In a farming society, which came after hunting and gathering, you really needed to marry the farmer next door so you could expand the land. You needed to marry for economic reasons or social reasons or even political reasons, and that seems to be just absolutely disappearing. We're now shedding 10,000 years of the agrarian tradition.
Is this a positive change?
I think it's a very positive change, and I think it comes directly from women piling into the job market and having more economic resources of their own. They don't have to marry somebody who has money; they don't have to marry someone of the same religious group so they're protected by their religion; they don't even have to marry somebody of a particular age.
Women now are looking for really personal things. It's a motion forward to the past, towards the kinds of relationships we had for millions of years, on which the brain was built, on which love is built on, on which more durable relationships are built.
Now, that can be more unstable. But demographers in America are now saying that we're seeing more happy marriages in the United States, because bad marriages can end. There are times when divorce is necessary.
What about kids? Is it better for them for their parents to stay in a bad marriage or is it better for the kids of the parents divorce?
There's very good data on this by a sociologist named Andrea Cherlin. What he says is that there was a great deal of data that looked at the effect of divorce on children, but they hadn't compared children of divorce to children who were stuck in marriages in which the parents were extremely unhappy. Cherlin found that those stuck in an unhappy marriage suffered just as badly as those who suffered from a divorce.
Almost 90% of survey respondents said that your attraction to someone changes over time. Can you describe the typical attraction pattern over a long-term relationship?
We've evolved three distinctly different brain systems for mating and reproduction. One is the sex drive, second one is romantic love, and the third one is a deep sense of attachment to this person—these are brain systems, not phases of a relationship. A relationship can start with any of the three and they can operate in any combination.