For decades, the story of the famous Stanford Prison Experiment has gone like this: Stanford professor Philip Zimbardo assigned paid volunteers to be either inmates or guards in a simulated prison in the basement of the school‘s psychology building. Very quickly, the guards became cruel, and the prisoners more submissive and depressed. The situation grew chaotic, and the experiment, meant to last two weeks, had to be ended after five days.
The lesson drawn from the research was that situations can bring out the worst in people. That, in the absence of firm instructions of how to act, we’ll act in accordance to the roles we’re assigned. The tale, which was made into a feature film, has been a lens through which we can understand human-rights violations, like American soldier’s maltreatment of inmates at the Abu Ghraib in Iraq in the early 2000s.
This month, the scientific validity of the experiment was boldly challenged. In a thoroughly reported exposé on Medium, journalist Ben Blum found compelling evidence that the experiment wasn’t as naturalistic and un-manipulated by the experimenters as we’ve been told.
A recording from the experiment reveals that the “warden,” a research assistant, told a reluctant guard that “the guards have to know that every guard is going to be what we call a ‘tough guard.’” The warden implored the guard to act tough because “we hope will come out of the study is a very serious recommendation for [criminal justice] reform.” The implication being that if the guard didn’t play the part, the study would fail.
Additionally, one of the “prisoners” in the study told Blum that he was “acting” during a what was observed to be a mental breakdown.
These new findings don’t mean that everything that happened in the experiment was theater. The “prisoners” really did rebel at one point, and the “guards” were cruel. But the new evidence suggests that the main conclusion of the experiment — the one that has been republished in psychology textbooks for years — doesn’t necessarily hold up. Zimbardo stated over and over the behavior seen in the experiment was the result of their own minds conforming to a situation. The new evidence suggests there was a lot more going on.
I wrote a piece highlighting Blum’s exposé and putting the prison experiment in the larger context of psychology’s replication crisis. Our headline stated “we just learned it [the Stanford Prison Experiment] was a fraud.”
Fraud is a moral judgment. And Zimbardo, now a professor emeritus, wrote to Vox, unhappy with this characterization of his study. (You can Zimbardo’s full written response to the criticisms here.)
So I called Zimbardo up to ask about the evidence in Blum’s piece. I also wanted to know: As a scientist, what do you do when the narrative of your most famous work changes dramatically and spirals out of your own control?
The conversation was tense. At one point, Zimbardo threatened to hang up.
Zimbardo believes Blum (and Vox) got the story wrong. He says only one guard was prodded to act tougher. (We did not discuss Blum’s evidence that the “prisoners” in the experiment were held against their will, despite pleas to leave.)
After talking with him, the results of the prison experiment still seem unscientific and untrustworthy. It’s an interesting demonstration, but should enduring lessons in psychology be based off of it? I doubt it.
Here’s our conversation, which has been edited for length and clarity.
Here’s my understanding of the criticisms that have come to light recently about the Stanford Prison Experiment.
For years, the conclusion that has been drawn from the study was that circumstances can bring out the worst in people or encourage bad behavior. And when some people are given power, and some people are stripped of it, that fosters ugly behavior.
What’s comes to light — what I got out of that Ben Blum’s report — was that it might not have all been the circumstance. That these guards that you employed were possibly coached in some ways.
There’s audio. And for me, it sounded pretty compelling that the warden in your experiment, who I understand was an experimental collaborator — was calling out a guard for not being tough enough. [The warden told the guard, “The guards have to know that every guard is going to be what we call a ‘tough guard.’” Listen to the tape here.]
So does that not invalidate the conclusion?
Not at all!
And why not?
Because he’s talking to one guard who was doing nothing. These are people we’ve hired who are doing it for a salary, $15 a day, to play the role of guard. And Jaffe [the warden] picks on this guy because he is doing nothing. He’s sitting on the sideline, doing nothing, watching. He’s gotta earn his keep as a guard.
The point is telling a guard to be tough does not mean telling a guard to be mean, to be cruel, to be sadistic, which many of the guards became of their own volition playing the role of what they thought was a prison guard. So I reject your assumption entirely.
Here’s the description of the experiment as written on your website: It says “the guards made up their own set of rules which they carried into effect.” In another paper, you wrote that the guards’ behavior was left up “to each subject’s prior societal learning of the meaning of prisons.”
