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The Hemispheric Specialization for Linguistic and Non-Linguistic Tactile Stimuli in Third Grade Children
THE HEMISPHERIC SPECIALIZATION FOR LINGUISTIC AND NON-LINGUISTIC TACTILE STIMULI IN THIRD GRADE CHILDREN! Sheldon P. Klein and Wayne D. Rosenfield (Department of Educational Psychology University of Connecticut)
INTRODUCTION
Dichotomous stimulation has become a widely utilized technique for investigating the role played by the right hemisphere and left hemisphere in processing various types of stimuli presented to the sensory modalities of neurologically intact individuals. The three prominent dichotomous techniques in use are: (1) Dichotic listening which involves the simultaneous presentation of auditory input to both ears through earphones (Kimura, 1967). (2) Visual hem i-field presentation which involve the simultaneous viewing of visual stimuli by both eyes. The visual stimuli are presented rapidly to the visual half fields of each eye by a tachistoscope to avoid scanning. (3) Dichaptic stimulation which involves the simultaneous tactual exploration of three dimensional stimuli concealed from view. The simultaneous fine motor palpation of the stimuli provides the individual tested with their sensory input (Witelson, 1974). Dichotomous tasks allow the investigation of "functional brain asymmetry" (Kimura, 1967) in neurologically intact individuals. In fact, their purpose is to allow us to make the same type of comparisons in regard to stimuli presented to the left hemisphere and right hemisphere of intact subjects as earlier studies of brain functioning made when they investigated the hemispheric functioning of unilaterally brain injured and commissurotomy patients (Nebes, 1975). Yet in our effort to examine the asymmetry of brain 1 Preparation of this paper was aided in part by a grant from the Bureau of Education for the Handicapped, U.S.O.E., "Learning Disabilities in Mathematics: A Curriculum Design for Upper Grades ", GOO7605223, N. 443CH60166, under the direction of J. F. Cawley, Project Director, University of Connecticut.
Illustrations by Johanna Sayre Shunman, Graphic Artist, University of Connecticut Cortex (1980) 16, 205-212.
206
Sheldon P. Klein and Wayne D. Rosenfield
function in its purest form, we may have impaired the generalizability of some of the results. The utilization of only right handed male subjects for the sake of experimental purity has made the results less applicable to the natural educational setting since the experimental sample is not representative of any normal classroom configuration. The current study was designed to repeat with minor modifications Sandra Witelson's experiment which utilized dichaptic stimulation and was designed to test "the relative participation of the left and right hemispheres in processing non-linguistic and linguistic stimuli presented in the tactual modality in neurologically intact individuals." (Witelson, 1974). The discussion of the results will focus on: (1) Whether or not there is a right hemisphere advantage for nonlinguistic stimuli in third-grade children. (2) Whether or not there is a left hemisphere advantage for linguistic stimuli in third-grade children. (3) Whether or not there are differences in performance on either task attributable to sex.
MATERIALS AND METHOD
Subjects
The sample in the current experiment consisted of 30 third-grade students, 15 boys and 15 girls, in attendance at a rural elementary school. All subjects were full time participants of the regular third-grade program. All were considered to be neurologically intact (according to school medical histories). Although lateral preference is extremely difficult to document, each child was administered an informal hand preference evaluation before testing. The evaluation included asking the child to tell his/her hand preference, asking the child to throw an object, and requiring the child to write his/her name. The results of this informal evaluation were as follows: (1) thirteen boys indicated right hand preference on all three tasks; (2) two boys indicated left hand preference on all three tasks; (3) eleven girls indicated right hand preference on all three tasks; (4) two girls indicated left hand preference on all three tasks; (5) two girls indicated mixed preference on the tasks. Apparatus
There were eight different stimuli for each of the dichaptic tasks. The eight nonsense shapes for the non-linguistic task were identical to eight of the stimuli utilized in Witelson's (1974) original study and eight upper case letters were selected at random as linguistic stimuli. Each stimulus was cut out of core board. They were approximately lIN' X lIN' X 3/16" in size and were glued onto a piece of cardboard 5" X 7". The stimuli were presented to the child in a wooden presentation box which was placed between the examiner and
Hemispheric specialization for tactile stimuli
207
the subject. The box was constructed so that the child could not see the stimuli but the examiner could watch the child palpate the shapes or letters presented (see Figure O.
