Date | August 14–21, 1971 |
---|---|
Location | Single corridor in the basement of Stanford University's psychology building |
Coordinates | 37°25′43″N 122°10′23″W / 37.4286304°N 122.1729957°W |
Also known as | SPE |
Type | Psychology experiment |
Organised by | Philip Zimbardo |
The Stanford prison experiment (SPE) was a psychological experiment performed during August 1971. It was a two-week simulation of a prison environment that examined the effects of situational variables on participants' reactions and behaviors. Stanford University psychology professor Philip Zimbardo managed the research team who administered the study.[1]
Participants were recruited from the local community with an advertisement in the newspapers offering $15 per day ($113 in 2023) to male students who wanted to participate with a "psychological study of prison life". Volunteers were chosen after assessments of psychological stability and then assigned randomly to being prisoners or prison guards.[2] Critics have questioned the validity of these methods.[3]
Those volunteers selected to be "guards" were given uniforms specifically to de-individuate them, and they were instructed to prevent prisoners from escaping. The experiment started officially when "prisoners" were arrested by real police of Palo Alto. During the next five days, psychological abuse of the prisoners by the "guards" became increasingly brutal. After psychologist Christina Maslach visited to evaluate the conditions, she was troubled to see how study participants were behaving and she confronted Zimbardo. He ended the experiment on the sixth day.[4]
SPE has been referenced and critiqued as an example of an unethical psychology 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 subject experiments in order to prevent them from being similarly harmed. Other researchers have found it difficult to reproduce the study, especially given those constraints.[5]
Critics have described the study as unscientific and fraudulent.[6][7] In particular, Thibault Le Texier has established that the guards were asked directly to behave in certain ways in order to confirm Zimbardo's conclusions, which were largely written in advance of the experiment. However, Le Texier's article has been criticized by Zimbardo as being mostly ad hominem and ignoring available data that contradicts his counterarguments.