Helen Fisher

“Neither gender is routinely more jealous - although women are more willing to work to win back a lover, while men tend to flaunt their money and status and are more likely to walk out to protect their self-esteem or save face.”

“When somebody leaves Match.com or Chemistry.com, they ask you why you left. One box you can check is, 'I found somebody.' Between 15 and 20 percent of people check that box.”

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

“There's more than one person on the planet. When you're madly in love, that's not what you think.”

“I think the happiness we find, we make.”

“The Great Depression of the 1930s saw more American unmarried women working from nine to five, mostly in repetitive, boring, subordinate, dead-end jobs. But the number of working women doubled between 1870 and 1940. During World War II it doubled once again.”

“Women like signs of money and education - things that indicate that not only is this guy going to have some resources, but he's also willing to share them.”

“When you can't have someone but you're not willing to accept that, you try harder and become more extreme about it. Either you win the person back or you drive him away.”

“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.”

“Kissing is not just kissing. It is a major escalation or de-escalation point in a powerful process of mate choice.”

“A lot of people head into courtship looking for fireworks. Don't pass up a chance by dumping someone after a first date because you don't feel the fireworks. The fireworks can happen at any time and be maintained.”

“You've got to remember that men are men and women are women. And although a lot of similarities, there are some real differences.”

“More and more of us live segmented, compartmentalized lives. This isn't natural. For millions of years, our forebears knew everyone around them and everyone knew them.”

“We're apt to fall in love with those who are mysterious and challenging to us.”

“We're not very dangerous animals; we don't have a horn like a rhino or quills like a porcupine.”

“Women have a better sense of color and a better color memory. They're more likely to notice when something doesn't match; more likely to notice what you're wearing.”

“Along with our many human propensities, we evolved a huge cerebral cortex with which we make decisions.”

“You size up someone physically in less than one second - too tall, too short, too fat, too thin, too old, too young, too stuffy, too scruffy.”

“Good-looking people are always looking for other good-looking people.”

“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.”