Cerebral processing of nonverbal affective stimuli: differential effects of cognitive and affective sets on hemispheric asymmetry.

The cerebral processing of emotion has been the subject of a number of recent studies, but results relating to hemispheric asymmetry have been quite mixed. The present study attempted to clarify and extend findings in this area by examining the differential effects of cognitive and affective sets on hemisphere asymmetry under conditions of nonverbal emotional stimulation. Electroencephalographic (EEG) data, recorded bilaterally, showed that differential hemispheric processing interacted with emotion (positive or negative), condition (cognitive or affective), and sex. In those emotion/condition combinations where hemispheric asymmetry was observed, there was greater activity in the left hemisphere than in the right. In addition, positive affect produced greater asymmetry than negative, and females showed greater activity in response to positive emotional stimuli than did males. Further, affective conditions yielded higher levels of activity than did cognitive. Finally, electrodermal activity showed lateralization effects as a differential function of cognitive and affective conditions.