ABSTRACT
Kimura and Archibald proposed that human cerebral asymmetries did not evolve from language, but from particular motor skills that were employed in basic communication functions. Collins suggested that the even distribution of right- and left-pawed animal preferences is due to chance factors initially determining which limb is to be the dominant one. The right sylvian fissure of the great apes typically curls upward at the posterior end and terminates in a higher position than its left counterpart. Cross-species similarities also have been identified with the temporal planum. The left planum is typically larger than the right in chimpanzees as well as humans. A morphological body side distinction would appear to be related to this functional asymmetry. Split-brain experiments also have been employed to examine lateralization of functions in various species. With respect to humans, the split-brain operations have worked quite successfully in containing epileptic seizures to one brain side.
