Debunking Common Psychology Myths #2: The Stanford Prison Experiment

Issue 136: Shining a light on evidence that was left out of the findings from the Stanford Prison Experiment.

In the summer of 1971, one of the most famous experiments in the history of psychology was conducted in a 35-foot section of the Stanford Psychology Department basement. Each participant had responded to an advertisement in the local newspaper offering $15 per day to male students who wanted to participate with a "psychological study of prison life" that would last for one or two weeks in the basement of Jordan Hall.

After signing up to participate, eighteen healthy young men were randomly assigned to play the role of a prisoner or guard. Efforts were made to create as realistic a situation as possible. Before the prisoners arrived, the guards were provided with wooden batons, uniforms and mirrored sunglasses. This uniform was specifically to de-individuate them, and they were instructed to prevent prisoners from escaping.

The experiment effectively began when real Palo Alto police officers “arrested” the participant prisoners in their homes and charged them with robbery. They were brought to the makeshift prison at Stanford, fingerprinted, searched, and given identification numbers. Thus began one of the most controversial studies in the field—a study that set in motion a myth about human nature that would spread far beyond the confines of psychology community.

During the next five days, the "guards" engaged in the psychological abuse of the prisoners. It became increasingly brutal with every passing day. The guards employed psychological tactics to control and humiliate the prisoners, and several guards began to exhibit genuine sadistic tendencies. The sanitary conditions swiftly declined when the guards forced the prisoners to urinate and defecate in a bucket placed in their cell—and refused to let the prisoners empty it.

The cruelty of the guards eventually led one prisoner to “act crazy,” including screaming, cursing, and begging to be released. When another prisoner went on a hunger strike to protest the abuse, he was locked in a dark closet for “solitary confinement.” The abuse of prisoners continued to escalate until psychologist Christina Maslach visited to evaluate the conditions.

She was shocked to see how study participants were behaving and she confronted Professor Zimbardo, the young professor in charge of the experiment (they were married in 1972). Her role as the key dissident was highlighted in the fictional movie on “The Stanford Prison Experiment”. Zimbardo (played by Billy Crudup in the movie) was eventually convinced to end the experiment on the sixth day—several days before the study was scheduled to end. It had gotten well out of hand.

Within weeks, these shocking findings hit the press and the study quickly became a staple of social science classes around the country. Indeed, we both learned about the experiment 25 years ago in our Introduction to Psychology classes. Zimbardo, became a star witness in congressional testimony on issues ranging from American prison riots to the torture of prisoners at Abu Ghraib.

The power of roles was cemented in the public consciousness. This became a canonical finding affirming the power of the situation. Alongside the work on obedience to authorities by Stanley Milgram (which we will analyze in a future newsletter), these conclusions have played a key role in shaping public understanding of the psychology of tyranny and evil for the past half century.

The lesson about the study, distilled, simplified, and retold in countless lectures, textbooks, documentaries, and movies, seemed clear: people slip naturally into social roles. Guards become terrifying psychopaths by virtue of donning a uniform and aviator glasses, and prisoners become compliant when they are stripped of their identities in a prison environment.

In our view, this constitutes one of the biggest myths in the history of the field.

“Act as you picture the pigs reacting”

Nearly a half century after the original experiment, Zimbardo and his team kindly gave scholars full access to the full archives of data from the Stanford Prison Experiment. To the surprise of many people, it contained bombshell new evidence that shed a radical new light on the famous study. Specifically, a series of analyses by Ben Blum, Thibault Le Texier, along with Alex Haslem, Steve Reicher and Jay, led to a new understanding of this classic experiment and stirred up a heated debate in the field.

These scholars were finally able to listen to audio tapes of the prisoners receiving instructions from the experimenters. These materials suggest a shockingly different explanation for the vicious behavior in the original experiment.

As Alex Haslam, Steve Reicher and Jay argued in the American Psychologist, this new evidence made it very clear that merely assigning people to play the role of a prison guards did not lead them to engage in cruelty naturally, of their own accord. Instead, the tapes provide clear evidence that the experimenters in charge of the “prison” used psychological tactics to persuade reluctant guards to adopt an aggressive style in their interactions with the helpless prisoners. 

This shattered the longstanding myth.

In one recording, the prison “Warden”—a member of Zimbardo’s research team—meets with one of the guards who was reluctant to engage in cruelty towards the prisoners. The superintendent says “We noticed this morning that you weren’t really lending a hand … but we want to get you active and involved because the guards have to know every guard is going to be what we call a ‘tough guard’.”

In other words, the guards were not acting brutal enough to make the experiment a success. They did not naturally become nasty prison guards. So the research team ratcheted up the pressure.

