Recently in class we have discussed the ultimatum game and how its results have differed from those that would be expected from purely rational and profit-maximizing individuals. In recent years, the game has been played in numerous different scenarios and has resulted in a number of unique and interesting results. For example, behavior of participants in the game remains relatively constant among Western cultures, but large variations of outcomes have resulted in other societies.

In a recent paper (available online at http://www.pnas.org/cgi/content/full/104/40/15631?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=cesarini&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT ) published in an October issue of the Proceedings of the National Academy of Sciences, a Ph.D student at MIT and three Swedish researchers discussed the role of genetics on the ultimatum game. The researchers compared the results of identical twins (share the same genes) with fraternal twins (do not share the same genes) and found that the identical twins were more likely to play the same strategy. In fact, their research has shown that around 42% of the variation in responder behavior is attributable to genetic effects.

This study, along with others which examine the ultimatum game are important because while neoclassical economics assumes utility-maximizing and profit-maximizing behavior, there seem to be a number of factors, one being genetics, which complicate this belief. Better understanding what drives economic decision-making by recognizing the role of genetics in this process can help better explain the results of network exchange theory studies and can increase the effectiveness of the models designed to predict human behavior.