Self-face processing in a callosotomy patient.

Self-face recognition is reserved for humans, apes and possibly dolphins and is thought to be a marker of self-awareness. Previous data have indicated that self-face recognition may be mediated via frontal right hemisphere circuits within the brain. Testing patient M.L., who underwent a total callosotomy, we found that when searching for the self-face in a series of morphs (composite facial images made up of his own and a famous face in inversely varying percentages) the patient made (i) more true-positive and (ii) fewer false-positive responses when responding with the right hemisphere (i.e. indicating with the left hand). There was no hand difference when searching for familiar faces. These data imply a right hemisphere processing advantage for self-faces.