Some sneaky fiddler crab males are then manipulating the focused attention of the females to disguise the fact that they are losers. Where there is such reliance on one cue to determine quality it becomes possible to act dishonestly. Where novelty is valued, it’s much harder to be dishonest, says Dixson.
How is novelty valued in humans? For men, thick brows, facial hair and square jaws are an example of a phenotype that signals for high testosterone levels. In an evolutionary sense, it is an advantage for women, like with the fiddler crabs, to mate with the strongest, most capable men.
The recent popularity of beards among men has been used to coin the term “peak beard“, which suggests facial hair might be on its way out. Is the same anti-conformist bias the driver behind peak beard?
One study from 2014 shows that after seeing lots of bearded faces, women will find clean-shaven men more attractive and vice versa.
“So you get these novelty effects – it’s like: ‘Something different is being shown to me and it’s appealling’,” says Dixson.
“If we consider advantages as cultural, then anti-conformity might be advantageous in areas such as music, literature, fashion, or visual art,” says Denton. “Here, it is not necessary that a rare variant is better in any way; rather, the uniqueness itself may be intrinsically valued.”
This has been observed in the turnover of popular baby names. Where our ancestors might have chosen common names for their universality, modern popular baby names quickly go out of fashion – as if the fact that a name’s popularity makes it unpopular again. When it comes to naming our children, we have an anti-conformist bias.
It might be too soon to say we have reached peak beard, or maybe, like with waist-to-hip ratios, there’s just something attractive about beards that cannot be explained with genetics.
* William Park is a senior journalist for BBC Future and tweets at @williamhpark
This article is part of Laws of Attraction, a series co-produced by BBC Future and BBC Reel that explores the roles our senses play in how much we like each other. The articles and films were written by William Park. The films were animated by Michal Bialozej and produced by Dan John.
If you liked this story, sign up for the weekly bbc.com features newsletter, called “The Essential List”. A handpicked selection of stories from BBC Future, Culture, Worklife, and Travel, delivered to your inbox every Friday.