Romantic love is one of the most addictive substances on Earth.

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.

Any kind of novelty or excitement drives up dopamine in the brain, and dopamine is associated with romantic love.

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.

In courtship, who wins and who loses will determine who passes on their DNA to tomorrow.

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.

Real competition can drive up testosterone, which boosts libido.