Most men are not especially violent, but most people who are especially violent are men.
Now, there’s no real doubt that social forces help to shape violence and aggression. Decades of research have shown that people’s behavior—aggression included—is responsive to incentives and training. The question, then, is not whether social forces matter, but whether social forces are the whole story. And the answer, in a nutshell, is “almost certainly not.” Biology matters as well. Here’s how we know.
From the moment they can move around under their own their steam, boys engage in more rough-and-tumble play than girls. The same sex difference is found in other juvenile primates, and appears to be related to testosterone exposure in the womb.
…[However,] after the violence and mayhem of early adulthood, male aggression steadily nosedives through the remainder of the lifespan. The socialization hypothesis offers no particular reason to expect this. But the decline in violence coincides almost perfectly with the decline in testosterone found in men throughout the adult years, and mirrors the decline found in males of other species. Once again, this is much easier to explain in evolutionary than in sociocultural terms.
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