The Stanford Prison Experiment

## Overview

The Stanford Prison Experiment refers to a social psychology study conducted in 1971 at Stanford University under the direction of Dr. Philip Zimbardo. The goal of this study was to examine conditions of prison under the “dispositional hypothesis.” The dispositional hypothesis suggests the state of the social institution of prison is due to the ‘nature’ of the people who administer it, or the nature of people who populate it, or both.”

The study was planned to simulate the experience of prison in a fabricated jail-like setting with participants recruited from the community. The study itself has significant notoriety; it is one of the most famous psychological studies to have been conducted. It is frequently discussed because the study itself was stopped after six days, rather than the planned two-week schedule. Philip Zimbardo has described participants as becoming “sadistic” and “depressed…show[ing] signs of extreme stress.” However, since 1971, there has been significant criticism that has arose surround the study, its validity, and about how it is frequently taught in psychology classes and textbooks.

### The Study

There were no specific hypotheses set a priori in this study. Zimbardo and his team wanted to observe reactions of participants based upon their role as either a “guard” or a “prisoner.” The Stanford Prison Experiment website cites the goals of the study as to understand “What happens when you put good people in an evil place? Does humanity win over evil? Or does evil triumph? These are some of the questions we posed in this dramatic simulation of prison life.”

The only variable in the study was the random assignment of participants to either the role of a guard or prisoner. Participants were recruited via a newspaper ad, calling for male college students to participate in “psychological study of prison life,” and included compensation of $15 per day. Over 70 potential participants responded to their ad. These participants were then screened via a battery of psychological tests, which included questionnaires regarding their background, history of physical and mental health, involvement in crime and completed an in-person interview with one of two experimenters. The final sample of participants selected were deemed to be the most physically and mentally stable, most mature and least anti-social behaviors. Participants were randomly assigned to the different conditions via a coin flip.

The mock prison itself was constructed in the basement of the Stanford University’s psychology building. Three six by nine-foot cells were made in laboratory rooms, which were replaced with steel barred doors, and the furniture had been removed. Each room was equipped with a cot for each prisoner. The corridor itself was considered the “yard” where prisoners were allowed to eat meals, walk and exercise. Additionally, a small closet served as solitary confinement for “bad prisoners.” There was an intercom system in place so that the researchers could monitor prisoner discussion, as well as videotaping from one end of the “yard.”

The study was designed to be run for a two-week time period. In the participation contract, it was stated that participants who were assigned to the prisoner conditions should expect “little to no privacy” and some of their rights suspended during the time of the experiment. Additionally, there was an expressed note about not experiencing any physical violence, however, at times, it appeared that abusive techniques were encouraged by the researchers as the guards were not stopped from these behaviors.

Participants assigned to the prisoner condition remained in the prison environment 24 hours per day while those assigned to the guard condition worked eight hour shifts with two other “guards.” These participants were allowed to leave the prison environment when not on shift.

Prior to beginning the experiment, guards met for orientation with the “Superintendent” of the prison and the “Warden.” These two roles were filled by Dr. Phillip Zimbardo and an undergraduate research assistant. The participants were informed that their jobs as “guards” was to maintain order in the prison to ensure effective functioning. The instructions were vague regarding how to maintain order; however, they were informed what it meant to “be a guard,” but warned against the use of physical aggression.

From the start of this study, methods were put in place to dehumanize the prisoners, including having them picked up and processed by the Palo Alto City Police. Upon entering the “prison” the participants in the prisoner condition were subjected to being stripped, deloused and made to stand alone, naked before receiving their gown with their prisoner numbers. Prisoners also were required to wear a shackle on their ankle, as well as stockings on their heads to simulate having their heads shaved. In contrast, guards were given uniforms to encourage their anonymity, including khaki shirt and pants, whistles, nightsticks and reflective glasses to prevent the prisoners from being able to make eye contact with the guards.

