A comical article asks, “Are beards about to die out?” in reference to a recent study examining the frequency-dependent selection of bearded men. According to the article, beards have become very popular lately, but their current popularity will soon make them less attractive.
Though beardedness is a physical trait, it is determined by behavior—shaving or not shaving—rather than solely through genes (frequency-dependent selection is usually studied in organisms like guppies and butterflies with polymorphic color variations). Yet, the same fitness concepts may apply to a behavior if it influences the attraction of potential mates.
This study is unique, because it didn’t simply investigate whether or not people found beards attractive; it measured the attractiveness of beards in multiple frequency contexts. In the experiment, 36 men agreed to grow beards and photographs were taken of them at four intervals of the growth period under identical lighting conditions. The photographs were presented to 1453 women (heterosexual or bisexual) and 213 men (heterosexual). The researchers organized the photographs into multiple contexts ranging from mostly bearded to mostly clean-shaven.
The study found that the attractiveness of beards does fit the model of negative frequency-dependent selection: in the mostly clean-shaven groups, beards were rated about 20% more attractive, but when beards were more common, clean-shaven faces were rated with a similar spike.
This research gives an evolutionary explanation for the cycles of popularity for physical features and clothing. It’s not suggesting that beards will disappear forever due to over-popularity, but it does show that traits are likely to be less attractive when they become too common in a population. This article gave me a new perspective for what it means to be “hipster.”
This is hilarious to me. It actually makes me jump back to that article we discussed in class about sexual selection and MHC alleles: how though it may not be in any way representative of genotype, the female may look to phenotype on a subconscious level as an indication of a male with higher reproductive fitness. One of the claims of the study was that a female may look for dissimilarity and differences in general: so a male that stands apart from her and the crowd will attract her. In this case, beards (of course) are relevant (clearly). Its a stretch, but it seems that the trends you noted may be displaying the same thing: as beards become a common trait, the female will desire the phenotype that is most different/variable at the time, and vice versa. Of course, this is grasping at strings, because this phenotype is easily manipulated, exists in a spectrum, and honestly, there’s just so many different styles, its really tough to apply this train of thought without a flaw – but I still think its worth considering =). Great post.