Evidence for subgroups of adextrals based on speech lateralization and cognitive patterns.
Some non-right-handers may prefer the left hand by virtue of well-organized or high levels of spatial ability, vested primarily in the right hemisphere, rather than as a result of anomalous speech representation. This study tested the hypothesis that adextral (left-handed or ambidextrous) individuals with high spatial ability might have cerebral speech lateralization patterns similar to dextrals. Paper-and-pencil tests of various cognitive abilities, a verbal dichotic listening task, and a handedness inventory were administered to two groups (science or non-science students) of adextral and dextral subjects. The science group had predictably higher spatial ability than the non-science group. Adextral science students were as lateralized on dichotic listening, and had equal spatial ability, compared to dextral science students. Adextral non-science males were less lateralized and had (unexpectedly) poorer spatial ability than dextral non-science males. Thus in adextrals, variations in ability patterns may be related to variations in speech lateralization.
Kimura
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D
Department of Psychology, University of Western Ontario, London, Canada.
D'Amico
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C
D001288:Attention / Q000502:physiology; D002540:Cerebral Cortex / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D008297:Male; D009483:Neuropsychological Tests; D009949:Orientation / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D013028:Space Perception / Q000502:physiology; D013067:Speech Perception / Q000502:physiology*; D014705:Verbal Behavior / Q000502:physiology