Sublime

living in a group is solved by having a large enough brain to manage the stresses involved.

Suppose we took you and forty-nine of your coworkers and pitted you in a game of Survivor against a troop of fifty capuchin monkeys from Costa Rica. We would parachute both primate teams into the remote tropical forests of central Africa. After two years, we would return and count the survivors on each team. The team with the most survivors wins. O

female mammals, and primates in particular, being able to work effectively in a social environment is much more important for their reproductive success than anything

But, as the neuroscientist Jean Decety at the University of Chicago has shown, desensitization to our own or to other people’s pain tends to lead to an overall blunting of emotional sensitivity.

A different level of brain activity is involved for each response: the mammalian fight-or-flight system, which is protective and keeps us from shutting down, and the reptilian brain, which produces the collapse response.

BESIDES BEING BORN with plenty of oxytocin receptors, how can one attain a high degree of empathy? One answer, I believe, is to be depressed.

In species in which males stick by their mates or protect their own offspring, it’s because male brains were slightly modified to be more responsive to oxytocin.

The second candidate for sustaining within-group coordination is the mirror neuron system.

The social-engagement system depends on nerves that have their origin in the brain stem regulatory centers, primarily the vagus—also known as the tenth cranial nerve—together with adjoining nerves that activate the muscles of the face, throat, middle ear, and voice box or larynx.