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.

As societies continue to loosen their standards regarding what is appropriate female and male behavior, I think we are going to realize we have not only underestimated women, but also men.

The reason you take antidepressants is to feel calm. And romantic love is not calm -it's elation, it's mood swings, and you're killing all that when you take the drug.

You know, when you've been dumped, the one thing you love to do is just forget about this human being, and then go on with your life - but no, you just love them harder.

Romantic love is one of the most addictive substances on Earth.

A woman of 40 or 50 or 60 can take estrogen replacements, get facelifts, spend her money in bars.

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.