IDENTIFICATION OF EMOTION IN A DICHOTIC-LISTENING TASK - EVENT-RELATED BRAIN POTENTIAL AND BEHAVIORAL FINDINGS

The lateralization of emotion perception has been examined using stimu li in both auditory and visual modalities. Studies using dichotic stim uli have generally supported the hypothesis of right-hemisphere domina nce for emotion perception, whereas studies of facial and verbal emoti on perception have provided evidence for the right-hemisphere and vale nce hypotheses. A dichotic target detection task was developed to enab le acquisition of event-related potentials (ERP) from subjects engaged in emotion detection. Nonsense syllables (e.g., ba, pa) stated in sev en different emotional intonations were dichotically presented to 24 y oung adults, in a target detection task during four separate blocks (t arget emotions: happiness, interest, anger, or sadness). Accuracy and reaction time and ERP measures were also collected. ERPs were recorded from 14 scalp electrodes with a nose reference and quantified for N10 0, sustained negativity, late positivity, and slow wave. Significantly greater left- than right-ear accuracy was obtained for the identifica tion of target prosodic emotion. Hemispheric asymmetries of N100 and s ustained negativity were found, with left-hemisphere amplitudes greate r than right-hemisphere amplitudes. These ERP asymmetries were not sig nificantly correlated with the left-ear dichotic advantage and may be related more to early phonetic processing than to emotion perception. Since the behavioral evidence supports the right-hemisphere hypothesis for emotion perception, behavioral and ERP asymmetries evident in thi s task reflect separable patterns of brain lateralization. (C) 1998 Ac ademic Press.