Researchers at the University of Zurich have shown that revenge is, well, sweet. Their experiment, described in Scientific American, was based on a game where one player was given the opportunity to punish another player for financially screwing him. PET scans revealed that when a player contemplated revenge, his striatum, a "reward center" in the brain, became energized.
This sort of causal relationship may explain why people are willing to discipline a stranger even when there is no immediate gain in it for them. "Emotions play a proactive as well as reactive role," remarks Brian Knutson of Stanford University who penned an accompanying commentary (to a paper about the study in the journal Science). He notes that "passionate" forces may need to be included in economic models because, as this research shows, "people show systematic deviations from rationality."
