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Subject: Paper on Reading Disabilities
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NEUROPSYCHOLOGICAL BASES OF EDUCATIONAL DISABILITIES
Implications for Diagnosis and Remediation
Expert Paper Submitted to the United Nations
Disability Unit, Vienna
February, 1990
Robert Zenhausern, Ph.D.
Professor of Psychology
St. Johns University
Jamaica, NY 11439
USA
INTRODUCTION
The paragraphs below are in the form of a satire based on the
essay by Jonathan Swift entitled "A Modest Proposal" in which he
presented a solution to the "Irish Problem". The parallel here is
Learning Disability and the inflexible ways these children are
taught. It is the objective of this paper to show that the problem
of the learning disenfranchised is one that can be solved by
increasing the flexibility with which we teach.
Another Modest Proposal:
A Swift Response to an Old Problem
The purpose of this essay is to examine the possibility that we
are systematically doing a disservice to a large segment of the
school population. Students who have auditory or visual
impairments have been allowed to use artificial means, such as
glasses or hearing aids, to correct their deficits. Indeed, it is
considered praiseworthy to identify such problems early and then
use the services of professionals who prescribe optical or
electronic devices which alleviate the deficiencies.
The consequences of such actions, however, have not been
considered fully. Such children may become lazy and make no
attempt to overcome their problems. What motivation will they have
to strengthen their perceptual weaknesses when such devices make
it unnecessary for them to do so? What will such people do if, for
whatever reason, such devices are not available? It is the
contention of this paper that artificial devices are crutches which
interfere with the complete development of the child. As such,
they should be eliminated.
Some might argue (and not without a modicum of validity) that
by eliminating those "support systems," such children may not
progress beyond the elementary rudiments of learning. That,
however, should be secondary to the point that we are not dealing
directly with a serious problem. The fact that our present state
of knowledge does not allow us to correct such deficiencies should
not dissuade us from this course of action. Eventually specific
techniques will be developed to meet the problems of poor eyesight
and hearing in much the same way that techniques were developed to
alleviate reading and mathematical difficulties -- and probably
with as much success. There is a minor problem in the fact that
many of the authority figures in the child's environment use those
same artificial devices and thus do not serve as good role models.
Aside from the educational wisdom of this proposal, it has the
added advantage of eliminating the possibility of charges of
discrimination. Consider, for example, if someone raised the point
that a deficit in vision or hearing might be compared to a deficit
in arithmetic computation. They might argue that if vision can be
corrected by glasses why can a calculation deficit not be corrected
by the use of a calculator? It is difficult to counter these
arguments since the two deficits have so much in common. Even the
poor role model problem has a parallel since most of the authority
figures whom the children contact would have some difficulty in
taking a square root or doing long division of decimals by hand.
The conclusion is clear: take away glasses and hearing aids and
give the children with sensory defects the same advantages given
to children with calculation defects!
* * *
The essay is clearly satirical, but its point is clear. In
this Decade of the Disabled it is essential to consider the human
rights of the Learning Disabled to an education that more closely
fits their capabilities. The problems of the Learning Disabled are
unique because this is the only disabled group which is held
responsible for its disability. "If he worked harder, he could do
it", says the frustrated teacher. No one expects a blind person
to see, if he or she "worked harder". Furthermore, to call a child
"learning disabled" is to put the burden of responsibility on the
wrong person! It is our responsibility to teach much more than it
is the responsibility of the child to learn. It is we who should
be called teaching disabled. The purpose of this paper is to focus
attention on individual differences among both normal and learning
disabled children and to consider alternative approaches to
education and thus eliminate our teaching disability. The major
emphasis will be on the theory and remediation of reading
disability based on a 10 year program of research within a
neuropsychological framework. The initial Chapter will introduce
the concepts of cerebral asymmetry and hemisphericity and put them
in perspective for education today. The second Chapter will
discuss behavioral and physiological measures of individual
differences in neuropsychological functioning. The third Chapter
will describe a study that underlines the importance of these
individual differences in an educational setting. The fourth and
fifth Chapters will describe a series of studies dealing with the
theory, diagnosis and remediation of reading disability that has
been based on these neuropsychological concepts. The final Chapter
will be a summary that includes the basic information on the Direct
Access approach to reading with specific recommendations. It can
serve as an abstract of the whole paper.
This Introduction ends with a short quote, found hanging on
the walls of an elementary school in Greensboro, North Carolina and
attributed to Ken Dunn.
If children cannot learn the way we are teaching them,
then we must teach them the way they can learn.
CHAPTER 1
THE CEREBRAL HEMISPHERES OF THE BRAIN AND THE NEW PHRENOLOGY
Recent work in the areas of neuropsychology, especially that
of Sperry who won the Nobel Prize, has popularized the notion of
cerebral asymmetry. That is, the two hemispheres of the brain are
different in terms of the cognitive processes in which they excel.