The study itself was originally planned to run for two weeks, as previously mentioned. However, after six days, Philip Zimbardo decided to stop the experiment. Largely, this was due to another researcher stepping in and reporting that the experiment itself seemed to be unethical.  This, by the earliest accounts was due to inhumane treatment by the guards, as well as reports of prisoners going on hunger strikes and “acting crazy.”

## The Results

The major findings from this study found that "normal, healthy" participants began to display symptoms of emotional distress, severe negative emotions which included crying and anxiety and requests to leave the study early. Additionally, interactions between guards and prisoners were frequently hostile or dehumanizing.

Unexpectedly, just weeks after the termination of the study, the findings became available to the press, thus quickly becoming an example of what can happen to seemingly “normal” people when put in certain social situations. Especially, when the social institutions support these behaviors.  This study not only became a staple within the field of psychology, frequently taught in introductory classes of psychology, but also garnered national attention as Zimbardo was invited to testify in front of a Congressional Committee on causes of prison riots  and at later date, he was invited to speak to a Senate Judiciary Committee focused on the detention of juveniles  Not only was this study the topic of hearings, by the time the research article had been published in 1973, Zimbardo had taken a very public role, even appearing on NBC to discuss this "shocking" study.

## Legacy

Over the five decades since this study has been conducted, many different voices have entered the discussion, looking to criticize elements of this study. Much of the criticism garnered by this study falls not only under the ethical failures of treatment of participants, the inability to replicate such a study or the lack of generalizability of the results, but also is more closely related to how it is taught in courses and in more recent years the suspected “fraud” on behalf of the principal investigators.

Interestingly, in an attempt to examine if certain personalities are drawn to participate in a study about "prison life," Carnahan and McFarland (2007) attempted to see if it was perhaps the personalities of the type of people who would respond to an advertisement about participating in a prison life study.  In this study, researchers used the identical ad utilized in the original Stanford Prison Experiment and an another condition with the same ad, however, "prison life" was left out. The results of this study suggested that the participants who responded to the "prison life" ad, scored signficantly higher on measures of aggressivessness, authoritarianism, Machiavellianism, narcissim and social dominance. In addition, these participants scored signficantly lower scores in empathy and altruism. These findings, while conducted after the original study had been performed, provides some evidence that those participants may have been more prone to engage in certain aggressive behaviors.

Similarly, research has begun to examine how this experiment is covered in psychology courses. As it is frequently discussed however, there appears to be incosistencies regarding how this research experiment is discussed. Bartels (2015) conducted a content analysis in introducty psychology textbooks to examine what theoretical and metholodogical problems are discussed.  In this content analysis, Bartels examined 17 introductory psychology textbooks. His content analysis revealed that a majority of the textbooks minimally covered problems with the study, and instead, discussed this experiment in terms of the "power of the situation" interpretation, which has been commonstance.

Recently, there has been a large discussion about the validity of the Stanford Prison Experiment. Specifically, in some popular media, it has been suggested that the experiment is a "fraud" due largely to the deceit of investigators.  Medium published an expose on the Stanford prison experiment, where previous recordings of investigators such as Zimbardo and Jaffe, have been made readily available as they had not been prior.  In this expose, recordings of Zimbardo and Jaffe, the "prison" Superindendent and Warden respectively, have suggested that participants were coached on how to behave as guards. In one particular recording, Jaffe can be heard telling guards they are not being tough enough on the prisoners. Additionally, it is in this article that it is suggested that participants, specifically the prisoners were restricted from exiting the study, even upon request. In part, Zimbardo is questioned about this, which he denies, saying the consent form required participants to ask specifically to be allowed to leave the experiment.  Another interesting feature of this article included interviews with participants of the experiment. These interviews suggested that some of the symptoms observed, such as prisoners "going crazy" was more to meet the goal of release, one participant stated he behaved in this manner because he was worried about "failing grad school." Similarly, one of the guard participants recalls that he created a persona, which was intended to be cruel because he wanted to see what limits he could push while in the study.

