Are hairy chests making a comeback?

A good deal of the research into human attractiveness is based upon evolutionary theory, with researchers theorising that beauty signals genetic health or a strong constitution: characteristics that can be passed from parent to offspring. But if this is true, how do we explain cultural differences in what is perceived as attractive? And why do criteria of attractiveness change over time?

For example, a hairy torso was once part of the Western ideal of male beauty, but a 70s style rug of chest hair is currently less fashionable than A-line flares and cravats. If hirsuteness is equated with masculinity, surely a shaved or waxed chest gives the appearance of femininity or immaturity?

Markus Rantala of the University of Turku in Finland has recently carried out a study that might help us to answer these questions.

First he photographed the torsos of 20 young men with visible body hair. The men shaved their chests, and a second photo was taken. These pairs of images were shown to 299 heterosexual women, who were asked to choose which picture they preferred: the hairy or the shaved.

Women also supplied information on their menstrual cycles, because previous research has shown that preferences for masculine male traits are strongest in women who are most fertile. This is thought to be because masculine men have the kind of genes that women most want for their offspring, and they can only make use of those genes at the time of the month when they are most likely to conceive.

Rantala found that younger women tended to prefer the men when they were shaved. He also found that preferences for a shaved torso were stronger when women were in the fertile phase of their cycles. This may seem counterintuitive, because we might expect the hairier, more typically masculine, images to indicate manliness. But it turns out that body hair isn’t really a good cue to masculinity, because other researchers have shown that hairy men don’t tend to be more muscular, nor do they have deeper voices or higher levels of testosterone.

So how do we explain the findings? Rantala suggests that it could have something to do with social class. Finnish men are generally less hairy than recent immigrants into Finland, who tend to come from further south where men are hairier. If body hair predicts low income, the preference for shaved men could be driven by an underlying desire for men with good prospects.

Another possibility is that images of muscular and shaved men, that have become increasingly prominent in the media in recent years, have cued women to associate a hairless torso with dominant personality traits or athleticism, both of which we might expect women to prefer when they’re most likely to conceive. Hairiness, in turn, may signal that a man cares less about his physical appearance, and perhaps that he isn’t the sort to be interested in short-term sexual liaisons.

More research is needed before we can say for sure what’s going on, but in the meantime might I suggest that men hedge their bets by shaving their chests on the left side only. That probably signals a good sense of humour.

Or mild insanity.

Rantala, M. J., Pölkki, M., & Rantala, L. M. (2010). Preference for human male body hair changes across the menstrual cycle and menopause. Behavioral Ecology, 21(2), 419–423. Read summary

The content of this post first appeared in the March 2010 episode of The Psychology of Attractiveness Podcast.

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