Hormonal and morphological predictors of women’s body attractiveness

Abstract

Does women’s body attractiveness predict indices of reproductive capacity? Prior research has provided evidence that large breast size and low waist-to-hip ratio (WHR) are positively associated with women’s estrogen and progesterone concentrations, but no previous studies appear to have directly tested whether ratings of women's body attractiveness are predicted by higher concentrations of ovarian hormones measured across broad regions of the menstrual cycle. Here, we collected daily saliva samples across 1–2 menstrual cycles from a sample of young women; assayed the samples for estradiol, progesterone, and testosterone; obtained anthropometric measurements of the women’s bodies; and also obtained attractiveness ratings of the women’s bodies from photographs of them taken in standardized clothing with faces obscured. Contrary to previous research, mean hormone concentrations were uncorrelated with breast size and WHR. Body mass index (BMI) was a very strong negative predictor of body attractiveness ratings, similar to previous findings. Zero-order associations between women’s mean hormone concentrations and mean attractiveness ratings were not significant; however, after controlling for BMI, attractiveness ratings were independently and positively associated with both estradiol and testosterone concentrations. Discussion focuses on the implications of these findings for whether attractiveness assessment mechanisms are specialized for the detection of cues of differential fecundity in young women’s bodies.

Introduction

Functional approaches to understanding women’s body attractiveness posit the evolution of specialized mechanisms in perceivers that hone in on bodily features that would have predicted reproductively valuable qualities in human ancestral environments, such as health or fecundity (e.g., Gangestad and Scheyd, 2005, Symons, 1995). A low waist-to-hip ratio (WHR), for instance, has been proposed to signal qualities such as health, fecundity, and greater specialized fat stores for healthy fetal brain development (Lassek and Gaulin, 2008, Singh, 1993b, Singh and Singh, 2006, Singh and Singh, 2011), and, as such, men’s preference for this trait in mating partners (e.g., Furnham et al., 1997, Singh, 1993a, Streeter and McBurney, 2003) may provide an example of specialized preference mechanisms honing in on reproductively valuable traits in others. Complicating this issue, however, are findings from some non-Western cultures that suggest preferences for larger body size and associated higher WHRs in women (Marlowe and Wetsman, 2001, Wetsman and Marlowe, 1999, Yu and Shephard, 1998; c.f. Marlowe et al., 2005, Sugiyama, 2004, Swami and Tovee, 2007); some have argued from such findings that preferences for traits such as low WHR are not products of specialized preference mechanisms but are instead attributable to Western media influences (Yu & Shephard, 1998).

One strategy for testing whether attractiveness judgments are generated by specialized preference mechanisms is to assess whether such judgments correlate with biological markers of health or fecundity, since positive correlations would be difficult to explain if attractiveness standards were culturally arbitrary. Women’s concentrations of estradiol and progesterone appear to act as biological markers of fecundity given evidence that these concentrations are positively correlated with conception probabilities (see Baird et al., 1999, Lipson and Ellison, 1996, Stewart et al., 1993, Venners et al., 2006). Jasienska, Ziomkiewicz, Ellison, Lipson, and Thune (2004) demonstrated that low WHR and large breast size predicted higher concentrations of these ovarian hormones across broad regions of the menstrual cycle, suggesting that these body shape characteristics may be valid cues of fecundity, at least within their sample of well-nourished Polish women. These authors did not report associations between hormone concentrations and ratings of the women’s body attractiveness, but such associations would more directly test whether preference mechanisms are attuned to physical cues of fecundity.

A few previous studies have provided evidence regarding the relationship between women’s hormone concentrations and perceptions of their attractiveness. Law Smith et al. (2006) reported that ratings of women’s facial attractiveness were positively correlated with the women’s late follicular estradiol concentrations (see also Puts et al., 2013). Durante and Li (2009) observed a positive association between the mean of two estradiol measurements – one from the late follicular phase and the other from the luteal phase – and ratings of women’s combined facial and body attractiveness. Rilling, Kaufman, Smith, Patel, and Worthman (2009) collected ratings of women’s body attractiveness without face information, but failed to find a significant correlation between such ratings and a single measure of the women’s estradiol that did not control for cycle day. In summary, with respect to hormonal correlates of women’s body attractiveness, one study has reported significant correlations between ovarian hormone concentrations and both WHR and breast size, but no previous study has tested for hormonal correlates of isolated body attractiveness ratings when hormones were sampled frequently across broad regions of the menstrual cycle.

In the present research, we obtained salivary measurements of estradiol, progesterone, and testosterone across 1–2 menstrual cycles from a sample of young women; collected ratings of the women’s body attractiveness from photos of them in standardized clothing (with faces obscured); and also obtained measurements of body mass index (BMI), breast size, and WHR. We hypothesized replication of higher estradiol and progesterone among women with lower WHR and larger breast size (Jasienska et al., 2004), and also predicted that concentrations of these hormones would positively predict body attractiveness ratings. Although not a primary purpose of the study, our data additionally allowed us to test for associations between body dimensions and attractiveness ratings, and here we expected replication of negative correlations (in Western cultures) between body attractiveness and both BMI and WHR (e.g., Rilling et al., 2009, Singh and Singh, 2011, Streeter and McBurney, 2003, Tovee & Cornelissen, 2001).