Everyday Economics

Sex, Discipline, and Your Refrigerator

The evolutionary advantages of self-restraint.

It has always seemed to me that the two great mysteries of the universe are: “Why is there something instead of nothing?” and “Why do people put locks on their refrigerator doors?” Long ago, I concluded that both these mysteries must remain forever unfathomable. More recently, two remarkable works of popular science have convinced me that it is too early to despair.

First, the refrigerator locks. Why would any rational creature want to erect an obstacle between itself and a midnight snack? Midnight snacks have costs (usually measured in calories or grams of fat), but they must also have benefits–otherwise, they wouldn’t tempt us. We snack when we believe the benefits exceed the costs. In other words, we snack when snacking is, on net and in our best judgment, a good thing. What could be the point of making a good thing more difficult?

B ut people do lock their refrigerators. They also destroy their cigarettes, invest their savings in accounts that are designed to discourage withdrawals, and adopt comically elaborate schemes to force themselves to exercise. Odysseus resisted the Sirens’ call by lashing himself to the mast. I used to have my secretary lock my computer in a drawer every afternoon so I couldn’t spend my entire day surfing the Net.

Economists have tried to explain such behavior in all sorts of unsatisfying ways. You can say that people like to avoid making choices–but isn’t the purchase of the lock a choice? You can suppose that our minds house multiple “individuals” with conflicting preferences–but it’s unclear how to turn that into a precise theory of exactly how many people we’re sharing our minds with, and how their conflicts get resolved. You can throw up your hands and say that some behavior is rational and some isn’t, and this particular behavior is in the second category–but that’s tantamount to giving up without a fight. Or, most unsatisfying of all, you can simply posit a “taste” for self-control.

T he problem with that one is that once you allow yourself to start positing “tastes” for everything under the sun, you abandon all intellectual discipline–any behavior at all can be “explained” by the assertion that somebody had a taste for it. Economist Deirdre McCloskey warns against hollow triumphs like, “Why did the man drink the motor oil? Because he had a taste for drinking motor oil!” If you can explain everything, you’ve explained nothing.

But in his entirely marvelous book How the Mind Works, cognitive scientist Steven Pinker suggests that we can safely posit a taste for self-control without opening the floodgates that would allow us to posit a taste for drinking motor oil. Here’s why: Unlike a taste for drinking motor oil, a taste for self-control confers a reproductive advantage.

When you snack at midnight, you get most of the benefits, but your spouse (who cares about your health and appearance) shares many of the costs. So a taste for locking the refrigerator in the afternoon–even when you know that, by a purely selfish calculation, you ought to make yourself a giant hot fudge sundae every night–makes you more desirable as a mate. Therefore, we shouldn’t be surprised that natural selection favored people with a taste for refrigerator locks.

What about people who aren’t looking for mates or who are already securely married? They have a taste for self-control because their ancestors (who must have mated successfully or they wouldn’t have become ancestors) had that taste. The bottom line is that it is intellectually honest to explain behavior by positing surprising tastes, provided those tastes are useful in the mating game. Presumably the sociobiologists and evolutionary psychologists have had this idea all along, but economists have been slow to recognize its significance.

Now as to the origin of the universe–or, as I prefer to phrase the question, “Where did all this stuff come from?”–I now believe that everything is made of pure mathematics. I came to this insight from Frank J. Tipler’s book The Physics of Immortality, all of which is wonderfully provocative and some of which is convincing. His point is to take seriously the claims of those artificial intelligence researchers who assert that consciousness can emerge from sufficiently complex software. Pure mathematics is pure software and contains patterns of arbitrary complexity. The universe itself, together with the conscious beings who inhabit it, could be one of those patterns.

Or maybe not. The argument only works if you believe that mathematics is eternal and precedes the universe. One could equally well argue that mathematics arises from counting and measuring and so can’t exist until after there is a universe of things to count and measure. I should also say that while I love the idea that the universe is nothing but a mathematical model of itself, I’ve never met anyone else who found the idea of “software without hardware” even remotely plausible.

But there might be a good economic reason why we’re stymied. Steven Pinker points out that understanding the origin of the universe is not a terribly useful skill. It confers no reproductive advantage, so there’s no reason we should have evolved brains capable of thinking about such a question. Nature is too good an economist to invest in such frivolities. On the other hand, the ability to understand human behavior has clear payoffs for a social animal like Homo sapiens. So it’s not too much to hope that we could work out a detailed and convincing theory of refrigerator locks.