Zimbardo and his colleagues (1973) were interested in finding out whether the brutality reported among guards in American prisons was due to the sadistic personalities of the guards (i.e., dispositional) or had more to do with the prison environment (i.e., situational).
Just Some More Information
To study the roles people play in prison situations, Zimbardo converted a basement of the Stanford University psychology building into a mock prison.
He advertised asking for volunteers to participate in a study of the psychological effects of prison life.
The 75 applicants who answered the ad were given diagnostic interviews and personality tests to eliminate candidates with psychological problems, medical disabilities, or a history of crime or drug abuse.
24 men judged to be the most physically & mentally stable, the most mature, & the least involved in antisocial behaviors were chosen to participate. The participants did not know each other prior to the study and were paid $15 per day to take part in the experiment.
