Twenty-five years ago, a group of psychologically healthy, normal college students (and several presumably mentally sound experimenters) were temporarily but dramatically transformed in the course of six days spent in a prison-like environment, in research that came to be known as the Stanford Prison Experiment (SPE).
The outcome of that study was shocking and unexpected to us, our professional colleagues, and the general public. Otherwise emotionally strong college students who were randomly assigned to be mock-prisoners suffered acute psychological trauma and breakdowns. Some of the students begged to be released from the intense pains of less than a week of merely simulated imprisonment, whereas others adapted by becoming blindly obedient to the unjust authority of the guards.
The guards, too—who also had been carefully chosen on the basis of their normal–average scores on a variety of personality measures—quickly internalized their randomly assigned role. Many of these seemingly gentle and caring young men, some of whom had described themselves as pacifists or Vietnam War “doves,” soon began mistreating their peers and were indifferent to the obvious suffering that their actions produced. Several of them devised sadistically inventive ways to harass and degrade the prisoners, and none of the less actively cruel mock-guards ever intervened or complained about the abuses they witnessed. Most of the worst prisoner treatment came on the night shifts and other occasions when the guards thought they could avoid the surveillance and interference of the research team.
Our planned two-week experiment had to be aborted after only six days because the experience dramatically and painfully transformed most of the participants in ways we did not anticipate, prepare for, or predict.
The Stanford Prison Experiment
Haney, C., Banks, W., & Zimbardo, P. (1973). Interpersonal dynamics in a simulated prison. International Journal of Criminology and Penology, 1, 69–97.