Monday, October 20, 2008

More ultimatum game ignorance

I wonder what it is about the ultimatum game that makes for journalistic error? More of the same from Emily Yoffe in Slate:

We like to think we go through life as rational beings. Much of economic theory is based on the notion that humans make rational choices (which may mean that economists don't get out much). 

"Rationality" is a model, and admits any form of behavior. It does not say how someone "should" behave.

In 1982, some economists came up with a little game to study negotiating strategies. The results showed that rationality is subservient to more powerful drives—and demonstrated why human beings so easily conclude they are being wronged. The idea of the "ultimatum game" is simple. Player A is given 20 $1 bills and told that, in order to keep any of the money, A must share it with Player B. If B accepts A's offer, they both pocket whatever they've agreed to. If B rejects the offer, they both get nothing. Economists naturally expected the players to do the rational thing: A would offer the lowest possible amount—$1; and B, knowing $1 was more than zero, would accept. Ha!

This is the Nash Equilibrium of the game, if both players cared only about money. It has nothing to do with "rationality". 

In the years the game has been played, it's been found that almost half the A's immediately offer to split the money—an offer B's accept. When A offers $9 or even $8, B usually says yes. But when A's offer drops to $7, about half the B's walk away. The lower A's offer, the more likely the B's are to turn their backs on a few free dollars in favor of a more satisfying outcome: punishing the person who offended their sense of fairness. This impulse is not illogical; it is essential. 

Only the hypothetical economists in the article found it illogical, and they're not real. Once more: rejection of a lowball offer in the ultimatum game is rational under the entirely realistic assumption that people care about more than money. Please stop attacking the straw economist who disagrees with that statement.  

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Andrew said...
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Andrew said...
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