Zimbardo's Research Into Conformity - Stanford Prison Experiment


Aim of Study

  • To find out about conformity to social roles after an increased levelof violence in prison guards
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  • All PPs male uni students
  • PPs found through volunteering
  • 75 volunteers overall
  • Psychological testing on every volunteer to find the most psychologically stable
  • Ended up with 24 PPs overall
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  • Controlled observation - lab experiment
  • Transformed the basement of Stanford Uni into a mock prison 
  • Advertised for students to play roles of guards and prisoners for 2 weeks (14 days) 
  • 24 PPs chosen out of the 75 that volunteered
  • PPs paid $15 a day
  • PPs randomly assigned prisoner or guard
  • "Prisoners" were arrested in their home by real police who delivered them to the 'prison' where they were fingerprinted, booked and photographed. Prisoners were blindfolded, stripped naked and deloused
  • Prisoners were given a prisoner smock to wear and a number, which they would be reffered to as
  • The guards were issued with a khaki uniform, handcuffs and dark glasses to make eye contact with prisoners impossible
  • Zimbardo was observing the behaviours of the prisoners and guards, but also played the role of prison warden
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Social Roles of Prisoners and Guards

  • Social roles of guards and prisoners were heavily divided
  • Prisoners daily routines were strictly regulated 
  • There was 16 rules that they had to follow which were enforced by the guards 
  • Guards were told they had complete power over the prisoners, even being able to decide whether they could go to the toilet
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  • One prisoner was released on the first day because he showed signs of psychological disturbance
  • The guards took to their roles with enthusiasm, but their behaviour became a threat to the prisoners' physical and mental health, so the simulation was stopped after 6 days instead of 14
  • Within two days, the prisoners rebelled against the guards' harsh treatment, ripping their smocks, shouting and swearing at the guards, who reacted with fire extinguishers
  • The guards employed 'divide-and-rule' tactics, playing the prisoners off of each other
  • They harassed the prisoners constantly to demonstrate their power, e.g. waking them up in the middle of the night to do head counts
  • After their rebellion, the prisoners became subdued, depressed and anxious
  • Two more prisoners were released on the fourth day
  • One prisoner went on a hunger strike - the guards tried to force feed him and then put him in 'the hole' to punish him and turned the other prisoners against him
  • The guards identified more with their roles, becoming more aggressive and seeming to enjoy their positions of power
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  • The simulation revealed that power within a situation can influence people's behaviour
  • These roles were very easily adopted by the participants, even volunteers who came in to perform certain functions (e.g. prison chaplain) found themselves behaving as if they were in a prison and not a psychological study
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