conformity prison experiment

Stanford Prison Experiment: Zimbardo’s Famous Study

Saul Mcleod, PhD

Editor-in-Chief for Simply Psychology

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Saul Mcleod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

Learn about our Editorial Process

Olivia Guy-Evans, MSc

Associate Editor for Simply Psychology

BSc (Hons) Psychology, MSc Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

On This Page:

• The experiment was conducted in 1971 by psychologist Philip Zimbardo to examine situational forces versus dispositions in human behavior.
• 24 young, healthy, psychologically normal men were randomly assigned to be “prisoners” or “guards” in a simulated prison environment.
• The experiment had to be terminated after only 6 days due to the extreme, pathological behavior emerging in both groups. The situational forces overwhelmed the dispositions of the participants.
• Pacifist young men assigned as guards began behaving sadistically, inflicting humiliation and suffering on the prisoners. Prisoners became blindly obedient and allowed themselves to be dehumanized.
• The principal investigator, Zimbardo, was also transformed into a rigid authority figure as the Prison Superintendent.
• The experiment demonstrated the power of situations to alter human behavior dramatically. Even good, normal people can do evil things when situational forces push them in that direction.

Zimbardo and his colleagues (1973) were interested in finding out whether the brutality reported among guards in American prisons was due to the sadistic personalities of the guards (i.e., dispositional) or had more to do with the prison environment (i.e., situational).

For example, prisoners and guards may have personalities that make conflict inevitable, with prisoners lacking respect for law and order and guards being domineering and aggressive.

Alternatively, prisoners and guards may behave in a hostile manner due to the rigid power structure of the social environment in prisons.

Zimbardo predicted the situation made people act the way they do rather than their disposition (personality).

To study people’s roles in prison situations, Zimbardo converted a basement of the Stanford University psychology building into a mock prison.

He advertised asking for volunteers to participate in a study of the psychological effects of prison life.

The 75 applicants who answered the ad were given diagnostic interviews and personality tests to eliminate candidates with psychological problems, medical disabilities, or a history of crime or drug abuse.

24 men judged to be the most physically & mentally stable, the most mature, & the least involved in antisocial behaviors were chosen to participate.

The participants did not know each other prior to the study and were paid $15 per day to take part in the experiment.

Participants were randomly assigned to either the role of prisoner or guard in a simulated prison environment. There were two reserves, and one dropped out, finally leaving ten prisoners and 11 guards.

Prisoners were treated like every other criminal, being arrested at their own homes, without warning, and taken to the local police station. They were fingerprinted, photographed and ‘booked.’

Then they were blindfolded and driven to the psychology department of Stanford University, where Zimbardo had had the basement set out as a prison, with barred doors and windows, bare walls and small cells. Here the deindividuation process began.

When the prisoners arrived at the prison they were stripped naked, deloused, had all their personal possessions removed and locked away, and were given prison clothes and bedding. They were issued a uniform, and referred to by their number only.

The use of ID numbers was a way to make prisoners feel anonymous. Each prisoner had to be called only by his ID number and could only refer to himself and the other prisoners by number.

Their clothes comprised a smock with their number written on it, but no underclothes. They also had a tight nylon cap to cover their hair, and a locked chain around one ankle.

All guards were dressed in identical uniforms of khaki, and they carried a whistle around their neck and a billy club borrowed from the police. Guards also wore special sunglasses, to make eye contact with prisoners impossible.

Three guards worked shifts of eight hours each (the other guards remained on call). Guards were instructed to do whatever they thought was necessary to maintain law and order in the prison and to command the respect of the prisoners. No physical violence was permitted.

Zimbardo observed the behavior of the prisoners and guards (as a researcher), and also acted as a prison warden.

Within a very short time both guards and prisoners were settling into their new roles, with the guards adopting theirs quickly and easily.

Asserting Authority

Within hours of beginning the experiment, some guards began to harass prisoners. At 2:30 A.M. prisoners were awakened from sleep by blasting whistles for the first of many “counts.”

The counts served as a way to familiarize the prisoners with their numbers. More importantly, they provided a regular occasion for the guards to exercise control over the prisoners.

The prisoners soon adopted prisoner-like behavior too. They talked about prison issues a great deal of the time. They ‘told tales’ on each other to the guards.

They started taking the prison rules very seriously, as though they were there for the prisoners’ benefit and infringement would spell disaster for all of them. Some even began siding with the guards against prisoners who did not obey the rules.

Physical Punishment

The prisoners were taunted with insults and petty orders, they were given pointless and boring tasks to accomplish, and they were generally dehumanized.

Push-ups were a common form of physical punishment imposed by the guards. One of the guards stepped on the prisoners” backs while they did push-ups, or made other prisoners sit on the backs of fellow prisoners doing their push-ups.

Asserting Independence

Because the first day passed without incident, the guards were surprised and totally unprepared for the rebellion which broke out on the morning of the second day.

During the second day of the experiment, the prisoners removed their stocking caps, ripped off their numbers, and barricaded themselves inside the cells by putting their beds against the door.

The guards called in reinforcements. The three guards who were waiting on stand-by duty came in and the night shift guards voluntarily remained on duty.

Putting Down the Rebellion

The guards retaliated by using a fire extinguisher which shot a stream of skin-chilling carbon dioxide, and they forced the prisoners away from the doors. Next, the guards broke into each cell, stripped the prisoners naked and took the beds out.

The ringleaders of the prisoner rebellion were placed into solitary confinement. After this, the guards generally began to harass and intimidate the prisoners.

Special Privileges

One of the three cells was designated as a “privilege cell.” The three prisoners least involved in the rebellion were given special privileges. The guards gave them back their uniforms and beds and allowed them to wash their hair and brush their teeth.

Privileged prisoners also got to eat special food in the presence of the other prisoners who had temporarily lost the privilege of eating. The effect was to break the solidarity among prisoners.

Consequences of the Rebellion

Over the next few days, the relationships between the guards and the prisoners changed, with a change in one leading to a change in the other. Remember that the guards were firmly in control and the prisoners were totally dependent on them.

As the prisoners became more dependent, the guards became more derisive towards them. They held the prisoners in contempt and let the prisoners know it. As the guards’ contempt for them grew, the prisoners became more submissive.

As the prisoners became more submissive, the guards became more aggressive and assertive. They demanded ever greater obedience from the prisoners. The prisoners were dependent on the guards for everything, so tried to find ways to please the guards, such as telling tales on fellow prisoners.

Prisoner #8612

Less than 36 hours into the experiment, Prisoner #8612 began suffering from acute emotional disturbance, disorganized thinking, uncontrollable crying, and rage.

After a meeting with the guards where they told him he was weak, but offered him “informant” status, #8612 returned to the other prisoners and said “You can”t leave. You can’t quit.”

Soon #8612 “began to act ‘crazy,’ to scream, to curse, to go into a rage that seemed out of control.” It wasn’t until this point that the psychologists realized they had to let him out.

A Visit from Parents

The next day, the guards held a visiting hour for parents and friends. They were worried that when the parents saw the state of the jail, they might insist on taking their sons home. Guards washed the prisoners, had them clean and polish their cells, fed them a big dinner and played music on the intercom.

After the visit, rumors spread of a mass escape plan. Afraid that they would lose the prisoners, the guards and experimenters tried to enlist help and facilities of the Palo Alto police department.

The guards again escalated the level of harassment, forcing them to do menial, repetitive work such as cleaning toilets with their bare hands.

Catholic Priest

Zimbardo invited a Catholic priest who had been a prison chaplain to evaluate how realistic our prison situation was. Half of the prisoners introduced themselves by their number rather than name.

The chaplain interviewed each prisoner individually. The priest told them the only way they would get out was with the help of a lawyer.

Prisoner #819

Eventually, while talking to the priest, #819 broke down and began to cry hysterically, just like two previously released prisoners had.

The psychologists removed the chain from his foot, the cap off his head, and told him to go and rest in a room that was adjacent to the prison yard. They told him they would get him some food and then take him to see a doctor.

While this was going on, one of the guards lined up the other prisoners and had them chant aloud:

“Prisoner #819 is a bad prisoner. Because of what Prisoner #819 did, my cell is a mess, Mr. Correctional Officer.”

The psychologists realized #819 could hear the chanting and went back into the room where they found him sobbing uncontrollably. The psychologists tried to get him to agree to leave the experiment, but he said he could not leave because the others had labeled him a bad prisoner.

Back to Reality

At that point, Zimbardo said, “Listen, you are not #819. You are [his name], and my name is Dr. Zimbardo. I am a psychologist, not a prison superintendent, and this is not a real prison. This is just an experiment, and those are students, not prisoners, just like you. Let’s go.”

He stopped crying suddenly, looked up and replied, “Okay, let’s go,“ as if nothing had been wrong.

An End to the Experiment

Zimbardo (1973) had intended that the experiment should run for two weeks, but on the sixth day, it was terminated, due to the emotional breakdowns of prisoners, and excessive aggression of the guards.

Christina Maslach, a recent Stanford Ph.D. brought in to conduct interviews with the guards and prisoners, strongly objected when she saw the prisoners being abused by the guards.

Filled with outrage, she said, “It’s terrible what you are doing to these boys!” Out of 50 or more outsiders who had seen our prison, she was the only one who ever questioned its morality.

Zimbardo (2008) later noted, “It wasn’t until much later that I realized how far into my prison role I was at that point — that I was thinking like a prison superintendent rather than a research psychologist.“

This led him to prioritize maintaining the experiment’s structure over the well-being and ethics involved, thereby highlighting the blurring of roles and the profound impact of the situation on human behavior.

Here’s a quote that illustrates how Philip Zimbardo, initially the principal investigator, became deeply immersed in his role as the “Stanford Prison Superintendent (April 19, 2011):

“By the third day, when the second prisoner broke down, I had already slipped into or been transformed into the role of “Stanford Prison Superintendent.” And in that role, I was no longer the principal investigator, worried about ethics. When a prisoner broke down, what was my job? It was to replace him with somebody on our standby list. And that’s what I did. There was a weakness in the study in not separating those two roles. I should only have been the principal investigator, in charge of two graduate students and one undergraduate.”

According to Zimbardo and his colleagues, the Stanford Prison Experiment revealed how people will readily conform to the social roles they are expected to play, especially if the roles are as strongly stereotyped as those of the prison guards.

Because the guards were placed in a position of authority, they began to act in ways they would not usually behave in their normal lives.

The “prison” environment was an important factor in creating the guards’ brutal behavior (none of the participants who acted as guards showed sadistic tendencies before the study).

Therefore, the findings support the situational explanation of behavior rather than the dispositional one.

Zimbardo proposed that two processes can explain the prisoner’s “final submission.”

Deindividuation may explain the behavior of the participants; especially the guards. This is a state when you become so immersed in the norms of the group that you lose your sense of identity and personal responsibility.

The guards may have been so sadistic because they did not feel what happened was down to them personally – it was a group norm. They also may have lost their sense of personal identity because of the uniform they wore.

Also, learned helplessness could explain the prisoner’s submission to the guards. The prisoners learned that whatever they did had little effect on what happened to them. In the mock prison the unpredictable decisions of the guards led the prisoners to give up responding.

