How raising children can change a father’s brain

Consider a man who leaves his menopausal wife and family to start a new family with a younger, fertile woman. Or think of certain high-status, married fathers who spend considerable time and money on girlfriends, mistresses and even prostitutes. Yet, many other men choose to forego these pursuits. They override impulses that evolution has programmed into their brains, impulses that evolved because they enhanced the reproductive success of their ancestors. They do so out of love and respect for their partners and their children, and out of respect for social and cultural norms. But how do they do what males of other species seem incapable of?

The answer, I believe, is that they rely on the crowning achievement of human brain evolution: the prefrontal cortex. Not only is the human brain three times larger than the brain of our closest living primate relatives, the great apes, but the human prefrontal cortex is also larger than expected for our brain size. Our prefrontal cortex is what allows us to override ancient, evolved impulses in the service of honouring commitments, abiding by social norms, and exercising our moral responsibilities. We are privileged to have this remarkable organ, and we fathers would all do well to make use of it.