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Nov112013

Curves Ahead: The Science of Female Waist-to-Hip Ratio and Attractiveness  

Semi-renowned armchair relationship expert Sir Mix-a-Lot once said, “So Cosmo says you're fat, well I ain't down with that! 'Cause your waist is small and your curves are kickin' …To the beanpole dames in the magazines: You ain't it, Miss Thing!” What Mr. Mix-a-Lot so melodically points out is that women’s attractiveness does not rely on thinness, but rather the kickin’ nature of her curves. In fact, for women there’s a universal formula -- the waist-to-hip ratio -- that contributes to how attractive males find females’ bodies.1

We’ll avoid asking you to do any unnecessary math, but let’s play with some numbers. Assume that a woman like Scarlett Johansson has “34–23–35” proportions. First, if you can manage to do it, ignore her bust size (i.e., the first measurement). The next two numbers refer to her waist size and hip size, respectively. The optimal waist-to-hip ratio appears to be about .70, or when the waist’s width is about 70% of the hips’ width (think of your typical hourglass figure). I’ll pause for a moment while you take some quick measurements of the picture of Modern Family's Sophia Vergara that accompanies this article (or you can trust us; the science elves at SofR have done the measurements). Interested in calculating your own waist-to-hip ratio? Click here. 

Women with a waist-to-hip ratio near .70 have a curvy figure. As ratios climb higher toward .80 and .90 curves become less apparent. For example, men generally have waist-to-hip ratios close to .90. The interesting part about the waist-to-hip ratio is that it works for different-sized bodies. Someone like Beyoncé is heavier than Mila Kunis, Adriana Lima, Jessica Alba, or Megan Fox, but they all conform to the magical .70. You will also find this same ratio cross-culturally; although the average overall female body size may vary considerably, men find the same ratio attractive around the world. Researchers have actually studied this phenomenon by analyzing the waist-to-hip ratio of Playboy centerfolds and Miss America winners (gotta love science!).2 Their results strongly demonstrated the consistency in preference for this ratio dating back to the 1920s. Whereas they found that overall body size of these beauties decreased over time, the waist-to-hip ratio remained remarkably consistent. In other words, although the centerfolds ranged from Marilyn Monroe (who would be relatively heavy-set by Playboy’s current standards) to Twiggy (the Kate Moss or Keira Knightley of the 1970s, minus the drug scandals), they all had similar waist-to-hip proportions.  

A more recent study wanted to see how important waist-to-hip ratio was to men by tracking guys’ eye movements. Essentially, the researchers wanted to know where men look when checking out a woman.3 To do this, researchers showed men naked images of women in upright poses from the front or back. Importantly, the women represented a range of waist-to-hip ratios. Regardless of pose, the results indicated that men rated women with a .7 waist-to-hip ratio as most attractive. Results also indicated that men paid most attention to women’s midriff and buttocks when the image depicted the woman from the back. When depicted from the front, men focused more on the breasts and then shifted attention to the midriff. Thus, the eye-gaze results demonstrate the important of waist-to-hip ratio, especially when viewing a woman from behind.

It’s clear that men prefer a certain ratio, with some other research suggesting some reasons why. In particular, waist-to-hip ratio relates to sexual behavior: females with more desirable ratios have a greater number of sexual partners, have intercourse at an earlier age, and are more likely to have sex outside of their primary relationship (translation: they cheat).4 So why is a .70 ratio so appealing in women? As evolutionary psychologists explain, the .70 waist-to-hip ratio suggests that a woman is more fertile and better suited for bearing children5 (or what your grandmother might have called “good child bearing hips”). 

An important take home message from this research is that women’s attractiveness isn’t as much about body weight, as it is about how they carry their weight. Thus, women should not try to become more attractive through starvation or excessive exercise. Or as Sir Mix-a-Lot says, “You can do side bends or sit-ups, but please don't lose that .7 waist-to-hip ratio.”

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1Singh, D., Dixson, B. J., Jessop, T. S., Morgan, B. B., & Dixson, A. F. (2010). Cross-cultural consensus for waist–hip ratio and women's attractiveness. Evolution and Human Behavior, 31 (3), 176–81. doi:10.1016/j.evolhumbehav.2009.09.001

2Singh, D. (1993). Adaptive significance of female physical attractiveness: Role of waist-to-hip ratio. Journal of Personality and Social Psychology, 65(2), 293–307. doi:10.1037/0022-3514.65.2.293

3Dixson, B. J., Grimshaw, G. M., Linklater, W. L., & Dixson, A. F. (2010). Watching the hourglass: Eye tracking reveals men’s appreciation of the female form. Human Nature, 21(4), 355-370. doi:10.1007/s12110-010-9100-6

4Hughes, S. M., & Gallup, G. R. Gallup (2003).  Sex differences in morphological predictors of sexual behavior: Shoulder to hip and waist to hip ratios. Evolution and Human Behavior, 24 (3), 173–78. doi:10.1016/S1090-5138(02)00149-6

5Singh, D., & Singh, D. (2011). Shape and significance of feminine beauty: An evolutionary perspective. Sex Roles, 64(9-10), 723-731. doi:10.1007/s11199-011-9938-z

Dr. Gary Lewandowski - Science of Relationships articles | Website
Dr. Lewandowski's research explores the role of the self in romantic relationships with a specific focus on self-expansion. He has authored dozens of publications for both academic and non-academic audiences and is a member of the Editorial Board for the Journal of Social and Personal Relationships.

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