stanford prison experiment

• where was the study done?

  in the university of Stanford in California
• when was the study done?

  1973
• how did Zimbardo obtain his sample?


  by using opportunity sampling

  advertised for male volunteers to take part in the experiment (gender bias)

  he screened these applicants(psychology questionnaire) and chose the 24 most stable
• how many guards and prisoners?


  randomly selected into 12 guards and 12 prisoners
• prisoner

  arrested by LAPD

  • taken to mock prison in a mock cell(in the basement of Stanford)
  • they were striped/deloused and showered
  • given uniform(smock/hat)
  • given a number, photographed, finger printed
  • only addressed by their number not name
• guards

  given a uniform - brown khaki military style uniform

  given a baton

  given mirrored sunglasses
• what role did Zimbardo adopt?


  prison ward
• prisoner rights


  3 meals

  3 supervised toilet trips

  2 visits per week
• how did the guards behave?


  in the way they thought guards would behave so conformity to social roles
• conclusion

  "conformity to roles is automatic"

  but some guards did not change into sadistic behaviour so automatic conformity is probably not true -Haslam and Reicher 2012

  • an example of demand characteristics
• day 1 and day 2


  guards became increasingly tyrannical and abusive

  prisoners started to reject the system imposed

  prisoners were woken up in the night and forced to clean toilets with bare hands
• day 3 and day 4


  situation got worse with guards becoming more abusive

  guards also volunteered to do extra hours without pay

  5 prisoners had to be released early due to psychological harm
• day 6


  Christina Maslach (researcher) reviewed the experiment and was shocked and complained
• day 7


  project terminated 1 week early
• how was the experiment unethical?

  uninformed consent

  difficult to withdraw