After the prison experiment was terminated, Zimbardo interviewed the participants. Here’s an excerpt:

‘Most of the participants said they had felt involved and committed. The research had felt “real” to them. One guard said, “I was surprised at myself. I made them call each other names and clean the toilets out with their bare hands. I practically considered the prisoners cattle and I kept thinking I had to watch out for them in case they tried something.” Another guard said “Acting authoritatively can be fun. Power can be a great pleasure.” And another: “… during the inspection I went to Cell Two to mess up a bed which a prisoner had just made and he grabbed me, screaming that he had just made it and that he was not going to let me mess it up. He grabbed me by the throat and although he was laughing I was pretty scared. I lashed out with my stick and hit him on the chin although not very hard, and when I freed myself I became angry.”’

Most of the guards found it difficult to believe that they had behaved in the brutal ways that they had. Many said they hadn’t known this side of them existed or that they were capable of such things.

The prisoners, too, couldn’t believe that they had responded in the submissive, cowering, dependent way they had. Several claimed to be assertive types normally.

When asked about the guards, they described the usual three stereotypes that can be found in any prison: some guards were good, some were tough but fair, and some were cruel.

A further explanation for the behavior of the participants can be described in terms of reinforcement.  The escalation of aggression and abuse by the guards could be seen as being due to the positive reinforcement they received both from fellow guards and intrinsically in terms of how good it made them feel to have so much power.

Similarly, the prisoners could have learned through negative reinforcement that if they kept their heads down and did as they were told, they could avoid further unpleasant experiences.

Critical Evaluation

Ecological validity.

The Stanford Prison Experiment is criticized for lacking ecological validity in its attempt to simulate a real prison environment. Specifically, the “prison” was merely a setup in the basement of Stanford University’s psychology department.

The student “guards” lacked professional training, and the experiment’s duration was much shorter than real prison sentences. Furthermore, the participants, who were college students, didn’t reflect the diverse backgrounds typically found in actual prisons in terms of ethnicity, education, and socioeconomic status.

None had prior prison experience, and they were chosen due to their mental stability and low antisocial tendencies. Additionally, the mock prison lacked spaces for exercise or rehabilitative activities.

Demand characteristics

Demand characteristics could explain the findings of the study. Most of the guards later claimed they were simply acting. Because the guards and prisoners were playing a role, their behavior may not be influenced by the same factors which affect behavior in real life. This means the study’s findings cannot be reasonably generalized to real life, such as prison settings. I.e, the study has low ecological validity.

One of the biggest criticisms is that strong demand characteristics confounded the study. Banuazizi and Movahedi (1975) found that the majority of respondents, when given a description of the study, were able to guess the hypothesis and predict how participants were expected to behave.

This suggests participants may have simply been playing out expected roles rather than genuinely conforming to their assigned identities.

In addition, revelations by Zimbardo (2007) indicate he actively encouraged the guards to be cruel and oppressive in his orientation instructions prior to the start of the study. For example, telling them “they [the prisoners] will be able to do nothing and say nothing that we don’t permit.”

He also tacitly approved of abusive behaviors as the study progressed. This deliberate cueing of how participants should act, rather than allowing behavior to unfold naturally, indicates the study findings were likely a result of strong demand characteristics rather than insightful revelations about human behavior.

However, there is considerable evidence that the participants did react to the situation as though it was real. For example, 90% of the prisoners’ private conversations, which were monitored by the researchers, were on the prison conditions, and only 10% of the time were their conversations about life outside of the prison.

The guards, too, rarely exchanged personal information during their relaxation breaks – they either talked about ‘problem prisoners,’ other prison topics, or did not talk at all. The guards were always on time and even worked overtime for no extra pay.

When the prisoners were introduced to a priest, they referred to themselves by their prison number, rather than their first name. Some even asked him to get a lawyer to help get them out.

Fourteen years after his experience as prisoner 8612 in the Stanford Prison Experiment, Douglas Korpi, now a prison psychologist, reflected on his time and stated (Musen and Zimbardo 1992):

“The Stanford Prison Experiment was a very benign prison situation and it promotes everything a normal prison promotes — the guard role promotes sadism, the prisoner role promotes confusion and shame”.

Sample bias

The study may also lack population validity as the sample comprised US male students. The study’s findings cannot be applied to female prisons or those from other countries. For example, America is an individualist culture (where people are generally less conforming), and the results may be different in collectivist cultures (such as Asian countries).

Carnahan and McFarland (2007) have questioned whether self-selection may have influenced the results – i.e., did certain personality traits or dispositions lead some individuals to volunteer for a study of “prison life” in the first place?

All participants completed personality measures assessing: aggression, authoritarianism, Machiavellianism, narcissism, social dominance, empathy, and altruism. Participants also answered questions on mental health and criminal history to screen out any issues as per the original SPE.

Results showed that volunteers for the prison study, compared to the control group, scored significantly higher on aggressiveness, authoritarianism, Machiavellianism, narcissism, and social dominance. They scored significantly lower on empathy and altruism.

A follow-up role-playing study found that self-presentation biases could not explain these differences. Overall, the findings suggest that volunteering for the prison study was influenced by personality traits associated with abusive tendencies.

Zimbardo’s conclusion may be wrong

While implications for the original SPE are speculative, this lends support to a person-situation interactionist perspective, rather than a purely situational account.

It implies that certain individuals are drawn to and selected into situations that fit their personality, and that group composition can shape behavior through mutual reinforcement.

Contributions to psychology

Another strength of the study is that the harmful treatment of participants led to the formal recognition of ethical  guidelines by the American Psychological Association. Studies must now undergo an extensive review by an institutional review board (US) or ethics committee (UK) before they are implemented.

Most institutions, such as universities, hospitals, and government agencies, require a review of research plans by a panel. These boards review whether the potential benefits of the research are justifiable in light of the possible risk of physical or psychological harm.

These boards may request researchers make changes to the study’s design or procedure, or, in extreme cases, deny approval of the study altogether.

Contribution to prison policy

A strength of the study is that it has altered the way US prisons are run. For example, juveniles accused of federal crimes are no longer housed before trial with adult prisoners (due to the risk of violence against them).

However, in the 25 years since the SPE, U.S. prison policy has transformed in ways counter to SPE insights (Haney & Zimbardo, 1995):

• Rehabilitation was abandoned in favor of punishment and containment. Prison is now seen as inflicting pain rather than enabling productive re-entry.
• Sentencing became rigid rather than accounting for inmates’ individual contexts. Mandatory minimums and “three strikes” laws over-incarcerate nonviolent crimes.
• Prison construction boomed, and populations soared, disproportionately affecting minorities. From 1925 to 1975, incarceration rates held steady at around 100 per 100,000. By 1995, rates tripled to over 600 per 100,000.
• Drug offenses account for an increasing proportion of prisoners. Nonviolent drug offenses make up a large share of the increased incarceration.
• Psychological perspectives have been ignored in policymaking. Legislators overlooked insights from social psychology on the power of contexts in shaping behavior.
• Oversight retreated, with courts deferring to prison officials and ending meaningful scrutiny of conditions. Standards like “evolving decency” gave way to “legitimate” pain.
• Supermax prisons proliferated, isolating prisoners in psychological trauma-inducing conditions.

The authors argue psychologists should reengage to:

• Limit the use of imprisonment and adopt humane alternatives based on the harmful effects of prison environments
• Assess prisons’ total environments, not just individual conditions, given situational forces interact
• Prepare inmates for release by transforming criminogenic post-release contexts
• Address socioeconomic risk factors, not just incarcerate individuals
• Develop contextual prediction models vs. focusing only on static traits
• Scrutinize prison systems independently, not just defer to officials shaped by those environments
• Generate creative, evidence-based reforms to counter over-punitive policies

Psychology once contributed to a more humane system and can again counter the U.S. “rage to punish” with contextual insights (Haney & Zimbardo, 1998).

Evidence for situational factors

Zimbardo (1995) further demonstrates the power of situations to elicit evil actions from ordinary, educated people who likely would never have done such things otherwise. It was another situation-induced “transformation of human character.”

• Unit 731 was a covert biological and chemical warfare research unit of the Japanese army during WWII.
• It was led by General Shiro Ishii and involved thousands of doctors and researchers.
• Unit 731 set up facilities near Harbin, China to conduct lethal human experimentation on prisoners, including Allied POWs.
• Experiments involved exposing prisoners to things like plague, anthrax, mustard gas, and bullets to test biological weapons. They infected prisoners with diseases and monitored their deaths.
• At least 3,000 prisoners died from these brutal experiments. Many were killed and dissected.
• The doctors in Unit 731 obeyed orders unquestioningly and conducted these experiments in the name of “medical science.”
• After the war, the vast majority of doctors who participated faced no punishment and went on to have prestigious careers. This was largely covered up by the U.S. in exchange for data.
• It shows how normal, intelligent professionals can be led by situational forces to systematically dehumanize victims and conduct incredibly cruel and lethal experiments on people.
• Even healers trained to preserve life used their expertise to destroy lives when the situational forces compelled obedience, nationalism, and wartime enmity.

Evidence for an interactionist approach

The results are also relevant for explaining abuses by American guards at Abu Ghraib prison in Iraq.

An interactionist perspective recognizes that volunteering for roles as prison guards attracts those already prone to abusive tendencies, which are intensified by the prison context.

This counters a solely situationist view of good people succumbing to evil situational forces.

Ethical Issues

The study has received many ethical criticisms, including lack of fully informed consent by participants as Zimbardo himself did not know what would happen in the experiment (it was unpredictable). Also, the prisoners did not consent to being “arrested” at home. The prisoners were not told partly because final approval from the police wasn’t given until minutes before the participants decided to participate, and partly because the researchers wanted the arrests to come as a surprise. However, this was a breach of the ethics of Zimbardo’s own contract that all of the participants had signed.

Protection of Participants

Participants playing the role of prisoners were not protected from psychological harm, experiencing incidents of humiliation and distress. For example, one prisoner had to be released after 36 hours because of uncontrollable bursts of screaming, crying, and anger.

Here’s a quote from Philip G. Zimbardo, taken from an interview on the Stanford Prison Experiment’s 40th anniversary (April 19, 2011):

“In the Stanford prison study, people were stressed, day and night, for 5 days, 24 hours a day. There’s no question that it was a high level of stress because five of the boys had emotional breakdowns, the first within 36 hours. Other boys that didn’t have emotional breakdowns were blindly obedient to corrupt authority by the guards and did terrible things to each other. And so it is no question that that was unethical. You can’t do research where you allow people to suffer at that level.”

“After the first one broke down, we didn’t believe it. We thought he was faking. There was actually a rumor he was faking to get out. He was going to bring his friends in to liberate the prison. And/or we believed our screening procedure was inadequate, [we believed] that he had some mental defect that we did not pick up. At that point, by the third day, when the second prisoner broke down, I had already slipped into or been transformed into the role of “Stanford Prison Superintendent.” And in that role, I was no longer the principal investigator, worried about ethics.”

However, in Zimbardo’s defense, the emotional distress experienced by the prisoners could not have been predicted from the outset.

Approval for the study was given by the Office of Naval Research, the Psychology Department, and the University Committee of Human Experimentation.

This Committee also did not anticipate the prisoners’ extreme reactions that were to follow. Alternative methodologies were looked at that would cause less distress to the participants but at the same time give the desired information, but nothing suitable could be found.

