SI - Zimbardo

• Procedure

  • Mock prison - basement of Stanford uni
  • aim to test whether brutality of prison guards was the result of sadistic personalities or the situation
  • 24 emotionally stable students
  • randomly assigned to guards/prisoners
  • prisoners = arrested in home, delivered to prison, strip searched, deloused, issued uniforms and number - deindividuation
  • guards = were given uniform like wooden clubs, handcuffs, keys, mirrored glasses, told to enforce the rules
• Findings

  • within 2 days prisoners rebelled against treatment (ripped uniforms, shouted, swore at guards)
  • guards conducted head counts in the middle of the night, and created opportunities to enforce the rules and punish slight misdemeanours, their behaviour threatened prisoner’s psychological and physical health (subdued, anxious, depressed)
  • study was stopped after 6 days rather than planned 8 days
• Conclusion


  guards and prisoners conformed to their social roles within the prison, the more the guards identified with their roles the more brutal and aggressive their behaviour became
• :) researchers had some control over variables

  • emotionally stable participants were recruited and randomly assigned
  • the guards and prisoners had those roles only by chance so their behaviour was due to pressures of the situation and not their personalities
  • control increases the study’s internal validity so we can be more confident in drawing conclusions about the influences of social roles on behaviour
• :( Banuazizi & Mohavedi - lack of realism


  suggested ppts were play acting as their performances reflected stereotypes of how prisoners and guards are supposed to behave - one guard based his role on a character from a film, and prisoners rioted because they thought that is what real prisoners did - however, Zimbardos data showed 90% of the prisoners conversations were about prison life showing the simulation seemed real to them increasing the study’s internal validity
• :( Zimbardo understated dispositional influences

  1. only 1/3 guards behaved brutally - 1/3 applied rules fairly - 1/3 supported the prisoners, offering cigarettes & reinstating privileges
  2. his conclusion that ppts conformed to social roles may be over stated exaggerating the power of the situation
  3. the differences in the guard’s behaviour show that they could exercise right and wrong choices despite situational pressures to conform to a role