Helen Fisher

Until recently, we regarded love as supernatural. We were willing to study the brain chemistry of fear and depression and anger but not love.

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

People compose poetry, novels, sitcoms - for love.

I think romantic love evolved to enable you to focus your mating energy on just one individual at a time, thereby conserving mating time and energy.

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.

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

Any kind of novelty or excitement drives up dopamine in the brain, and dopamine is associated with romantic love.

Psychologists maintain that the dizzying feeling of intense romantic love lasts only about 18 months to - at best - three years.

When you're in the throes of this romantic love, it's overwhelming - you're out of control, you're irrational, you're going to the gym at 6 A.M. every day - Why? Because she's there.

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

Blushing is thought to be linked to increased levels of norepinephrine in the brain, which may be associated with romantic feelings. It signals that we are interested and excited, which is attractive to men.

Anthropologists have found evidence of romantic love in 170 societies. They've never found a society that did not have it.

Romantic love is an addiction.

In general, men are wired to notice obvious signs that convey interest in mating - a warm smile, for example - and ignore other subtleties, like if your lipstick is faded.

You can get into a very fancy car and know everything about the engine, but when you drive in that car, you feel that rush. In the same way, I think the more you know about love, the more you can enjoy it. And knowing about your personality type, who you are and what kind of person you're dealing with gives you a great leg up.

A Rolex watch or an expensive car are the things guys often use to show status, wealth, and basic desirability.

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.

Natural beauty really entices men. They will tell you this time and time again, and studies consistently prove it.