It is hard to imagine that such sexual humiliation could happen in only five days, when the young men all know that this is a simulated prison experiment. Moreover, initially they all recognized that the “others” were also college students like themselves. Given that they were all randomly assigned to play these contrasting roles, there were no inherent differences between the two categories. They all began the experience as seemingly good people. Those who were guards knew that but for the random flip of a coin they could have been wearing the prisoner smocks and been controlled by those they were now abusing. They also knew that the prisoners had done nothing criminally wrong to deserve their lowly status. Yet, some guards have transformed into perpetrators of evil, and other guards have become passive contributors to the evil through their inaction. Still other normal, healthy young men as prisoners have broken down under the situational pressures, while the remaining surviving prisoners have become zombie-like followers.
The power of this situation ran swiftly and deeply through most of those on this exploratory ship of human nature. Only a few were able to resist the situational temptations to yield to power and dominance while maintaining some semblance of morality and decency. Obviously, I was not among that noble class.
——Philip Zimbardo, The Lucifer Effect: Understanding How Good People Turn Evil, New York: Random House, 2007, pp. 172-173.