Stanford prison experiment

The Stanford prison experiment was a psychological study led by Philip Zimbardo at Stanford University in the summer of 1971. About two dozen male students were randomly assigned to play prisoners or guards in a mock prison set up in the basement of a university building. It was planned to last two weeks but was stopped after six days, when some guards had become abusive and some prisoners showed signs of distress. Zimbardo concluded that situations can strongly shape behaviour, and the study became famous in textbooks and popular culture. Later critics questioned its scientific value, arguing that the guards were influenced by the experimenters' instructions and that the participants may have been acting out expected roles.

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