But a study by David Cesarini, a Ph.D. student in MIT's Department of Economics, and by colleagues in Sweden indicates that there is a genetic component to people's perception of what is fair and what is unfair.Some days I wonder if there is any economic researchers do anything other than test people playing the ultimatum game.
The paper, to be published in the Oct. 1 advanced online issue of the Proceedings of the National Academy of Sciences, looked at the ultimatum game, in which a proposer makes an offer to a responder on how to divide a sum of money. This offer is an ultimatum; if the responder rejects it, both parties receive nothing.
Because rejections in the game entail a zero payoff for both parties, theories of narrow self-interest predict that any positive amount will be accepted by a responder. The intriguing finding in the laboratory is that responders routinely reject free money, presumably in order to punish proposers for offers perceived as unfair.
To study genetic influence in the game, Cesarini and colleagues took the unusual step of recruiting twins from the Swedish Twin Registry, and had them play the game under controlled circumstances. Because identical twins share the same genes but fraternal twins do not, the researchers were able to detect genetic influences by comparing the similarity with which identical and fraternal twins played the game. The researchers' findings suggest that genetic influences account for as much as 40 percent of the variation in how people respond to unfair offers. In other words, identical twins were more likely to play with the same strategy than fraternal twins.
This is interesting, but these days just testing for a genetic influence seems quaint. Lets take a DNA sample from these people, and figure out which genes might be responsible. It has already been shown that testosterone levels influence the ultimatum game, so maybe those genes have something to do with it.