Withdrawal 

Although guards were explicitly instructed not to physically harm prisoners at the beginning of the Stanford Prison Experiment, they were allowed to induce feelings of boredom, frustration, arbitrariness, and powerlessness among the inmates.

This created a pervasive atmosphere where prisoners genuinely believed and even reinforced among each other, that they couldn’t leave the experiment until their “sentence” was completed, mirroring the inescapability of a real prison.

Even though two participants (8612 and 819) were released early, the impact of the environment was so profound that prisoner 416, reflecting on the experience two months later, described it as a “prison run by psychologists rather than by the state.”

Extensive group and individual debriefing sessions were held, and all participants returned post-experimental questionnaires several weeks, then several months later, and then at yearly intervals. Zimbardo concluded there were no lasting negative effects.

Zimbardo also strongly argues that the benefits gained from our understanding of human behavior and how we can improve society should outbalance the distress caused by the study.

However, it has been suggested that the US Navy was not so much interested in making prisons more human and were, in fact, more interested in using the study to train people in the armed services to cope with the stresses of captivity.

Discussion Questions

What are the effects of living in an environment with no clocks, no view of the outside world, and minimal sensory stimulation?

Consider the psychological consequences of stripping, delousing, and shaving the heads of prisoners or members of the military. Whattransformations take place when people go through an experience like this?

The prisoners could have left at any time, and yet, they didn’t. Why?

After the study, how do you think the prisoners and guards felt?

If you were the experimenter in charge, would you have done this study? Would you have terminated it earlier? Would you have conducted a follow-up study?

Frequently Asked Questions

What happened to prisoner 8612 after the experiment.

Douglas Korpi, as prisoner 8612, was the first to show signs of severe distress and demanded to be released from the experiment. He was released on the second day, and his reaction to the simulated prison environment highlighted the study’s ethical issues and the potential harm inflicted on participants.

After the experiment, Douglas Korpi graduated from Stanford University and earned a Ph.D. in clinical psychology. He pursued a career as a psychotherapist, helping others with their mental health struggles.

Why did Zimbardo not stop the experiment?

Zimbardo did not initially stop the experiment because he became too immersed in his dual role as the principal investigator and the prison superintendent, causing him to overlook the escalating abuse and distress among participants.

It was only after an external observer, Christina Maslach, raised concerns about the participants’ well-being that Zimbardo terminated the study.

What happened to the guards in the Stanford Prison Experiment?

In the Stanford Prison Experiment, the guards exhibited abusive and authoritarian behavior, using psychological manipulation, humiliation, and control tactics to assert dominance over the prisoners. This ultimately led to the study’s early termination due to ethical concerns.

What did Zimbardo want to find out?

Zimbardo aimed to investigate the impact of situational factors and power dynamics on human behavior, specifically how individuals would conform to the roles of prisoners and guards in a simulated prison environment.

He wanted to explore whether the behavior displayed in prisons was due to the inherent personalities of prisoners and guards or the result of the social structure and environment of the prison itself.

What were the results of the Stanford Prison Experiment?

The results of the Stanford Prison Experiment showed that situational factors and power dynamics played a significant role in shaping participants’ behavior. The guards became abusive and authoritarian, while the prisoners became submissive and emotionally distressed.

The experiment revealed how quickly ordinary individuals could adopt and internalize harmful behaviors due to their assigned roles and the environment.

Banuazizi, A., & Movahedi, S. (1975). Interpersonal dynamics in a simulated prison: A methodological analysis. American Psychologist, 30 , 152-160.

Carnahan, T., & McFarland, S. (2007). Revisiting the Stanford prison experiment: Could participant self-selection have led to the cruelty? Personality and Social Psychology Bulletin, 33, 603-614.

Drury, S., Hutchens, S. A., Shuttlesworth, D. E., & White, C. L. (2012). Philip G. Zimbardo on his career and the Stanford Prison Experiment’s 40th anniversary.  History of Psychology ,  15 (2), 161.

Griggs, R. A., & Whitehead, G. I., III. (2014). Coverage of the Stanford Prison Experiment in introductory social psychology textbooks. Teaching of Psychology, 41 , 318 –324.

Haney, C., Banks, W. C., & Zimbardo, P. G. (1973). A study of prisoners and guards in a simulated prison . Naval Research Review , 30, 4-17.

Haney, C., & Zimbardo, P. (1998). The past and future of U.S. prison policy: Twenty-five years after the Stanford Prison Experiment.  American Psychologist, 53 (7), 709–727.

Musen, K. & Zimbardo, P. (1992) (DVD) Quiet Rage: The Stanford Prison Experiment Documentary.

Zimbardo, P. G. (Consultant, On-Screen Performer), Goldstein, L. (Producer), & Utley, G. (Correspondent). (1971, November 26). Prisoner 819 did a bad thing: The Stanford Prison Experiment [Television series episode]. In L. Goldstein (Producer), Chronolog. New York, NY: NBC-TV.

Zimbardo, P. G. (1973). On the ethics of intervention in human psychological research: With special reference to the Stanford prison experiment.  Cognition ,  2 (2), 243-256.

Zimbardo, P. G. (1995). The psychology of evil: A situationist perspective on recruiting good people to engage in anti-social acts.  Japanese Journal of Social Psychology ,  11 (2), 125-133.

Zimbardo, P.G. (2007). The Lucifer effect: Understanding how good people turn evil . New York, NY: Random House.

Further Information

• Reicher, S., & Haslam, S. A. (2006). Rethinking the psychology of tyranny: The BBC prison study. The British Journal of Social Psychology, 45 , 1.
• Coverage of the Stanford Prison Experiment in introductory psychology textbooks
• The Stanford Prison Experiment Official Website

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In This Article Expand or collapse the "in this article" section Stanford Prison Experiment (SPE): Icon and Controversy

Introduction, archival sources.

• Primary Documentation of the SPE
• Biographical Background
• SPE and Related Experiments in Media
• SPE in Textbooks, Handbooks, and Histories of Psychology
• Replication of the SPE and Related Replications
• Psychological Prison and Punishment Literature Related to the SPE
• Methodological Criticisms
• Ethical Criticisms
• Thibault Le Texier

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Stanford Prison Experiment (SPE): Icon and Controversy by David C. Devonis LAST REVIEWED: 26 August 2020 LAST MODIFIED: 26 August 2020 DOI: 10.1093/obo/9780199828340-0269

The Stanford Prison Experiment (SPE) took place at a time when the sources of authoritarianism and evil were a focal concern in psychology. It emerged from a tradition of activist social psychological research beginning with Solomon Asch in the 1940s and extending through Stanley Milgram’s obedience experiments in the early 1960s. The SPE was a product of the research program of social psychologist Philip Zimbardo, a member of the Stanford psychology faculty since 1968. Discussions among Zimbardo’s students in spring 1971 led to a plan to simulate a prison environment. They converted portions of the basement of a University building into a combination booking room and jail. Zimbardo and a number of his graduate and undergraduate students took on supervisory roles. Before the Experiment began, paid participants recruited through newspaper advertisements were screened to eliminate obvious psychopathology, then randomly assigned to either the role of ‘guard’ or ‘prisoner.’ On the first experimental morning August 14, 1971, actual local police simulated an arrest of each of the prisoner participants. After they arrived, blindfolded, a simulated booking took place. Guards escorted them to the prison hallway where prisoners were required to strip and exchange their clothing for simple shifts and slippers. After a simulated spray delousing, they entered makeshift cells. After this, the Experiment evolved as an extended improvisation, by both the guards and prisoners, on prison-related themes. Episodes of deprivation, bullying, and humiliation emerged unplanned. Originally planned to run for two weeks, the Experiment lasted only six days, prematurely terminated when its supervising personnel judged that the simulation had gotten out of their control. The coincidence of its termination with the Attica prison uprising in New York led to its immediate dissemination in the news. Since then the SPE has become one of the most iconic psychological studies of psychology’s modern era. Although intended to expose and ameliorate bad prison conditions, its effectiveness in this regard diminished during a rapid shift in US prison policy, in the mid-1970’s, from reform to repression. Over succeeding decades, the Experiment continued to stimulate the popular imagination, leading to an extensive replication on British television and its portrayal in two feature films. Soon after its original publication, the SPE attracted criticisms of its methodology. After 2010, critical scrutiny of the SPE as well as similar iconic studies from the 1960s and 1970s increased, fueled by the growing ‘replication crisis’ in psychology. This most recent phase of criticism reflects not just a turn toward reflexive disciplinary self-criticism but also the increased availability of archival sources for examination. The SPE continues to excite both passionate support and equally passionate obloquy, much as have other comparable simulations of human social behavior.

Philip Zimbardo, the primary investigator of the SPE, has been unusually generous in making archival donations during his lifetime. Two of these are physical archives in two different locations: the Zimbardo (Philip G.) Papers at the Stanford University Archives and the Philip Zimbardo Papers at the Drs. Nicholas and Dorothy Cummings Center for the History of Psychology (CCHP) at the University of Akron. Alongside these is a virtual archive, the Stanford Prison Experiment website, maintained for over twenty years by Zimbardo and others. The Stanford Prison Experiment: 40 Years Later , a website constructed by the Stanford University archivist in connection with an exhibition at Stanford, contains links to much of the transcribed data collected by Zimbardo and his colleagues in 1971. Le Texier 2018 and Le Texier 2019 (cited under Thibault Le Texier ) represent the most complete use of the archives to date, and citations in these critiques of the SPE form a virtual finding aid for the many subdivisions of the available archival material.

Philip Zimbardo Papers. Drs. Nicholas and Dorothy Cummings Center for the History of Psychology (CCHP). Univ. of Akron, Akron, Ohio.

This collection, a subset (4.5 linear feet in 16 boxes) of the Stanford Zimbardo archive, is focused on the SPE. It contains SPE-specific materials, teaching materials, and materials relating to the development of Zimbardo 2008 (cited under Primary Documentation of the SPE ). The CCHP also holds several oversize folders of SPE materials and has some of the original props and costumes from the SPE. The finding aid also has a brief Zimbardo biography. The finding aid is available online .

The Stanford Prison Experiment .

Well-designed and informative website, maintained with National Science Foundation (NSF) funding under sponsorship of the Social Psychology Network, with links to much of the primary documentary and contextual material relating to the SPE as well as to major media presentations of the Experiment. Historically it evolved from the original slide show Zimbardo and White 1972 (cited under SPE and Related Experiments in Media ) circulated among social psychologists in the 1970s.

The Stanford Prison Experiment: 40 Years Later In Stanford Libraries: Special Collections and University Archives .

This site contains copies of material related to the SPE from the Stanford Archives, including accessible transcripts of several documents related to the SPE such as the original informed consent forms, audio clips, and photos, as well as links to the original eighty-slide slideshow from the 1970s.

Zimbardo (Philip G.) Papers. Stanford University Archives, Collection SC0750.

This collection runs 256 linear feet in 182 boxes, and contains material directly and peripherally related to the SPE, including a substantial amount of audiovisual and film material and materials used in Zimbardo’s classes at Stanford. The finding aid, available online , has a brief Zimbardo biography attached.

