In the ultimatum game two players are offered a set amount of money. If they agree on how to divvy it up, they will keep that money for themselves. If they don't, neither will get anything. The game pits selfish impulses against social norms of fairness. Researchers at the University of Zurich recently found that damping activity in the prefrontal cortex region of the brain can set free our selfish side using transcranial magnetic stimulation (TMS), which alters the firing of neurons in the area where it is applied. Almost 45 percent of men who experienced TMS on the right side of their prefrontal cortex accepted the most unfair offers in the ultimatum game. In comparison, about 15 percent of those whose left side had been stimulated and around 9 percent of the control subjects that did not receive TMS accepted inequitable offers. Science published the findings online on October 5.
This article was originally published with the title "Brain Zaps for Generosity" in Scientific American 295, 6, 38 (December 2006)