7EJ7ER
Figure 1.
There were eight response boards for the non-linguistic task and eight for the linguistic task. Each board measured 8" X 8" and presented an array of six test stimuli to the child. This array was composed of two stimuli which were identical to those palpated and four other test stimuli randomly chosen. Each of the six response items was randomly assigned to one of six pre-determined positions on the response board. These positions were such that the six letters or nonsense shapes were arranged on the response board in a circular pattern with one placed in the center. This arrangement of the items on the response board was utilized in order to prevent children from scanning left to right during their responses. A "double-handed" pointer in the shape of a divining rod was utilized as a method of subject response (see Figure 2). This is important since some investigators stress the type of response (e.g., talking vs. pointing or drawing) as influencing the results of cerebral specialization tasks, while other stress the type of stimulus material (Nebes, 1975). We were careful to select a mode of responding that would accomplish the following purposes: (1) constancy across both tasks (linguistic and non-linguistic); (2) elimination of the influence of the mode of response on the test results. We anticipated that this response procedure would give us results which reflected which hemisphere is specialized for a particular type of dichaptically presented stimulus. This response procedure differed from the procedure in Witelson's (1974) experiment where nonsense shapes were responded to by pointing with the non-dominant hand and letters were responded to verbally.
208
Sheldon P. Klein and Wayne D. Rosenfield
Figure 2.
Procedure .
Each set of trials proceeded in a similar manner. The child was presented with two test stimuli (either two nonsense shapes or two letters) in the presentationbox to palpate simultaneously for ten seconds. After this time period the two stimuli were removed and a response board was presented. The child picked up the "double-handed" pointer and pointed, one at a time, to the two stimuli believed to be the ones which had been felt. There was no time limit placed on responding. The examiner recorded the response and the child put the pointer down. The next two stimuli were then presented by the examiner in the presentation box to be palpated by the child. Testing continued in this manner until all eight pairs (each of four pairs presented twice) of test stimuli for that dichaptic task (letters or nonsense shapes) had been presented. After the first task had been completed, the remaining dichaptic task was presented in exactly the same manner. Thus every child received the two dichotomous stimulization tasks, nonsense shapes and letters, consisting of four pairs of stimuli presented in the previously described manner. Each pair of stimuli was presented twice with the stimuli randomized for left-right arrangement and order of presentation of pairs. The
Hemispheric specialization for tactile stimuli
209
order of presentation of each dichaptic task was counter-balanced to control for any order effect. We were primarily interested in the influence the type or stimulus might have on the subject's response. Thus the two tests (letters or linguistic and nonsense shapes or non-linguistic) were identical except for the fact that the child received letters as a stimulus in one instance and nonsense as a stimulus in the other. Each subject received some training with feedback as to the correctness of responses prior to the start of the testing. A child could receive up to a maximum of 15 pre-test trials with non-test stimuli. The purpose of pre-test training was to familiarize the child with the testing procedure and to facilitate a feeling of rapport, comfort, and success within the testing situation. Each child was instructed on each pre-test trial that in order to complete the task in the desired manner they needed to do certain things. The examiner used simple language, practice sessions and demonstrations to convey the following notions: (1) Feel with both hands simultaneously. (2) Utilize fine motor movements of the hands while palpating (to minimize ipsilateral feedback). (3) Don't speak to the examiner while feeling the stimuli or pointing to a response. Instead, wait until responding is complete to converse. (Some children tended to give verbal responses while pointing.) (4) Grasp the pointer firmly with both hands while responding. (Some children tended to hold it only with the dominant hand.)
