Zimbardo' research

• Zimbardo set up a mock prison in the basement of Stanford University. They selected willing students who were deemed 'emotionally stable' after psychological testing. The students were randomly assigned the roles of guards or prisoners.
• The 'prisoners' were arrested in their homes, blindfolded, strip-searched and assigned a uniform and number. The prisoners' names were never used, only their numbers. Prisoners had to follow 16 rules which were enforced by the guards and their daily routines were heavily regulated.
• The guards had their own uniforms, complete with a wooden club, handcuffs, keys and mirror shades. They were told they had complete power over the prisoners, even including when they went to the toilet.
• After a slow start to the simulation, the guards took up their roles with enthusiasm. Their behaviour became a threat to the prisoners' psychological and physical health and the study was stopped after 6 days instead of the intended 14.
• Within two days, the prisoners rebelled against their harsh treatment. They ripped their uniforms, and shouted and swore at the guards who retaliated with fire extinguishers.
• The guards employed 'divide-and-rule' tactics by playing the prisoners against each other. They harassed the prisoners constantly. The guards highlighted the differences in social roles by creating plenty of opportunities to enforce the rules and punish even the smallest misdemeanour.
• One prisoner was released on the first day because he showed symptoms of psychological disturbance. Two more were released on the fourth day.
• The guards identified more and more closely with their role. Their behaviour became more aggressive and brutal, with some of them appearing to enjoy the power they had over the prisoners.
• The simulation revealed the power of the situation to influence people's behaviour. Guards, prisoners and researchers all conformed to their roles. These roles were easily taken on by all participants - including volunteers who came in to perform certain functions found themselves behaving as though they were in a real prison rather than a psychological study.
• A strength of this study is that Zimbardo and his colleagues had some control over variables, such as the selection of participants. Emotionally stable individuals were chosen and randomly assigned a role. This was one way in which the researchers tried to rule out individual personality differences as an explanation of the findings. If guards and prisoners behaved very differently but were in those rules by chance then their behaviour must have been due to the pressures of the situation.
• Having control over such variables increases the internal validity of the study and we can more confidently draw conclusions about the influence of roles on behaviour.
• Banuazizi and Mohavedi argued the participants were merely play-acting rather than genuinely conforming to a role. Their performances were based on stereotypes of how prisoners and guards should behave (one of the guards said he based his role on a brutal character from the film Cool Hand Luke). This suggests the study lacked realism.
• However, quantitative data gathered during the procedure showed that 90% of the prisoners' conversations were about prison life. 'Prisoner 416' expressed the view that the prison was a real one, but run by psychologists rather than the government. It seems the situation was real to the participants, which gives the study a high degree of internal validity.
• Fromm accused Zimbardo of exaggerating the power of the situation to influence behaviour, and minimising the role of personality factors (dispositional influences). Only a minority of the guards behaved in a brutal manner. Another third were keen on applying the rules fairly. The rest actively tried to help and support the prisoners, sympathising with them and reinstating privileges. This suggests Zimbardo's conclusion may be over-stated.
• The differences in the guards' behaviour indicates that they were able to make right and wrong choices, despite the situational pressures to conform to a role.