Verbal Involvement of the Left Hemisphere in Processing Facial Expressions of Emotion

Abstract

Verbal involvement of the left hemisphere in processing facial expressions of emotion was investigated with normal subjects by examining the effects for hemispheres (right or left hemisphere), stimulus processing codes (imagery or verbal code), and the degree of cognitive demands of the task (unilateral or bilateral tachistoscopic projection) on accuracy for recognizing emotional expressions. When a “target” cartoon-like face was unilaterally projected, right-hemisphere superiority in face recognition accuracy was observed whether the “test” emotional stimuli were imagery faces or verbal labels. But when two different target faces were bilaterally presented simultaneously (i. e., one face to the right hemisphere and the other to the left hemisphere), right-hemisphere superiority was obtained only when the test stimuli were emotional labels. These results were predicted and interpreted in terms of the inter ruption effect of verbal processing on visual processing in the left hemisphere and of the interference and collaboration effects between two hemispheres on processing of differentiated emotional codes of facial expressions.