Other articles have suggested that the study itself is "fatally flawed."  In an attempt to "debunk" the Stanford Prison Experiment, Le Texier (2019) examined archival data of interviews with participants of the original study. Interestingly, in this archival review it was discovered that guards were, in fact, trained. Zimbardo provided examples of what the guards should be doing, as well as examples of ways to dehumanize prisoner participants. Additionally, it was also discovered that guards were unaware that their behavior was also being obeserved, as Zimbardo decieved guard participants into believing they were research assistants.

Additionally, this study demonstrates a larger issues in psychology known as the "replication crisis."  This experiment is often used to describe how one may engage in certain behaviors, however, since the field is unable to replicate it, this study may need to be approached with more scrutiny.

###### Further Reading:

1. Haslam, S.A., & Reicher, S.D. (2012). Contesting the "nature" of conformity: What Milgram and Zimbardo's studies really show. *PLOS Biology,* 10(11). https://doi.org/10.1371/journal.pbio.1001426
2. Bartels, J. M., & Griggs, R. A. (2019). Using new revelations about the Stanford prison experiment to address APA undergraduate psychology major learning outcomes. *Scholarship of Teaching and Learning in Psychology, 5*(4), 298-304. https://doi.org/10.1037/stl0000163
3. Reicher, S. D., & Haslam, S. A. (2011). Rethinking the psychology of tyranny: The BBC prison study. *British Journal of Social Psycholoygy, 45*, 1-4. https://doi.org/10.1348/014466605X48998

