This study explores the relation between patterns of asymmetry in left and right hemisphere processing and level of ability on cognitive tests in children six and ten years of age. Hemisphere asymmetry is assessed using dichotic pairs of CV syllables and environmental sounds, and by a free vision chimeric face perception task. The verbal and visuo-spatial cognitive abilities tests are: syntax comprehension, verbal fluency, rapid automatized naming, mazes, face recognition, and digit span forward and backward.; Results suggest that the relation between hemisphere asymmetry and cognitive abilities is complex. No correlations between asymmetry scores and cognitive ability test scores reached significance (p < .01). Strong and weak asymmetry groups, formed for each of the three asymmetry measures, did not differ on cognitive ability tests. However, when subjects were grouped on the basis of both asymmetry and overall performance on verbal dichotic listening, the weak asymmetry/high performance group had higher verbal memory scores than either the weak asymmetry/low performance group or the strong asymmetry group. The only difference between the high and low performance/weak asymmetry groups was the number of bilateral correct responses, suggesting that a high level of bilateral processing is associated with superior performance on some measures of verbal cognitive ability.; Additional findings include an unexpected left hemisphere advantage for environmental sounds in a majority of subjects; a sex difference in favor of females on overall verbal cognitive abilities, in general, and on digit span forward, in particular; and a significant relation between right hemisphere processing of chimeric faces and environmental sounds. This last finding provides external validity for the chimeric face perception task as a measure of right hemisphere processing asymmetry and suggests that different patterns of hemisphere arousal asymmetry may have played a role in determining which hemisphere processed the environmental sounds.
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