Event-related potentials modulated by the perception of sexual dimorphism: The influence of attractiveness and sex of faces

• Published in: Biological psychology 2018-09, Vol.137, p.1-11
• Main Authors: Carrito, M.L., Bem-Haja, P., Silva, C.F., Perrett, D.I., Santos, I.M.
• Format: Article
• Language: English
• Subjects: Attractiveness; Event-related potentials (ERP); Face perception; Sex differences; Sex discrimination; Sexual dimorphism
• ISSN: 0301-0511; 1873-6246
• DOI: 10.1016/j.biopsycho.2018.06.002

•The perception of sexually dimorphic shape in faces was investigated through ERPs.•Masculinity/femininity features elicited different responses in P2, EPN, and LPP.•Faces of the opposite-sex of participants elicited specific P2 and EPN modulations.•Between sexes’ differences, absent in behavioural responses, were evident in ERPs. Sexual dimorphism has been proposed as one of the facial traits to have evolved through sexual selection and to affect attractiveness perception. Even with numerous studies documenting its effect on attractiveness and mate choice, the neurophysiological correlates of the perception of sexual dimorphism are not yet fully understood. In the present study, event-related potentials (ERPs) were recorded during visualisation of faces that had been previously transformed in shape to appear more masculine or more feminine. The participants’ task consisted of judging the attractiveness of half of the total number of faces, and performing a sex discrimination task on the other half. Both early and late potentials were modulated by the sex of faces, whereas the effect of the sexually dimorphic transform was mainly visible in the P2 (positive deflection around 200 ms after stimulus onset), EPN (early posterior negativity) and LPP (late positive potential) components. There was an effect of sexual dimorphism on P2 and EPN amplitudes when female participants visualised male faces, which may indicate that masculinity is particularly attended to when viewing opposite sex members. Also, ERP results seem to support the idea of sex differences in social categorisation decisions regarding faces, although differences were not evident on behavioural results. In general, these findings contribute to a better understanding of how humans perceive sexually dimorphic characteristics in other individuals’ faces and how they affect attractiveness judgements.