There is clear evidence that the Left Hemisphere has unique control
of expressive speech and operates using a sequentially organized
system. The Right Hemisphere, on the other hand, has systems that
are more capable of spatially and pictorially oriented processing.
While there are clear differences between the hemispheres,
these differences have been overgeneralized into a new phrenology
of brain functions. A typical list of "Left Hemisphere Functions"
reads something like: logical, verbal, analytic, inductive,
controlled; the Right Hemisphere is often called: synthetic,
emotional, deductive, intuitive, and abstract. Some of these
labels are self-contradictory. The Left Hemisphere is called both
analytic and inductive and the Right Hemisphere both synthetic and
deductive. The term "abstract" has two diametrically opposed
meanings: an article abstract versus abstract art. These
inconsistencies aside, this neo-phrenological approach must be
rejected on the grounds that it is atomistic. A hemisphere is
neither verbal, logical, emotional, nor creative; it is a person
who has these characteristics! All behavior flows from the
integrated functioning of the whole brain. This does not mean,
however, that there are no individual differences associated with
the brain. The concept of Hemispheric Related Strategies provides
a framework on which to base an individual difference variable.
For the most part, the two hemispheres do the same things but
do them using different approaches. Cerebral asymmetries reflect
relative efficiency rather than a "can do-can't do" dichotomy.
There seems to be one exception to this relative rather than
absolute difference between the hemispheres: for most people, only
the left hemisphere is capable of speech and of phonetic
representation (Levy, 1974). The isolated Left Hemisphere can tell
whether the two words "though" and "blow" rhyme but the isolated
Right Hemisphere can not, even though it may understand their
meaning. Rhyming demands that the written word be converted to an
auditory form and only the left hemisphere has this capability.
A second factor that differentiates the two hemispheres is their
type of processing systems: sequential for the left hemisphere and
parallel for the right hemisphere (see Bradshaw and Nettleton, 1981
for a review.) Compare these two situations: 1) You are given a
description of someone and must then identify that person; and 2)
You are shown a picture of the person and then must select the
person. The first task demands the sequential system of the left
hemisphere--the words, descriptive of the various facial features,
are read in sequence and must be combined into an overall
perception. The latter situation reflects the parallel system of
the right hemisphere -- the picture is seen as a whole and various
facial features can be extracted. The picture is seen all at once
in parallel while the verbal description must be sequentially
processed. The sequential processing system of the Left
Hemisphere and its ability in speech production are the
characteristics that underlie the notion that the Left Hemisphere
is the verbal hemisphere. Language, by its very nature, is
sequential. Word order and syntax are essential to meaning--
language cannot be easily processed in parallel. Thus the left
hemisphere has been labeled the "verbal" hemisphere because its
sequential processing system is compatible with the sequential
nature of language, and its control of auditory linguistic
processes makes it essential for speech.
For other tasks, even though the processing system of either
hemisphere is compatible with the task, one hemisphere is clearly
superior. The example of face recognition shows intuitively that
the Right Hemisphere pictorial approach is better than a Left
Hemisphere written description. Note, however, that the task can
be done using Left Hemisphere strategies, but it takes a thousand
words to describe one picture. Spatial relations tasks are
also more easily handled using Right Hemisphere processes. Other
tasks can be handled equally well using the strategies of either
hemisphere. For example, a list of words could be learned by
converting and storing them as visual representations or in an
auditory form. The term Hemispheric Related Strategies can be used
to describe this relationship between observable behavior and its
underlying neuropsychological bases.
Hemispheric Cognitive Style
Two individuals, when faced with the same task, do not
necessarily use the same strategies, that is, people do things in
different ways. Sometimes those different approaches can be
associated with processing differences between the two cerebral
hemispheres. These different approaches can be termed Hemispheric
Related Traits. Hemispheric Cognitive Style is the tendency of an
individual to use distinct patterns of Hemispheric Related Traits.
It does not imply that one hemisphere is used exclusively, but that
individuals tend to approach tasks in unique and consistent ways.
For example, if a group of individuals were asked to remember the
words "dog, cat, tree, table, chair", few would have difficulty.
If these same individuals were asked what strategies they used,
there would be wide variation. Some would report they repeated
the words to themselves, others that they "saw" the written form
of the word, and others would create images of the words.
