Stanford Prison Experiment
Are we always shaped by our circumstances? Our behavior is often determined by the conditions we find ourselves in. Today, let’s talk about one of the most famous and controversial psychological studies: the Stanford Prison Experiment. This experiment was led by American psychologist Philip Zimbardo. Its goal was to study people’s psychological reactions to the loss of freedom, life in confinement (prison conditions), and the assignment of specific roles to participants. In other words, Zimbardo was investigating human behavior under pressure.
Through this experiment, Zimbardo demonstrated that when given power, people tend to dominate those of lower status and may even show aggression or cruelty toward them. However, this was no ordinary experiment. Let’s take a closer look at what happened.
How the Experiment Was Set Up
To recruit participants, Zimbardo and his team placed an ad in the newspaper. More than 70 people responded. All applicants underwent diagnostic interviews and personality tests to rule out anyone with psychological or medical issues, a criminal record, or a history of drug abuse. In the end, 24 men were selected. By flipping a coin, they were randomly divided into two groups: 12 guards and 12 prisoners.
The experiment was supposed to last 14 days but ended after just 6.
The setting was the basement corridors of Stanford University’s psychology department. The corridor served as a yard for walking, eating, and exercising. The “cells” were actually university labs, with the doors replaced by steel-barred ones to mimic real prison cells.
The Start of the Experiment
To make the experiment more realistic, all participants were sent home and told to wait. On a quiet Sunday morning, the guards were simply invited to the “prison.” The prisoners, however, were picked up by a police car, read their rights, and told the charges against them. To prevent them from knowing the prison’s location or trying to escape, they were transported blindfolded. Upon arrival, they underwent a full sanitation process, and the blindfolds were only removed once they were inside their cells. Unlike a real prison, their heads were not shaved. Instead, they wore special caps that completely covered their hair, and each was given a smock and assigned a number. A heavy chain was fastened to their right ankle, which they had to wear at all times, and they wore rubber sandals. These measures were designed to quickly create the same psychological effects as in a real prison, minimizing individuality and enforcing the experiment’s strict rules.
The Guards’ Role
The guards received no special training. Instead, they were given relative freedom to do whatever they thought necessary to maintain order and ensure the prisoners’ respect. However, they were strictly forbidden from using physical force. The guards all wore identical khaki uniforms, whistles, police batons, and dark sunglasses to hide their eyes from the prisoners.
At a meeting, Zimbardo told the guards:
“Create in the prisoners a sense of boredom, a sense of fear, an idea that their life is totally controlled by us, by the system, by you, by me, and that they have no privacy at all… We’re going to take away their individuality in various ways. All this will lead to a sense of powerlessness. In this situation, we will have all the power, and they will have none.”
What Happened During the Experiment
The experiment quickly spiraled out of control. The guards rapidly embraced their authority. The prisoners began to experience abusive and sadistic treatment from the guards, and most suffered severe emotional distress by the end.
The first day was relatively calm, but the guards soon started to assert their power and became verbally harsh with the prisoners. On the second day, a rebellion broke out. Some guards volunteered for extra shifts to help suppress it. Prisoners were forced to do push-ups at night, punished by being placed in a tiny solitary cell (a small closet where one could only sit or stand), and subjected to random cell raids. Guards could force prisoners to strip naked, intimidate them, and pit them against each other. Even using the bathroom became a privilege.
Less than 36 hours in, one prisoner began to suffer from severe emotional distress. The organizers initially suspected he was faking it, thinking he was trying to manipulate the situation.
The End of the Experiment
Zimbardo ended the study early for two main reasons:
- Video recordings revealed that guards intensified their abuse of prisoners at night, when they believed no researchers were watching and the experiment was “off.”
- Christina Maslach, a recent Stanford PhD brought in to interview guards and prisoners, was appalled when she saw prisoners being marched to the bathroom and forced to run while chained together. She was outraged and said, “It’s terrible what you’re doing to these boys!” Out of more than 50 outsiders who saw the prison, she was the only one to question its morality. After she confronted the situation, it became clear the study had to stop.
So, after just six days, the planned two-week prison simulation was canceled.
Lessons and Reflections
French writer Thibault Le Texier wrote that the experiment relieved participants of guilt, suggesting that the guards were not inherently aggressive or bad people, but that the environment made them act that way. In some ways, he’s right—bullying did emerge among the participants. However, we can often control how we respond to situations, especially when we work together as a group, not just as individuals.