A Fake Prison Turned Students Into Monsters

In the summer of 1971, psychology professor Philip Zimbardo converted the basement of Stanford University's Jordan Hall into a mock prison. He recruited 24 male college students, screened them for psychological stability, and randomly assigned them to be either "guards" or "prisoners."

The experiment was designed to last two weeks and study how institutional roles affect behaviour. It barely lasted six days.

Within 36 hours, the guards became sadistic.

They forced prisoners to do push-ups, stripped them naked, put bags over their heads, and woke them at 2 a.m. for arbitrary "counts." They sprayed prisoners with fire extinguishers. They put one prisoner in solitary confinement (a dark closet) and told others to pound on the door and shout at him.

The prisoners became passive and depressed. Some identified so deeply with their role that when offered the chance to leave (by forfeiting their participation payment), they shuffled back to their cells instead.

The experiment was finally stopped on Day 6 — not by Zimbardo, but by Christina Maslach, a graduate student and his girlfriend, who witnessed the conditions and told him he was running an unethical nightmare. She was the only one of 50 outside observers to object.

The Stanford Prison Experiment became one of the most famous studies in psychology — and one of the most criticized. Modern researchers have questioned whether the guards were coached, whether the results were exaggerated, and whether the experiment proves what Zimbardo claimed it proved.