These differences in memory strategies can be related to
Hemispheric Related Traits. A person who would be more likely to
use imaginal strategies could be said to use a right Hemispheric
Related Trait, and a person who used auditory strategies could be
said to use a left Hemispheric Related Trait. Some individuals
tend to use the Hemispheric Related Traits associated with one
hemisphere more than those of the other hemisphere and others show
little or no bias. Those who do favor the Hemispheric Related
Traits of one hemisphere can be said to have a Right or Left
Hemispheric Cognitive Style. It is important not to
overgeneralize the scope of Hemispheric Cognitive Style. The fact
that a person tends to use particular strategies implies neither
a disuse nor deficiency in one hemisphere of the brain. On a very
simple level, a right Hemispheric Cognitive Style individual has
access to the speech centers of the left hemisphere just as a left
Hemispheric Cognitive Style individual has access to the prosody
centers of the right hemisphere. Thus both right and left
Hemispheric Cognitive Style individuals rely on the integrated
functioning of both hemispheres for expressive speech, and, in
fact, all behavior. In an intact individual, no task can be
accomplished without the integrated functioning of both
hemispheres. To call an individual "left or right brained" is to
ignore the fact that all activity depends on the integrated
functioning of the whole brain. These differences, however, can
be related to different strategies with which people approach
specific tasks. One purpose of this paper is to show how these
strategy differences can affect the educational system. The next
chapter will describe how differences in Hemispheric Related Traits
can be measured. The following chapters will focus on the
application of these traits to mainstream and learning disabled
education.
CHAPTER 2
THE MEASUREMENT OF HEMISPHERIC COGNITIVE STYLE
Two distinct tools have been used in the measurement of
Hemispheric Cognitive Style, one behavioral and the other
physiological. The behavioral measure is a self rating
questionnaire and the physiological measure relies on the
predominant direction of Lateral Eye Movement (LEM).
The Hemispheric Preference Questionnaire
There are many questionnaires that have been used to measure
"hemisphericity" including many from popular magazines. Over the
past 12 years I have developed an instrument that has been
successfully used to separate right and left Hemispheric Cognitive
Styles. A copy of the questionnaire and its scoring key has been
included. The following studies used the instrument successfully.
Coleman and Zenhausern (1979) compared those who used right and
left Hemispheric Related Traits on a memory retrieval task. They
found the two groups differed on processing speed and the extent
of a left hemisphere bias induced by a verbal memory load. The
bias was four times stronger for the those who use left Hemispheric
Related Traits than for those who use right Hemispheric Related
Traits. Zenhausern and Nickel (1979) found that Right style
individuals learned a finger maze in fewer trials, in less time and
with fewer errors than Left style individuals. Zenhausern, Notaro,
Grosso, and Schiano (1981) presented right and left style
individuals with auditory messages in which there was a conflict
between verbal content and emotional tone of voice. Overall, those
who used right Hemispheric Related Traits responded significantly
more often to the inflection cues and those who use left
Hemispheric Related Traits significantly more often to the verbal
content. Zenhausern and Dunivin (1981) found that left style
subjects were more obsessive compulsive, while right style subjects
had more hysterical traits. Zenhausern and Parisi (1983) have
found that schizophrenics rate themselves as using left while
depressives rate themselves as using right hemisphere related
strategies. The instrument has been used in the area of
reading disability to distinguish two separate syndromes. Oexle
and Zenhausern (1980), Golden and Zenhausern (1981), Zenhausern
and Sinatra (1983), Maxwell and Zenhausern (1983) have found that
85% of reading disabled children rate themselves as using more
right than left hemisphere strategies. A copy of the test and its
scoring key can be found in Table 2.1.
Lateral Eye Movements
Research into the phenomenon of lateral eye movements (LEM)
as a behavioral measure of neuropsychological activity has been
pursued along two separate dimensions. LEM have been considered
a measure of both individual differences and task demands. From a
neuropsychological perspective, the individual difference aspects
have been associated with the concept of cognitive style and the
effects of task demands with hemispheric asymmetry. There is,
however, considerable controversy as to whether LEM do indeed have
neuropsychological relevance. The importance of LEM has been
overgeneralized to the point of faddism, which has led to a general
reluctance on the part of the scientific community to give them
credence. In addition, researchers in the area have sometimes
failed to distinguish between these two different aspects of LEM.
Table 2.1
The Preference Test for Hemispheric Related Strategies
Indicate your choice by assigning a number from 1 to 10 (with 1
being the lowest) on each question. To score the test, refer to
the scoring key below. Add the ratings for all the items that are
to be scored right and those that are to be scored left, subtract
the two and divide by 10. The larger number shows the predominant
preference and the greater the difference the larger the HRS
preference. You should then develop your own local norms, but as
a rule of thumb a score of .7 or higher can be considered a clear
indication of a preference for a Hemispheric Related Strategy.
Test Items
1) Do you base your decisions on objective facts rather than
feelings?
2) Are you psychic?
3) Do you like using symbols or images in solving problems?
4) Are you artistically or musically creative?
5) Are you logical?
6) Are you good at solving crossword puzzles?
7) Can you read quickly?
