Disentangling the interaction of sex differences and hemispheric specialization for face processing - Evidence from ERPs.

Recent studies on face processing and its hemispheric lateralization suggest that inconsistencies in earlier findings might be partially explained by sex differences, as findings from event-related potential studies indicated a more asymmetric functioning of the visual cortex during face encoding in men, whereas women seemed to display a more bilateral activation pattern. The aim of this study was to further investigate the role of sex differences in hemispheric specialization during face recognition. Fifty-four healthy participants (27 females and 27 males) engaged in a familiarity decision task in which famous and unfamiliar faces were presented in a lateralized tachistoscopic fashion with unilateral und bilateral presentation modes and measurement of event-related potentials and behavioral responses. Results showed a clear N170 component for males and females in all experimental conditions. No hemispheric differences of the N170 were observed in the bilateral condition and both groups showed larger right-hemispheric than left-hemispheric N170 amplitudes in the left visual field condition. In the right visual field condition, however, only female participants showed significantly larger left-hemispheric compared to right-hemispheric N170 amplitudes, whereas male participants did not show such a modulation. The effect corresponds to a greater responsivity of left-hemispheric processes underlying the N170 component in female participants. Further analyses revealed N170 differences in the left and right hemisphere for females only, when stimuli were presented unilaterally. In contrast, this modulation of N170 amplitudes was only observed in the left hemisphere in males. The results suggest a stronger hemispheric lateralization in men than in women during face processing.