Dan Gilbert, a social psychologist at Harvard, had an interesting op-ed piece in the New York Times yesterday. Using the childhood example of punching his brother in the backseat, Gilbert hypothesized about two basic principles of retaliatory behavior. First, in a typical hit-for-tat, the number of hits should be an even number (e.g., you hit me three times, so I hit you three times). Second, as Gilbert puts it, "an even-numbered punch may be no more forceful than the odd-numbered punch that preceded it." However, people often ignore this second principle. He illustrates this point by reporting the results of a study by Shergill et al. (2003) in Science. Titled "Two Eyes for an Eye: The Neuroscience of Force Escalation," in this study twelve participants took turns applying pressure to a partner's finger. They were instructed to apply the same pressure that their partner gave them, but an analysis of the force pressure they produced showed otherwise. Soon the pair would escalate the pressure each member would give the other, apparently believing that they were exerting less force than they actually were (as an aside, I wonder what makes this a "neuroscience" study--I guess it's just a sexy word that Science can't resist). Gilbert applies this finding to explain why Israel (and I guess, Hezbollah) has responded "disproportionately" with its heavy bombing. Of course, real world situations are far more complicated that the controlled conditions of a laboratory, but I appreciate Gilbert's attempt to show the relevance of social psychological thinking to current events.