If you want to understand how the abuses occurred at Abu Ghraib, the best explanation is contained in a story in today’s New York Times. The story recounts a 1971 experiment at Stanford University in which 24 students were randomly assigned to be either prison guards or prisoners. The story notes that “within days, the ‘guards’ had become swaggering and sadistic, to the point of placing bags over the prisoners’ heads, forcing them to strip naked and encouraging them to perform sexual acts.” Although the experiment was scheduled to last for two weeks, it was ended after just a week, because of the ‘guards’ remarkable sadism. Dr. Philip G. Zimbardo, a leader of the experiment, is quoted in the story as saying he was not surprised by what happened at Abu Ghraib. “I have exact, parallel pictures of prisoners with bags over their heads,” he said. “It’s not that we put bad apples in a good barrel. We put good apples in a bad barrel. The barrel corrupts anything it touches.” The only way to prevent such behavior is to have strong discipline from commanders, and this was absent at Abu Ghraib.