ランダム図形認知における大脳半球機能の非対称性について

八田 武志

doi:10.4992/jjpsy.46.152

FUNCTIONAL HEMISPHERIC ASYMMETRY IN PERCEPTION OF RANDOM FORMS

TAKESHI HATTA

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JOURNAL FREE ACCESS

1975 Volume 46 Issue 3 Pages 152-161

DOI https://doi.org/10.4992/jjpsy.46.152

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Published: September 30, 1975 Received: February 24, 1975 Available on J-STAGE: July 16, 2010 Accepted: - Advance online publication: - Revised: -
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Date of correction: July 16, 2010 Reason for correction: - Correction: ABSTRACT Details: Wrong : Many investigations working on asymmetrical perception have demonstrated that verbal materials are more accurately recognized when they are presented to the right VF than to the left VF. Kimura proposed that such perceptual asymmetry reflects the functional asymmetry of the brain with respect to the processing of verbal and non-verbal materials.
While many studies of the perception of verbal materials supported her hypothesis, a few studies demonstrated the left VF superiority for non-verbal materials. The major purpose of this study was to demomstrate the right hemisphere superiority in perceiving non-verbal materials.
In Exp. I and II, the Ss made the “same” or “different” judgement to the paired random forms simultaneously or serially presented to the right and left VF. The hypothesis put forward applies to both experiments: if there is intrinsically no functional differences between both hemispheres, no differences in accuracy will appear between the judgements whichever hemisphere initially receives a standard stimulus. However, if the right hemisphere is superior for the perception of non-verbal materials as hypothesized by Kimura, the condition where the right hemisphere initially receives information from the standard stimulus will make less errors than the reverse order condition.
In Exp. I, the task of 10 Ss was to decide whether two random forms (painted all over) serially presented to the right and left VF were identical. The results indicated that there were more errors produced in the 16th polygon condition than in the 8th polygon condition, and in the right VF-lead condition than in the left VF-lead superiority was more observed in the longer lead condition. The first purpose of Exp. II was to replicate the finding of Exp. I by eliminating the after image effect of the stimuli. Twenty Ss were tested for lateral differences in the perception of contour random forms. The results showed that more errors were produced by the 24th polygon group than by the 8th polygon group, and in the right VF-lead condition than in the left VF-lead condition. The tendency of left VF-lead superiority was more outstanding in the longer lead condition. The second purpose of Exp. II was to examine the Fontenot's hypothesis that “Codability” is the primary stimulus dimension influencing lateral differeces. According to the data obtained, the two factors of association value and complexity did not influence much the degree of left VF-lead superiority, and this is not in accordance with the “Codability” hypothesis. The results of both experiments were essentially similar, and could be interpreted by the following hypothesis: information value or an increase in the amount of interference will decrease less rapidly in the superior hemisphere as time elapses. Therefore, if one hemisphere, superior in perceiving random forms, initially receives visual information concerning a standard stimulus, and the other hemisphere receives comparison stimulus information only subsequently, the accuracy in the “same-different” judgement will be superior in this condition than in the reverse order condition. Consequently, if the right hemisphere is superior for the perception of non-varbal materials, thee condition in which the hemisphere initially receives the standard stimulus information will make less error judgements than the reverse order condition. Hence the reults demonstrated in both experiments suggest the possibility of right hemisphere superiority for the perception of non-verbal materials.
Right : 2 experiments were conducted in which Ss made the “same-different” judgement with respect to a pair of random forms which were serially presented to the right and the left VF tachistoscopically. In Exp. I, the stimulus materials were random form painted solidly, and in Exp. II they were contour forms. The major results of both experiments were essentially the same. The results indicated that right VF-lead condition produced more errors than the left VF-lead condition, and that the high complexity form group produced more errors than the low complexity form group. The tendency of left VF-lead superiority was more pronounced when the interval between the 2 stimuli was longer. These results suggest the possibility of the right hemisphere's superior function concerning the perception of random forms.

Abstract

2 experiments were conducted in which Ss made the “same-different” judgement with respect to a pair of random forms which were serially presented to the right and the left VF tachistoscopically. In Exp. I, the stimulus materials were random form painted solidly, and in Exp. II they were contour forms. The major results of both experiments were essentially the same. The results indicated that right VF-lead condition produced more errors than the left VF-lead condition, and that the high complexity form group produced more errors than the low complexity form group. The tendency of left VF-lead superiority was more pronounced when the interval between the 2 stimuli was longer. These results suggest the possibility of the right hemisphere's superior function concerning the perception of random forms.

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