Zimbardo

• Zimbardo's prison experiment

  • Mock prison to test whether the brutality of prison guards was the result of sadistic personalities or whether it was made by the situation
  • Recruited 24 emotionally stable students and randomly assigned to roles of guards or prisoners
  • Prisoners were arrested in their homes, blindfolded, strip-searched, deloused and issued with a uniform and a number
• Prisoner's daily routine


  1. Heavily regulated

  2. 16 rules to follow, enforced by the guards

  3. Prisoners' names were never used, only their number
• Guards


  • Had their own uniform
  • Wooden club, handcuffs, keys and mirrored sunglasses
  • Told they had complete power over the prisoners, such as deciding when they could go to the toilet
  • worked shifts, three working at a time.
• Within 2 days of the experiment, the prisoners rebelled against their treatment. they ripped their uniforms and shouted and swore at the guards who retaliated using fire extinguishers- the guards harassed the prisoners constantly by conducting a headcount, sometimes in the middle of the night.- guards highlighted the differences in social roles by creating opportunities to enforce the rules and punish misdemeanours.
• the guards took their role with enthusiasm. their behaviour threatened the prisoners psychological and physical wellbeing. for example:

  • after the rebelling had ended, the prisoners became subdued, anxious and depressed.
  • three prisoners were released early because they showed signs of psychological disturbance
  • one prisoner went on a hunger strike and the guards attempted to force feed him and eventually put him in 'the hole' (a tiny dark cupboard)
  • The study was ended after 6 days instead of the planned 8
• the situation revealed the power of the situation to influence peoples behaviour. guards prisoners and researchers all conformed to their social roles when they were in the prison. the more the guards identified with their roles, the more brutal and aggressive their behaviour became.
• a strength of Stanford prison experiment

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  • emotionally stable participants were selected and randomly assigned the roles of prisoner and guard.
  • the guards and prisoners had those roles only by chance, so their behaviour was due to the pressures of the situation and not their personalities.
  • control increases the study's internal validity. we can be more confident in drawing conclusions about the influences of social roles on behaviour.
• a potential limitation

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  • Banuazizi and Mohavedi (1975) suggest that participants were play acting. their performances reflected stereotypes of how prisoners and prison guards are supposed to behave
  • One guard based his role on a character from the film cool hand Luke. prisoners rioted because they thought that is what real prisoners did
  • But Zimbardo data showed 90% of the prisoners conversations were about prison life. the simulation seemed real to them, increasing the study's internal validity.
• Fromm (1973) argues that zimbardo understated dispositional influences

  • only a third of the guards behaved brutally. another third applied the rules fairly. the rest supported the prisoners, offering them cigarettes and reinstating privileges.
  • zimbardos conclusion- that participants conformed to social roles- may be over stated, exaggerating the power of the situation.
  • the differences in the guards behaviour show that they could exercise right and wrong choices, despite situational pressures to conform to a role.
• Stanford prison experiment lacks research support and had been contradicted by subsequent research
• Reicher and Halsam (2006)

  Partially replicated SPE with different findings, prisoners eventually took control
• Tajfel's (1981) social identity theory

  Explains the findings of the Reicher and Halsam replication
• Guards in the replication failed to develop a shared social identity as a group, but prisoners did and refused to accept limits of their assigned roles
• The brutality of the guards (in the original) was due to a shared social identity as a cohesive group, rather than conformity to their social roles
• a limitation

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  • One issue arose because Zimbardo was both lead researcher and prison superintendent.
  • a student who wanted to leave the study spoke to zimbardo, who responded as the superintendent worried about the running of his prison rather than as a researcher.
  • this limited zimbardos ability to protect the participants from harm because his superintendent role conflicted with his lead researcher role.