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The Stanford Prison Experiment: The Power of the Situation

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Philip Zimbardo is best known for his 1971 Stanford Prison Experiment (SPE). Early in his career, he conducted experiments in the psychology of deindividualization, in which a person in a group or crowd no longer acts as a responsible individual but is swept along and participates in antisocial actions. After moving to Stanford University, he began to focus on institutional power over the individual in group settings, such as long-term care facilities for the elderly and prisons. His research proposal for a simulated prison was approved by the Stanford University Human Subjects Research Review Committee in July 1971. He built a mock prison in the basement of the University’s psychology building and recruited college-aged male subjects to play prisoners and guards. The study began on Sunday, August 8th, and was to run for 2 weeks but ended on Friday morning August 13th. In less than a week, several of the mock guards hazed and brutalized the mock prisoners, some of whom found ways of coping, while others exhibited symptoms of mental breakdown.

The degree of civilization in a society can be judged by entering its prisons. — attributed to Fyodor Dostoevsky, The House of the Dead

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I wish to thank Chris Herrera, Jonathan K. Rosen, David Segal and Ruth Spivak for their comments on this chapter.

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Perlstadt, H. (2023). The Stanford Prison Experiment: The Power of the Situation. In: Assessing Social Science Research Ethics and Integrity. Clinical Sociology: Research and Practice. Springer, Cham. https://doi.org/10.1007/978-3-031-34538-8_8

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What the Stanford Prison Experiment Taught Us

In August of 1971, Dr. Philip G. Zimbardo of Stanford University in California conducted what is widely considered one of the most influential experiments in social psychology to date. Made into a New York Times best seller in 2007 ( The Lucifer Effect ) and a major motion picture in 2015 ( The Stanford Prison Experiment ), the Stanford Prison Experiment has integrated itself not only into the psychology community but also popular culture. The events that occurred within this experiment, though disturbing, have given many people insight into just how much a situation can affect behavior. They have also caused many to ponder the nature of evil. How disturbing was it? Well, the proposed two-week experiment was terminated after just six days, due to alarming levels of mistreatment and brutality perpetrated on student “prisoners” by fellow student “guards.”

The study aimed to test the effects of prison life on behavior and wanted to tackle the effects of situational behavior rather than just those of disposition. After placing an ad in the newspaper, Zimbardo selected 24 mentally and physically healthy undergraduate students to participate in the study. The idea was to randomly assign nine boys to be prisoners, nine to be guards, and six to be extras should they need to make any replacements. After randomly assigning the boys, the nine deemed prisoners were “arrested” and promptly brought into a makeshift Stanford County Prison, which was really just the basement of the Stanford Psychology Department building. Upon arrival, the boys’ heads were shaved, and they were subjected to a strip search as well as delousing (measures taken to dehumanize the prisoners). Each prisoner was then issued a uniform and a number to increase anonymity. The guards who were to be in charge of the prisoners were not given any formal training; they were to make up their own set of rules as to how they would govern their prison.

Over the course of six days, a shocking set of events unfolded. While day one seemed to go by without issue, on the second day there was a rebellion, causing guards to spray prisoners with a fire extinguisher in order to force them further into their cells. The guards took the prisoners’ beds and even utilized solitary confinement. They also began to use psychological tactics, attempting to break prisoner solidarity by creating a privilege cell. With each member of the experiment, including Zimbardo, falling deeper into their roles, this “prison” life quickly became a real and threatening situation for many. Thirty-six hours into the experiment, prisoner #8612 was released on account of acute emotional distress, but only after (incorrectly) telling his prison-mates that they were trapped and not allowed to leave, insisting that it was no longer an experiment. This perpetuated a lot of the fears that many of the prisoners were already experiencing, which caused prisoner #819 to be released a day later after becoming hysterical in Dr. Zimbardo’s office.

The guards got even crueler and more unusual in their punishments as time progressed, forcing prisoners to participate in sexual situations such as leap-frogging each other’s partially naked bodies. They took food privileges away and forced the prisoners to insult one another. Even the prisoners fell victim to their roles of submission. At a fake parole board hearing, each of them was asked if they would forfeit all money earned should they be allowed to leave the prison immediately. Most of them said yes, then were upset when they were not granted parole, despite the fact that they were allowed to opt out of the experiment at any time. They had fallen too far into submissive roles to remember, or even consider, their rights.

On the sixth day, Dr. Zimbardo closed the experiment due to the continuing degradation of the prisoners’ emotional and mental states. While his findings were, at times, a terrifying glimpse into the capabilities of humanity, they also advanced the understanding of the psychological community. When it came to the torture done at Abu Ghraib or the Rape of Nanjing in China, Zimbardo’s findings allowed for psychologists to understand evil behavior as a situational occurrence and not always a dispositional one.

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Conformity to Social Roles as Investigated by Zimbardo

Last updated 22 Mar 2021

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Zimbardo (1973) conducted an extremely controversial study on conformity to social roles, called the Stanford Prison Experiment.

His aim was to examine whether people would conform to the social roles of a prison guard or prisoner, when placed in a mock prison environment. Furthermore, he also wanted to examine whether the behaviour displayed in prisons was due to internal dispositional factors, the people themselves, or external situational factors, the environment and conditions of the prison.

Zimbardo’s sample consisted of 21 male university students who volunteered in response to a newspaper advert. The participants were selected on the basis of their physical and mental stability and were each paid $15 a day to take part. The participants were randomly assigned to one of two social roles, prisoners or guards.

Zimbardo wanted to make the experience as realistic as possible, turning the basement of Stanford University into a mock prison. Furthermore, the ‘prisoners’ were arrested by real local police and fingerprinted, stripped and given a numbered smocked to wear, with chains placed around their ankles. The guards were given uniforms, dark reflective sunglasses, handcuffs and a truncheon. The guards were instructed to run the prison without using physical violence. The experiment was set to run for two weeks.

Zimbardo found that both the prisoners and guards quickly identified with their social roles. Within days the prisoners rebelled, but this was quickly crushed by the guards, who then grew increasingly abusive towards the prisoners. The guards dehumanised the prisoners, waking them during the night and forcing them to clean toilets with their bare hands; the prisoners became increasingly submissive, identifying further with their subordinate role.

Five of the prisoners were released from the experiment early, because of their adverse reactions to the physical and mental torment, for example, crying and extreme anxiety. Although the experiment was set to run for two weeks, it was terminated after just six days, when fellow postgraduate student Christina Maslach convinced Zimbardo that conditions in his experiment were inhumane. [Maslach later became Zimbardo’s wife].

Zimbardo concluded that people quickly conform to social roles, even when the role goes against their moral principles. Furthermore, he concluded that situational factors were largely responsible for the behaviour found, as none of the participants had ever demonstrated these behaviours previously.

Evaluation of Zimbardo

A recent replication of the Stanford Prison Experiment, carried out by Reicher and Haslam (2006), contradicts the findings of Zimbardo.

Reicher and Haslam replicated Zimbardo’s research by randomly assigning 15 men to the role of prisoner or guard. In this replication, the participants did not conform to their social roles automatically. For example, the guards did not identify with their status and refused to impose their authority; the prisoners identified as a group to challenge the guard’s authority, which resulted in a shift of power and a collapse of the prison system. These results clearly contradict the findings of Zimbardo and suggest that conformity to social roles may not automatic, as Zimbardo originally implied.

Furthermore, individual differences and personality also determine the extent to which a person conforms to social roles. In Zimbardo’s original experiment the behaviour of the guards varied dramatically, from extremely sadistic behaviour to a few good guards who helped the prisoners. This suggests that situational factors are not the only cause of conformity to social roles and dispositional factors also play a role.

Zimbardo’s experiment has been heavily criticised for breaking many ethical guidelines, in particular, protection from harm. Five of the prisoners left the experiment early because of their adverse reactions to the physical and mental torment. Furthermore, some of the guards reported feelings of anxiety and guilt, as a result of their actions during the Stanford Prison Experiment. Although Zimbardo followed the ethical guidelines of Stanford University and debriefed his participants afterwards, he acknowledged that the study should have been stopped earlier.

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Conformity To Social Roles Zimabardo’s Prison Study

March 4, 2021 - paper 1 introductory topics in psychology | social psychology, ao1: description, key terms.

Conformity to Social Roles  Definition  the parts individuals play as members of a social group, which meet the expectations of that situation.

Each social situation has its own  social norms , an expected way for individuals to behave; these vary depending on the situation. For example joining a queue.

Conformity to social roles therefore involves  identification . Stronger than compliance, involving both public and private acceptance of behaviour and attitudes, it exists as long as the group does.

AO1: Description Research Into Conformity To Social Roles, Zimbardo 1973

Aim:  To investigate the extent to which people would conform to the roles of guard and prisoner in a role-playing simulation of prison life.

Conclusions: It was considered that the participants€™ behaviour was due to situational (the prison setting) factors rather than dispositional (as no participants had demonstrated such character traits before the investigation).

Individuals readily conform to the social roles that were demanded by the situation, these roles only existed as long as the participants were in the prison setting.https://www.youtube.com/embed/F4txhN13y6A?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-GB&autohide=2&wmode=transparent

AO3: Evaluation Of Zimbardo’s Research

Weaknesses:

(1) Point:  Zimbardo’s research can be criticised as lacking  ecological validity .  Evidence:   For example,  the participants were placed in an unfamiliar artificial setting and were expected to carry out an artificial task (the prisoners knew that they were not actually in prison and so many researchers have stated that the prisoners and guards were just simply playing a game and were not actually buying into the roles.  Evaluation:   This is a weaknesses  as the study is not reflective of the participants real life behaviour and therefore the findings regarding social roles from the study cannot be generalised beyond the artificial setting.

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4.3: The Stanford Prison Experiment

Chapter 1: research methods, chapter 2: the social self, chapter 3: social judgement and decision-making, chapter 4: understanding and influencing others, chapter 5: attitudes and persuasion, chapter 6: close relationships, chapter 7: stereotypes, prejudice, and discrimination, chapter 8: helping and hurting, chapter 9: group dynamics.

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There’s a dark side to the summer of 1971. Police “arrested” a number of college students who responded to an ad seeking volunteers for a psychological study of prison life.

Little did they know, in the basement of the Stanford Psychology Department, they were about to embark upon one of the most famous and controversial psychological studies: The Stanford Prison Experiment, led by Philip Zimbardo and colleagues.

After filling out an informational questionnaire, participants were randomly assigned to one of two groups: Prisoners—who were realistically picked up and booked by police—or Guards, who were in direct control of the inmates.

Depending on the assignment, they were dressed to fit their role —a set of expectations defining how those in the social position should behave.

For example, each guard was given a nightstick and whistle, along with mirrored aviator glasses, to emphasize their status and authority.

In addition, two researchers were present and oversaw the day-to-day operations: the lead experimenter, Zimbardo, acted as the prison superintendent, while another researcher, David Jaffe, was the Warden.

During one orientation session for the guards, Zimbardo vaguely outlined behaviors that they should conform with, like limiting the prisoners’ freedom and using their power to evoke fear and dominate non-violently.

In a follow-up session, the Warden provided more explicit directions to encourage the creation of a prison environment, for the collective good of the experiment.

With the correctional authorities in place, the prisoners entered the mock jail, which contained three cells and a closet for solitary confinement. They were stripped down, immediately degraded, and blindfolded to confuse them. Also, as part of their assigned role, they were outfitted in numbered gowns and nylon-stocking caps to depersonalize them.

