Helen Fisher

"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."

"I think that property is very important in this day and age. It defines you; you worked hard to get it. It's meaningful to you, and when you divorce, a lot of people have a lot of battles over their property for good reasons."

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

"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."

"Men have a psychological need to show off their courage and strength. When he sees you talking to another guy, that instinct kicks in and he jumps to protect you and prove he's worthy of your love."

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

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

"Romantic love is an addiction."

"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."

"Throughout evolution, ostracism was death indeed."

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

"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."