Sexual Selection More Complicated Than Previously Thought

It’s a relatively common idea that sexual selection works in exactly one way: males develop exaggerated traits (peacock feathers and stag’s antlers) to compete for female attention, because males want to spread their sperm everywhere while females want to only mate with the best. Unfortunately, it turns out that the real situation is more  complicated.

A replication of the initial sexual selection study showed that, if one counted fruit flies that died before hatching and not just fruit flies that lived, the mathematics work out completely differently. More adults mate multiple times than previously predicted, fewer don’t mate at all, and there are more mothers than supposed. In short, there is very little evidence for picky mothers and promiscuous fathers– at least in that species of fruit fly.

Some reporting explained this as “sexual selection has been disproven forever!”, which is of course not true. There are lots of species that do follow the males-compete-for-female-attention model. It’s just not the only possible model and shouldn’t be the default assumption. Animal species’s sexualities are incredibly diverse: even in the great apes family, we have chimpanzees (alpha male/beta male structure), bonobos (let’s have sex with everyone!), orangutans (solitary except when occasionally they meet up for sex), and gorillas (lady gorillas hit on the the gentleman gorillas). A lot depends on the environment, the life cycle of the species, and sheer bloody random chance.

Of course, the natural question here is “what about humans?” Humans are and have always been an intensely cultural species; therefore, I think it’s fallacious to explain most complex behaviors with a simplistic “because evolution.” (Or, for that matter, with a simplistic “because culture.” Most behaviors have both a cultural and a biological component. We might like sweets because that helped us survive in hunter-gatherer times, but Skittles are clearly a cultural artifact.)

I am not sure that the science is in to say any more than the broadest generalities about how humans as a species work. People of all genders try to be attractive to the people that they are attracted to, sometimes doing dangerous or ludicrous things to make this happen. (If they aren’t attracted to anyone, then fortunately they don’t have to worry about that shit.) In some cultures, being attractive is more important for one gender than for another: for instance, if you’re a 19th century middle-class British girl and choosing a good husband is the difference between poverty and wealth, you’re going to be far more concerned about your attractiveness than the average middle-class British guy of the period. (Note that this is the exact opposite of what sexual selection theory would predict.) What counts as attractive is incredibly culturally influenced– otherwise, explain to me how the Victorians had a fetish for girls with TB and why a billion Chinese women had their feet bound– although I’m not ruling out the idea that there are biological aspects.

Basically, you cannot say that “men compete for women and women choose whom they want to date.” That’s not even true for animals, and the evidence is far from in that it’s true for humans, and really those dudes on Reddit need to stop feeling sorry for themselves about how women have all the power in dating. Dating sucks for people of all genders.