There are cognitive processes and limbic reactions associated with basic emotions. And you can change brain chemistry, but you're still not going to change memories and experiences in a human being.

It's almost as if men who get tribal tattoos are trying to signal that they are dangerous, they're to be respected, and they're powerful.

Games are the way we keep romance alive. They're based in human hardwiring. Playing hard-to-get or leaving a little to the imagination allows the woman to be wooed and appreciated and the man to be challenged and intrigued.

Saliva has testosterone and estrogen. When you kiss, you're having a chemical experience.

It certainly would have been adaptive for ancestral man to have a chubby wife during stressful times of famine. Not only would she have had more calories to burn, and thus more energy and endurance, but since fat stores estrogen, she would have remained fertile for longer.

There's all kinds of reasons that you fall in love with one person rather than another: Timing is important. Proximity is important. Mystery is important. You fall in love with somebody who's somewhat mysterious, in part because mystery elevates dopamine in the brain, probably pushes you over that threshold to fall in love.

Young women today do not marry the men they met in high school, or even the one they go out with at college, because they do not need to.