Punishment may explain why most people live together in relative tranquility, according to the behavior of 23 male students who played an “ultimatum game.” Each participant could split a sum of money however he chose with an anonymous partner. In some cases, the recipient had to accept any offer made; other times, after an offer was made, the recipient could penalize the giver by taking some or all of his money. Brain scans of the giver revealed that two areas were particularly active when punishment was an option: the lateral orbitofrontal cortex, a region previously implicated in processing a threat stimulus, and a section near it called the dorsolateral prefrontal cortex, involved in impulse control. Next, the University of Zurich team that conducted the study intends to test patients suffering from antisocial anxiety and personality disorders to determine if their behaviors result from a lack of impulse control or a poor assessment of punishment. Scan the October 4 Neuron for the study.