Brain damage and person perception. Discrimination of handwriting

Like the face or the voice, handwriting is a parameter enabling the perception of persons. The right hemisphere appears to predominate in the processing of voices and faces, especially when a discriminative procedure is used. In order to see if this brain asymmetry may be generalized to person perception, a handwriting discrimination task was submitted to 15 left-, 12 right-, and two bilaterally injured subjects. The subject was asked to decide whether two simultaneously presented stimuli had been written by the same person; 72 pairs were presented in three ways: normally, inverted, and mirror-reversed. The results suggest that such processing is essentially preserved after focal brain damage; defects were found only after right lesions inducing hemineglect, after bilateral posterior lesion, and after left lesion when stimuli were displayed upside-down or mirror-reversed (i.e. unreadable).