By exploring the political and moral colorings of discoveries about what makes us tick, we can have a more honest science and a less fearful intellectual milieu.

It is true that raids and battles killed a tiny percentage of the numbers that die in modern warfare. But in tribal violence, the clashes are more frequent, the percentage of men in the population who fight is greater, and the rates of death per battle are higher.

Consciousness surely does not depend on language. Babies, many animals, and patients robbed of speech by brain damage are not insensate robots; they have reactions like ours that indicate that someone's home.

By all measures men are the more violent gender.

Cognitive psychology has shown that the mind best understands facts when they are woven into a conceptual fabric, such as a narrative, mental map, or intuitive theory. Disconnected facts in the mind are like unlinked pages on the Web: They might as well not exist.

If the myth of pure evil is that evil is committed with the intention of causing harm and an absence of moral considerations, then it applies to very few acts of so-called 'pure evil' because most evildoers believe what they are doing is forgivable or justifiable.

We are visual creatures. Visual things stay put, whereas sounds fade.