Case Study 7: The Stanford University Prison Experiment (1971)

This study was designed and first tested in 1971 in the Psychology Department at Stanford University. Philip Zimbardo, the Professor of Psychology, to test the effects of putting normal people in extraordinary circumstances, to examine whether inherent personality traits were key to understanding the tensions that arose in prisons.

The key question was:

‘What happens when you put good people in an evil place? Does humanity win over evil, or does evil triumph?'

The study:

The basement of a building on the Stanford Campus was converted to a mock prison.
Volunteers were invited and from 75 undergraduates who applied 24 were chosen.
The volunteers were randomly split into two groups: guards and prisoners.

The aim was to run a two-week simulation of life in a prison.

The guards were instructed to create an atmosphere of fear, boredom, and arbitrariness. The prisoners should lose their sense of individuality. The guards were not to use physical violence.

At the start of the study Zimbardo (who played the role of the Prison Warden) had the assistance of the local police force who helped to arrest all of those plying the roles of prisoners, so they were taken to the police station and charged (with armed robbery) before they were taken to the mock prison where they were strip searched.

The prisoners all wore smocks and stocking caps, chains around their ankles and they had a number issued to them instead of a name.

The guard had khaki uniforms, wooden batons as symbols of office and mirror spectacles

What is the significance of the kit given to the prisoners and the guards?
Prisoners Guards

Once the study had started things went as follows:

Day 1: Routines established – no special problems.
Day 2: One prisoner became uncontrollably enraged and stressed. As he did not calm down Zimbardo removed him from the trial. A stand-by prisoner replaced him.
Day 3: There are rumours that the prisoner who left might organise a breakout. The guard dismantled the prison and moved it to another location and then rebuilt it – but no breakout took place and the guards became angry.
Days 4-6: As time went on conditions in the prison deteriorated. Guards used a variety of routines as punishments – counting exercises, refusals to allow prisoner to use the toilet, removing mattresses, forcing some prisoners to go naked and using sexual humiliation, including simulated sodomy.
Day 6: Concerns about the falling standards are raised and Zimbardo decides to halt the experiment.

The study was filmed and a film was made of the experiment later.
Zimbardo's conclusions

The prisoners showed how they had internalised their roles – they became prisoners and remained in role even though they knew that they could quit the study. Zimbardi considered this a very powerful demonstration of situational attribution of a role: the volunteers were not hardened criminals or institutionalised offenders – they were most white, middle class and bright undergraduates. Yet they embraced and became the role they played. When the stand-by prisoner complained to the guards about how prisoners were treated he was locked in a closet as a punishment The guards told the other prisoners he could only be released if they gave up their blankets. Only one of the prisoners bought into this! The others played the hardened prisoners roles! Members of the Royal Shakespeare Company might well have been able to assist Zimbardo here!

The guards were upset that the exercise ended early. But one third of the guards had been observed showing ‘genuine sadistic tendencies'. Like the prisoners, the guards showed situational rather than dispositional attribution.

The overall conclusion is that the attributes of a sadistic or at least tough and abusive guard in a prison is not down to disposition – to the person's nature – but it is determined by the situation, by being agents in the role.

The Zimbardo experiment has been very influential in many cases of prisoner abuse, including the Abu Ghrihab prison case of 2004.

Your thoughts about the Zimbardo experiment and the ‘Determinism vs. Freewill' debate