title: Handedness and spatial ability.
abstract: Data from a large-scale study of cognitive abilities were used to test the hypothesis that there are handedness-related differences in spatial visualization. The spatial factor score of the cognitive test battery provided a measure of spatial visualization. Analyses revealed a sex X handedness X ethnicity interaction on the spatial factor, and no significant handedness-related differences on verbal factor. In all ethnic groups strongly left-handed males had higher spatial scores than strongly right-handed males, whereas strongly left-handed females had lower spatial scores than strongly right-handed females. Among subjects of Japanese or Chinese ancestry, strongly left-handed subjects differed from ambidextrous subjects as well as from right-handed subjects, and these differences, too, were of opposite sign for males and females. It is suggested that the use of spatial ability measures which are relatively insensitive to differences in right hemisphere ability, as well as the failure to attend to degree of handedness, ethnicity, and particularly gender, may be responsible for the negative findings in this area of research.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003867:Depth Perception; D004193:Discrimination Learning; D005006:Ethnicity / Q000523:psychology; D005260:Female; D005556:Form Perception; D007839:Functional Laterality; D006254:Hawaii; D006801:Humans; D007360:Intelligence; D008297:Male; D008875:Middle Aged; D009949:Orientation; D012737:Sex Factors; D013028:Space Perception