[Effect of unilateral right hemisphere lesions upon recognition of faces tachistoscopically presented to the left hemisphere].

Normal subjects recognize a tachistoscopically presented face faster when it is flashed to the left visual field (right hemisphere) than when it is presented to the right visual field (left hemisphere). In order to assess the capacity of the left hemisphere in processing physiognomical material, a comparison was done between the choice-reaction times of a group of normals and of a group of right brain-damaged patients, to face photographs tachistoscopically projected to the right visual filed (left hemisphere). All subjects were right-handed adult males. In the brain damaged group it took almost as twice as the time taken in the controls for the left hemisphere to perform the task, even when unspecific factors, lengthening the reaction times, were excluded. These results are interpreted as favouring the hypothesis of an "absolute" right hemisphere dominance for recognizing faces, suggesting that in normal conditions a face projected to the left hemisphere is analyzed either exclusively by the right hemisphere or with a preponderant cooperation of it after the transfer of information across commissural pathways.