RESULTS
A Lindquist type I repeated measures analysis of variance was utilized with sex as the between subjects factor and hand as the within subjects factor. It seemed prudent to examine first each dichaptic task discussing the results in regard to the specialization of the cerebral hemispheres for that particular type of dichaptically presented stimulus (linguistic or spatial). After that an evamination of any differences attributable to sex on these two dichaptic tasks was appropriate.
Letters test (1) There was no significant difference between the mean right hand correct score and the mean left hand correct score for either boys or girls on dichaptically presented letters. The mean accuracy scores for both boys and girls indicated a slight, but non significant left hand advantage. (See Table I and Figure 3.)
(2) The girls scored higher than boys on dichaptically presented letters but the difference was not significant.
Sheldon P. Klein and Wayne D. Rosenfield
210
FEMALE- ___ _ MALE _ __
FEMALE MALE
10
10
9 >- 8 ~ 7 D::
9
------------
:;,
v 6 ~ 5
z .... ::
.:(
8
>~ 7
D::
:;,
v
6
-~ ------
~ 5 4 z .:(
4
....
::
3 2
3
2
o
1 0
_____________________
RIGHT HAND
LEFT HAND
RIGHT HAND
~
Figure 3.
LEFT HAND
Figure 4.
TABLE I
Analysis of Variance for Letters (Linguistic) Test Source Between 8's Sex (A) Error between Within 8's Hand (B) AxB Error within
*p
d.f..
M.S.
F
1 28
4.817 4.060
1.186
1 1 28
1.350 0.150 0.893
1.512 0.168
< .01
Nonsense shapes test (1) There was a significant difference between the mean right hand correct score and the mean left hand correct score for both boys and girls on dichaptically presented nonsense shapes, The mean accuracy scores for both boys and girls indicates a significantly higher (p <.01) score for nonsense shapes presented to the left hand. (See Table II and Figure 4.) (2) The boys scored higher than girls on dichaptically presented nonsense shapes but the difference was not significant.
Hemispheric specialization for tactile stimuli
211
TABLE II
Analysis of Variance for Nonsense Shapes (Spatial) Test Source Between S's Sex (A) Error between Within S's Hand (B) AxB Error within
d.f.
M.S.
F
1 28
1.350 4.791
0.282
1 1 28
18.150 0.017 2.048
8.864* 0.008
* p < .01
DISCUSSION
The results indicate that these dichaptic tasks were useful for determining right hemisphere specialization for spatial stimuli. However, the left hemisphere specialization for linguistic stimuli in accordance wtch commonly held models of brain asymmetry was not found by dichaptically presenting letters to these third-grade children. Our results at this point are in agreement with those reported by Witelson (1974) in her study on linguistic and non-linguistic tactual perception which utilized 47 righthanded male subjects. Witelson summarized " ...that non-linguistic tactile information was more efficiently processed in the right (non speech) hemisphere in neurologically intact individuals as had previously been inferred on the basis of the study of subjects with unilateral brain damage. The right hemisphere specialization for non-linguistic tactual perception was found to be present as early as six years of age. It was also found, contrary to expectation, that simple tactile linguistic stimuli such as letters were not processed more efficiently by the left hemisphere. The results were interpreted as indicating that linguistic stimuli presented tactually must be analyzed first in a spatial code and then translated into a linguistic code." (Wite1son, 1974).
The current study departs from some of Witelsons' results in its appraisal of how hemispheric specialization for spatial processing differs between boys and girls at the third-grade level. In her article, Sex and the single hemisphere, Witelson states, "For boys of age six the right hemisphere is more specialized than the left for spatial processing; in girls, however, there is bilateral representation at least until adolescence." (Witelson, 1976). The current findings with a population of third-grade students (8 years 4 months - 9 years 9 months of age) indicate a significant right hemisphere advantage for both the boys and the girls tested. Thus the cerebral specialization for spatial processing may be present in girls much earlier than previous studies have indicated, and we may need to look for
212
Sheldon P. Klein and Wayne D. Rosenfield
other reasons than simply "sexual dimorphism in neural organization" (Witelson, 1976) to explain sexual learning dichotomies. One interesting facet of the current study is the implication of differences in superiority on various tasks attributable to sex. Although statistically significant results were not found, the boys did better than the girls on the spatial task, and conversely, the girls did better than the boys on the linguistic task. Whether this is a result of neurological factors, environmental factors, sociological factors, or some combination of factors, girls in the early elementary grades seem to be more favorably equipped to deal with the linguistically loaded primary curriculum. A further investigation of this topic regarding superiority for processing different types of stimuli in school age boys and girls could yield more definitive results. In any event, further research providing experimental data and correlation studies are needed to investigate neurological processing and educational performance.
