Stanford prison experiment

The Stanford prison experiment (SPE), also referred to as the Zimbardo prison experiment (ZPE), was a controversial psychological experiment performed in August 1971 at Stanford University. It was designed to be a two-week simulation of a prison environment that examined the effects of situational variables on participants' reactions and behaviors. Stanford psychology professor Philip Zimbardo managed the research team that administered the study. Participants were recruited from the local community through an advertisement in the newspapers offering US$15 (equivalent to $119.25 in 2025) per day to male college students who agreed to participate in a "psychological study of prison life". Twenty-four participants were chosen after assessments of psychological stability and then assigned randomly to the role of prisoners or prison guards. Critics have questioned the validity of these methods. Those volunteers selected to be "guards" were given uniforms designed specifically to de-individuate them, and they were instructed to prevent prisoners from escaping. The experiment started officially when "prisoners" were arrested by the real police of Palo Alto, California. During the next five days, psychological abuse of the prisoners by the "guards" worsened. After psychologist Christina Maslach visited to evaluate the conditions, she was troubled to see how study participants were behaving and treated and confronted Zimbardo. He ended the experiment on the sixth day, reporting that he was surprised by how much he had internalized his role as superintendent in the prison. The experiment has been referenced and critiqued as an example of an unethical psychological experiment, and the harm inflicted on the participants in this and other experiments during the post-World War II era prompted American universities to improve their ethical requirements and institutional review for human experiment subjects in order to prevent them from being similarly harmed. Other researchers have found it difficult to reproduce the study, especially...