After the guard repeatedly resisted the pressure to engage in the harsh treatment of the prisoners, the Warden made it clear what’s expected:

Warden: …for the time being, you know, I, we need you to play the part of, you know, tough Guard and forget some of the more sophisticated psychology that you might know. And, um, and try and react as you picture the pigs reacting.

Guard:  Well I’ve met a lot of police that, er, that act a whole lot of different ways. You can’t do it just by the movies or something. ‘Cause you know I’ve met plenty of police.

Warden:  Well, you know, I’m not... We’re trying to set up the stereotype Guard, not, you know … Alright, and we realize that you’re going to have your own individual style. But, but so far your individual style has been a little bit too soft pedal.  And we want you to get in there, OK?

Guard:  You mean just doing things like in the counts and stuff…

Warden: In the counts and in other things. I mean when there’s a situation like this, um, to have to go in there and shout if necessary. And, and to be more into the action. OK?  Alright.

Drawing on this new evidence, the superintendent in the experimental prison was using a form of "identity leadership.” Specifically, he encouraged the guard to see himself as sharing the same mission as the experimenters—cultivating a shared in-group identity (and us versus them). In fact, the Warden also makes it clear that they are working together with the Guard to reform the prison system. They are in it together in a virtuous mission.

Warden: I’m saying, you know, above and beyond the fact that this is just a psych experiment, the importance of it in terms of, especially for people who are concerned about the correctional system which both Professor Zimbardo and I are. Um, you know, we happen to agree with you that basically it’s rotten and that it doesn’t produce the kind of rehabilitation, quote unquote, that you would want to produce, and, um, and that perhaps, you know, some of the better ways to produce rehabilitation is to remove the things in society…You know, all that stuff. I, I am very deeply committed to that…what we want to do is be able to, to study the thing that exists, or as nearly as we can make it to what exists and to, and to be able to go to the world with what we’ve done and say “Now look, this is what happens when you have Guards who behave this way”.

We analyzed the transcript and noticed that the warden used collective pronouns 57 times during the short conversation (or once every 30 words) to cultivate a sense of shared identity with the guard—centered around toughness towards the prisoners. This is the same language that politicians who win elections are far more likely to use (using them once every 79 words) than losing candidates (using them only once every 136 words). (You can read the full transcript in the supplement of our paper).

The superintendent framed toughness towards prisoners as necessary for the achievement of a shared goal to help revolutionize the prison system. He says “We’re not trying to do this just because we’re sadists,” and then supplies a rationale for harming the prisoners: “If you need an excuse, and I think most of us do really, it is so we can learn what happens in a total institution.… And we want to know about them so that we can get on the media and into press with it and say ‘Now look at what, what this really about.’”

But you do not need to take our word for it. The audio tape we quoted and analyzed can be accessed directly online. For the first time, people can learn what happened behind the scenes of one of the most famous experiments in psychology. Listen to it yourself and draw your own conclusions (and share your thoughts or theories in the comments section).

A more recent paper by Jared Bartels came to a similar conclusion. He analyzed the impact of Zimbardo’s instructions to the guards and found that it had a similar impact. The day before the experiment began, the Stanford research team held an orientation for the guards in which they communicated their expectations about hostility towards the prisoners. How was this perceived?

This new research showed a completely fresh set of participants this same script from 50 years earlier as if they were new guards taking part in the experiment. Upon reading the original orientation script, the “new guards” expected hostile and oppressive behavior and assumed it was expected from themselves.

Thus, the language of the research team clearly sanctioned abuse among the guards at numerous phases of the Stanford Prison Experiment. This came across in how they oriented the guards. And, if individual guards did not comply, they pressured them aggressively behind the scenes. This is hardly a case of guards automatically adopting a new role.

This new evidence suggests that adopting a role or entering a system of brutality is not sufficient to produce cruel behavior. Perhaps the role is necessary, but not sufficient for brutality—it requires identity leadership to tip people over the edge.

These findings converge with recent work showing how identity leadership was central to Milgram’s famous studies on obedience to authority and to the dynamics of tyranny and cruelty outside the lab. Once one appreciates the role of identity leadership in both the Stanford Prison Experiment and Milgram’s obedience studies, the underlying lesson comes into focus. This is how leaders throughout history have validated cruelty to minorities or immigrants—by signaling that these are out-group members and that the ends justify the means. The actions and language of leaders matter. (We will review this research in a future newsletter where we continue to debunk the biggest myths in the field of social psychology. Stay tuned!)

