Body shape preferences: associations with rater body shape and sociosexuality

Abstract

There is accumulating evidence of condition-dependent mate choice in many species, that is, individual preferences varying in strength according to the condition of the chooser. In humans, for example, people with more attractive faces/bodies, and who are higher in sociosexuality, exhibit stronger preferences for attractive traits in opposite-sex faces/bodies. However, previous studies have tended to use only relatively simple, isolated measures of rater attractiveness. Here we use 3D body scanning technology to examine associations between strength of rater preferences for attractive traits in opposite-sex bodies, and raters' body shape, self-perceived attractiveness, and sociosexuality. For 118 raters and 80 stimuli models, we used a 3D scanner to extract body measurements associated with attractiveness (male waist-chest ratio [WCR], female waist-hip ratio [WHR], and volume-height index [VHI] in both sexes) and also measured rater self-perceived attractiveness and sociosexuality. As expected, WHR and VHI were important predictors of female body attractiveness, while WCR and VHI were important predictors of male body attractiveness. Results indicated that male rater sociosexuality scores were positively associated with strength of preference for attractive (low) VHI and attractive (low) WHR in female bodies. Moreover, male rater self-perceived attractiveness was positively associated with strength of preference for low VHI in female bodies. The only evidence of condition-dependent preferences in females was a positive association between attractive VHI in female raters and preferences for attractive (low) WCR in male bodies. No other significant associations were observed in either sex between aspects of rater body shape and strength of preferences for attractive opposite-sex body traits. These results suggest that among male raters, rater self-perceived attractiveness and sociosexuality are important predictors of preference strength for attractive opposite-sex body shapes, and that rater body traits -with the exception of VHI in female raters- may not be good predictors of these preferences in either sex.

Figure 1. Example of body model stimuli (two frames of 360-degree rotation).

Raters were presented with a video in which a rendered body model was rotated through 360 degrees over approximately 8 seconds. Figure depicts two frames from one of these videos.

Figure 2. Association between target VHI and mean target attractiveness.

Associations between target VHI and mean attractiveness ratings (mean of both STR and LTR attractiveness ratings given by all raters). (a) For male bodies, the best fitting quadratic function (r² = .409; F = 12.82; p<0.0001) modelled the association more closely than the best fitting linear and cubic functions. (b) For female bodies, the best fitting quadratic function (r² = .593; F = 24.10; p<0.0001) was also superior to the best fitting linear and cubic functions. These negative quadratic functions indicated that, as a predictor of mean attractiveness, the optimal VHI (VHI_opt) is 28.42 for males and 24.00 for females (the vertices of the quadratic functions).

Figure 3. Association between target absolute deviation from sex-specific VHI optimum and mean target attractiveness.

For each target, its absolute deviation from the sex-specific VHI optimum was computed (VHI_dev =|VHI−VHI_opt|). These deviation from optimality scores are linearly related to mean attractiveness (average of the STR & LTR attractiveness ratings given by all opposite sex raters) for (a) male targets (r = −735; n = 40; p<0.0001) and for (b) female targets (r = −762; n = 36; p<0.0001) with higher scores being associated with lower attractiveness. The deviation scores have been used in subsequent analyses so that a dimension based on VHI can be considered as a linear predictor along with other variables.

Figure 4. Association between rater specific VHI preference peaks and individual preference slopes for; (a) WHR for male raters and (b) WCR for female raters.

The association between individual raters’ VHI quadratic preference function vertices and (a) for male raters their individual WHR-Mean attractiveness preference function slopes (unstandardized regression coefficients), and (b) for female raters their WCR-Mean attractiveness preference function slopes (unstandardized regression coefficients). For both, as slopes increase towards zero this indicates weaker preferences for low WHR or WCR. Consequently, associations shown here indicate that preference for high VHI is associated with reduced strength of preference for low WHR in male raters, and for low WCR in female raters. All functions are based on mean of STR and LTR attractiveness ratings given by each rater.