Conformity to Social Roles: Zimbardo’s Study

– Following reports in the 1960s USA of brutality by prison guards, Zimbardo wanted to know if the brutality was created by statistic personalities or the situation


– In 1973 Zimbardo et al set up a mock prison in the basement of the psychology department at Stanford University.

– He wanted to find out if prison guards behaved brutally because they have sadistic personalities, or is it the situation that created such behaviour?


They advertised for male student volunteers and selected those who were deemed ‘emotionally stable’ after extensive psychological testing.

– 24 were chosen

– The students were randomly assigned the roles of guards or prisoners.

– The prisoners were treated as extreme as real prisoners and were randomly arrested

– They were given a uniform and an ID number and were only referred to as their number

– The social roles of these were strictly divided and the prisoner’s daily routines heavily regulated.

– There were 16 rules they had to follow which were enforced by the guards.

– The guards were told they had complete power over the prisoners, for instance even deciding when they could go to the toilet


– Over the first few days of the study the guards grew increasingly tyrannical and abusive towards the prisoners

– They made the prisoners carry out degrading activities

– Within two days, the prisoners rebelled as the guards harassed the prisoners constantly.

– After the rebellion, the prisoners became subdued, depressed and anxious.

– One prisoner was released on the first day because he showed symptoms of psychological disturbance.

– Two more were released on the fourth day, with one prisoner going on hunger strike and then shunned by the other prisoners.

– The guards identified more and more closely with their role, with some of them appearing to enjoy the power they had over the prisoners.

– The guard’s behaviour became a risk to the prisoner’s psychological and physical health and the study was stopped after six days instead of the intended 14.


– Zimbardo concluded that all guards, prisoners and researchers conformed to their roles within the prison

– Even volunteers who came in to perform certain functions found themselves behaving as if they were in a prison rather than a psychological study



High Control

– Zimbardo has some control over variables.

– For example, the selection of participants.

– Emotionally stable individuals were chosen and randomly assigned the roles.

– This was one way to rule out individual personality differences as an explanation of the findings.

– Having this control over variables is a strength because it increases the internal validity of the study.

– So we can be much more confident in drawing conclusions about the influence of roles on behaviour.

– Therefore, as this study has high control extraneous variables are less likely to affect the results meaning there is a higher validity


Demand Characteristics

– Some say that the behaviour of the participants in the experiment was more a consequence of demand characteristics than conformity to roles.

– They presented some of the details of the procedure to a large sample of students who had never heard of the study.

– The vast majority correctly guessed that the purpose of the experiment was to show that ordinary people assigned to the role of guard or prisoner would act like a real prisoner and guard

– They predicted that guards would act in a hostile domineering way and that prisoners would react in a passive way.

– This suggests that the behaviour of Zimbardo’s guards and prisoners was not due to their response to a compelling prison environment but rather it was a responsible for the demand characteristics in the experimental situation itself

– Instead of conforming to the roles because of the prison situation, they were playing the roles that the thought they had to do

Conformity to Roles is Not Automatic

– Haslam and Reicher challenge Zimbardo’s believe that the guards drifted into sadistic behaviour due to an automatic consequence of them embracing their role.

– The guard’s behaviour varied from being fully statistic to being good guards who did not degrade or harass the prisoners

– Haslam and Reicher argue that this shows that the guards choose how to behave, rather than blindly conforming to the social role, as suggested by Zimbardo