Stanford Prison Experiment

Posted by on May 19, 2013 in Featured, Philip Zimbardo's Stanford Prison Experiment | 0 comments

Stanford Prison Experiment

Imagine being harassed, humiliated and dehumanized daily. Imagine the screeching sound of a whistle piercing your ears at 2:30 am, forcing you up and out of bed. Imagine your name and identity being stripped from you to be replaced by a cold, unfeeling number. Imagine there’s no way out. Now imagine you signed up for this.


The famous Stanford prison experiment was conducted by Dr. Zimbardo in 1971. Little did he know what he had unleashed when he designed the study. Curious to answer the question, what happens to good people when put in evil places, he decided to simulate a prison environment. The experiment would consist of nine guards and nine prisoners and was to last two weeks. In order to interest participants, Zimbardo and his colleagues sent out an ad in the papers, $15 for anyone who wanted to take part in his prison experiment. 70 applicants responded to the ad. After undertaking personality assessments, 24 male college students from U.S.A and Canada were chosen. They were considered the most stable of the candidates after eliminating those with medical problems, histories of drug or crime abuse and mental disorders.


A mere coin toss was the deciding factor of who was to become a guard or a prisoner. The guards were given all the paraphernalia of power. They had truncheons, handcuffs, badges, whistles, khaki uniforms and reflective sunglasses which concealed their eyes completely. The prisoners had to wear a smock uniform with no underwear, chains of their feet, stocking caps on their heads and numbers on their uniforms to which they would reply to instead of their names. This was designed to make them all appear similar to one another and to dehumanize them. Their attire was to remind them of their prisoner status and loss of freedom. Zimbardo had initially thought that two weeks of this treatment would not have any damaging psychological side effects. The experiment didn’t even last the appointed two weeks. Prisoners were having break downs. Guards behaving inhumanely. And Zimbardo himself, so engrossed in his superintendent role, forgot he was actually a psychologist conducting an experiment.


When the prisoners first arrived, they were stripped and doused in spray to remove any supposed dirt and lice and then sent to their cells, which were set up in the basement of Stanford University. At 2:30 am the prisoners were woken up by blasting whistles. They had to engage in counts which were designed to make sure all the prisoners were present and to familiarize the prisoners with their numbers. And, of course, for the guards to exercise control over them.


On the first day of the experiment, it was all a bit awkward. The guards didn’t feel comfortable barking orders and the prisoners didn’t feel like listening. On the second day, the prisoners rebelled in an attempt to assert their independence. They threw off their caps, tore their numbers off and barricaded themselves in their cells. They also taunted and cursed the guards. The guards became more aggressive and forceful at this point. Whipping out a fire extinguisher, they sprayed the gases into the cells to punish the prisoners. They then broke into the cells, took the beds out and shoved the ringleader in solitary confinement, a tiny closet in the hallway. This is when the guards starting viewing the prisoners as a real threat to be dealt with. The experiment had morphed into reality. They started harassing the prisoners. All behaviours, even going to the toilet, were monitored by the guards.


Barely 36 hours into the experiment, one of the prisoners had an emotional breakdown. He displayed uncontrollable crying, rage and disorganized thinking. At first the guards believed he was trying to trick them into giving him better treatment. They viewed him as weak and pathetic. He was released, however, due to his symptoms increasing.


Push-ups were a common form of punishment, a tactic used by Nazi guards in the concentration camps. Guards would place their foot on prisoners back while they did the exercises. Prisoners were also forced to do menial, repetitive tasks such as cleaning out toilet bowls with their bare hands.


Zimbardo then had a priest come in and assess the realities of the prison. When the priest sat with the prisoners they surprisingly referred to themselves by number rather than name. When he asked how they were planning to get out of the prison, they looked puzzled. The priest suggested he contact their parents and help them get a lawyer. Some accepted this offer. Clearly role play and reality were utterly confused at this point.


Soon after, another prisoner broke down. He refused to eat and claimed he needed to see a doctor. The guards ordered the prisoners to start chanting that he was a bad prisoner. All traces of empathy appeared to be erased from the guard psyche.


A parole meeting was then held. When the prisoners were asked if they would forfeit the money they earned up to this point for parole, most said they would. Why did they believe in parole? This was an experiment which they could quit any time they chose. Why did they feel so hopeless that escape from this set up prison was impossible? When ordered to return to their cells, all of them did without batting an eyelid. This was their new reality.


After a prisoner learned his parole request had been turned down, a psychosomatic rash broke out all over his body. Another prisoner went on a hunger strike. The guards were also becoming more sadistic. They were abusing the prisoners at night when they thought the researchers weren’t watching.


It wasn’t until Christina Maslach, a recent Stanford Ph.D., saw the experimental conditions, told Zimbardo the study had to be put to an end. She was horrified by what she saw. When the guards found out the experiment was to be terminated early, most were disappointed whereas, every single prisoner was clearly delighted.


How did this happen? Why did the prisoners feel trapped in an experiment they could have terminated at their own will? And why did the guards start behaving so cruelly to prisoners whom they knew had done nothing wrong? If they had received a heads or tails, they would be in the prisoner role themselves.


The prisoners were made to feel anonymous and worthless through the attire they wore and the way they were treated. They lost their individuality and their sense of autonomy. The guards with their reflective sunglasses were able to hide behind a mask and take on this new authoritative persona. They were told they had to maintain law and order as well as get respect and compliance from prisoners. The guards were free to make up their own rules to achieve these ends. Three types of guards emerged: good guys, tough but fair guys and guys who thoroughly enjoyed their new power role. Preliminary personality tests did not predict this. After the experiment, many of the ex-guards seemed shocked at how far they went to torment their prisoners and were unsure if they would have gone further had the experiment continued.


Based on this experiment, it appears that people can be defined by the role they play in society. The culture one lives in can play a deciding part in how one’s personality is formed. It seems Zimbardo got an answer to his question. What happens to good people when put in evil situations…



Zimbardo, G., P. (n.d.). A Simulation Study of the Psychology of Imprisonment Conducted at Stanford University. Stanford Prison Experiment. Retrieved May 19, 2013, from

Image credit: Samuel Eddy. (March 31, 2010). Posts tagged ‘Stanford Prison Experiment.’ Psychohawks. Retrieved September 2, 2013, from

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