ABSTRACT
Thirty third-grade children were given two dichaptically presented tests of hemispheric specialization. Specialization for linguistic stimuli was measured by a letters task and specialization for spatial stimulus was measured by a nonsense shapes task. The results showed a significant right hemisphere processing advantage for tactually presented spatial stimuli. There was no significant processing advantage for either hemisphere with tactually presented linguistic stimuli. The right hemisphere specialization for tactually presented spatial stimuli was present for both boys and girls. Thus there was no evidence of sexual bimorphism in the neurological organization of third grade children for spatial processing.
REFERENCES KIMURA, D. (1967) Functional asymmetry of the brain in dichotic listening, Cortex, 3, 163. NEBES, R. D. (1975) Man's so called minor hemisphere, UCLA Educator, 7(2), 13-16. WITELSON, S. F. (1974) Hemispheric specialization for linguistic and non linguistic tactual
-
perception using a dichotomous stimulization technique, Cortex, 10, 3. (1976) Sex and the single hemisphere: Sepcialization of the right hemisphere for spatial processing, Science, 193, 425-427. (1977) Developmental dyslexia, two right hemispheres and none left, Science, 195, 309-311.
Sheldon P. Klein, Graduate Assistant, University of Connecticut, Dept. of Educational Psychology, Box U-7, Storrs, CT 06268, U.S.A. Wayne D. Rosenfield, Graduate Assistant, University of Connecticut, Dept. of Educational Psychology, Box U-7, Storrs, CT 06268, U.S.A.
INTRODUCTION
Dichotomous stimulation has become a widely utilized technique for investigating the role played by the right hemisphere and left hemisphere in processing various types of stimuli presented to the sensory modalities of neurologically intact individuals. The three prominent dichotomous techniques in use are: (1) Dichotic listening which involves the simultaneous presentation of auditory input to both ears through earphones (Kimura, 1967). (2) Visual hem i-field presentation which involve the simultaneous viewing of visual stimuli by both eyes. The visual stimuli are presented rapidly to the visual half fields of each eye by a tachistoscope to avoid scanning. (3) Dichaptic stimulation which involves the simultaneous tactual exploration of three dimensional stimuli concealed from view. The simultaneous fine motor palpation of the stimuli provides the individual tested with their sensory input (Witelson, 1974). Dichotomous tasks allow the investigation of "functional brain asymmetry" (Kimura, 1967) in neurologically intact individuals. In fact, their purpose is to allow us to make the same type of comparisons in regard to stimuli presented to the left hemisphere and right hemisphere of intact subjects as earlier studies of brain functioning made when they investigated the hemispheric functioning of unilaterally brain injured and commissurotomy patients (Nebes, 1975). Yet in our effort to examine the asymmetry of brain 1 Preparation of this paper was aided in part by a grant from the Bureau of Education for the Handicapped, U.S.O.E., "Learning Disabilities in Mathematics: A Curriculum Design for Upper Grades ", GOO7605223, N. 443CH60166, under the direction of J. F. Cawley, Project Director, University of Connecticut.
Illustrations by Johanna Sayre Shunman, Graphic Artist, University of Connecticut Cortex (1980) 16, 205-212.