8) Are your daydreams vivid?
9) Can you think of synonyms for words easily?
10) Do you remember dreams?
11) Are your dreams vivid?
12) Are you fluent in using words?
13) Are you good at using images in remembering and thinking?
14) Do you use a playful approach to problem solving?
15) Do you use a serious, all business approach to problem
solving? 16) Do you like to keep experiences planned and
structured?
17) Do you like to read or think while sitting upright?
18) How much does your thinking consist of words?
19) How much does your thinking consist of mental imagery?
20) Do you like to explain something using visual presentation?
SCORING KEY
Item Scoring
1 L
2 R
3 R
4 R
5 L
6 L
7 L
8 R
9 L
10 R
Item Scoring
11 R
12 L
13 R
14 R
15 L
16 L
17 L
18 L
19 R
20 R
Individual Differences and LEM
Research into whether LEM
reflect individual personality differences was initiated by Day
(1964), who reported that the direction of LEM was related to
individual styles of coping with anxiety. Bakan (1971) was the
first to propose that the direction in which a person consistently
shifted gaze was related to which of the cerebral hemispheres an
individual used more often.
The relationship between LEM and various dimensions of
individual differences has been explored. Tucker and Suib (1978)
found that left-movers had higher scores on the Performance tests
of the WAIS and did better with imagery oriented questions while
right-movers had better scores on the Verbal subtests of the WAIS
and with questions that were letter and number oriented (e.g., how
many letters are in the word house). Gur and Gur (1975)
showed a relationship between direction of LEM and defensive style.
Predominantly rightward movers more often reported using projection
and "turning against others" as their main defenses, while
predominantly leftward movers reported using repression and denial
more often. LEM were again shown to be related to defensive styles
in males as measured by the Defense Mechanism Inventory (Krikorian
and Rafales, 1983). This effect was not replicated with females,
however (Thompson, Greenberg, Fisher, 1982). In addition, subjects
who moved their eyes bidirectionally rather than predominantly to
the left or the right were shown to have better adaptive coping
styles ratings on the adjective check list (Parrott, 1984).
Smokler and Shevrin (1979) showed that normal subjects with
hysterical tendencies made more leftward LEM than subjects with
obsessive compulsive tendencies. The latter group was more likely
to show rightward LEM. Gur (1978) and Schweitzer (1979) found that
schizophrenics had predominantly leftward LEM.
The relationship between LEM and cognitive styles has also
been explored. Subjects, who scored as left or right style
oriented on the Laterality Preference Schedule, were shown to have
consistent patterns of LEM, indicating the existence of consistent
patterns of information processing (Breitling and Bonnet, 1985;
Bruce, Herman, and Stern, 1982). When using the Your Style of
Learning and Thinking Test (SOLAT) to measure style of thinking,
however, no relationship was found between LEM and thinking style
preference (Alberts and McCallum, 1982). In addition, Owens and
Limber (1983) found no relationship between cognitive style and
LEM.
One area of interest in the cognitive style research is the
relationship between what are considered right style ways of
thinking (holistic and broad) and left style ways of thinking
(analytic and narrow) based on proposed functions of the individual
hemispheres. In support of the theory that eye movements indicate
hemispheric activation, and that left hemisphere activation is
associated with more analytic and narrow styles, Huang and Byrne
(1978) showed that narrow categorizers based on the Pettigrew's
Category Width Scale made more leftward LEM than broad
categorizers.
Another area of interest has been the relationship between the
ability to recall dreams and LEM. Predominantly leftward LEM have
been associated with the ability to vividly recall dreams in male
subjects (Leboeuf, Mckay, Clark, 1983), but the same has not been
found with females (Van Nuys, 1985). A related issue is that of
creativity and LEM. Leftward eye movement has been associated with
thinking of more uses of objects on the Uses Test, which is often
used as a measure of creativity (Falcone and Loder, 1984).
Zenhausern (1987) has shown that LEM can differentiate between two
different types of reading disabled children. Specifically,
rightward LEM are characteristic of reading disabled children who
are unable to derive meaning from the written word despite being
able to say it. Leftward LEM are characteristic of reading
disabled children who are unable to pronounce the word despite
understanding what it means. This sampling of research indicates
the scope of individual differences that have been associated with
LEM. In their critique of the LEM literature, Ehrlichman and
Weinberger (1978) concluded that LEM are reliable measures of
individual differences. They found that despite differences in
methodology and experimental situations the direction a person
moves his or her eyes is a consistent behavior of that individual.
The individual difference studies above indicate their behavioral
relevance.
