In 1973, Zimbardo carried out an experiment to investigate how readily people would conform to new roles by observing how quickly people would adopt the roles of a guard or prisoner in a simulated prison. Zimbardo took healthy male volunteers and pain them $15 per day to take part in the two-week simulation study of prison life. Volunteers were randomly chosen to be either guards or prisoners. Local police helped “arrest” 9 prisoners at their homes without warning; they were then taken and blindfolded to the “prison”, stripped and sprayed with disinfectant, given smocks to wear and their prison number to memorize.
There were guards on duty and they wore green khaki uniforms and aviators and carried wooden batons. There was no physical aggression allowed. The guards then ended up harassing and humiliating the prisoners and each conformed to their perceived roles, this caused the experiment to be discontinued after six days, out of the original two-weeks. The prisoners rebelled against the guards after two days and the guards controlled this rebellion using fire-extinguishers. Some prisoners became depressed and anxious and had to be released before the six days were finished.
This study showed that people will readily conform to the social roles that they are expected to play, especially if the roles are strongly stereotyped such as prison guards. The study had many ethical issues, one being that Zimbardo had a lack of fully informed consent from the participants, the participants did not know that they were going to be arrested at home. They also had a large deal of humiliation and distress that they experienced during the study due to the conformity of roles on the guards part.
However, Zimbardo thought that the withholding of this information was allowed as it was a major part of the procedure. The guards had to face the unpleasant fact that they had decided to mistreat the prisoners, and if they had been prisoners they may have been faced with psychological harm. However, Zimbardo stated that after the study the participants did not suffer from psychological harm and had no negative lasting effects. Zimbardo was wrong to act as both the prison-superintendant and the chief researcher as this produced a conflict of roles where he had lost sight of the harm being done to the participants.