206
Sheldon P. Klein and Wayne D. Rosenfield
function in its purest form, we may have impaired the generalizability of some of the results. The utilization of only right handed male subjects for the sake of experimental purity has made the results less applicable to the natural educational setting since the experimental sample is not representative of any normal classroom configuration. The current study was designed to repeat with minor modifications Sandra Witelson's experiment which utilized dichaptic stimulation and was designed to test "the relative participation of the left and right hemispheres in processing non-linguistic and linguistic stimuli presented in the tactual modality in neurologically intact individuals." (Witelson, 1974). The discussion of the results will focus on: (1) Whether or not there is a right hemisphere advantage for nonlinguistic stimuli in third-grade children. (2) Whether or not there is a left hemisphere advantage for linguistic stimuli in third-grade children. (3) Whether or not there are differences in performance on either task attributable to sex.
MATERIALS AND METHOD
Subjects
The sample in the current experiment consisted of 30 third-grade students, 15 boys and 15 girls, in attendance at a rural elementary school. All subjects were full time participants of the regular third-grade program. All were considered to be neurologically intact (according to school medical histories). Although lateral preference is extremely difficult to document, each child was administered an informal hand preference evaluation before testing. The evaluation included asking the child to tell his/her hand preference, asking the child to throw an object, and requiring the child to write his/her name. The results of this informal evaluation were as follows: (1) thirteen boys indicated right hand preference on all three tasks; (2) two boys indicated left hand preference on all three tasks; (3) eleven girls indicated right hand preference on all three tasks; (4) two girls indicated left hand preference on all three tasks; (5) two girls indicated mixed preference on the tasks. Apparatus
There were eight different stimuli for each of the dichaptic tasks. The eight nonsense shapes for the non-linguistic task were identical to eight of the stimuli utilized in Witelson's (1974) original study and eight upper case letters were selected at random as linguistic stimuli. Each stimulus was cut out of core board. They were approximately lIN' X lIN' X 3/16" in size and were glued onto a piece of cardboard 5" X 7". The stimuli were presented to the child in a wooden presentation box which was placed between the examiner and
Hemispheric specialization for tactile stimuli
207
the subject. The box was constructed so that the child could not see the stimuli but the examiner could watch the child palpate the shapes or letters presented (see Figure O.
7EJ7ER
Figure 1.
There were eight response boards for the non-linguistic task and eight for the linguistic task. Each board measured 8" X 8" and presented an array of six test stimuli to the child. This array was composed of two stimuli which were identical to those palpated and four other test stimuli randomly chosen. Each of the six response items was randomly assigned to one of six pre-determined positions on the response board. These positions were such that the six letters or nonsense shapes were arranged on the response board in a circular pattern with one placed in the center. This arrangement of the items on the response board was utilized in order to prevent children from scanning left to right during their responses. A "double-handed" pointer in the shape of a divining rod was utilized as a method of subject response (see Figure 2). This is important since some investigators stress the type of response (e.g., talking vs. pointing or drawing) as influencing the results of cerebral specialization tasks, while other stress the type of stimulus material (Nebes, 1975). We were careful to select a mode of responding that would accomplish the following purposes: (1) constancy across both tasks (linguistic and non-linguistic); (2) elimination of the influence of the mode of response on the test results. We anticipated that this response procedure would give us results which reflected which hemisphere is specialized for a particular type of dichaptically presented stimulus. This response procedure differed from the procedure in Witelson's (1974) experiment where nonsense shapes were responded to by pointing with the non-dominant hand and letters were responded to verbally.
208
Sheldon P. Klein and Wayne D. Rosenfield
Figure 2.
Procedure .