Functional Hemispheric Asymmetry and LEM
A second perspective on the nature of LEM was introduced by
Kinsbourne (1972) who proposed that LEM reflect the task demands
on the subject. He suggested that those tasks that require input
predominantly from the left hemisphere resulted in rightward LEM,
the direction away from the left hemisphere; those tasks that
required predominantly right hemisphere functions resulted in
leftward LEM, away from the right hemisphere. There has been
mixed support for this relationship between LEM and question type.
The critical variable has usually been whether rightward LEM are
associated with verbal questions, indicating a relationship between
a verbal task and left hemisphere activation. A wide variety of
what have been called "verbal" questions have been used, however.
Galin and Ornstein (1974) reported a relationship between
rightward LEM and logical problems and leftward LEM and visual
imagery tasks. Proverb interpretation has been shown to be
related to rightward LEM (Kinsbourne, 1972; Gur, 1975). Schwartz,
Davidson and Maer, 1977, found a relationship between LEM and task
demands. There have been recent reports of relationships
between both rightward LEM and verbal questions (Hugdahl and
Carlgren, 1981; Ogorman and Siddle, 1981) and leftward LEM and
visual spatial tasks (Swinnen, 1984). In addition to the
verbal/non-verbal dichotomy, emotionally laden questions were used
to elicit predominantly leftward LEM (Krikorian and Rafales, 1983;
Jamieson and Sellick, 1985).
Not all studies have resulted in significant findings. In
fact, Ehrlichman and Weinberger concluded that the evidence for a
relationship between LEM and question type was not convincing on
both empirical and theoretical grounds. From the empirical point
of view, they noted that of the 21 studies reviewed, 10 resulted
in rightward movement in response to verbal questions, and 11
resulted in no difference in LEM to verbal and non verbal
questions. The authors concluded that the literature thus did not
offer strong support that LEM were related to question type.
A re-evaluation of the empirical studies, however, indicates
that there is a consistent relationship found between the type of
question asked and the direction of LEM. In only one of the 21
studies reported by Erhlichman and Weinberger did verbal questions
lead to leftward LEM. While the conclusion that verbal questions
lead to rightward LEM may be in question, the conclusion that
verbal questions do not lead to leftward LEM is strongly supported.
There may be a relationship between task demands and LEM, but it
is not a simplistic "verbal question leads to rightward LEM
relationship".
There is clear evidence that LEM are related to both the type
of question asked and individual difference factors. Therefore,
in any situation, LEM reflect the type of question asked
interacting with the individual differences and it is essential to
separate the two effects.
Two distinct tasks were used in a study by Zenhausern and
Kraemer (1989) to investigage the dual nature of LEM. One task is
purely informational and cannot be uniquely connected with either
hemisphere of the brain. The second task involves rhyming of non-
words which clearly demands the speech centers of the left
hemisphere. Two experimental questions were addressed. 1) Is the
direction of LEM consistent within an individual both across time
and across tasks? 2) Does the type of question asked have an
effect on the direction of LEM?
A total of 50 adult subjects were tested. There were 16 males
and 34 females, with an average age of 27 and a range of 16 to 50.
The stimuli for the rhyme task were four to five letter nonsense
words printed in black ink on white index cards and a series of
prepared questions.
The subjects were informed that they were participating in a
study involving the different ways in which people think. They
were asked two kinds of questions in a face to face encounter with
the experimenter. The subject responded yes or no with a nod or
shake of the head and the initial direction of eye movement to each
of 40 questions was recorded for each subject. These non-verbal
responses were used to eliminate left hemisphere involvement
through speech which was unrelated to the task. The 20
informational questions did not call on any clearly defined brain
areas (Is Miami the capitol of Florida?). The 20 rhyme questions,
on the other hand, clearly demanded the auditory linguistic
capabilities of the left hemisphere. The subject was shown a
nonsense word on an index card and told to remember it. The card
was removed and another nonsense word was verbally spelled by the
examiner and the subjects were asked whether the two words rhymed.
The subjects were tested in two blocks of 20 trials separated by
30 minutes. Within each block 10 informational and 10 rhyme
questions were asked.
The data were first explored by means of a correlational
analysis. Both test-retest and split half reliabilities for
informational questions and for rhyme questions are shown in Table
2.2. In addition, the correlation between rhyme and informational
questions is also presented. LEM are clearly a consistent measure
of individual differences with reliability coefficients averaging
approximately .80 for the same type of question. When the type of
question was changed, however, there was a dramatic drop in the
consistency of LEM although the correlations were still
significant. The direction of LEM changed as a function of task
demands, but not to the extreme that would result in no
correlation.
Table 2.2
Intercorrelations Among LEM for Information and Rhyme Questions
Split Half Test Retest
Rhyme .85 .78
Information .79 .83
Rhyme with Information .59
An initial analysis on the two 20 question blocks indicated
no significant differences and the two were collapsed into a single
set of questions. The data were then analyzed by means of a split-
plot analysis of variance with LEM Group (whether a subject had
predominantly rightward or leftward movement) as a between factor
and Task (Rhyme and Informational questions) and Direction of
Movement (Right, Left, and Stares) as between factors. Since the
scores are ipsative and the Grouping factor and dependent variable
are related, only the interactions are of interest in this design.