On the second day, the prisoners started to rebel by blockading the cell door with the bed. As punishment, the ring leader was placed in confinement. This event precipitated the guards now turning on the other inmates, and the level of cruelty escalated.

Several guards… but not all …upped their performance to act tough—to fit the preconceived expectations of their label—all under the watchful eyes of the Warden and Superintendent. These leaders promoted toughness as a shared attribute of conforming to the in-group to achieve the goal of exposing the toxicity of the penal system.

Due to the increased and creative oppression placed on the prisoners, the experiment was terminated early, after six days instead of two weeks.

Ultimately, the guards behaved in a stereotypical tough-guy manner, striving to fit the normative guidance they were given. Sometimes, toxic situations can bring out the worst in someone, especially in cases where the individual identifies with a leader and the group’s collective cause.

The famous and controversial Stanford Prison Experiment , conducted by social psychologist Philip Zimbardo and his colleagues at Stanford University, demonstrated the power of social roles, social norms, and scripts.

Social Roles

One major social determinant of human behavior is our social role— a pattern of behavior that is expected of a person in a given setting or group (Hare, 2003). Each one of us has several social roles. You may be, at the same time, a student, a parent, an aspiring teacher, a son or daughter, a spouse, and a lifeguard. How do these social roles influence your behavior? Social roles are defined by culturally shared knowledge. That is, nearly everyone in a given culture knows what behavior is expected of a person in a given role. For example, what is the social role for a student? If you look around a college classroom you will likely see students engaging in studious behavior, taking notes, listening to the professor, reading the textbook, and sitting quietly at their desks. Of course, you may see students deviating from the expected studious behavior such as texting on their phones or using Facebook on their laptops, but in all cases, the students that you observe are attending class—a part of the social role of students.

Social roles, and our related behavior, can vary across different settings. How do you behave when you are engaging in the role of son or daughter and attending a family function? Now imagine how you behave when you are engaged in the role of employee at your workplace. It is very likely that your behavior will be different. Perhaps you are more relaxed and outgoing with your family, making jokes and doing silly things. But at your workplace you might speak more professionally, and although you may be friendly, you are also serious and focused on getting the work completed. These are examples of how our social roles influence and often dictate our behavior to the extent that identity and personality can vary with context (that is, in different social groups; Malloy, Albright, Kenny, Agatstein, & Winquist, 1997).

Social Norms

As discussed previously, social roles are defined by a culture’s shared knowledge of what is expected behavior of an individual in a specific role. This shared knowledge comes from social norms—a group’s expectations of what is appropriate and acceptable behavior for its members—how they are supposed to behave and think (Deutsch & Gerard, 1955; Berkowitz, 2004). How are we expected to act? What are we expected to talk about? What are we expected to wear? In our discussion of social roles, we noted that colleges have social norms for students’ behavior in the role of student and workplaces have social norms for employees’ behaviors in the role of employee. Social norms are everywhere including in families, gangs, and on social media outlets. 

Because of social roles, people tend to know what behavior is expected of them in specific, familiar settings. A script is a person’s knowledge about the sequence of events expected in a specific setting (Schank & Abelson, 1977). How do you act on the first day of school, when you walk into an elevator, or are at a restaurant? For example, at a restaurant in the United States, if we want the server’s attention, we try to make eye contact. In Brazil, you would make the sound “psst” to get the server’s attention. You can see the cultural differences in scripts. To an American, saying “psst” to a server might seem rude, yet to a Brazilian, trying to make eye contact might not seem an effective strategy. Scripts are important sources of information to guide behavior in given situations. Can you imagine being in an unfamiliar situation and not having a script for how to behave? This could be uncomfortable and confusing. How could you find out about social norms in an unfamiliar culture?

Zimbardo’s Stanford Prison Experiment

In the summer of 1971, an advertisement was placed in a California newspaper asking for male volunteers to participate in a study about the psychological effects of prison life. More than 70 men volunteered, and these volunteers then underwent psychological testing to eliminate candidates who had underlying psychiatric issues, medical issues, or a history of crime or drug abuse. The pool of volunteers was whittled down to 24 healthy male college students. Each student was paid $15 per day and was randomly assigned to play the role of either a prisoner or a guard in the study. Based on what you have learned about research methods, why is it important that participants were randomly assigned?

A mock prison was constructed in the basement of the psychology building at Stanford. Participants assigned to play the role of prisoners were “arrested” at their homes by Palo Alto police officers, booked at a police station, and subsequently taken to the mock prison. The experiment was scheduled to run for several weeks. To the surprise of the researchers, both the “prisoners” and “guards” assumed their roles with zeal. In fact, on day 2, some of the prisoners revolted, and the guards quelled the rebellion by threatening the prisoners with night sticks. In a relatively short time, the guards came to harass the prisoners in an increasingly sadistic manner, through a complete lack of privacy, lack of basic comforts such as mattresses to sleep on, and through degrading chores and late-night counts.

The prisoners, in turn, began to show signs of severe anxiety and hopelessness—they began tolerating the guards’ abuse. Even the Stanford professor who designed the study and was the head researcher, Philip Zimbardo, found himself acting as if the prison was real and his role, as prison supervisor, was real as well. After only six days, the experiment had to be ended due to the participants’ deteriorating behavior. 

The Stanford prison experiment demonstrated the power of social roles, norms, and scripts in affecting human behavior. The guards and prisoners enacted their social roles by engaging in behaviors appropriate to the roles: The guards gave orders and the prisoners followed orders. Social norms require guards to be authoritarian (such behavior was reinforced; see Haslam, Reicher, & Van Bavel, 2018) and prisoners to be submissive. When prisoners rebelled, they violated these social norms, which led to upheaval. The specific acts engaged by the guards and the prisoners derived from scripts. For example, guards degraded the prisoners by forcing them do push-ups and by removing all privacy. Prisoners rebelled by throwing pillows and trashing their cells. Some prisoners became so immersed in their roles that they exhibited symptoms of mental breakdown; however, according to Zimbardo, none of the participants suffered long term harm (Alexander, 2001).

This text is adapted from OpenStax, Psychology. OpenStax CNX.

Haslam, S. A., Reicher, S., & Van Bavel, J. J. (2018, June 27). Rethinking the nature of cruelty: The role of identity leadership in the Stanford Prison Experiment. https://doi.org/10.31234/osf.io/b7crx

Alexander, M. (2001, August 22). Thirty years later, Stanford prison experiment lives on.  Stanford Report . Retrieved from http://news.stanford.edu/news/2001/august22/prison2-822.html.

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How is the Stanford Prison Experiment connected to Conformity?

I am still not very clear with what the Stanford Prison Experiment conducted by Zimbardo was trying to conclude about from the experiment.

From Wikipedia, it says the conclusion was to:

demonstrate the impressionability and obedience of people when provided with a legitimizing ideology and social and institutional support. The experiment has also been used to illustrate cognitive dissonance theory and the power of authority.

How does this have any relation or impact on the Conformity theory?

I know that the experiments by Sherif and Asch have concluded the theory of Conformity quite clearly. The Zimbardo's one however seems somewhat implicit. The notes that I read seem to put the Stanford Prison experiment right after the ones by Sherif and Asch. So I believe it should have some relation with the Conformity theory. But I cannot see clearly how is it related to the Conformity theory, particularly in the context of Communications.

• social-psychology

• $\begingroup$ An earlier question on the connection between cognitive-psychology and the SPE might be of interest. $\endgroup$ –  Artem Kaznatcheev Commented Apr 15, 2012 at 16:53
• $\begingroup$ @ArtemKaznatcheev Thanks for the link to the question! I have read about that question before posting this. But I am still not very clear with how the Stanford Prison Experiment connected to the Conformity Theory, which seem to talk only about the Informational/Normative Influences. $\endgroup$ –  xenon Commented Apr 15, 2012 at 17:28
• 1 $\begingroup$ The SPE wasn't really an "experiment" by a formal definition, so take it's "conclusion" with a grain of salt. There wasn't a measurable dependent variable either, something even the creators recognized. $\endgroup$ –  Ben Brocka Commented Apr 15, 2012 at 17:40
• 2 $\begingroup$ Current interviews with participants cast doubt on the interpretation of their action medium.com/s/trustissues/the-lifespan-of-a-lie-d869212b1f62 $\endgroup$ –  CMS Commented Aug 4, 2018 at 20:19

Zimbardo himself states that both informative and normative conformity played an important role in the Stanford Prison Experiment.

Source: http://www.lucifereffect.com/guide_conform.htm [...] Informative conformity often occurs in situations in which there is high uncertainty and ambiguity. In an unfamiliar situation, we are likely to shape our behavior to match that of others. The actions of others inform us of the customs and accepted practices in a situation. Others inform us of what is right to do, how to behave in new situations. In addition to conforming to the group norms due to lack of knowledge, we also conform when we want to be liked by the group. This type of conformity, called normative conformity, is the dominant form of social conformity when we are concerned about making a good impression in front of a group. Though we may disagree secretly with the group opinion, we may verbally adopt the group stance so that we seem like a team player rather than a deviant. Both of these pressures impact us everyday, for good or for worse. [...] Similarly, in the Stanford Prison Experiment, the subjects who were randomly assigned as guards gradually adopted the behavior of cruel and demanding prison guards because that became the behavioral norm in an alien situation.

• $\begingroup$ The statement "In addition to conforming to the group norms due to lack of knowledge, we also conform when we want to be liked by the group." is not relevant to the work of Sherif. Having studied with Sherif, his understanding of the auto kinetic effect and normative behavior is much more profound than the simplistic phrasing presented above. $\endgroup$ –  CMS Commented Aug 4, 2018 at 20:40
• $\begingroup$ @CMS Welcome to the site! Your comments are most welcome, but they did not constitute an answer (rather, a reply to this particular answer, which is why I moved it here). Unfortunately, I had to shorten it since comments are limited in length. I suggest you visit the about page to learn a bit more about how this site works. Once you get a couple of up votes on an answer you posted you will be able to comment on posts directly yourself. $\endgroup$ –  Steven Jeuris ♦ Commented Aug 5, 2018 at 10:52

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Revisiting the Stanford Prison Experiment

40 years later, a classic study resonates..

Posted July 17, 2015

Zimbardo’s classic Stanford Prison Study will be thrust back into the spotlight this weekend with the release of a film based on the experiment, aptly titled The Stanford Prison Experiment. I had the opportunity to attend an early screening of the film this week. The screening, hosted by Psychology Today, included a panel discussion with Philip Zimbardo, and the director and actors of the film, who took the time to reflect on the significance of this study more than 40 years after it was done, and the challenges that came with bringing it to the big screen.

Of course, for social psychologists, the Zimbardo study is part of a trifecta of studies—including the Asch and Milgram experiments—that serve as significant reflections of conformity , destructive obedience, and the power of the social situation to trump or overtake individual disposition when trying to understand behavior. Forty years after Zimbardo’s landmark study, the results still resonate when we look at the role that institutions and the social situation plays in shaping human behavior.

