Stanford Prison Experiment (1971)

Philip Zimbardo's Stanford Prison Experiment assigned college students random roles as guards or prisoners, turning a simulated prison into a psychological nightmare within six days as guards exhibited sadistic behavior and prisoners suffered emotional breakdowns. Though hailed as a landmark demonstration of situational authority in 1971, later critiques revealed demand characteristics, explicit coaching of guards, and Zimbardo's dual role as superintendent, casting doubt on the scientific validity of the results. Outperforms the Milgram Obedience Experiment in methodological controversy due to direct institutional manipulation, with a 2019 replication finding only one-third of participants, or 33%, showing genuine guard brutality compared to Zimbardo's reported 70%.