There was a significant interaction between the Direction of
Movement and Task. The results are shown in Table 2.3 below.
Table 2.3
Number and Direction of LEM as a Function of Type of Question
Task Direction of LEM
Right Left Stare
Rhyme 6.82 7.64 4.92
Information 5.50 7.50 6.50
Simple effects analysis indicated that the number of leftward
LEM to informational and rhyme questions were not significantly
different, but there were significantly more rightward LEM than
leftward LEM to rhyme questions. There were no interactions
involving the LEM Group factor, indicating that the effects of the
type of question were the same for both groups.
These results lead to two conclusions. The first is a
verification of the Ehrlichman and Weinberger (p 1093) conclusion
"...that LEM patterns are reliable characteristics of persons."
Individuals do move their eyes in a consistent direction and
direction of LEM is a reliable measure of individual differences.
The questions, however, remain as to whether LEM differences can
be related to behavior and whether these behaviors have
neuropsychological implications. Some of the research reported
above has shown the scope of the variables that have been related
to differences in LEM. (A fuller listing can be found in Beaumont,
Young, and McManus, 1984). Not every study has shown that LEM
differences were related to differences in performance, but no one
should expect LEM to be related to all behavior.
The final question remains, however, as to whether LEM have
neuropsychological implications. In a very general sense, all
behavior results from brain activity and thus all behavior has
neuropsychological implications. From a more focused point of
view, LEM have been related to behaviors that neuropsychologists
have associated with the brain. The problem has been, however,
that the association of the behavior with the brain has not always
been clearly specified. Logical problems, proverbs, and spelling
have all been used as verbal tasks. These tasks are extremely
complex and clearly involve both hemispheres of the brain, even
though there may be a portion of the task that is especially
dependent on left hemisphere processing. This was clearly shown
in the present study since the rhyming task demanded the unique
ability of the left hemisphere to create the sound of the printed
word. The information task had no such clear connections to either
hemisphere of the brain. Both the correlations and analysis of
variance results pointed to the fact that LEM were different for
the two tasks, with an increase in the number of rightward
movements for the rhyming task. This change, however, was
relatively subtle. Even though the task demanded specific left
hemisphere input, subjects did not make predominantly rightward
LEM; there was only a shift in that direction. A subject who made
predominantly leftward movement continued to do so, but the number
of rightward movements increased and the number of stares
decreased.
Lateral Eye Movements have been shown to be a reliable measure
of individual differences, as well as a response to the type of
questions asked. The importance of both aspects, however, should
not be overemphasized. The individual difference aspect must be
investigated from a more behavioral point of view. Rather than
comparing a lawyer or a scientist with an artist, determine whether
a courtroom lawyer has more in common with an actor or a corporate
lawyer, or whether a geometrician has more in common with an artist
or an algebraist.
The LEM response to task demands must also be considered in
conjunction with the fact that any task demands the integrated
functioning of the whole brain. The variable extent to which a
task places special emphasis on one hemisphere must be considered
within this integrated functioning. LEM can be a useful tool, but
their value and meaning can be misunderstood all too easily. The
next Chapter provides evidence of the usefulness of LEM within a
normal classroom setting.
This chapter has presented the evidence that Hemispheric
Related Strategies can be measured by means of questionnaires and
LEM. The following chapters will provide evidence that this
individual difference variable has significance for education.
Chapter 3
THE INTERACTION OF HEMISPHERIC RELATED STRATEGIES
AND INDIVIDUAL DIFFERENCES
The purpose of this Chapter is to provide evidence that the
individual difference aspect of LEM has meaningful behavioral
correlates in an educational setting. No assumptions were made as
to the neuropsychological substrate of LEM. They were used simply
as a means of dividing subjects into two groups: those who move
their eyes predominantly to the right and those who move them
predominantly to the left. Half of the right movers were taught
a learning strategy involving verbal rehearsal and the other half
a learning strategy involving imagery. The same procedure was
followed for the left movers. The question was whether there is
a relationship between the typical direction of LEM and the
effectiveness of the two learning strategies.
The subjects were drawn from a pool of 120 average or above
average fifth and sixth graders in a suburban school system. A
series of verbal, spatial, imaginal, and informational questions
were asked in a face to face situation and the 72 subjects who had
the most extreme number of left movements and the most extreme
number of right movements participated in the study. The subjects
were divided into equal numbers of male and female right and left
movers.
