The Standford Prison experiment started in the Summer of 1971 by Philip Zimbardo who was a social psychology professor at Standford University. He chose a group of college students to participate in his study. They were all actors, half of the college students were either prisoners or guards. In the study, volunteers were randomly chosen to participate in this study. Zimbardo served himself as a superintendent and was part of the experiment. The original study was supposed to last for two weeks but only lasted for six days because of two of the prisoners left in the middle of the study because they just couldn’t handle the torture anymore.