Logic of Life – Chapter 2: Game Theory isn’t Always about the Games We Play

Fabio

This review is cross posted from the Marginal Revolution blog, which is having a book forum on The Logic of Life by Tim Harford.

Today, I’ll focus on Chapter Two of Tim’s book, “Las Vegas – The Edge of Reason.” In this chapter, Harford describes game theory. In a nutshell, game theory studies any situation where (a) you have multiple people striving to achieve a goal and (b) your actions depend on the actions of the other people in the “game.” By most accounts, game theory is one of the great accomplishments of modern social science. Once you realize that people’s actions are both utility maximizing and interdependent, then game theory can help you model just about any form of cooperation or conflict.

Harford discusses the basics concepts of game theory with vivid examples ranging from poker, to nuclear war, to quitting smoking. And, as expected, game theory usually provides a great deal of insight. Harford shows how game theory can also be enormously useful, even life saving. Harford recounts how economist Thomas Schelling realized that some situations might encourage participants to “jump the gun” and initiate devastating conflict. What Schelling realized is that these dangerous games had low information, such as the US misunderstanding a Soviet action, and starting nuclear war. Schelling advocated increased communication between the US and Soviet leadership, including the creation of the “hotline” between Moscow and the US, which helped defuse tensions in later Cold War disputes.

I’ll finish this post with my one big criticism of game theory, at least the basic version described by Harford and taught in intro courses. In “game theory 101,” you assume that people develop optimal strategies in response to other rational actors. One huge problem with a lot of these models is that the games are very complicated. It’s hard to imagine most people perform the mental acrobatics of game theory actors.

One response is that game theory is empirically well supported, which suggests that some process drives people to the strategies described by game theory. For example, Harford describes how economists and mathematicians used game theory to sort through the insanely complex game of poker and that the optimal game theory strategy was actually fairly similar to what world class poker players do.

So game theory is supported, right? Not so fast. Game theory has two parts (a) a description of optimal strategies, and (b) a prediction that people will actually solve the game and find these strategies. In my view, “game theory 101” is well supported, in poker at least, on point (a), but not (b). In other words, world class poker players rarely sit around and do “backwards induction,” or any other flavor of equilibrium analysis, but they still obtain strong strategies through trial and error.

What I suspect is that world class poker emerged from an evolutionary process. Very smart people can figure out certain strategies, but nobody can figure out the whole game by themselves, lest they become full time mathematicians. The typical world class poker player probably inherits a bunch of rules that were tested by earlier generations, and adds a few new twists. Competition weeds out bad rules. Even Steve Levitt, star economist, Harvard & MIT grad, consulted a more experienced player during his run at the World Series of Poker, rather than solve the game himself.* In the end, game theory is really a first step in understanding complex interactions. The next step is developing an evolutionary theory of games where actors inherit a “tool box” of strategies from previous generations of players. Already, there is a fairly well developed genre of game theory taking this approach, but I welcome the day when it becomes refined enough so that it can account not just the strategies of leading poker players, but how these strategies emerged from generations of competition.

 

*According to the news reports, he developed his own “weird style” rather than completely solve the poker game. But it works for him! What would Johnny von Neumann say?