Seventy-two words appropriate to fifth and sixth graders and
matched for abstractness, concreteness, and imagery were chosen
from the list provided by Pavivo, Yuille, and Madigan (1968). Two
equivalent sets consisting of 18 pairs, created from this list,
served as the learning stimuli. Two distractor lists of 12 pairs
each were also created using the same procedure. Each pair was
then photographed and developed as 35mm slides.
Each subject, tested individually, was seated approximately
4 ft. from a screen on which the 18 pairs of words were presented
by means of a slide projector for 4 sec. The child was then asked
to recall as many pairs of words as possible and the number of
correct pairs served as one dependent variable. The subjects were
then shown 24 pairs of words, half of which they had already seen
and half of which were distractors. These slides were then
presented and the subject had to indicate by switch closure whether
they had seen the word pair. Both accuracy and response time (in
milliseconds) were measured. Following this pre-training
procedure, half of the subjects whose LEM were predominantly
leftward and half whose LEM were predominantly rightward, were
taught a verbal rehearsal strategy in order to improve performance.
They were instructed to repeat the pairs of words as many times as
possible during the 4 sec interval between pairs. They were then
given six practice trials. The remaining subjects were instructed
on how to form an integrated image from the word pairs. They were
also given six practice trials. The subjects were then tested on
18 new pairs of words using the same procedures as in the pre-
training condition. This effectively created four groups: right
movers taught to use either imagery or verbal rehearsal strategies
and left movers taught the same strategies.
There were three dependent measures that were analyzed in this
study: the number of pairs recalled, the number of pairs
recognized, and the response time for recognition. The design for
all three variables was a split plot factorial with Direction
(leftward or rightward LEM) and Strategy (verbal rehearsal or
imagery) as the between factors and Time (before or after
training) as the within factor. The mean number of correct pairs
recalled under all conditions is shown in Table 3.1.
Table 3.1
Mean Number of Word Pairs Recalled for Right and Left Movers Under
Verbal Rehearsal and Imagery Instructions
Set Pre Test Post Test
Verbal
Left Movers 3.39 1.78
Right Movers 1.89 2.61
Imagery
Left Movers 2.61 3.28
Right Movers 2.39 2.56
The analysis of variance indicated no significant differences
involving Direction or Strategy, but there was a significant
interaction of Direction, Strategy. and Time. Simple effects
analysis indicated that children with rightward LEM did not change
as a result of imagery instructions, but made a significant
improvement as a result of verbal rehearsal instructions. Children
with leftward LEM made a significant improvement as a result of
imagery instructions, but showed a significant decrement as a
result of verbal rehearsal instructions.
Mean performance for the recognition scores is presented in
Table 3.2. The analysis of variance again indicated a significant
interaction between Direction, Strategy and Time.
Table 3.2
Set Pre Test Post Test
Verbal
Left Movers 29.28 27.61
Right Movers 28.11 29.44
Imagery
Left Movers 29.56 30.67
Right Movers 29.89 29.44
The simple effects analysis indicated that children with
rightward LEM showed a significant improvement using a verbal
rehearsal strategy and children with leftward LEM showed a
significant decrement using a verbal rehearsal strategy. The mean
reaction times for the recognition task is shown in Table 3.3. The
analysis of variance indicated that there was an overall decrease
in reaction time from pre to post testing and the same significant
three way interaction of Direction x Strategy x Time.
Table 3.3
Mean Reaction Times (in milliseconds) for the Recognition Task
Set Pre Test Post Test
Verbal
Left Movers 2059 2118
Right Movers 2447 1894
Imagery
Left Movers 2244 1829
Right Movers 1846 1627
Statistical analysis indicated that children with rightward
LEM were significantly faster using a verbal rehearsal strategy and
children with leftward LEM were significantly slower using a verbal
rehearsal strategy. The analyses of the three variables lead to the
single conclusion that children who have predominantly leftward LEM
should not be taught by a verbal repetition strategy.
From the theoretical perspective, these results support the
findings of Ehrlichman and Weinberger that LEM are a reliable
measure of an individual difference variable. It also provides
evidence of the validity of LEM; individuals who differed on LEM
showed differences on a relevant behavioral measure -- verbal
learning. The most important question, however, is whether LEM
have any relationship to brain organization. Individuals who had
predominantly rightward LEM showed better retention when using the
left hemisphere oriented strategy of verbal rehearsal and
individuals who had predominantly leftward LEM showed decreased
retention when using the left hemisphere oriented strategy. These
are the facts, and while it is premature to draw firm conclusions,
these facts are consistent with the existence of a relationship
between LEM and brain organization. The clearest conclusion
from these findings is that children differ in the extent they can
benefit from a verbal repetition strategy in learning. From the
educational perspective it is clear that there are children in
schools who not only do not benefit from a verbal rehearsal
strategy, but whose performance is actually decreased. Spelling
and arithmetic tables are examples of subjects that usually stress
a rote memorization based on oral repetition. One alternative
would be to have the child repeatedly image the letters of the word
or number facts without verbalizing them. When it came time to use
the word or number fact the child would recall the image.
