Zimbardos prison experiment

• Zimabardo (1970s)

  Aim - To find out how quickly and easily ppts would conform to their roles
• Procedure

  1. 21 male ppts who were tested as emotionally stable and randomly assigned them to prisoner or guard
  2. They were made to conform to each role, wore uniforms to de - individualize them
• Findings - Guards

  • The guards took up roles easily treating prisoners harshly
  • Used fire extinguishers when rebellion
  • Constantly reminded prisoners of their powerlessness
  • Awoke prisoners up for head counts
  • Only referred to them by their number
  • Became more agressive
• Findings - prisoners


  1. Prisoners rebelled after day 2
  2. After rebelion prisoners became subdued and depressed
  3. One was released due to psycological disturbance
  4. 2 more were released on the 4th day
  5. One went on hunger strike, guards force fed and put him in closet
• The experiment ended after the

  6th day instead of 14th
• Conclutions

  Social roles have a strong influence in how we act
• EVALUATION - Strength - Control


  • Zimbardo had a strong level of control over variables
  • Only had ppts who had been proved mentally stable
  • High internal validity
• EVALUATION - Weakness - Lack of realism 


  • Didn't have the realism of a real prison
  • Some argued they were more play acting
  • One guard said he based his character on cool hand luke

  COUNTERPOINT

  • Ppts did behave as if it was real
  • 90% of prisoners conversations were about prison life
  • Talked about how it was impossible to leave SPE until their sentences were over
  • Prisoner 416 believed prison was real
• EVALUATION - Weakness - Exaggerates the power of roles

  • Only 1/3 of guards actually behaved brutally
  • 1/3 tried to apply the rules fairly
  • 1/3 tried to help the prisoners and sympathized by offering cigarettes and reinstating privileges