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

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

“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.”

“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.”

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

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

“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.”

“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.”

“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.”