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.

What our grandmothers told us about playing hard to get is true. The whole point of the game is to impress and capture. It's not about honesty. Many men and women, when they're playing the courtship game, deceive so they can win. Novelty, excitement and danger drive up dopamine in the brain. And both sexes brag.

Romantic love is an obsession. It possesses you. You lose your sense of self. You can’t stop thinking about another human being.

Real competition can drive up testosterone, which boosts libido.

I've always maintained that men were more romantic than women.

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.

Men want to think women don't cheat, and women want men to think they don't cheat, and therefore the sexes have been playing a little psychological game with each other.