Patterns of cerebral organization.

An analysis of the concurrent incidence of aphasia and spatial disorder in 270 patients with unilateral brain damage suggests that the two functions are statistically independent. These data can also be used to estimate the distribution of left, right, and bilateral representation of linguistic and spatial functions in the population. In right-handers, sex affects the pattern of cerebral asymmetries, while the familial history of sinistrality has a stronger effect on the pattern of cerebral asymmetries in left-handers. These findings suggest that complementary specialization exists only as a statistical norm: It is suggested that differences in complementary and noncomplementary specialization may underlie individual differences in cognitive skills.