Experiences shape the brain, but the brain shapes the way we view experiences, too.

When chimps threaten, they open their mouth and show their teeth. It's a little like waving a knife in front of you. It's very primitive, and therefore bizarre.

We spend our lives trying to get along with people so we can keep our jobs, keep our marriages together, so that we can raise our kids properly.

Romantic love allows you to focus mating energy. Attachment sustains that relationship as long as necessary to raise your baby.

Women are very attracted to a low voice because it's linked to testosterone, which for millions of years was a sign that men had very good spacial skills and would have been very good at hunting and finding their way back home.

The Internet lets women use words, which is their natural tool. Little girls speak in more complex, grammatical sentences than little boys do, and women never lose that superiority in verbal ability.

When you fight, anger drives up testosterone in both men and women.