A new study conducted by researchers at Aalto University and the University of Tampere shows that the human brain processes nude and clothed bodies in different ways; the study reflects the pattern of arousal elicited by the former.
Researchers recorded visual brain responses of participants shown both nude and scantily-clad photographs, of models of both genders. They found that the participants processed images of the nude body in less than 0.2 seconds.
The brain responses were strongest when participants looked at the photograph of nude models, followed by those in swimsuits or partially clothed. The weakest processing times were for fully clothed models.
The belief that the opposite sex attracts each other held somewhat true; male participants' brains responded stronger to photographs of female models. However, the women's responses were unaffected by the gender of the models.
Autonomic measurements and self-evaluations showed that nude bodies were affectively more arousing compared to the other stimulus categories, the authors Jari K. Hietanen and Lauri Nummenmaa said, in a report published in the November issue of the journal PLoS ONE.
Hietanen and Nummenmaa used MRI technology to map the brain and concluded that early visual processing of human bodies is sensitive to the visibility of the sex-related features and that the visual processing of other people's nude bodies is enhanced in the brain. The authors stated that past evidence and studies proved the triggered response of human and primate brains to facial expressions.
The researchers also explained how visual processing of other people's nude bodies is possibly beneficial in identifying potential mating partners and competitors, and for triggering sexual behavior.
Clothing hides bodily features relevant for sexual selection and arousal, the authors wrote.
The study, to some extent explains why nude art and paintings or photographs of scantily clad bodies appeal more than fully clad ones.