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Survival of the Sexiest

iordani/Adobe

Credit: iordani/Adobe

By Barnaby Dixson & Monica Awasthy

“Survival of the fittest” never applied to beards, so why did they evolve and what role do they play in mate selection in modern society?

Facial hair has seen a resurgence in popularity in recent years. Beards are definitely “in”, and men go to great lengths to groom and maintain them. In fact, the male grooming industry is estimated at US$15 billion globally.

But why do beards exist in the first place, and how do biology and culture interplay to shape their meaning as an animal signal?

The Beard as a Badge of Status

Mention the word “evolution” and most people will instantly think about natural selection and survival of the fittest. When we think about the physical traits that were important for ancestral survival, we imagine men who were physically strong hunters who ran fast and provided for their families. Now add to this image a beard and we have the quintessential caveman.

Yet beards don’t make you a better hunter, they don’t make you stronger and they certainly don’t make you faster. So if beards didn’t evolve to help us survive, what are they for?

Beards are an important signal of maleness. They first emerge at puberty with the expression of male sex hormones such as testosterone. Beards are only fully developed by young adulthood, slowly emerging in a pattern from the upper lip down to the chin, and eventually connecting to the sides of the jaw.

This occurs precisely at a time when men become interested in attracting a partner, but are doing so in competition with other males around them. This is known as sexual selection, an evolutionary process that explains the persistence of traits that enhance dominance to the same sex and attractiveness to the opposite sex without necessarily contributing to survival.

Sexual selection involving male–male competition favours characteristics that enhance social dominance and fighting ability. People tend to rate fully bearded men as being 3–5 years older, more masculine, socially dominant and of higher social status. And when a bearded man displays an angry facial expression, other men rate him as more aggressive than when he’s clean-shaven.

Classic examples from other species include the large horns on stags and sharp canines in many monkeys. But the human beard does not directly enhance fighting ability. It’s not a weapon. Instead it may be used as a badge of status and a signal of status.

In a study of 154 primate species it was found that males with the most elaborate and conspicuous ornamentation tended to live in large social groups with hierarchies (tinyurl.com/

primatebadges). These ornaments are used to stand out and signal identity, rank, dominance and attractiveness to others in the group. Think, for example, of the silver crest on a mountain gorilla or the bright red-and-white facial coloration of male mandrills.

The same holds true for humans. In large groups where we’re surrounded by strangers, we need a quick, reliable way to evaluate someone’s strength and quality. Secondary sexual traits, or those characteristics that give us an advantage in the mating (and dating) game, do just that. And traits such as beards could increase a man’s courting potential by enhancing manliness and helping him stick out from the crowd, in essence acting as his badge of status.

To Beard or not to Beard?

The bigger and more crowded your environment is, the more important it becomes to stick out from the crowd. In a global analysis across 37 countries, beards and other styles of facial hair, such as moustaches and goatees, were more common in larger cities where women expressed a strong preference for them. This suggests that large-scale patterns of facial hair grooming in men are likely to be driven by female choice and the need for men to compete with each other for female attention.

But what happens when everyone else catches onto this idea and starts growing a beard? How does a bearded man stay ahead of the mating game?

Looking different and having rare traits has many advantages. In evolutionary biology, this phenomenon is called negative frequency-dependent selection. In guppies, for example, males with the most distinctive and rare colour patterns avoid predation and get more mates. Eventually these rare colour patterns spread and become so ordinary that female guppies are no longer impressed and predators start to notice.

Could the same hold true for facial hair fashion? In experimental trials, women presented with an excess of beards started to rate them as less attractive (tinyurl.com/frequencybeards). On the flip side, make beards rare and they become intriguing again and more attractive. So as soon as everyone else starts sporting whiskers, the value of your own facial hairstyle could start to diminish.

Are Beards Actually Sexy?

While beards clearly signal age and sexual maturity, female preferences for male facial hair are remarkably mixed. In fact, only a handful of studies have shown that beards increase men’s attractiveness, while others have found that women prefer a clean-shaven partner. Recent research using lower doses of facial hair found that around 10 days of beard growth, or “stubble”, is considered most attractive (tinyurl.com/10daystubble; tinyurl.com/beardsmating). This suggests that having at least some facial hair can make men sexy because it may be signalling the ability to produce the male hormones required to grow a beard.

Although beards might not immediately make men look more handsome, physical attractiveness is just one component of being a good mate. Humans raise highly dependent offspring in the context of long-term pair bonds, and beards are viewed more favourably when considering a man’s suitability as a long-term partner and parent (tinyurl.com/10daystubble; tinyurl.com/beardsmating).

Bearded men themselves tend to endorse stereotypic gender roles in heterosexual relationships (i.e. men are the “bread winners”). The associations between age, masculinity and social dominance become associated with the ability to provide for a family, making beards more attractive for long-term relationships.

How Culture Influences Grooming

While evolutionary theory can explain why beards exist, culture might influence how we treat them and respond to them.

The human face is important in communication. You can learn a lot about someone’s age, gender, personality and emotions simply by looking at their face. Adding a beard can enhance these signals. Yet many men expend considerable effort every day shaving this prominent cue of masculinity off, either partially or entirely.

A man’s decision to groom his beard might occur in response to both prevailing preferences and fashions. There are certain times when beards are attractive and others when they are not, so the social context may drive the direction and strength of people’s preferences.

For example, the frequency and popularity of facial hairstyles of men photographed in the London Illustrated News fluctuated considerably from 1842 to 1972. Sideburns enjoyed a spike in popularity in 1853, moustaches with sideburns in 1877, full beards were fashionable during 1892 and moustaches were preferred from 1917 to 1919. Patterns in popularity for each of these styles rose gradually over time, peaked and then diminished to be replaced by the rise of a newer style.

Men’s responses do not appear to be arbitrary: beards were more popular when men outnumbered women in the available marriage pool. These are exactly the kinds of social conditions that elevate competition for mates. When there is a greater abundance of men, signalling masculinity to other males may enhance attractiveness to women, highlighting how the value of facial hair fluctuates with the mating market.

Maybe beards have seen the best of times and we will see a decline in coming years. Or maybe it’s time for sideburns to make a comeback. Either way, facial hair appears to be one of the few human characteristics that has clearly evolved as a conspicuous signal of maleness, but the value of this signal for outcompeting rivals and attracting a mate is far more complex.

Barnaby Dixson is a postdoctoral research fellow at The University of Queensland’s, School of Psychology. Monica Awasthy is a postdoctoral researcher at Macquarie University’s Department of Biological Sciences.