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.

There's all kinds of reasons that you fall in love with one person rather than another: Timing is important. Proximity is important. Mystery is important. You fall in love with somebody who's somewhat mysterious, in part because mystery elevates dopamine in the brain, probably pushes you over that threshold to fall in love.

Experiences shape the brain, but the brain shapes the way we view experiences, too.

For so many generations, a woman's only career path was to marry well and to marry up. Those days have changed.

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

We spend our lives trying to get along with people so we can keep our jobs, keep our marriages together, so that we can raise our kids properly.

Men tend to be hierarchical, but women are driven to make lateral connections so they can cooperate.