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.

When you massage someone, the levels of oxytocin go up in the brain, and oxytocin is one of the chemicals that drives attachment.

Research shows that couples who have a lot of similarities, including intellectual compatibility, end up staying together.

At first I assumed hate was the opposite of love. But it isn't. The opposite of love is indifference.

Mothers really were not built to raise babies not only by themselves, but with only a partner. For millions of years, a woman had much more than just her husband to help rear her young... This whole idea of 'it takes a village to raise a child' is exactly how we're supposed to live.

There is more and more data indicating that there is a biological basis to your political views.

When chimps threaten, they open their mouth and show their teeth. It's a little like waving a knife in front of you. It's very primitive, and therefore bizarre.

When you look at the brain regions associated with picking up data from the body, a huge amount of the brain is devoted to picking up information from the lips and tongue.

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.

The human brain is built to compare; it's Darwinian to consider an alternative when one presents itself.

Saliva has testosterone and estrogen. When you kiss, you're having a chemical experience.

It certainly would have been adaptive for ancestral man to have a chubby wife during stressful times of famine. Not only would she have had more calories to burn, and thus more energy and endurance, but since fat stores estrogen, she would have remained fertile for longer.

Hair that gleams can send a clear sign that you're young and in your prime, whatever your actual age.

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

Both sexes like the exercise and challenge of sports, but for men it's also a basic display behavior for impressing and winning a mate.

Hair that looks like it's been naturally sun-bleached makes you seem youthful, like you spend a lot of time outdoors. And that appeals to most people.

Your sweetheart calls you by another's name. His eyes linger too long on your best friend. He talks with excitement about a girl at work. And the fire catches. Jealousy - that sickening combination of possessiveness, suspicion, rage, and humiliation - can overtake your mind and threaten your very core as you contemplate your rival.

Young women today do not marry the men they met in high school, or even the one they go out with at college, because they do not need to.

Jealousy can even be good for love. One partner may feel secretly flattered when the other is mildly jealous. And catching someone flirting with your beloved can spark the kind of lust and romance that reignites a relationship.

Overdone lipstick is a deterrent to men. It rubs off easily onto their skin and the edges of their shirts, so it discourages them from kissing, touching, and coming closer to you, which is what they really want to do!

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.

There exists no culture in which adultery is unknown, no cultural device or code that extinguishes philandering.

Once you fall for someone, their smell can be a powerful thing. Women will wear their boyfriends' T-shirts, and throughout tales in history men have held on to their lover's handkerchief.

My hypothesis is that conservative Republicans have very clear values, and when you have that, you're simply more relaxed.

For men, being too put-together implies femininity.

People have been looking for love potions since hunter-gatherer societies.

We evolved in a tropical climate where the smells of plants and flowers were all around us. We spent a lot of time in the trees with a lot of sunlight and no clothes.

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.

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.

In that early-love stage, you're in that state of exhilaration. You talk till dawn. You become obsessed with 'What does he think?' 'Does he like me?' 'Does he think I'm fat?'

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

After a man falls madly in love, he no longer cares how old she is.

Men want to think women don't cheat, and women want men to think they don't cheat, and therefore the sexes have been playing a little psychological game with each other.

Women are naturally prone to compete over their mates.

As women in industrial societies join the paid workforce, they gain the economic means to depart unhappy marriages more easily.

Women are better at reading body language everywhere in the world. As a matter of fact, it's associated with the female hormone estrogen. Women are better at figuring out of tone of voice, reading your face and posture and gesture.

A woman will toss her head and a man will say, 'Oh she's trying to pick me up,' when in fact she's not doing that at all. So, women actually have to be a little careful with what they do, because men will pick up things that they didn't mean.

When people tell you to walk a certain way, it's like not thinking of a purple tomato. You can't not do it.

In America, we are demanding everything from our marriage.

Since when is anyone truly honest with anyone?

Office romances are few, short, and not usually destructive.

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.

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.

You can really get poked in the back and not feel it very much, but just a feather around your lips and you really do feel it.

There were real reasons that you were attracted to somebody originally. The brain doesn't pick willy-nilly. Unless you part ways hating each other for some reason, that mechanism could get triggered again. You can literally fall in love again.

Liberals and conservatives are looking for entirely different things. Their attitudes toward romance and how they court are really dramatically different. There's almost no overlap.

I can't conceive of caring more about my president than my own partner.

There's every reason to think SSRIs blunt your ability to fall and stay in love.

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.

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