Saturday, January 22, 2005

Evolutionary game theory: people are strategies in a "game" played by natural selection

Marginal Revolution: Are you a player or a strategy?

This is new to me, but it has face validity. In some ways humans can be thought of as "strategies" in a kind of meta-game that emerges from the fundamental properties of natural selection.
Our colleague, Dan Houser, has just published an important new paper (co-authored with Robert Kurzban) that supports the assumption of evolutionary game theory. (The paper is also featured in the Economist.)  In a public goods game, Kurzban and Houser are able to identify three systematic strategies; cooperate, free ride and reciprocate (cooperate more when others do so).  The first surprising result of their paper is that these strategies can be tied to specific individuals.  Some individuals cooperate, others free ride and others reciprocate and the strategies that these individuals 'choose' are stable.  (This doesn't mean that individuals play strategies robotically regardless of context a better analogy may be to think of strategies like personalities - even a quiet person can yell sometimes.)

Strategy choice is so stable that Kurzban and Houser can create very cooperative groups simply by weeding out the free riders.  What is even more surprising, however, is that when individuals are randomly assigned to groups each strategy type earns about the same payoff.  Even though the strategies are very different, no strategy dominates the others in a randomly assigned group - this is exactly what one would predict if individuals are strategies in an evolutionary game.
Hmm. Reminds me of this.

No comments: