Abstract:
The two cerebral hemispheres are specialized in different ways, as evident from studies of unilateral brain injury, testing of split-brained patients, and brain imaging. The most robust finding is that the left hemisphere in most people is specialized for language and skilled manual action, with some right hemisphere specialization for nonverbal functions, including spatial attention, emotion, and mental imagery. Although long-considered unitary, or based on complementarity of function, human cerebral asymmetry is multidimensional, comprising as many as four independent dimensions. And although often assumed to be uniquely human, cerebral asymmetries are widespread in nonhuman species.