Each set of trials proceeded in a similar manner. The child was presented with two test stimuli (either two nonsense shapes or two letters) in the presentationbox to palpate simultaneously for ten seconds. After this time period the two stimuli were removed and a response board was presented. The child picked up the "double-handed" pointer and pointed, one at a time, to the two stimuli believed to be the ones which had been felt. There was no time limit placed on responding. The examiner recorded the response and the child put the pointer down. The next two stimuli were then presented by the examiner in the presentation box to be palpated by the child. Testing continued in this manner until all eight pairs (each of four pairs presented twice) of test stimuli for that dichaptic task (letters or nonsense shapes) had been presented. After the first task had been completed, the remaining dichaptic task was presented in exactly the same manner. Thus every child received the two dichotomous stimulization tasks, nonsense shapes and letters, consisting of four pairs of stimuli presented in the previously described manner. Each pair of stimuli was presented twice with the stimuli randomized for left-right arrangement and order of presentation of pairs. The
Hemispheric specialization for tactile stimuli
209
order of presentation of each dichaptic task was counter-balanced to control for any order effect. We were primarily interested in the influence the type or stimulus might have on the subject's response. Thus the two tests (letters or linguistic and nonsense shapes or non-linguistic) were identical except for the fact that the child received letters as a stimulus in one instance and nonsense as a stimulus in the other. Each subject received some training with feedback as to the correctness of responses prior to the start of the testing. A child could receive up to a maximum of 15 pre-test trials with non-test stimuli. The purpose of pre-test training was to familiarize the child with the testing procedure and to facilitate a feeling of rapport, comfort, and success within the testing situation. Each child was instructed on each pre-test trial that in order to complete the task in the desired manner they needed to do certain things. The examiner used simple language, practice sessions and demonstrations to convey the following notions: (1) Feel with both hands simultaneously. (2) Utilize fine motor movements of the hands while palpating (to minimize ipsilateral feedback). (3) Don't speak to the examiner while feeling the stimuli or pointing to a response. Instead, wait until responding is complete to converse. (Some children tended to give verbal responses while pointing.) (4) Grasp the pointer firmly with both hands while responding. (Some children tended to hold it only with the dominant hand.)
RESULTS
A Lindquist type I repeated measures analysis of variance was utilized with sex as the between subjects factor and hand as the within subjects factor. It seemed prudent to examine first each dichaptic task discussing the results in regard to the specialization of the cerebral hemispheres for that particular type of dichaptically presented stimulus (linguistic or spatial). After that an evamination of any differences attributable to sex on these two dichaptic tasks was appropriate.
Letters test (1) There was no significant difference between the mean right hand correct score and the mean left hand correct score for either boys or girls on dichaptically presented letters. The mean accuracy scores for both boys and girls indicated a slight, but non significant left hand advantage. (See Table I and Figure 3.)
(2) The girls scored higher than boys on dichaptically presented letters but the difference was not significant.
Sheldon P. Klein and Wayne D. Rosenfield
210
FEMALE- ___ _ MALE _ __
FEMALE MALE
10
10
9 >- 8 ~ 7 D::
9
------------
:;,
v 6 ~ 5
z .... ::
.:(
8
>~ 7
D::
:;,
v
6
-~ ------
~ 5 4 z .:(
4
....
::
3 2
3
2
o
1 0
_____________________
RIGHT HAND
LEFT HAND
RIGHT HAND
~
Figure 3.
LEFT HAND
Figure 4.
TABLE I
Analysis of Variance for Letters (Linguistic) Test Source Between 8's Sex (A) Error between Within 8's Hand (B) AxB Error within
*p
d.f..
M.S.
F
1 28
4.817 4.060
1.186
1 1 28
1.350 0.150 0.893
1.512 0.168
< .01
Nonsense shapes test (1) There was a significant difference between the mean right hand correct score and the mean left hand correct score for both boys and girls on dichaptically presented nonsense shapes, The mean accuracy scores for both boys and girls indicates a significantly higher (p <.01) score for nonsense shapes presented to the left hand. (See Table II and Figure 4.) (2) The boys scored higher than girls on dichaptically presented nonsense shapes but the difference was not significant.
Hemispheric specialization for tactile stimuli
211
TABLE II
Analysis of Variance for Nonsense Shapes (Spatial) Test Source Between S's Sex (A) Error between Within S's Hand (B) AxB Error within
d.f.
M.S.
