Algorithms to Live By: The Computer Science of Human Decisions

by Brian Christian

The prisoner’s dilemma has been the focal point for generations of debate and controversy about the nature of human cooperation, but University College London game theorist Ken Binmore sees at least some of that controversy as misguided. As he argues, it’s “just plain wrong that the Prisoner’s Dilemma captures what matters about human cooperation. On the contrary, it represents a situation in which the dice are as loaded against the emergence of cooperation as they could possibly be.”* Well, if the rules of the game force a bad strategy, maybe we shouldn’t try to change strategies. Maybe we should try to change the game. This brings us to a branch of game theory known as “mechanism design.” While game theory asks what behavior will emerge given a set of rules, mechanism design (sometimes called “reverse game theory”) works in the other direction, asking: what rules will give us the behavior we want to see? And if game theory’s revelations—like the fact that an equilibrium strategy might be rational for each player yet bad for everyone—have proven counterintuitive, the revelations of mechanism design are even more so. Let’s return you and your bank-robbing co-conspirator to the jail cell for another go at the prisoner’s dilemma, with one crucial addition: the Godfather. Now you and your fellow thief are members of a crime syndicate, and the don has made it, shall we say, all too clear that any informants will sleep with the fishes. This alteration of the game’s payoffs has ...