Evaluation of Zimbardo's SPE

• strengths

  • high internal validity
  • real-life applications
• high internal validity

  Zimbardo and his researchers had an element of control over variables. emotionally stable individuals were chosen and randomly assigned to the roles of guard and prisoner- to try and rule out individual personality differences as an explanation for findings. if guard and prisoners behaved very differently, but were in those roles only by chance, then their behaviour must have been due to the pressures of the situations
• real-life applications

  findings can be used to explain events in Abu Ghraib, a military prison in Iraq, notorious for torture and abuse of Iraqi prisoners by US soldiers in 2003 and 2004

  Zimbardo believed that the guards who committed the abuses were the victims of situational factors that made abuse more likely. these factors, such as lack of training, boredom and no accountability to higher authority were present in both the SPE and Abu Ghraib. if we are aware of these factors and aware that they can lead to abuse, we can prevent this from happening in the future
• limitations

  • demand characteristics
  • ethical issues
• demand characteristics

  it has been argued that the behaviour of ppts in the SPE was more a consequence of demand characteristics (ppts guessing how the experimenter wanted them to behave) than conformity to roles

  to demonstrate some of the details of the SPE procedure were presented to a sample of students who had never heard of the study. the majority correctly guessed that the purpose of the experiment was to show that ordinary people assigned the role of guard or prisoner would act like real prisoners and guards as they thought was expected of them
• demand characteristics COUNTER

  Zimbardo pointed to evidence that the situation was very real to the ppts- 90% of the prisoners' conversations were about prison life. 'Prisoner 416' expressed the view that the prison was a real one, but run by psychologists rather than the government
• ethical issues

  despite the fact that the study followed the guidelines of the Stanford University ethics committee, ppts experienced extreme emotional distress- breaching protection from psychological harm

  in addition, Zimbardo played a dual role (he was researcher, but also played the prison superintendent). on one occasion a student who wanted to leave the study spoke to Zimbardo in his role as superintendent. the whole conversation was conducted on the basis that the student was a prisoner in a prison, asking to be 'released'. Zimbardo responded to him as a superintendent worried about the running of a prison rather than a researcher responsible for patients