Identification of emotion in a dichotic listening task: event-related brain potential and behavioral findings

Abstract

The lateralization of emotion perception has been examined using stimuli in both auditory and visual modalities. Studies using dichotic stimuli have generally supported the hypothesis of right-hemisphere dominance for emotion perception, whereas studies of facial and verbal emotion perception have provided evidence for the right-hemisphere and valence hypotheses. A dichotic target detection task was developed to enable acquisition of event-related potentials (ERP) from subjects engaged in emotion detection. Nonsense syllables (e.g., ba, pa) stated in seven different emotional intonations were dichotically presented to 24 young adults, in a target detection task during four separate blocks (target 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 N100, sustained negativity, late positivity, and slow wave. Significantly greater left-than right-ear accuracy was obtained for the identification of target prosodic emotion. Hemispheric asymmetries of N100 and sustained negativity This study is based on a doctoral dissertation conducted by the first author for Queens College and the Graduate School of the City University of New York. Partial support was provided by National Institutes of Mental Health Grants MH36295 (GB) and MH42172 ( JB). We are grateful to Drs. H. Ehrlichman, R. Johnson, and H. Sackeim for their insightful comments as members of the dissertation committee; to Dr. J. Towey for his contributions and support; to Dr. J. Welkowitz for consultation regarding aspects of methodology; to Dr. L. K. Obler for access to equipment during the stimulus development phase; and to D. Schechter for access to the normal subject pool at the New York State Psychiatric Institute. Address were found, with left-hemisphere amplitudes greater than right-hemisphere amplitudes. These ERP asymmetries were not significantly 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 this task reflect separable patterns of brain lateralization