Facial recognition and brain asymmetries: clues to underlying mechanisms.

A series of similar faces was presented to either the left or right visual field of three adults with brains surgically split along the corpus callosum. The left hemisphere displayed a marked and persistent deficit in performing a match-to-sample task, whereas the right hemisphere performed the task well. Additional test results suggest that the superiority is not specific to faces and is also not caused by specialized differences in sensory processes, but rather is related to differences in each hemisphere's ability to encode stimuli that cannot be adequately differentiated with a verbal description.