Educators must become more aware of the individual differences in
the way people learn. This becomes even more evident in the next
chapter where these individual differences can be seen to be at the
heart of what has been called reading disability.
Chapter 4
THE DIAGNOSIS OF READING DISABILITY
Although there is general agreement that reading disability
is not a single entity, there is considerably less than a consensus
as to the number of different syndromes that actually exist.
Neuropsychological assessment, the types of errors made with verbal
material, cognitive tests, and differences in processing strategies
have all been used in the classification of the reading disabled
into symptom-related subtypes. As many as five different subtypes
of reading disability have been found through the use of
neuropsychological tests.
For example, Mattis, French and Rapin (1978) reported three
groups and Doehring, Honshko, and Byans (1979) distinguished four
types. Fisk and Rourke (1979) Petroskas and Rourke (1979) have
identified subgroups which were consistent. These subtypes,
however, can be considered in terms of the presence or absence of
auditory linguistic deficits, a distinction reported throughout the
reading disability literature. Subtypes that include auditory
linguistic deficits comprise 80 to 90 percent of the total
population of reading disabled children. The smaller group has
usually been reported to show deficits in visual spatial
processing.
Boder (1973) examined the nature of the spelling errors made
by reading disabled children. She used the term dysphonetic to
describe the type of reading disability marked by linguistic and
phonetic difficulties; and the term dyseidetic to describe the type
which had difficulties with the overall visual spatial aspects of
the written word. Boder estimated that the dysphonetic group was
four to five times more prevalent than the dyseidetic group.
Pirozzolo (1979) used ratings, writing samples, and psychological
and neuropsychological tests to separate two reading disability
groups that were similar to those suggested by Boder. Bakker
(1982) proposed a similar distinction that he related to
hemispheric functioning. The auditory linguistic disabled reader
was not effective in the use of left hemisphere related tasks.
There was also an association of the visual spatial disabled reader
and the effective use of right hemisphere related strategies.
Zenhausern (1987) distinguished these two types on the basis
of both reading related tasks and the predominant direction of
their lateral eye movements. He found that the majority of
children with leftward lateral eye movements had difficulty
determining whether words in their sight vocabulary did or did not
rhyme. He also found that a group of children with predominantly
rightward lateral eye movements had no difficulty in determining
whether two words rhymed, but were deficient in determining whether
words and pictures represented the same concept. The auditory
linguistic group had difficulty converting a word to its sound and
the smaller group showed deficits in converting a word to its
meaning. He used the terms Phonetic and Semantic to describe this
distinction. From a behavioral perspective, phonetic disabled
readers are the children who struggle with every word when they
read aloud and thus lose continuity in the text. They are
frequently anomic and have a general difficulty with the auditory
linguistic aspects of reading, especially the grapheme to phoneme
conversion. The Semantic disabled reader, on the other hand, is the
child who will give a perfect word for word rendition of text, but
has no comprehension of the meaning of that text. The Semantic
disabled readers can convert words into their phonetic
representation, but this representation is not converted into its
meaning. They have no problems with the sound of a word but are
at deficit for tasks involving the meaning of words.
The original study was based on 13 Phonetic and 13 Semantic
readers from the second to fourth grades. One purpose of this
research was to determine whether these Phonetic and Semantic
subtypes would replicate across the entire elementary school
population. A second goal of this study was to replicate the
second finding of the original study. The Phonetic disabled readers
moved their eyes predominantly to the left and Semantic disabled
readers predominantly to the right. This second purpose was an
attempt to determine whether lateral eye movements can be used as
a marker variable for the two types of reading disability.
The subjects in this study were 160 children from the second
to the eighth grades. All were of at least average intelligence.
Forty children were selected at grades 2 or 3, grades 4 or 5,
grades 6 or 7, and grade 8. Of the 40 children at each age level,
20 were at or above grade level and 20 children were at least one
year below grade level in reading. Half of each group were chosen
on the basis of showing rightward LEM and half leftward LEM. The
predominant direction of LEM was determined individually for each
child. A series of 20 informational questions were asked in a face
to face situation and the predominant direction of LEM was noted.
Normal readers split evenly between right and left movers, but 84%
of the disabled readers were left movers.
There were four kinds of reading related tasks that used words
selected from the individual sight vocabulary of each child. A
rhyme task stressed the auditory linguistic aspects of the written
word and the remaining three tasks placed more emphasis on the
meaning of the words.
1) The rhyme stimuli consisted of 10 each of four types of
word pairs: a) words which neither rhy