Women's worst invention was the plow. With the beginning of plow agriculture, men's roles became extremely powerful. Women lost their ancient jobs as collectors.

I don’t think we’re an animal that was built to be happy; we are an animal that was built to reproduce.

Office romances are few, short, and not usually destructive.

From my studies of genetics and neuroscience I have come to believe that people fall into four broad personality types - each influenced by a different brain chemical: I call them the Explorer, Builder, Director, and Negotiator.

The main characteristics of romantic love are craving: an intense craving to be with a particular person, not just sexually, but emotionally.

At first I assumed hate was the opposite of love. But it isn't. The opposite of love is indifference.

Like most animals, we're wired to associate height with power.