Given the extensive footage of the original study that is available online, the many documentaries that have been done about the experiment, and Zimbardo’s Lucifer Effect published several years ago that revisits the study, one might wonder, what would a dramatic film have to add to this story? The director of the film, Kyle Patrick Alvarez, was asked this very question at the event I attended, and his response was that he was less interested in the academics behind the study (in large part because that has been covered extensively by other sources) and more interested in the emotional impact the study had for all individuals involved (including Zimbardo and his research team).

From this perspective, the film does bring something new to the study. Based on the trailer, I was concerned that the film would not be true to the experiment—or in fact would wildly embellish what took place in the Stanford basement so many years ago—but for those of you familiar with transcripts or the real footage from the study, the screenplay is consistent with the original footage, oftentimes reflected in dialogue identical to the transcripts from the study. To Zimbardo’s credit, his character—handled expertly by Billy Crudup—is not portrayed in the most favorable light.

The dual role that Zimbardo assigned himself for the study (both head investigator and prison superintendent) was clearly a conflict of interest and resonates in Crudup’s portrayal on screen. Indeed, as Zimbardo became immersed in how quickly the participants took on the roles they were assigned, his scientific zeal and position as the head of the prison quickly overtook any ethical concerns regarding how the prisoners were being degraded and abused by the guards. The film’s depiction of him doesn’t hide from this reality, and shows multiple opportunities during the course of the study when Zimbardo was presented with whether or not he should enable a distressed participant to exit the experiment or end the study all together—and chose not to for the sake of maintaining the study and the conditions of the simulated prison.

In retrospect, Zimbardo has been very blunt that he, too, was overwhelmed by the dual roles he played, and should have ended the study even earlier than the six days it ultimately would take him to terminate the experiment (the study was originally conceived to be a two-week experiment). The film does an excellent job in tracing how rapidly all parties involved in the experiment—from its architect to the randomly assigned guards and prisoners, to consultants and the rest of the research team—became immersed in their social roles, losing sight of their personal identities, a process referred to as deindividuation.

For those of you familiar with this experiment, the film certainly revisits a lot of familiar themes. However, it also explores the emotional side of the experience from all parties involved, and offers a dramatic—and engrossing—dramatization of the study that reignites many of the questions regarding the human capacity for evil, particularly among ordinary people.

For those who have not been immersed in the study, this film marks a significant way of being exposed to a critical social psychological study outside of academia, that manages to be provocative, insightful, and even, yes, entertaining. I strongly recommend seeing the film this weekend, and taking the opportunity to ask yourself what many social psychology students do when confronted with these types of studies: what would you have done if put in the same situation?

Copyright 2015 Azadeh Aalai

Visit the official trailer for The Stanford Prison Experiment: https://www.youtube.com/watch?v=3XN2X72jrFk

Azadeh Aalai, Ph.D., is an assistant professor of Psychology at Queensborough Community College in New York.

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Contesting the “Nature” Of Conformity: What Milgram and Zimbardo's Studies Really Show

S. alexander haslam.

1 School of Psychology, University of Queensland, St. Lucia, Australia

Stephen. D. Reicher

2 School of Psychology, University of St. Andrews, St Andrews, Scotland

A re-analysis of classic psychology studies suggests that tyranny does not result from blind conformity to rules and roles, but may involve identification with authorities who represent vicious acts as virtuous.

Understanding of the psychology of tyranny is dominated by classic studies from the 1960s and 1970s: Milgram's research on obedience to authority and Zimbardo's Stanford Prison Experiment. Supporting popular notions of the banality of evil, this research has been taken to show that people conform passively and unthinkingly to both the instructions and the roles that authorities provide, however malevolent these may be. Recently, though, this consensus has been challenged by empirical work informed by social identity theorizing. This suggests that individuals' willingness to follow authorities is conditional on identification with the authority in question and an associated belief that the authority is right.

Introduction

If men make war in slavish obedience to rules, they will fail. Ulysses S. Grant [1]

Conformity is often criticized on grounds of morality. Many, if not all, of the greatest human atrocities have been described as “crimes of obedience” [2] . However, as the victorious American Civil War General and later President Grant makes clear, conformity is equally problematic on grounds of efficacy. Success requires leaders and followers who do not adhere rigidly to a pre-determined script. Rigidity cannot steel them for the challenges of their task or for the creativity of their opponents.

Given these problems, it would seem even more unfortunate if human beings were somehow programmed for conformity. Yet this is a view that has become dominant over the last half-century. Its influence can be traced to two landmark empirical programs led by social psychologists in the 1960s and early 1970s: Milgram's Obedience to Authority research and Zimbardo's Stanford Prison Experiment. These studies have not only had influence in academic spheres. They have spilled over into our general culture and shaped popular understanding, such that “everyone knows” that people inevitably succumb to the demands of authority, however immoral the consequences [3] , [4] . As Parker puts it, “the hopeless moral of the [studies'] story is that resistance is futile” [5] . What is more, this work has shaped our understanding not only of conformity but of human nature more broadly [6] .

Building on an established body of theorizing in the social identity tradition—which sees group-based influence as meaningful and conditional [7] , [8] —we argue, however, that these understandings are mistaken. Moreover, we contend that evidence from the studies themselves (as well as from subsequent research) supports a very different analysis of the psychology of conformity.

The Classic Studies: Conformity, Obedience, and the Banality Of Evil

In Milgram's work [9] , [10] members of the general public (predominantly men) volunteered to take part in a scientific study of memory. They found themselves cast in the role of a “Teacher” with the task of administering shocks of increasing magnitude (from 15 V to 450 V in 15-V increments) to another man (the “Learner”) every time he failed to recall the correct word in a previously learned pair. Unbeknown to the Teacher, the Learner was Milgram's confederate, and the shocks were not real. Moreover, rather than being interested in memory, Milgram was actually interested in seeing how far the men would go in carrying out the task. To his—and everyone else's [11] —shock, the answer was “very far.” In what came to be termed the “baseline” study [12] all participants proved willing to administer shocks of 300 V and 65% went all the way to 450 V. This appeared to provide compelling evidence that normal well-adjusted men would be willing to kill a complete stranger simply because they were ordered to do so by an authority.

Zimbardo's Stanford Prison Experiment took these ideas further by exploring the destructive behaviour of groups of men over an extended period [13] , [14] . Students were randomly assigned to be either guards or prisoners within a mock prison that had been constructed in the Stanford Psychology Department. In contrast to Milgram's studies, the objective was to observe the interaction within and between the two groups in the absence of an obviously malevolent authority. Here, again, the results proved shocking. Such was the abuse meted out to the prisoners by the guards that the study had to be terminated after just 6 days. Zimbardo's conclusion from this was even more alarming than Milgram's. People descend into tyranny, he suggested, because they conform unthinkingly to the toxic roles that authorities prescribe without the need for specific orders: brutality was “a ‘natural’ consequence of being in the uniform of a ‘guard’ and asserting the power inherent in that role” [15] .

Within psychology, Milgram and Zimbardo helped consolidate a growing “conformity bias” [16] in which the focus on compliance is so strong as to obscure evidence of resistance and disobedience [17] . However their arguments proved particularly potent because they seemed to mesh with real-world examples—particularly evidence of the “banality of evil.” This term was coined in Hannah Arendt's account of the trial of Adolf Eichmann [18] , a chief architect of the Nazis' “final solution to the Jewish question” [19] . Despite being responsible for the transportation of millions of people to their death, Arendt suggested that Eichmann was no psychopathic monster. Instead his trial revealed him to be a diligent and efficient bureaucrat—a man more concerned with following orders than with asking deep questions about their morality or consequence.

Much of the power of Milgram and Zimbardo's research derives from the fact that it appears to give empirical substance to this claim that evil is banal [3] . It seems to show that tyranny is a natural and unavoidable consequence of humans' inherent motivation to bend to the wishes of those in authority—whoever they may be and whatever it is that they want us to do. Put slightly differently, it operationalizes an apparent tragedy of the human condition: our desire to be good subjects is stronger than our desire to be subjects who do good.

Questioning the Consensus: Conformity Isn't Natural and It Doesn't Explain Tyranny

The banality of evil thesis appears to be a truth almost universally acknowledged. Not only is it given prominence in social psychology textbooks [20] , but so too it informs the thinking of historians [21] , [22] , political scientists [23] , economists [24] , and neuroscientists [25] . Indeed, via a range of social commentators, it has shaped the public consciousness much more broadly [26] , and, in this respect, can lay claim to being the most influential data-driven thesis in the whole of psychology [27] , [28] .

Yet despite the breadth of this consensus, in recent years, we and others have reinterrogated its two principal underpinnings—the archival evidence pertaining to Eichmann and his ilk, and the specifics of Milgram and Zimbardo's empirical demonstrations—in ways that tell a very different story [29] .

First, a series of thoroughgoing historical examinations have challenged the idea that Nazi bureaucrats were ever simply following orders [19] , [26] , [30] . This may have been the defense they relied upon when seeking to minimize their culpability [31] , but evidence suggests that functionaries like Eichmann had a very good understanding of what they were doing and took pride in the energy and application that they brought to their work. Typically too, roles and orders were vague, and hence for those who wanted to advance the Nazi cause (and not all did), creativity and imagination were required in order to work towards the regime's assumed goals and to overcome the challenges associated with any given task [32] . Emblematic of this, the practical details of “the final solution” were not handed down from on high, but had to be elaborated by Eichmann himself. He then felt compelled to confront and disobey his superiors—most particularly Himmler—when he believed that they were not sufficiently faithful to eliminationist Nazi principles [19] .

Second, much the same analysis can be used to account for behavior in the Stanford Prison Experiment. So while it may be true that Zimbardo gave his guards no direct orders, he certainly gave them a general sense of how he expected them to behave [33] . During the orientation session he told them, amongst other things, “You can create in the prisoners feelings of boredom, a sense of fear to some degree, you can create a notion of arbitrariness that their life is totally controlled by us, by the system, you, me… We're going to take away their individuality in various ways. In general what all this leads to is a sense of powerlessness” [34] . This contradicts Zimbardo's assertion that “behavioral scripts associated with the oppositional roles of prisoner and guard [were] the sole source of guidance” [35] and leads us to question the claim that conformity to these role-related scripts was the primary cause of guard brutality.

But even with such guidance, not all guards acted brutally. And those who did used ingenuity and initiative in responding to Zimbardo's brief. Accordingly, after the experiment was over, one prisoner confronted his chief tormentor with the observation that “If I had been a guard I don't think it would have been such a masterpiece” [34] . Contrary to the banality of evil thesis, the Zimbardo-inspired tyranny was made possible by the active engagement of enthusiasts rather than the leaden conformity of automatons.

Turning, third, to the specifics of Milgram's studies, the first point to note is that the primary dependent measure (flicking a switch) offers few opportunities for creativity in carrying out the task. Nevertheless, several of Milgram's findings typically escape standard reviews in which the paradigm is portrayed as only yielding up evidence of obedience. Initially, it is clear that the “baseline study” is not especially typical of the 30 or so variants of the paradigm that Milgram conducted. Here the percentage of participants going to 450 V varied from 0% to nearly 100%, but across the studies as a whole, a majority of participants chose not to go this far [10] , [36] , [37] .

