The relationship of handedness, sex, familial sinistrality, and degree of speech laterality on style of cognitive processing in the human brain
LccQP 385 M84 1981 Fiche
LcshLeft- and right-handedness
Brain - Localization of functions
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AbstractClinical findings have consistently shown that the left-handed exhibit a degree of hemisphere laterality somewhat less than that shown by the right-handed. This finding of a reduced laterality in left-handers contributed to the latest in what has been a lengthy, if ignoble, listing of deficits attributable to left-handedness. In this latest case it has been proposed that left-handers suffer from a visual spatial deficit. Because the existence of such a deficit remains highly controversial, the overriding purpose of the present study was to examine in some detail whether such a spatial deficit exists. If such a deficit were found, the study was further designed to distinguish whether all or only a subgroup of left-handers exhibit the deficit. To this end 12 strongly left-handed (7 males; 5 females); 12 mixedhanders (4 males; 8 females) and 56 strongly right-handed children (29 males; 27 females) were tested on selected subtests of the WISC-R verbal (Vocabulary and Similarities) and performance (Block Design and Object Assembly) scales. Additional information as to the presence of familial sinistrality, and the hemisphere dominant for speech based on a dichotic listening task was gathered. An analysis-of-variance confirmed that the three handedness groups were equivalent in verbal ability - a necessary condition to the problem being addressed. Further analysis showed that while there was no difference in spatial abilities between the two strongly-handed groups, the mixed-handers did score significantly lower on this cognitive task. Conditional evidence supporting the proposal of a spatial deficit in sinistrals was thus found; the condition being that not all left-handers, show such a deficit. Rather it is the mixed-handers, who are almost always designated as left-handed, who show the deficit. It was further reported that while familial sinistrality did not affect spatial performance, the strength of hemisphere laterality as determined by dichotic listening did. Based on these findings and others reported in the literature a theory of hemisphere function based on strength of hemisphere laterality was forwarded.
Bibliography: p. 129-142.
CitationMunroe, M. (1981). The relationship of handedness, sex, familial sinistrality, and degree of speech laterality on style of cognitive processing in the human brain (Unpublished master's thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/11578
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