Abstract
Men reportedly have a strong preference for women’s bodies with a waist-to-hip ratio (WHR) of 0.70. Based on the well-established relationship between women’s WHR and fecundity, this preference has been interpreted to reflect sensitivity of the human visual system to perceive a physical signal of fertility and mate potential. However, the bulk of research supporting this claim did not use ecologically valid stimuli nor systematically vary the WHR within the normal range in the population, which is between 0.67-0.80 for adult fertile women. Here, we hypothesized that if the WHR is truly a visual signal used to identify potential fertile partners, men should be able to detect differences in WHR within this normal range in realistic female bodies. Furthermore, given that a woman’s WHR decreases by approximately .01-.015 during the luteal phase of the menstrual cycle, men might also be able to identify such minute changes in WHR. To address these questions, exclusively heterosexual young men and women performed a preference task and a visual discrimination task on images of a woman’s body and pairs of parallel line stimuli. The WHR and ratio between line stimuli systematically varied by .01 from .66-.90. Men and women participants exhibited different patterns of preferences for the body, but not line, stimuli. In contrast to previous findings, men preferred a wider range of WHRs between 0.66-0.82. Women had much sharper preferences that were focused on WHRs between 0.66-0.71. Men and women both had great difficulty discriminating ratios at the fine-grained level in the discrimination task; however, they were more accurate at detecting these differences in WHRs than in ratios between line stimuli. These findings indicate that the visual system may be biased to detect minute variations in ratios within bodies, like it does within faces, which may provide important social information about conspecifics.
Meeting abstract presented at VSS 2015