Zimbardo, Philip. The Lucifer Effect

Psychologist Zimbardo revisits his famous Stanford prison experiment (1971), in which he randomly assigned normal students the role of prisoner or guard for an experiment about the psychology of the relation between prisoners and guards that was meant to last two weeks. The experiment had to be terminated early, after six days, because the guards had started to seriously mistreat the prisoners. According to Zimbardo, people turning evil can be explained by looking at the social context and the system in which their actions take place, rather than by personality traits. In The Lucifer Effect Zimbardo connects the Stanford prison experiment and the conclusions drawn from it to the attrocities in Abu Graib prison (Iraq) in the early 2000s, having appeared as expert witness in the trial of one of the guards.

Zimbardo, Philip. The Lucifer Effect: Understanding How Good People Turn Evil. New York: Random House, 2007.