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.

Romantic love is not an emotion. ... It's a drive. It comes from the motor of the mind, the wanting part of the mind, the craving part of the mind.

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.

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

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.

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

There's biology in everything, even when you're feeling spiritual.