The reason I'm not a neurobiologist but a cognitive psychologist is that I think looking at brain tissue is often the wrong level of analysis. You have to look at a higher level of organization.

A decent government with an effective, but not gratuitously violent, police force and a fair court system are essential. This deters and incapacitates psychopaths, bullies and hotheads - and if it earns the confidence of the people, they don't have to become violent in self-defence.

The strongest argument against totalitarianism may be a recognition of a universal human nature; that all humans have innate desires for life, liberty and the pursuit of happiness. The doctrine of the blank slate... is a totalitarian's dream.

Trivers, pursuing his theory of the emotions to its logical conclusion, notes that in a world of walking lie detectors the best strategy is to believe your own lies. You can’t leak your hidden intentions if you don’t think they are your intentions. According to his theory of self-deception, the conscious mind sometimes hides the truth from itself the better to hide it from others. But the truth is useful, so it should be registered somewhere in the mind, walled off from the parts that interact with other people.

A successful learner, . . . must be constrained to draw some conclusions from the input and not others.

As women are empowered, violence can come down, for a number of reasons. By all measures, men are the more violent gender.

Human nature is complex. Even if we do have inclinations toward violence, we also have inclination to empathy, to cooperation, to self-control.