数字と線分方向知覚における大脳半球機能の非対称性に関する研究

八田 武志

doi:10.4992/jjpsy.47.268

FUNCTIONAL HEMISPHERIC ASYMMETRIES IN PERCEPTION OF DIGIT AND LINE ORIENTATION

TAKESHI HATTA

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JOURNAL FREE ACCESS

1976 Volume 47 Issue 5 Pages 268-276

DOI https://doi.org/10.4992/jjpsy.47.268

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Published: January 20, 1977 Received: February 12, 1976 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: TITLE Details: [in Japanese]

Date of correction: July 16, 2010 Reason for correction: - Correction: ABSTRACT Details: Wrong : It has been suggested by many investigators that a difference exists in information processing functions of the two cerebral hemispheres of man. Evidence indicates that verbal materials, e.g. letters, words, digits, are analyzed primarily by the major hemisphere, while non-verbal materials, e.g. complex random forms, dot locations, dot numeration, are analyzed primarily by the minor hemisphere. Recently, more analytical questions have been raised about this kind of perceptual difference between the two hemispheres Are they due to a fundamental difference in the mechanisms of “perceptual process” or of “memory process”, or in their combined effects? Several studies have demonstrated that “memory process” contributes to producing the lateral difference more than “perceptual process” in the recognition of verbal and non-verbal materials.
The purpose of the present study was to examine whether or not “perceptual process” yields the laterality effects.
In Experiment I, the Ss made the “same” or “different” judgement. In Experiment II, the Ss made the “same” or “different” judgement and pressed a key as fast as possible to paired stimuli presented simultaneously or serially to the right and left visual fields. The hypothesis proposed in this study was as follows: If there is intrinsically no functional difference between the hemispheres, no difference will appear in accuracy and reaction time whichever hemisphere initially receives a standard stimulus. However, if one hemisphere is superior for perception, the condition where a dominant hemisphere initially receives information from the standard will elicit less errors, and exhibit a faster reaction than the converse order condition.
In Experiment I, 20Ss had to judge whether two digits serially presented to the right and left visual field were identical. More errors were in fact produced in the left visual field lead condition than in the right visual field lead condition.
In Experiment II, 14 Ss had to judge whether two orientaions of lines (among eight cases) serially presented to the right and left visual field were identical, and pressed a key as fast as possible following the decision. The right visual field lead condition produced more errors than the left visual field lead condition, but there is no statistical difference in the reaction time between both conditions.
The results of both experiments were essentially similar, and could be accounted for as follows: In the so-called dominant hemisphere, the persistence of stimulation and information value are greater, or the amount of interference increases more slowly in time, than in the inferior hemisphere. Thus, the results of Experiment I indicate that the left hemisphere is superior in perception of digits than the right hemisphere and the results of Experiment II indicate that the right hemisphere is superior in perception of the line orientation than the left.
The overall results in this study suggest that not only the “memory process” as shown by the previous studies, but also the “perceptual process” contribute to the effects of hemispheric differences in the recognition of verbal and non-verbal materials.
Right : In Exp. I, right-handed Ss made the “same” or “different” judgement to paired digits serially presented to the right and left visual field, and exhibited erroneous judgements in the left visual field lead condition. These results suggest the left hemisphere superiority. In Exp. II, the Ss were requested to make the “same” or “different” judgement and to press a key as fast as possible to the paired line orientation. The right visual field lead condition produced more errors than the left visual field lead condition. This suggests the right hemisphere superiority. But no difference appeared between both conditions in the reaction time. The opposite hemispheric superiority, found in perceiving verbal and non-verbal materials in the 2 experiments, would be attributed to the basic difference in “perceptual” process.

Abstract

In Exp. I, right-handed Ss made the “same” or “different” judgement to paired digits serially presented to the right and left visual field, and exhibited erroneous judgements in the left visual field lead condition. These results suggest the left hemisphere superiority. In Exp. II, the Ss were requested to make the “same” or “different” judgement and to press a key as fast as possible to the paired line orientation. The right visual field lead condition produced more errors than the left visual field lead condition. This suggests the right hemisphere superiority. But no difference appeared between both conditions in the reaction time. The opposite hemispheric superiority, found in perceiving verbal and non-verbal materials in the 2 experiments, would be attributed to the basic difference in “perceptual” process.

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