The Naked Truth: The Face and Body Sensitive N170 Response Is Enhanced for Nude Bodies

Recent event-related potential studies have shown that the occipitotemporal N170 component - best known for its sensitivity to faces - is also sensitive to perception of human bodies. Considering that in the timescale of evolution clothing is a relatively new invention that hides the bodily features relevant for sexual selection and arousal, we investigated whether the early N170 brain response would be enhanced to nude over clothed bodies. In two experiments, we measured N170 responses to nude bodies, bodies wearing swimsuits, clothed bodies, faces, and control stimuli (cars). We found that the N170 amplitude was larger to opposite and same-sex nude vs. clothed bodies. Moreover, the N170 amplitude increased linearly as the amount of clothing decreased from full clothing via swimsuits to nude bodies. Strikingly, the N170 response to nude bodies was even greater than that to faces, and the N170 amplitude to bodies was independent of whether the face of the bodies was visible or not. All human stimuli evoked greater N170 responses than did the control stimulus. Autonomic measurements and self-evaluations showed that nude bodies were affectively more arousing compared to the other stimulus categories. We conclude that the early visual processing of human bodies is sensitive to the visibility of the sex-related features of human bodies and that the visual processing of other people's nude bodies is enhanced in the brain. This enhancement is likely to reflect affective arousal elicited by nude bodies. Such facilitated visual processing of other people's nude bodies is possibly beneficial in identifying potential mating partners and competitors, and for triggering sexual behavior

Do action goals mediate social inhibition of return?

Social inhibition of return is the phenomenon whereby an individual is slower to reach to locations to which another individual has recently responded. Although this suggests that an observer represents another person's action, little is known about which aspects of the action are encoded. The present work describes a series of three experiments examining whether social inhibition of return represents the endpoint goal of the action, i. e., is 'goal based'. Pairs of participants sat opposite to one another and alternated responses to a cued or non-cued object presented on a table top. Importantly, either the two participants performed the same interaction with the object or a different interaction. Although all our experiments showed social inhibition of return, the size of the effect was not modulated according to whether each participant had the same or different goal. We conclude that although the mechanisms giving rise to social inhibition of return do encode some aspects of a response they do not code for terminal action goals. © 2011 Springer-Verlag