But here’s a different possibility: Do you think it is possible that some of these guards were acting to please you, to please the study, and to do something good for science?
Even without telling the guards to explicitly do something, they might have gotten the impression that it was important for them to play these roles. And they were compelled to because of your authority.
Some of them might, but I think most of them didn’t.
For many of them, it was simply a way to make $15 a day during a two-week summer break between summer school and the start of classes in September. It was nothing more than that. It was not wanting to help science.
Some of them were increasingly mean, cruel, and sadistic way beyond any definition of tough. Some of them were guards who simply enforced the rules. And some of them were “good guards” who never did anything abusive to the prisoners. So it’s not that the situation brought a single quality in the guard. It’s a mix.
The criticism that you’re raising, that Blum raised, that others are raising, is that we told the guards to do what they ended up doing. And therefore, [the results were due to] obedience to authority, and it’s not the evolution of cruel behavior in the situation of a prison-like environment.
And I reject that.
Is it possible that some of the “prisoners” in your experiment were acting, playing along?
Zero? How can you say zero?
Okay, I can’t say.
I mean, the point was they locked themselves in their cells, they ripped off their numbers, they’re yelling and cursing at the guards. So, yeah, they could be acting. But why would they be acting. … What would they get out of that?
Blum quoted one of the prisoners, Douglas Korpi, who had a breakdown. Korpi told Blum that he was acting. That he was in the midsts of studying for the GREs and just really wanted to get out of the experiment. Korpi told Blum, “Anybody who is a clinician would know that I was faking.”
Brian, Brian, I’m telling you every fucking thing that Ben Blum said is a lie; it’s false.
Nothing Korpi said to Ben Blum has any truth, zero. Look at Quiet Rage [a documentary about the prison experiment], look at where he says, “I was overcome in that situation. I broke down, I lost control of myself.”
Retrospectively now, he’s ashamed of having broken down. So he says he “was studying the Graduate Record Exam, I was faking it, I wanted to show I could get out and liberate my colleagues,” etc, etc.
So he is the least reliable source of any information about the study, except he documents the power of the situation to get somebody who’s psychologically normal, 36 hours before, who in an experiment, knowing it’s an experiment, has an emotional “breakdown,” and had to be released.
Let’s say: Regardless of whether guards were coached or not…
Brian, I’m gonna stop you.
Can I finish the question?
A guard, a single guard, okay? When you say guards you’re slipping back into your assumption, you’re slipping back to be like Blum. A guard was coached to be tough, and end of sentence there.
[Note: As a reminder, the tape of the experiment quoted the Jaffe, the “warden,” who played a critical role in leading the experiment, as saying, “The guards have to know that every guard is going to be what we call a ‘tough guard.’” Also, as Blum discovered in the Stanford archives, Jaffe wrote in his notes, “I was given the responsibility of trying to elicit ‘tough-guard’ behavior.” Which, again, raises suspicions that the experiment wasn’t as naturalistic as the experimenters implied.]
What I want to ask is: What is the case that this experiment should be seen as anything more than an anecdote? I don’t think anyone denies its historical value. It’s an interesting demonstration. Ideas that generated from it are worthwhile to follow up on and to study more carefully. Do you think the experiment itself has a definitive scientific value? If so, what is it?
It depends what you mean by scientific value. From the beginning, I have always said it’s a demonstration. The only thing that makes it an experiment is the random assignment to prisoners and guards, that’s the independent variable. There is no control group. There’s no comparison group. So it doesn’t fit the standards of what it means to be “an experiment.” It’s a very powerful demonstration of a psychological phenomenon, and it has had relevance.
So, yes, if you want to call it anecdote, that’s one way to demean it. If you want to say, “Is it a scientifically valid conclusion?” I say … it doesn’t have to be scientifically valid. It means it’s a conclusion drawn from this powerful, unique demonstration.
Would you agree, as a scientist, that an early demonstration of an idea is bound to be reinterpreted in time, bound to be reevaluated?
Oh, they should. The essence of science is you don’t believe anything until it has a) been replicated, or b) been critically evaluated, as the study is being done now. I’m hoping a positive consequence of all of this is a better, fuller appreciation of what happened in the Stanford prison study.
Let me just add one thing: There are many, many classic studies that are now all under attack. … by psychologists from a very different domain. It’s curious.
I’ve talked to a lot of researchers who are interested in replication, and reevaluating past work. They want to correct the record. I think they’re scared about what