What were the results of this study? Though he had planned for two weeks, Zimbardo called off the experiment after only six days. The guards began to demoralize and abuse the prisoners. He identified three types of guards: those who acted like tyrants, those who behaved like moderately tough correctional officers, and those who were somewhat friendly and granted favors (though they never opposed the other guards). The prisoners tried unsuccessfully to revolt and experienced (or exaggerated) emotional stress. For their part, the guards, sporting sunglasses and wielding nightclubs, resorted to solitary confinement for some and withholding bathroom privileges for others. Like most laboratory experiments, the SPE does not sufficiently approximate reality. Nonetheless, the researchers demonstrated that guards and prisoners can switch off their individual identities and succumb to a different set of norms that escalate into brutality and sadism. More recently Zimbardo served as an expert consultant in the investigation over the Abu Ghraib prison scandal in which a renegade group of U.S. Army reservists abused and humiliated Iraqi prisoners.
(1) Neil Kressel, Mass Hate: The Global Rise of Genocide and Terror (2002)
(2) James Waller, Becoming Evil: How Ordinary People Commit Genocide ( 2002)
(3) Philip Zimbardo, The Lucifer Effect: Understanding How Good People Turn Evil (2008)