Vaughan, H. G., & Gross, C. G. (1969). Cortical responses to
light in unanesthesized monkeys and their alteration by
visual system lesions. Experimental Brain Research, 8,
19-36.
Wada, J., Sc Rasmussen, T. (1960). Intracarotid injection of
sodium Amytal for the lateralization of cerebral speech
dominance. Journal of Neurosurgery. 17, 266-282.
Warrington, E. K., & Shallice, T. (1979). Semantic access
dyslexia. Brain. 102. 43-63.
Watson, R. T., Valenstein, E., & Heilman, K. M. (1981).
Thalamic neglect: Possible role of the medial thalamus
and nucleus reticularis in behavior. Archives of
Neurology. 38, 501-506.
Welford, A. T. (1952). The "psychological refractory period"
and the timing of high speed performance: A review and a
theory. British Journal of Psychology. 43, 2-19.
Wickens, C. D. (1984). Engineering psychology and human
performance. Columbus, OH: Charles E. Merrill.

BIOGRAPHICAL SKETCH
Margaret Carthas Petry, daughter of Henry and Margaret
Anne Carthas, was born in Fort Lauderdale, Florida, on
October 31, 1966. She was raised in Coral Springs, Florida.
Margaret received her high school diploma from J.P.
Taravella High School in 1984. She earned her Bachelor of
Science degree at the University of Florida in 1988, where
she majored in psychology. In 1989, Margaret entered the
doctoral program in clinical and health psychology at the
University of Florida. Her area of specialization was
neuropsychology. While a graduate student, she was awarded
the Robert A. Levitt Research Award for Excellence in
Clinical Neuropsychology Research. In May of 1993, she
received her Master of Science degree. Presently, Margaret
is completing her predoctoral internship training at the
University of Miami's Mailman Center for Child Development
in Miami, Florida. She lives with her husband, Andy, in
Coconut Creek, Florida. During her spare time, Margaret
enjoys watching movies, playing tennis and golf, and reading
short stories.
232

I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.
Psychology
I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.
CllL'~ (3
Eileen B. Fennell
Professor of Clinical and Health
Psychology
I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.
IIakaaM AA /¿TUM
fcussell M.Bauer
lussell M. Bai
Associate Professor of Clinical and
Health Psychology
I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.

I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.
D
Leslie J/yGonzale# Rothi
Associate^Professor of Communication
Processes and Disorders
I certify that I have read this study and that in my
opinion it conforms to acceptable standards of scholarly
presentation and is fully adequate, in scope and quality, as
a dissertation for the degree of Doctor of Philosophy.
Alan Agresti
Professor of Statistics
This dissertation was submitted to the Graduate Faculty
of the College of Health Related Professions and to the
Graduate School and was accepted as partial fulfillment of
the requirements for the degree of Doctor of Philosophy.
August 1995
Dean, College of Health Related
Professions
Dean, Graduate School

UNIVERSITY OF FLORIDA
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UNIVERSITY OF FLORIDA
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