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A peek behind the science curtain

Bethany Brookshire

That beard is only hot because it’s not cool

A new study suggests that rarity increases the attractiveness of facial hair

James Harden

James Harden of the Houston Rockets might earn some of his attractiveness from his beard as well as his ball-handling skills.

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Every hipster knows that something is only cool before it becomes popular. There’s no point in liking a band once it hits the big time. That shirt is no good once it’s no longer ironic. And it’s certainly not enough to go clean shaven or grow a short beard — that’s much too mainstream. Recent years have seen a resurgence of moustaches, mutton chops and Fu Manchus. A style that really stands out sticks it to conformity.

It turns out that when people buck the facial hair trend, they may end up making themselves more attractive. A new study published April 16 in Biology Letters shows that either clean-shaven or fully bearded looks become more attractive when they are rare in the population. The study suggests that humans may practice what’s called negative frequency-dependent selection — people rate rare looks as more attractive than they might otherwise. But when we try to figure out why, the interpretations can get pretty hairy.

In every population, there is variation, both in genetics and in how individuals look. But at first blush, this variation doesn’t make a lot of sense. If one particular look is the most attractive and best for the population, sexual selection should make a species converge on a single, popular look. For example, if the best male guppies have stripes, soon all male guppies will have stripes, as females will only mate with stripey males.

But in nature, this is clearly not the case. Guppies come in a wild variety of patterns, and so do humans. In guppies, this variation is a result of negative frequency-dependent selection: Female guppies prefer male guppies that look unusual compared to others, rather than guppies that share common features. This helps keep looks and genes variable, a distinct advantage for the species. So an individual guppy’s attractiveness doesn’t just depend on his shining character, it depends on how rare his looks are in relation to other guppies.

Zinnia Janif and colleagues at the University of New South Wales wanted to see if humans displayed similar negative frequency-dependent selection that explains the wild variation in human appearance.

To investigate, the scientists focused on facial hair in men. Facial hair is an interesting trait to look at because it is so variable. Not only do men differ in whether they can grow a full beard, they also differ a great deal in whether they choose to do so. Janif hypothesized that men might trim their scruff to be distinctive — and take advantage of negative frequency-dependent selection.

With a fortuitous link from a popular science-themed Facebook site, the researchers easily recruited over 1,400 heterosexual women and 200 heterosexual men for their study. Participants viewed 24 average male faces with varying degrees of growth: Clean-shaven, light stubble, heavy stubble and full beard. In some conditions, the four beard lengths were evenly distributed among the photos. In some, either the clean-shaven condition or the fully bearded condition was rare. The participants rated the attractiveness of the faces.

The scientists found that neither the clean-shaven nor the fully bearded faces were very attractive when the facial hair types were evenly distributed. But when the clean-shaven faces or the bearded faces were the rare beards in the bunch, the participants, both men and women, rated them as significantly more attractive.

But don’t let this fool you. The heavy-beard and no-beard conditions were rated the least attractive under control circumstances. And making the clean-shaven or bearded look rare didn’t exactly make them the facial hair styles of the year. It only made clean chins or furry ones more attractive than they had previously been. When it comes to general attractiveness, says Rob Brooks, an evolutionary ecologist at the University of New South Wales and an author on the study, “guys should do heavy stubble if they possibly can.”

The results suggest that humans do indeed use negative frequency-dependent selection when judging the attractiveness of facial hair, with a rarer look becoming slightly more attractive merely because it is rare. Michael Jennions, an evolutionary ecologist at the Australian National University in Canberra, says that while the study probably doesn’t have major evolutionary implications, “it’s a great example of how to test a question using a rigorous scientific approach.” But understanding why humans might behave this way isn’t so clean-shaven.

After all, most studies seem to show that familiar features are the most attractive. Anthony Little, a psychologist at the University of Stirling in Scotland, says that usually “exposure to a greater number of faces with more hair would increase preferences for face hair and decrease preferences for clean-shaven faces.” But in this study, a preponderance of hair produced the opposite effect.

Brooks says that it might be a matter of recognizing other people. “One of the things that’s really important in societies is being able to recognize people,” he says. “So I think we base our judgments on variation in facial characteristics. There may be programs in our behavior that favor unusual and distinctive looks.”

A preference for rare facial hair may also just be a matter of novelty, Brooks suggests. One of the most important factors in whether people show this negative frequency-dependent response is what’s going on around you. “If you live on a base in Antarctica with heavily bearded men, the first clean shaven guy you see will probably be very attractive,” he says. Beards can be a competitive point for men, so when clean-shaven men are rare, Brooks hypothesizes that “novelty itself is not particularly interesting. Instead, common things become less interesting.”

Jennions agrees that it could be novelty, up to a point. “Humans tend to place value on the uncommon,” he explains, “but some things will never be attractive no matter how rare.” Little suggests that the study results might show that rarity is attractive not because it’s novel, but because it’s less mainstream. “It may be less a preference for novelty but more a preference for innovation or nonconformity,” he says.

In addition, all of the beards rated in the study were dark, so there’s no data on whether a blond or a red beard might really stand out from the crowd. And of course, the goatee, the soul patch and mutton chops went entirely unstudied.

Anne Houde, an evolutionary biologist at Lake Forest College in Lake Forest, Ill., says that the real importance of the studies lies not in the facial fuzz, but in future studies that might show whether humans display negative frequency-dependent selection of other traits. “The authors cite eye and hair color as other possible traits that do have a stronger genetic basis [than facial hair],” she says, “and whose diversity could be maintained by a generalized preference for less common or novel traits. And such a preference might favor the tendency of people to maximize their individuality through behavioral choices of hairstyle, clothing, etc.”

But why should humans experience this change in preference? After all, while the ability to grow facial hair has associations with high levels of androgens, hormones that stimulate the growth of male characteristics, facial hair itself has limitless styling possibilities. “The main thing for us,” Brooks says, “is that we hypothesize that beards aren’t attractive at all but a matter of competition, but that men would be competitive through beards.” The group’s next study, already in progress, aims to find out more about the relationship between facial hair and masculinity.

And when it comes to your own facial hair, remember, if you can’t stick with heavy stubble, you can always settle for a style that’s rare. It may not make you the hottest guy around, but at least you’ll stick out by the hair on your chinny chin chin.

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