There is also a hidden story here about dissent. Christina Maslach was obviously a key voice of dissent that was necessary to stop the study. Another the audio tape reveals that at least one guard was actively dissenting as well. Despite his role as a guard, he was actively resisting the attempts of the experimenter to pressure him into mistreating the prisoners. In fact, we reached out to the guard for his own story when we wrote our paper and he stands by this alternative narrative. He was a peacenik who was refused an unjust authority. As Jay mentioned in an article for Scientific American with Haslam and Reicher:

“Our analysis also highlights striking evidence that some guards were actively resisting engaging in brutality—fighting back against the pressures from leadership. From Oskar Schindler to Rosa Parks, history is brimming with people who have bucked oppressive authority figures and abusive systems. It is not only time for a radical rethink of one of psychology’s most influential experiments, but also for recognition that our most famous studies on cruelty, conformity and obedience have critical lessons to teach us about leadership and resistance.”

The Stanford Prison Experiment remains one of the most famous psychology studies of all time. It is covered in most introductory psychology and social psychology textbooks and courses and is a standard point of reference for media stories on tyranny and repression. The study has also been presented to government officials and in court cases to help understand events ranging from prison riots to the abuse of detainees during the Iraq War. It has provided the material for an extremely influential website (www.prisonexp.org), a best-selling book on evil, and several feature films that have grossed over $12 million at the Box Office.

As a result, the study has had a major role to play in shaping how millions of people think both about the nature of human cruelty and about the power of the situation to encourage toxic behavior. Something awful happened in the basement of the Stanford Psychology department—and there is ample video and audio evidence to back it up. It is therefore crucially important to understand what happened and why people engage in such cruelty. In our view, it’s time to retire the myth from this famous experiment and understand that people often do evil in the service of what they think is the greater good.

We also invite you to read Zimbardo & Haney’s rebuttal to our critique (along with Le Texier’s critique). We have posted a very short summary quote here:

Because the SPE was intended as an exploratory demonstration rather than an experiment in a classical sense, there is no definitive way to choose between role conformity and identity leadership explanations of what occurred in each study. Indeed, both dynamics were likely at play—in the studies themselves and in the institutional environments to which the results can be applied—and we are grateful to Haslam et al. for engaging so thoughtfully with these issues.

We are also grateful to Reicher and Haslam for joining with us in signing a “consensus statement” acknowledging that, although the SPE and the BBC Prison Study are “best viewed as one-trial demonstration studies rather than traditional experiments,” they are each “valid studies and resources” for advancing our understanding of “the abuse of authority and power” (see Haney, Haslam, Reicher, & Zimbardo, 2018). Like them, we continue to believe that the behaviors observed in both studies “were a function of many factors, including the roles, norms, leadership, social identification, group pressure, and individual differences” operating in these and other kinds of complex social contexts (Haney et al., 2018, p. 1).

In contrast, Le Texier’s (2019) article is excessively critical, ignores existing data that contradict what appears to be the author’s selective and unsystematically assembled counternarrative, and is unusually ad hominem in nature. Elsewhere we have provided longer responses to his and other recent criticisms (see http://www.prisonexp.org/links/ #responses). Although space constraints do not allow us to address all of the inaccuracies and misinterpretations contained in Le Texier’s article, we respond to several of his major claims…

And here is a link to our response paper (Steve Reicher, Jay, and Alex Haslam) with our final quote:

It is important to note that this debate is now accessible to all. The gates of the prison are open. Accordingly, all students, teachers, and researchers now have the opportunity to judge for themselves whether the guards in the SPE became cruel spontaneously or whether (and how) their behavior may have been shaped by the urgings of the experimenters-as-leaders. That is the true democracy of science. In a darkening world where, increasingly, authority seeks to define truth and deny reasoned debate, this opportunity is something to cherish.

This is the second column in a series where we debunk popular psychology myths. You can read the first column that debunks the bystander effect myth (both the story of Kitty Genovese and how many people have gotten the wrong impression from the original bystander studies). We will debunk several other popular myths over the next few weeks,

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News and Updates

Podcast: Jay was on the Work Life podcast to discuss How to stop doom scrolling and have a better experience online with host Adam Grant last week. Adam and Jay discuss the science of virality, why bad news often commands our attention, and how we can find common ground around more uplifting content.

Event: Jay will be giving a keynote talk on “The Power of Us” and how it relates to Bypassing Climate Polarization at the Vanderbilt University Law School this week (October 3rd). You can see the conference agenda below and join the conference if you are in the Nashville area.

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Catch up on the last one…

Last week, we interviewed Terry Szuplat, one of Barack Obama’s speech writers about his new book, Say it Well! He shares actionable tips and advice on how to write and deliver effective speeches that can inspire any audience.