Christie Wilcox in Quanta:
One of the most obvious physical differences between men and women are their average sizes. Men are, on the whole, taller. The standard explanation found in textbooks — sexual selection and male competition — goes all the way back to Charles Darwin: “There can be little doubt that the greater size and strength of man, in comparison with woman, together with his broader shoulders, more developed muscles, rugged outline of body, his greater courage and pugnacity … have been preserved or even augmented during the long ages of man’s savagery, by the success of the strongest and boldest men, both in the general struggle for life and in their contests for wives,” he wrote in The Descent of Man.
Essentially, were it not for men’s fiercely physical infighting for access to mates, all people would presumably be equally sized. Evolutionary psychology extends that argument to say that these biological directives underlie our behaviors; men can’t help but be aggressive and competitive, while women are by nature sneaky, conniving and choosy.
“There’s a lot of importance put on our differences in body size, as if that’s the keystone fundamental sex difference,” said Holly Dunsworth, a biological anthropologist at the University of Rhode Island. “This is what people think is fact, and if you don’t agree, they think you’re denying science.”
But in a recent paper in Evolutionary Anthropology, Dunsworth showed that the science points another way.