INTER-HEMISPHERIC INTEGRATION OF EMOTIONAL INFORMATION IN THE FACE: BEHAVIORAL AND ELECTROPHYSIOLOGICAL DATA
A lateralized emotion perception task with 1 second exposure durations was used involving the presentation of two emotional faces, one on each visual hemi-field, rather than the typical emotion-neutral arrangement. The two faces characteristically belonged to two distinct emotion categories (joy-fear, joy-anger, fear-anger), and varied along 3 levels of expression (obtained through morphing). Factorial combinations among the levels of the emotions were used for each pair, and subjects were required to rate the overall affective intensity of the pairs. Davidsonâ€™s framework for the cerebral lateralization of emotions according to an approach-withdrawal axis was provisionally adopted (approaching-inducing emotions lateralized on the left, withdrawal-inducing emotions lateralized on the right). Rating data displayed factorial patterns consistent with inter-hemispheric cooperation (adding or averaging). EEG data (event-related-alpha-desynchronization) clearly supported Davidsonâ€™s claim. EEG factorial patterns were suggestive of both inter-hemispheric cooperation and competition when visual-field lateralization agreed with preferential cerebral lateralization of emotions.