Stanford Prisoner Experiment
Philip Zimbardo’s Stanford prisoner experiment took place in the 1970s. The psychiatrist took 24 undergraduates and assigned them roles as either prisoners or guards, in a mock prison on campus. After just a few days, 1/3 of the guards exhibited sadistic tendencies, two prisoners had to be removed early due to emotional trauma, and the whole experiment only lasted six of the planned 14 days. It showed just how easily normal individuals can become abusive, in situations where it is encouraged.
Source: Stanford University & i09