Furthermore, close analysis of the experimental sessions shows that participants are attentive to the demands made on them by the Learner as well as the Experimenter [38] . They are torn between two voices confronting them with irreconcilable moral imperatives, and the fact that they have to choose between them is a source of considerable anguish. They sweat, they laugh, they try to talk and argue their way out of the situation. But the experimental set-up does not allow them to do so. Ultimately, they tend to go along with the Experimenter if he justifies their actions in terms of the scientific benefits of the study (as he does with the prod “The experiment requires that you continue”) [39] . But if he gives them a direct order (“You have no other choice, you must go on”) participants typically refuse. Once again, received wisdom proves questionable. The Milgram studies seem to be less about people blindly conforming to orders than about getting people to believe in the importance of what they are doing [40] .

Tyranny as a Product of Identification-Based Followership

Our suspicions about the plausibility of the banality of evil thesis and its various empirical substrates were first raised through our work on the BBC Prison Study (BPS [41] ). Like the Stanford study, this study randomly assigned men to groups as guards and prisoners and examined their behaviour with a specially created “prison.” Unlike Zimbardo, however, we took no leadership role in the study. Without this, would participants conform to a hierarchical script or resist it?

The study generated three clear findings. First, participants did not conform automatically to their assigned role. Second, they only acted in terms of group membership to the extent that they actively identified with the group (such that they took on a social identification) [42] . Third, group identity did not mean that people simply accepted their assigned position; instead, it empowered them to resist it. Early in the study, the Prisoners' identification as a group allowed them successfully to challenge the authority of the Guards and create a more egalitarian system. Later on, though, a highly committed group emerged out of dissatisfaction with this system and conspired to create a new hierarchy that was far more draconian.

Ultimately, then, the BBC Prison Study came close to recreating the tyranny of the Stanford Prison Experiment. However it was neither passive conformity to roles nor blind obedience to rules that brought the study to this point. On the contrary, it was only when they had internalized roles and rules as aspects of a system with which they identified that participants used them as a guide to action. Moreover, on the basis of this shared identification, the hallmark of the tyrannical regime was not conformity but creative leadership and engaged followership within a group of true believers (see also [43] , [44] ). As we have seen, this analysis mirrors recent conclusions about the Nazi tyranny. To complete the argument, we suggest that it is also applicable to Milgram's paradigm.

The evidence, noted above, about the efficacy of different “prods” already points to the fact that compliance is bound up with a sense of commitment to the experiment and the experimenter over and above commitment to the learner (S. Haslam, SD Reicher, M. Birney, unpublished data) [39] . This use of prods is but one aspect of Milgram's careful management of the paradigm [13] that is aimed at securing participants' identification with the scientific enterprise.

Significantly, though, the degree of identification is not constant across all variants of the study. For instance, when the study is conducted in commercial premises as opposed to prestigious Yale University labs one might expect the identification to diminish and (as our argument implies) compliance to decrease. It does. More systematically, we have examined variations in participants' identification with the Experimenter and the science that he represents as opposed to their identification with the Learner and the general community. They always identify with both to some degree—hence the drama and the tension of the paradigm. But the degree matters, and greater identification with the Experimenter is highly predictive of a greater willingness among Milgram's participants to administer the maximum shock across the paradigm's many variants [37] .

However, some of the most compelling evidence that participants' administration of shocks results from their identification with Milgram's scientific goals comes from what happened after the study had ended. In his debriefing, Milgram praised participants for their commitment to the advancement of science, especially as it had come at the cost of personal discomfort. This inoculated them against doubts concerning their own punitive actions, but it also it led them to support more of such actions in the future. “I am happy to have been of service,” one typical participant responded, “Continue your experiments by all means as long as good can come of them. In this crazy mixed up world of ours, every bit of goodness is needed” (S. Haslam, SD Reicher, K Millward, R MacDonald, unpublished data).

The banality of evil thesis shocks us by claiming that decent people can be transformed into oppressors as a result of their “natural” conformity to the roles and rules handed down by authorities. More particularly, the inclination to conform is thought to suppress oppressors' ability to engage intellectually with the fact that what they are doing is wrong.

Although it remains highly influential, this thesis loses credibility under close empirical scrutiny. On the one hand, it ignores copious evidence of resistance even in studies held up as demonstrating that conformity is inevitable [17] . On the other hand, it ignores the evidence that those who do heed authority in doing evil do so knowingly not blindly, actively not passively, creatively not automatically. They do so out of belief not by nature, out of choice not by necessity. In short, they should be seen—and judged—as engaged followers not as blind conformists [45] .

What was truly frightening about Eichmann was not that he was unaware of what he was doing, but rather that he knew what he was doing and believed it to be right. Indeed, his one regret, expressed prior to his trial, was that he had not killed more Jews [19] . Equally, what is shocking about Milgram's experiments is that rather than being distressed by their actions [46] , participants could be led to construe them as “service” in the cause of “goodness.”

To understand tyranny, then, we need to transcend the prevailing orthodoxy that this derives from something for which humans have a natural inclination—a “Lucifer effect” to which they succumb thoughtlessly and helplessly (and for which, therefore, they cannot be held accountable). Instead, we need to understand two sets of inter-related processes: those by which authorities advocate oppression of others and those that lead followers to identify with these authorities. How did Milgram and Zimbardo justify the harmful acts they required of their participants and why did participants identify with them—some more than others?

These questions are complex and full answers fall beyond the scope of this essay. Yet, regarding advocacy, it is striking how destructive acts were presented as constructive, particularly in Milgram's case, where scientific progress was the warrant for abuse. Regarding identification, this reflects several elements: the personal histories of individuals that render some group memberships more plausible than others as a source of self-definition; the relationship between the identities on offer in the immediate context and other identities that are held and valued in other contexts; and the structure of the local context that makes certain ways of orienting oneself to the social world seem more “fitting” than others [41] , [47] , [48] .

At root, the fundamental point is that tyranny does not flourish because perpetrators are helpless and ignorant of their actions. It flourishes because they actively identify with those who promote vicious acts as virtuous [49] . It is this conviction that steels participants to do their dirty work and that makes them work energetically and creatively to ensure its success. Moreover, this work is something for which they actively wish to be held accountable—so long as it secures the approbation of those in power.

Funding Statement

The authors received no specific funding for this work.

Psychologists add caveat to ‘blind conformity’ research

February 2013, Vol 44, No. 2

Print version: page 9

Two iconic sets of research — Stanley Milgram's 1960s "obedience to authority" studies and Philip Zimbardo's 1971 Stanford Prison Experiment — highlighted the unsavory reality that people can be prodded into harming others. Milgram found that participants were willing to administer apparently lethal electric shocks in the context of a scientific experiment, while Zimbardo demonstrated that some people assigned to the role of prison guard ended up treating prisoners brutally.

Are we all doomed to carry out evil deeds robotically under the right circumstances? Not necessarily, say psychologists S. Alexander Haslam, PhD, of the University of Queensland, and Stephen D. Reicher, PhD, of the University of St. Andrews. In a November essay in PLOS Biology , they offer evidence from history, from Zimbardo's and Milgram's work, and from their own research showing that people who tend to follow authority aren't sheep or robots, but rather people who enthusiastically identify with a group's or leader's agenda.

"We have this model of evil as a slippery slope, as something we fall carelessly into," says Haslam. "But there's plenty of evidence that many people don't go along with paradigms they don't believe in, and that when people do commit harmful actions in a group context, it's because they strongly identify with the cause."

A historical example is Adolf Eichmann, a chief organizer of the Holocaust who is often touted as the exemplar of a bland bureaucrat following orders. But historical texts show he was highly creative, elaborating many of the practical details of the "final solution" himself. What's more, Eichmann expressed no regret during his trial, justifying his decision to send millions of Jews and others to their deaths because he believed it would build a better Germany.

Similarly, a closer look at the Milgram and Zimbardo studies suggests that many participants don't fit the mold of blind conformist. Not all the guards in Zimbardo's study treated prisoners badly, and those who did were unusually ingenious in responding to Zimbardo's initial suggestion that they could create feelings in the prisoners, such as boredom or fear. In Milgram's studies, many subjects refused to deliver the highest level of shock allowed, and many obeyed the experimenter only when he justified their actions in terms of benefiting science — and even then, they were torn.

Newer studies are starting to add empirical teeth to these observations. Haslam and Reicher conducted a version of the Stanford Prison Experiment televised by the British Broadcasting Service in 2002, showing that participants didn't automatically conform to their assigned roles and only acted in line with group membership if they identified with the group. They're conducting other related studies now, as well.

These new perspectives suggest the need for more research questioning the notion that evil is always banal, Haslam says.

"It's important we keep examining this issue because the debate is germane to some central issues in psychology — the nature of group influence, processes and dynamics and the role of the individual in those domains."

— Tori DeAngelis

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Conformity to Social Roles: Zimbardo ( AQA A Level Psychology )

Revision note.

Head of Humanities & Social Sciences

Conformity to Social Roles: Zimbardo

Social rules.

This study focuses on social identity i.e. the ways in which group membership influences behaviour e.g. your social role as  teacher or  student, parent, child, etc.

Zimbardo wanted to investigate how readily people would conform to the assigned social roles of guard and prisoner in a role-playing exercise that simulated prison life.

• The Stanford prison experiment is one of the most memorable studies in psychology
• There had been many prison riots in America and Zimbardo wanted to know why prison guards behave brutally
• Did they have sadistic personalities or was it their social role, as a prison guard, that created their behaviour?
• Zimbardo et al (1973) co nverted a basement of the Stanford University psychology building into a mock prison
• They advertised for students to play the roles of prisoners and guards for a two-week study; 21 male student volunteers who were tested and found to be 'emotionally stable' were selected as participants
• Participants were randomly assigned to either the role of prisoner or guard
• Prisoners and guards were encouraged to conform to their social roles both through instructions and the uniforms they wore
• Prisoners were given a loose smock to wear and a cap to cover their hair and were identified by an assigned number only 
• Guards were given their own khaki uniform, wooden club, handcuffs and mirror shades to make eye contact with prisoners' difficult
• Both these uniforms created a loss of the individual's personal identity ( de-individuation ), meaning they would be more likely to conform to their perceived social role
• Both guards and prisoners settled into their new roles very quickly
• The guards adopted their social role quickly, easily and with enthusiasm
• Within hours of beginning the experiment some guards began to harass prisoners and treat them harshly
• Within two days the prisoners rebelled; they ripped their uniforms and shouted and swore at guards
• The guards used fire extinguishers to retaliate, using 'divide-and-rule' tactics, playing the prisoners off against each other and completing headcounts, sometimes at night
• The prisoners soon adopted prisoner-like behaviour too e.g. they became subdued; they 'snitched' to the guards about other prisoners; they took prison rules seriously; they increasingly became docile and obedient
• As the prisoners became more submissive, the guards became more aggressive and assertive taking on their social roles easily
• The guards demanded ever greater obedience from the prisoners
• A colleague of Zimbardo's visited the study and was horrified at the abuse and exploitation she saw
• Zimbardo ended the experiment after six days instead of the 14 originally planned

Conclusions

• Social roles appeared to have a strong influence on individuals' behaviour in this study
• Power may corrupt those who wield it i.e. the guards over the prisoners
• Institutions may brutalise people and result in deindividuation (for both guards and prisoners)
• A prison exerts psychological damage upon those who work and are incarcerated there

When asked to use as an example to explain what is meant by social roles, Zimbardo's experiment is a clear example to use. It allows you to both explain social roles and how we conform to them

Evaluation of the research

• Prisoners and guards were randomly assigned to their roles, increasing the control Zimbardo had over the internal validity (whether the study actually measured what it intended to) of the study
• A major practical application is that the study meant practices were changed in US prisons to protect the vulnerable and make prisons safer, and a lot of this was due to the study
• Individual differences and personality also determine the extent to which a person conforms to social roles
• The guards' behaviour differed between them: Not all guards were so harsh or cruel
• It has been said the participants were acting in a stereotypical way
•  For example, one guard said that he based his behaviour on a brutal character he had seen in a film
• There is a lack of realism and many argued that it did not have the realism of a real prison
• There were ethical issues with the study: The participants were subjected to psychological harm, which could have been long-lasting
• The right to withdraw was made difficult, perhaps because Zimbardo himself was playing the role of superintendent, which made it hard for at least one prisoner to withdraw from the study

Zimbardo's experiment is also a good example to use if you have an exam question that asks you to:

Discuss ethical issues in social influence research.

