Time Inconsistency in the Mating Game and Other Games

In the comments here the talk turned to the game that goes on between men and women who are potential mates. On the temptation to cheat, one commenter ironically asks,

“At once, she wants to defect, but also to provoke a forced cooperation?”

The answer is Sure, this can make sense. The game theory of such situations, in which a person benefits by limiting their own future behavior, is very well-established.

For example, consider a powerful monarch who can default on his debts without his creditors being able to do anything about it. Since potential creditors know this, no one is willing to lend to him in the first place. (This problem doesn’t always occur, but it does if people have sufficient reason to worry that he’ll default.) If the monarch could be submitted to a more powerful entity that could make him pay his debts back in the future – and if this were commonly known – then people would be willing to lend him money today.

Thus it is true that both

(1) the monarch in some sense wants to defect (default on his debts)
and
(2) the monarch in some sense wants to be forced to cooperate (pay his debts back).

This sort of situation is pervasive and much of human custom and law is devoted to dealing with it. Speaking of male/female mating games, it is the reason that in most societies, marital infidelity is illegal. It is the reason that people are disgusted by those who lie, break promises, welsh on bets, etc. Societies that enforce such norms do better in the long run than those without them. And think of credit markets in general, never mind the above monarch. If the law did not force borrowers to pay back their debts, imagine how difficult it would be to borrow money in the first place. In extreme scenarios, credit markets would disappear entirely.

Put “time inconsistency” commitment into a search engine.

“Time inconsistency” refers to the fact that people’s desires can be inconsistent across time. E.g., at the time that you’re trying to borrow money, you’d like to be forced to pay your future debts back, because knowing that makes lenders willing to lend to you right now. But later, after you’ve gotten your hands on the borrowed money, then (if you’re an amoral asshole) you’d like to be able to default on your debts. Thus we have mechanisms that enforce “commitment,” which in this example means the law commits you to paying back your debts.

In general, people often can benefit by being committed to a course of action in the future, whether it’s marital fidelity or paying your debts back, etc.