F
1 28
1.350 4.791
0.282
1 1 28
18.150 0.017 2.048
8.864* 0.008
* p < .01
DISCUSSION
The results indicate that these dichaptic tasks were useful for determining right hemisphere specialization for spatial stimuli. However, the left hemisphere specialization for linguistic stimuli in accordance wtch commonly held models of brain asymmetry was not found by dichaptically presenting letters to these third-grade children. Our results at this point are in agreement with those reported by Witelson (1974) in her study on linguistic and non-linguistic tactual perception which utilized 47 righthanded male subjects. Witelson summarized " ...that non-linguistic tactile information was more efficiently processed in the right (non speech) hemisphere in neurologically intact individuals as had previously been inferred on the basis of the study of subjects with unilateral brain damage. The right hemisphere specialization for non-linguistic tactual perception was found to be present as early as six years of age. It was also found, contrary to expectation, that simple tactile linguistic stimuli such as letters were not processed more efficiently by the left hemisphere. The results were interpreted as indicating that linguistic stimuli presented tactually must be analyzed first in a spatial code and then translated into a linguistic code." (Wite1son, 1974).
The current study departs from some of Witelsons' results in its appraisal of how hemispheric specialization for spatial processing differs between boys and girls at the third-grade level. In her article, Sex and the single hemisphere, Witelson states, "For boys of age six the right hemisphere is more specialized than the left for spatial processing; in girls, however, there is bilateral representation at least until adolescence." (Witelson, 1976). The current findings with a population of third-grade students (8 years 4 months - 9 years 9 months of age) indicate a significant right hemisphere advantage for both the boys and the girls tested. Thus the cerebral specialization for spatial processing may be present in girls much earlier than previous studies have indicated, and we may need to look for
212
Sheldon P. Klein and Wayne D. Rosenfield
other reasons than simply "sexual dimorphism in neural organization" (Witelson, 1976) to explain sexual learning dichotomies. One interesting facet of the current study is the implication of differences in superiority on various tasks attributable to sex. Although statistically significant results were not found, the boys did better than the girls on the spatial task, and conversely, the girls did better than the boys on the linguistic task. Whether this is a result of neurological factors, environmental factors, sociological factors, or some combination of factors, girls in the early elementary grades seem to be more favorably equipped to deal with the linguistically loaded primary curriculum. A further investigation of this topic regarding superiority for processing different types of stimuli in school age boys and girls could yield more definitive results. In any event, further research providing experimental data and correlation studies are needed to investigate neurological processing and educational performance.
ABSTRACT
Thirty third-grade children were given two dichaptically presented tests of hemispheric specialization. Specialization for linguistic stimuli was measured by a letters task and specialization for spatial stimulus was measured by a nonsense shapes task. The results showed a significant right hemisphere processing advantage for tactually presented spatial stimuli. There was no significant processing advantage for either hemisphere with tactually presented linguistic stimuli. The right hemisphere specialization for tactually presented spatial stimuli was present for both boys and girls. Thus there was no evidence of sexual bimorphism in the neurological organization of third grade children for spatial processing.
REFERENCES KIMURA, D. (1967) Functional asymmetry of the brain in dichotic listening, Cortex, 3, 163. NEBES, R. D. (1975) Man's so called minor hemisphere, UCLA Educator, 7(2), 13-16. WITELSON, S. F. (1974) Hemispheric specialization for linguistic and non linguistic tactual
-
perception using a dichotomous stimulization technique, Cortex, 10, 3. (1976) Sex and the single hemisphere: Sepcialization of the right hemisphere for spatial processing, Science, 193, 425-427. (1977) Developmental dyslexia, two right hemispheres and none left, Science, 195, 309-311.
Sheldon P. Klein, Graduate Assistant, University of Connecticut, Dept. of Educational Psychology, Box U-7, Storrs, CT 06268, U.S.A. Wayne D. Rosenfield, Graduate Assistant, University of Connecticut, Dept. of Educational Psychology, Box U-7, Storrs, CT 06268, U.S.A.