The experiment was stopped early due to the ethical issue of psychological harm, it lacked the right to withdraw and Zimbardo became a part of the experiment instead of remaining an observer.

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The Asch Conformity Experiments

What These Experiments Say About Group Behavior

Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

Emily is a board-certified science editor who has worked with top digital publishing brands like Voices for Biodiversity, Study.com, GoodTherapy, Vox, and Verywell.

What Is Conformity?

Factors that influence conformity.

The Asch conformity experiments were a series of psychological experiments conducted by Solomon Asch in the 1950s. The experiments revealed the degree to which a person's own opinions are influenced by those of a group . Asch found that people were willing to ignore reality and give an incorrect answer in order to conform to the rest of the group.

At a Glance

The Asch conformity experiments are among the most famous in psychology's history and have inspired a wealth of additional research on conformity and group behavior. This research has provided important insight into how, why, and when people conform and the effects of social pressure on behavior.

Do you think of yourself as a conformist or a non-conformist? Most people believe that they are non-conformist enough to stand up to a group when they know they are right, but conformist enough to blend in with the rest of their peers.

Research suggests that people are often much more prone to conform than they believe they might be.

Imagine yourself in this situation: You've signed up to participate in a psychology experiment in which you are asked to complete a vision test.

Seated in a room with the other participants, you are shown a line segment and then asked to choose the matching line from a group of three segments of different lengths.

The experimenter asks each participant individually to select the matching line segment. On some occasions, everyone in the group chooses the correct line, but occasionally, the other participants unanimously declare that a different line is actually the correct match.

So what do you do when the experimenter asks you which line is the right match? Do you go with your initial response, or do you choose to conform to the rest of the group?

Conformity in Psychology

In psychological terms, conformity refers to an individual's tendency to follow the unspoken rules or behaviors of the social group to which they belong. Researchers have long been been curious about the degree to which people follow or rebel against social norms.

Asch was interested in looking at how pressure from a group could lead people to conform, even when they knew that the rest of the group was wrong. The purpose of the Asch conformity experiment was to demonstrate the power of conformity in groups.

Methodology of Asch's Experiments

Asch's experiments involved having people who were in on the experiment pretend to be regular participants alongside those who were actual, unaware subjects of the study. Those that were in on the experiment would behave in certain ways to see if their actions had an influence on the actual experimental participants.

In each experiment, a naive student participant was placed in a room with several other confederates who were in on the experiment. The subjects were told that they were taking part in a "vision test." All told, a total of 50 students were part of Asch’s experimental condition.

The confederates were all told what their responses would be when the line task was presented. The naive participant, however, had no inkling that the other students were not real participants. After the line task was presented, each student verbally announced which line (either 1, 2, or 3) matched the target line.

Critical Trials

There were 18 different trials in the experimental condition , and the confederates gave incorrect responses in 12 of them, which Asch referred to as the "critical trials." The purpose of these critical trials was to see if the participants would change their answer in order to conform to how the others in the group responded.

During the first part of the procedure, the confederates answered the questions correctly. However, they eventually began providing incorrect answers based on how they had been instructed by the experimenters.

Control Condition

The study also included 37 participants in a control condition . In order to ensure that the average person could accurately gauge the length of the lines, the control group was asked to individually write down the correct match. According to these results, participants were very accurate in their line judgments, choosing the correct answer 99% of the time.

Results of the Asch Conformity Experiments

Nearly 75% of the participants in the conformity experiments went along with the rest of the group at least one time.

After combining the trials, the results indicated that participants conformed to the incorrect group answer approximately one-third of the time.

The experiments also looked at the effect that the number of people present in the group had on conformity. When just one confederate was present, there was virtually no impact on participants' answers. The presence of two confederates had only a tiny effect. The level of conformity seen with three or more confederates was far more significant.

Asch also found that having one of the confederates give the correct answer while the rest of the confederates gave the incorrect answer dramatically lowered conformity. In this situation, just 5% to 10% of the participants conformed to the rest of the group (depending on how often the ally answered correctly). Later studies have also supported this finding, suggesting that having social support is an important tool in combating conformity.

At the conclusion of the Asch experiments, participants were asked why they had gone along with the rest of the group. In most cases, the students stated that while they knew the rest of the group was wrong, they did not want to risk facing ridicule. A few of the participants suggested that they actually believed the other members of the group were correct in their answers.

These results suggest that conformity can be influenced both by a need to fit in and a belief that other people are smarter or better informed.

Given the level of conformity seen in Asch's experiments, conformity can be even stronger in real-life situations where stimuli are more ambiguous or more difficult to judge.

Asch went on to conduct further experiments in order to determine which factors influenced how and when people conform. He found that:

• Conformity tends to increase when more people are present . However, there is little change once the group size goes beyond four or five people.
• Conformity also increases when the task becomes more difficult . In the face of uncertainty, people turn to others for information about how to respond.
• Conformity increases when other members of the group are of a higher social status . When people view the others in the group as more powerful, influential, or knowledgeable than themselves, they are more likely to go along with the group.
• Conformity tends to decrease, however, when people are able to respond privately . Research has also shown that conformity decreases if people have support from at least one other individual in a group.

Criticisms of the Asch Conformity Experiments

One of the major criticisms of Asch's conformity experiments centers on the reasons why participants choose to conform. According to some critics, individuals may have actually been motivated to avoid conflict, rather than an actual desire to conform to the rest of the group.

Another criticism is that the results of the experiment in the lab may not generalize to real-world situations.

Many social psychology experts believe that while real-world situations may not be as clear-cut as they are in the lab, the actual social pressure to conform is probably much greater, which can dramatically increase conformist behaviors.

Asch SE. Studies of independence and conformity: I. A minority of one against a unanimous majority . Psychological Monographs: General and Applied . 1956;70(9):1-70. doi:10.1037/h0093718

Morgan TJH, Laland KN, Harris PL. The development of adaptive conformity in young children: effects of uncertainty and consensus . Dev Sci. 2015;18(4):511-524. doi:10.1111/desc.12231

Asch SE. Effects of group pressure upon the modification and distortion of judgments . In: Guetzkow H, ed.  Groups, Leadership and Men; Research in Human Relations. Carnegie Press. 1951:177–190.

Britt MA. Psych Experiments: From Pavlov's Dogs to Rorschach's Inkblots . Adams Media. 

Myers DG. Exploring Psychology (9th ed.). Worth Publishers.

By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

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The Asch Conformity Experiment and Its Implications

• by Psychologs Magazine
• June 13, 2024
• 4 minutes read

Social Psychology is a field of psychology that aims to study the behaviour of human beings in a social context. It examines how our behaviour, ideas, feelings, and emotions are affected by the presence of others in an environment. Group behaviour, peer pressure, interpersonal relations, prejudice, and conformity are some of the major concepts studied in this field. The information on these is derived from social experiments conducted by psychologists in the past. The Stanford Prison Experiment , the Bystander Experiment , and the Asch Conformity Test remain some of the important ones. These tests have been replicated several times over the many years, and hence remain valuable in the study of psychology.

The Asch Conformity Experiment

The Asch Conformity Experiment is a popular experiment that is used to study group behaviour and conformity. It was designed by the pioneering social psychologist Solomon Asch. In this test, he studied how individual cognition can be affected by external influence when in a group.

Experiment Design

For this experiment, Asch seated several students in a classroom, some of which were confederates or actors who already knew the experiment, while others were unaware of it. He then showed them a picture and asked them to match the target line to the line which they believed was equal to it.

Experiment Procedure

In the first few rounds, the actors were asked to respond first and were told to give the correct answer. This affected the opinion of the others, and the subjects began to give similar answers, despite whatever their personal opinion was. In the later rounds, the Confederates started to change their answer to the wrong option. Hence, even though the participants knew what the correct answer was, due to the first trials, they began to doubt their choice and shifted their opinion according to the majority.

Results and Analysis

Eighteen such trials were conducted with 123 subjects. When the experimenters analyzed the results, they concluded that:

• 23% of the students always gave the right answer,
• 72% conformed with the majority at least once,
• 5% of them were always with the majority group, giving the wrong answer.

This change in opinion was due to peer pressure. According to his analysis, Asch concluded that the opinion of a minimum of 3 students was needed to get the majority group to reconsider their opinions.

Implications of the Experiment

Groupthink and peer pressure.

The success of this experiment and its replicability over time have led to further exploration in the domain, leading to the ideas of groupthink and peer pressure. Several examples of this can be seen in our daily life as well.

Social Media Influence

With changing times and expanding technology, social media is now more accessible than ever before. This increased access and continuous exposure leads to youngsters succumbing to the changing trends owing to the need to identify with the majority and remain relevant in changing times. This sometimes also leads to unhealthy comparisons with others. It also kills the individuality and uniqueness of a person which was supposed to make them stand out from one another.

Education and Peer Pressure

Similarly, the expression of peer pressure can be largely seen in the domain of education, where students today feel the need to excel and prove themselves due to the growing competitiveness and comparison among them. When cohesive group behaviour is within a certain limit, it is beneficial for the students as it becomes a source of motivation for each other. Here, group conformity leads to increased self-esteem . But when this cohesiveness and comparison reach unhealthy levels, it begins to take a toll on mental health due to the dissonance between personal and external needs, eventually forcing students to take extreme steps in certain severe cases, by indulging in self-harm or even suicide.

Household Conformity and Obedience

This constant comparison of different domains of life on social media takes place almost subconsciously. It eventually makes a person look down upon themselves, based on an unreal projection of the life of another person on these public platforms. Similar forms of compulsive conformity can be seen within the household as well. It increases when there are elders involved in the situation because one is expected to accept and uphold their opinions and decisions out of respect and reverence. This is done despite the cognitive dissonance between the two parties or opposing opinions they may possess. This is referred to as obedience and is an example of conformity out of respect.

Over the years, several studies have been conducted to assess the effects of this need for social conformity and cohesion and the peer pressure it leads to. These studies have dealt with understanding its effect on different ages, genders, and social groups. In most cases, this need for cohesiveness has proved detrimental, more specifically in cases related to gender because of the prejudices and the expectation to conform to society’s pre-established gender norms.

• Asch’s Conformity Experiment on Groupthink
• Lally, M., & Valentine-French, S. (2018). Introduction to Psychology.

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