Chapter Eight is a tough chapter. It’s not much fun reading about human weakness, and recognizing at least some of those weakness in yourself. Pinker discusses five demons: predation, dominance, revenge, sadism, and ideology. The section on revenge is particularly chilling, more so because Pinker follows his descriptions of studies showing how much humans enjoy revenge with an airtight argument describing how revenge must evolve in a social creature.

The most depressing of the demons, though, has to be ideology. Pinker describes experiment after experiment that shows how easily swayed we humans are by the opinions of others. It’s as if we’re always looking around for validation, trying to make sure that we’re on the right track. Do you approve? Do you approve of me? Am I doing what I ought? It’s not hard to see how this tendency can lead to some of the worst atrocities in history.

Pinker begins the chapter by turning the traditional question about violence on its head. Who are the most violent members of our society? Prepare yourself, you’re not going to like this. It isn’t 20-something men. It isn’t teenagers. It is two-year-olds.

Pinker quotes Richard Tremblay: “Babies do not kill each other, because we do not give them access to knives or guns. The question . . . we’ve been trying to answer for the past 30 years is how do children learn to aggress. [But] that’s the wrong question. The right question is how do they learn not to aggress.”

We are all wired for violence. Our task is to overcome it.

Fortunately, after this depressing chapter Pinker moves into chapter nine, describing how we can.