Waist to hip ratio and breast size modulate the processing of female body silhouettes: An EEG study

Abstract

Abstract Waist-to-hip ratio (WHR) and breast size are considered important biological features defining female body attractiveness; but their neurophysiological correlates remain largely unknown. To shed light on this issue, behavioral and electroencephalographic responses were recorded while healthy heterosexual men and women completed an oddball task, which was then followed by an attractiveness judgement task. In both cases participants were presented with female body forms that combined 0.6, 0.7 or 0.8 WHRs with small or large breast sizes. Brain activity dynamics were explored using temporal principal component analysis of the event-related potentials data. Variance in the data was explained mostly by eight temporal factors for the oddball task and six for the attractiveness judgement task. Lower WHRs seemed to gather larger processing resources than higher WHRs at early perceptual-related processes during the oddball task. The less attractive WHRs and breast sizes, in contrast, seemed to boost allocation of resources later in the processing stream, which may be due to a negativity bias enhancing evaluation and decision-making processes. This inference is supported by results from the attractiveness judgement task, although the observer's gender may also play a role. Finally, LORETA analysis of the temporal factors indicate that variations in WHR may modulate activation of frontal regions, such as the anterior cingulate and orbitofrontal cortex, that are related with reward processing and decision-making; while variations in breast size may influence activity in posterior parietal regions involved in human body perception. This paper highlights the biological importance of female body physical features in defining attractiveness, and the neurophysiological correlates that are implicated.