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.

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.

A hundred years ago, if you had a child out of marriage, you'd be a social disgrace. Today women feel comfortable enough economically and culturally to bring up a child without a recognized commitment from a man.

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

If we remained perpetually infatuated, we couldn't eat, sleep or work.

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

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.