1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 Haney, C., Banks, C., & Zimbardo, P. (1973). Interpersonal dynamics in a simulated prison. *International Journal of Criminology and Penology, 1*, 69-97. https://doi.org/10.21236/ad0751041
2. ↑ 2.0 2.1 2.2 2.3 2.4 Stanford Prison Experiment. (n.d.). Retrieved December 3, 2021, from https://www.prisonexp.org/.
3. ↑ 3.0 3.1 Ratensar, R. (2011, July). *The menace within*. STANFORD magazine. Retrieved December 3, 2021, from https://stanfordmag.org/contents/the-menace-within.
4. ↑ 4.0 4.1 Cherry, K. (2021, April 16). *Why the stanford prison experiment is still infamous decades later*. Verywell Mind. Retrieved December 3, 2021, from https://www.verywellmind.com/the-stanford-prison-experiment-2794995.
5. ↑ Dolan, E. W. (2015, April 16). *Intro to psychology textbooks gloss over criticisms of Zimbardo's stanford prison experiment*. PsyPost. Retrieved December 4, 2021, from http://www.psypost.org/2014/09/intro-psychology-textbooks-gloss-criticisms-zimbardos-stanford-prison-experiment-27970.
6. ↑ Talk of the Nation. (2004, May 4). Prison Psychology and the Stanford Prison Experiment: NPR. *NPR*. other. Retrieved December 3, 2021, from https://www.npr.org/templates/story/story.php?storyId=1870756.
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9. ↑ 9.0 9.1 9.2 9.3 Konnikova, M., & Lemann, N. (2015, June 12). *The real lesson of the stanford prison experiment*. The New Yorker. Retrieved December 3, 2021, from https://www.newyorker.com/science/maria-konnikova/the-real-lesson-of-the-stanford-prison-experiment.
10. ↑ Zimbardo , P., Haney, C., Banks, W. C., & Jaffee, D. (n.d.). *The Stanford Prison Experiment*. The Stanford Prison Experiment: A Simulation Study of the Psychology of Imprisonment. Retrieved December 3, 2021, from https://web.stanford.edu/dept/spec\_coll/uarch/exhibits/spe/SPE.pdf.
11. ↑ 11.0 11.1 11.2 Bavel, J. V., Haslam, A., & Reicher, S. (2019, May 30). *Rethinking the infamous Stanford Prison Experiment*. Scientific American Blog Network. Retrieved December 4, 2021, from https://blogs.scientificamerican.com/observations/rethinking-the-infamous-stanford-prison-experiment/.
12. ↑ 12.0 12.1 American Psychological Association. (n.d.). *Demonstrating the power of social situations via a simulated prison experiment*. American Psychological Association. Retrieved December 5, 2021, from https://www.apa.org/research/action/prison.
13. ↑ *Hearings before subcommittee no. 3 of the committee on the judiciary House of Representatives*. (n.d.). Retrieved December 4, 2021, from http://pdf.prisonexp.org/congress.pdf.
14. ↑ Perry, G. (2018, November 7). *Inside the prison experiment that claimed to show the roots of evil*. New Scientist. Retrieved December 3, 2021, from https://www.newscientist.com/article/mg24031990-200-inside-the-prison-experiment-that-claimed-to-show-the-roots-of-evil/.
15. ↑ 15.0 15.1 Carnahan, T., & McFarland, S. (2007). Revisiting the Sanford prison experiment: Could participant self-selection have led to the cruelty? *Personality and Social Psychology Bulletin, 33*(5), 603-614. https://doi.org/10.1177/0146167206292689
16. ↑ 16.0 16.1 Bartels, J. M. (2015). The Stanford prison experiment in introductory psychology textbooks: A content analysis. *Psychology Learning & Teaching, 14*(1), 36-50. https://doi.org/10.1177/1475725714568007
17. ↑ Resnick, B. (2018, June 13). *The Stanford prison experiment was massively influential. we just learned it was a fraud.*Vox. Retrieved December 5, 2021, from https://www.vox.com/2018/6/13/17449118/stanford-prison-experiment-fraud-psychology-replication.
18. ↑ Caroll, L. (2021, October 14). *Remember the stanford prison experiment? it was a lie*. Medium. Retrieved December 4, 2021, from https://historyofyesterday.com/remember-the-stanford-prison-experiment-it-was-a-lie-7957c9f09060.
19. ↑ 19.0 19.1 19.2 19.3 Blum, B. (2019, September 6). *The lifespan of a lie*. Medium. Retrieved December 5, 2021, from https://gen.medium.com/the-lifespan-of-a-lie-d869212b1f62.
20. ↑ Leithead, A. (2011, August 17). *Stanford prison experiment continues to shock*. BBC News. Retrieved December 3, 2021, from https://www.bbc.com/news/world-us-canada-14564182.
21. ↑ Cohen, N. (2019, August 19). *Beware the epiphany-industrial complex*. Wired. Retrieved December 5, 2021, from https://www.wired.com/story/beware-the-epiphany-industrial-complex/.
22. ↑ Geggel, L. (2018, June 15). *One of psychology's most famous experiments was deeply flawed*. LiveScience. Retrieved December 5, 2021, from https://www.livescience.com/62832-stanford-prison-experiment-flawed.html.
23. ↑ Toppo, G. (n.d.). *New Stanford Prison Experiment Revelations Question findings*. New Stanford Prison Experiment revelations question findings. Retrieved December 4, 2021, from https://www.insidehighered.com/news/2018/06/20/new-stanford-prison-experiment-revelations-question-findings.
24. ↑ McGreal, S. A. (2019, September 27). *Twilight of the stanford prison experiment*. Psychology Today. Retrieved December 4, 2021, from https://www.psychologytoday.com/us/blog/unique-everybody-else/201909/twilight-the-stanford-prison-experiment.
25. ↑ 25.0 25.1 Le Texier, T. (2019). Debunking the Stanford prison experiment. *American Psychologist, 74*(7), 823-839. https://doi.org/10.1037/amp0000401
26. ↑ Gray, P. (2013, October 19). *Why Zimbardo’s prison experiment isn’t in my textbook ...* PsychologyToday. Retrieved December 4, 2021, from https://www.psychologytoday.com/us/blog/freedom-learn/201310/why-zimbardo-s-prison-experiment-isn-t-in-my-textbook.
27. ↑ Carey, B. (2018, July 16). *Psychology itself is under scrutiny*. The New York Times. Retrieved December 5, 2021, from https://www.nytimes.com/2018/07/16/health/psychology-studies-stanford-prison.html.