“The 24 volunteers were then randomly assigned to either the prisoner group or the guard group. Prisoners were to remain in the mock prison 24-hours a day for the duration of the study. Guards, on the other hand, were assigned to work in three-man teams for eight-hour shifts. After each shift, guards were allowed to return to their homes until their next shift. Researchers were able to observe the behavior of the prisoners and guards using hidden cameras and microphones….
While the prisoners and guards were allowed to interact in any way they wanted, the interactions were generally hostile or even dehumanizing. The guards began to behave in ways that were aggressive and abusive toward the prisoners, while the prisoners became passive and depressed. Five of the prisoners began to experience such severe negative emotions, including crying and acute anxiety, that they had to be released from the study early.
Even the researchers themselves began to lose sight of the reality of the situation. Zimbardo, who acted as the prison warden, overlooked the abusive behavior of the prison guards until graduate student Christina Maslach voiced objections to the conditions in the simulated prison and the morality of continuing the experiment….
According to Zimbardo and his colleagues, the Stanford Prison Experiment demonstrates the powerful role that the situation can play in human behavior. Because the guards were placed in a position of power, they began to behave in ways they would not normally act in their everyday lives or in other situations. The prisoners, placed in a situation where they had no real control, became passive and depressed….”