In 1971, psychologist Philip Zimbardo recruited 24 male college students and randomly assigned them as either guards or prisoners in a simulated prison in the Stanford psychology building basement.

What Happened

The experiment was scheduled for two weeks. It was terminated after six days. Guards became increasingly cruel and sadistic. Prisoners broke down psychologically. Zimbardo himself became so immersed in his role as prison superintendent that he lost his objective perspective.

Key Findings

• Normal, psychologically healthy people rapidly adopt the behaviors dictated by their assigned role
• Institutions shape behavior more powerfully than individual character
• Power corrupts — and does so quickly and invisibly

Controversy and Legacy

The Stanford Prison Experiment became one of the most famous studies in psychology — and also one of the most criticized. Subsequent researchers raised serious methodological concerns, including that guards were coached to be cruel. Its status as definitive proof of situational power has been significantly revised, but its cultural impact remains enormous.

Reference:

Wikipedia: Stanford Prison Experiment

https://en.wikipedia.org/wiki/Stanford_prison_experiment