Macho Macho Men
The science of why masculine men are sexy.
Source: 'Tony Fischer/Flickr Creative Commons'
Source: 'Brendan Spragg/Flickr Creative Commons'.
Source: Ebner, Riediger, & Lindenberger, 2010
In a recent study published in Psychological Science (link is external), my colleagues and I investigated whether such genetic influences might underlie female preferences for masculine faces. By measuring these influences, we would also be able to compare their magnitude against the impact of the context-dependent factors suggested by the good-genes hypothesis such as ovulatory cycle and pathogen sensitivity. To do this, we used data collected from thousands of identical and non-identical twins. Because identical twins share all of the same genes while non-identical twins only share half, we can use statistical modeling to estimate genetic effects on many different traits.
We found that the combined effect of contextual factors accounted for less than 1 percent of variation in women’s preferences for facial masculinity. On the other hand, genetic effects accounted for nearly 40 percent of the variation. This means that any differences between two women’s preferences for masculine males is more likely to be due to their genes than any of the previously proposed evolutionary contextual factors.
This doesn’t mean that contextual factors are unimportant or that genes determine whom we’re attracted to though. The majority of variation in facial preferences (around 60 percent) was still unexplained in our study, leaving ample room for alternative explanations and other environmental influences.
What we have shown here is the relative importance of genetic variation in influencing romantic preferences, and more generally, highly complex traits. It’s currently unknown whether these preferences actually push us towards partners who carry these traits. Choice of romantic partner is one of the most important decisions we will ever make in our lifetime, and the idea that our genes could influence this process has enormous ramifications. The next challenge will be explaining how this genetic variation fits into the broader story of our evolution, including how it influences actual partner choice.
1. Enlow, D.H., R.E. Moyers, and W.W. Merow, Handbook of facial growth. 1982, Philadelphia: Saunders.
2. Little, A.C., B.C. Jones, and L.M. DeBruine, Facial attractiveness: evolutionary based research. Philosophical Transactions of the Royal Society B-Biological Sciences, 2011. 366(1571): p. 1638-1659.
3. Zahavi, A., Mate selection: A selection for handicap. Journal of Theoretical Biology, 1975. 53(1): p. 205-214.
4. Rhodes, G., et al., Does sexual dimorphism in human faces signal health? Proceedings of the Royal Society of London. Series B: Biological Sciences, 2003. 270(Suppl 1): p. S93-S95.
5. Thornhill, R. and S.W. Gangestad, Facial sexual dimorphism, developmental stability, and susceptibility to disease in men and women. Evolution and Human Behavior, 2006. 27(2): p. 131-144.
6. Boothroyd, L.G., et al., Partner characteristics associated with masculinity, health and maturity in male faces. Personality and Individual Differences, 2007. 43(5): p. 1161-1173.
7. Penton-Voak, I.S. and D.I. Perrett, Female preference for male faces changes cyclically: Further evidence. Evolution and Human Behavior, 2000. 21(1): p. 39-48.
8. Penton-Voak, I.S., et al., Menstrual cycle alters face preference. Nature, 1999. 399(6738): p. 741-742.
9. Burt, D.M., et al., Q-cgi: New techniques to assess variation in perception applied to facial attractiveness. Proceedings of the Royal Society B: Biological Sciences, 2007. 274(1627): p. 2779-2784.
10. Little, A.C., et al., Partnership status and the temporal context of relationships influence human female preferences for sexual dimorphism in male face shape. Proceedings of the Royal Society of London.Series B: Biological Sciences, 2002. 269(1496): p. 1095-1100.
11. Waynforth, D., S. Delwadia, and M. Camm, The influence of women's mating strategies on preference for masculine facial architecture. Evolution and Human Behavior, 2005. 26(5): p. 409-416.
12. DeBruine, L.M., et al., The health of a nation predicts their mate preferences: cross-cultural variation in women's preferences for masculinized male faces. Proceedings of the Royal Society B-Biological Sciences, 2010. 277(1692): p. 2405-2410.
13. Little, A.C., L.M. DeBruine, and B.C. Jones, Exposure to visual cues of pathogen contagion changes preferences for masculinity and symmetry in opposite-sex faces. Proceedings of the Royal Society of London.Series B: Biological Sciences, 2011. 278(1714): p. 2032-2039.
14. DeBruine, L.M., et al., Women's preferences for masculinity in male faces are predicted by pathogen disgust, but not by moral or sexual disgust. Evolution and Human Behavior, 2010. 31(1): p. 69-74.
15. Little, A.C., et al., Human preferences for facial masculinity change with relationship type and environmental harshness. Behavioral Ecology and Sociobiology, 2007. 61(6): p. 967-973.
16. Lee, A.J., et al., Human facial attributes, but not perceived intelligence, are used as cues of health and resource provision potential. Behavioral Ecology, 2013. 24(3): p. 779-787.
17. Gildersleeve, K., M.G. Haselton, and M.R. Fales, Do women's preferences change across the ovulatory cycle? A meta-analytic review. Psychological Bulletin, 2014. 140(5): p. 1205-1259.
18. Wood, W., et al., Meta-analysis of menstrual effects on women's mate preferences. Emotion Review, 2014. 6(3): p. 229-249.
19. Boothroyd, L.G., et al., Facial masculinity is related to perceived age but not perceived health. Evolution and Human Behavior, 2005. 26(5): p. 417-431.
20. Verweij, K.J.H., A.V. Burri, and B.P. Zietsch, Evidence for genetic variation in human mate preferences for sexually dimorphic physical traits. PLoS ONE, 2012. 7(11): p. e49294.
21. Zietsch, B.P., K.J.H. Verweij, and A.V. Burri, Heritability of preferences for multiple cues of mate quality in humans. Evolution, 2012. 66: p. 1762-1772.