The Stanford Prison Experiment : In 1971 researchers at Stanford University created a simulated prison in the basement of the campus psychology building. They randomly assigned 24 students to be either prison guards or prisoners for two weeks.

Within days the "guards" had become swaggering and sadistic, to the point of placing bags over the prisoners' heads, forcing them to strip naked and encouraging them to perform sexual acts.

The landmark Stanford experiment and studies like it give insight into how ordinary people can, under the right circumstances, do horrible things ...

Conclusions of the failed experiment: The experiment's result has been argued to demonstrate the impressionability and obedience of people when provided with a legitimizing ideology and social and institutional support..

In psychology, the results of the experiment seemed to entail that the situation caused the participants' behavior rather than anything inherent in their individual personalities.

In this way it is compatible with the results of the also-famous (or infamous) Milgram experiment, in which ordinary people fulfilled orders to administer what appeared to be fatal electric shocks to a confederate of the experimenter.