Aim

1. The aim was to test whether the situation and the social role, rather than the personality of the individual, drive the way people behave inside a prison.
2. That sets the situational explanation against the dispositional one.

Procedure

1. 75 people answered a newspaper advertisement, 24 were selected as normal and healthy males after psychological assessment and interview, and 22 of them took part with 2 kept on standby.
2. The roles of guard and prisoner were then assigned at random, and each man was paid $15 a day.
3. A mock prison was built at Stanford University for the men to live in.
4. Each prisoner was issued a smock carrying an identification number and an ankle chain, and from then on was known by his number rather than his name.
5. The guards were told only to maintain the functioning of the prison, with no physical punishment as the single explicit prohibition.

Results

1. The verbal aggression of the guards escalated day by day and was worst when they believed they were not being watched.
2. Five prisoners had to be released early, four of them with symptoms beginning as early as day two.
3. At a parole meeting on day four, three of the five men who attended offered to give up their pay in order to leave.
4. The prisoners judged the guards to be physically bigger than themselves, although there was no real difference in size.
5. The study was terminated on day six of the planned fourteen.

Conclusions

1. Social roles, deindividuation and the coercive power given to the guards shaped what both groups did, which supports a situational explanation of behaviour.
2. The situation was powerful rather than irresistible, because not every guard was cruel and about half the prisoners lasted to the end.

Strengths and weaknesses

1. A strength is that the men were screened as normal and healthy and then allocated to roles by chance, so the differences that appeared cannot be put down to the kind of people they already were.
2. A second strength is that the men were observed day after day, so the study captures the escalation in the guards rather than a single snapshot.
3. A weakness is that five men had to be released early with symptoms starting on day two, and there was no effective right to withdraw once the roles were running.
4. A second weakness is that all 22 participants were male and recruited in one American university town, so the findings cannot be assumed to describe women or other cultures.

Turning this into marks

1. Give accurate sample facts, such as 24 selected, 22 taking part and the roles assigned at random.
2. Weigh the control from screening and random allocation against the harm done to the men rather than retelling the six days.