How a Decades-Old Experiment Sparked a War Over the Future of Psychology

Like everyone else, Ben Blum believed in the Stanford Prison Experiment.

Why wouldn’t he? After all, it was not only one of psychology’s most enduring studies, but also one of its most vivid. By putting 21 college-age males in the positions of prisoners and guards, it demonstrated the power of roles and authority — and appeared to provide a window into the dark side of human behavior. It showed, or seemed to show, how, under certain circumstances, normal people could act bizarrely out of character.

Normal people, that is, like Ben Blum’s cousin.

In 2006, Alex Blum was a 19-year-old U.S. Army Ranger recruit about to ship out to Iraq when he, two fellow soldiers, and two other men robbed a bank. It was baffling behavior to the Blum family, who knew Alex as a strait-laced kid who’d always dreamed of being a Ranger. Why, they wondered, would he throw it all away?

Alex’s participation in the intensive Ranger Indoctrination Program had taught him to obey his superiors without question. He told his family he’d thought the robbery was part of a training exercise, that he’d merely been acting on orders. The Stanford Prison Experiment, with its accounts of subjects acting out roles at the expense of their own ethics, seemed to back that explanation almost perfectly. Alex’s lawyers called the psychologist behind that experiment, Philip G. Zimbardo, to provide written testimony on Alex’s behalf as an expert witness. Alex ended up landing a lenient sentence — 16 months in jail.

Having grown up a “science kid,” Ben Blum was persuaded that the Stanford Prison Experiment offered a justification for Alex’s crime. In his cousin, Blum saw “the incredible potency of this argument that our circumstances, our environments, our role are the determining factors in guiding our behavior” — the very argument Zimbardo made on Alex Blum’s behalf. It made sense.

Until it didn’t.

Years later, Alex Blum confessed to his family that he’d knowingly participated in the bank robbery. Ben Blum was left to reckon with a sense of “profound disillusionment” in his cousin — and in the experiment that had seemed to put his crime in context.

“I took the story that I’d been taught about the Stanford Prison Experiment as totally authoritative. I had a deep trust in it as a canonical product of the scientific community,” Blum said. “And so when I started discovering these bits and pieces of evidence that all was not as it seems, it really shook me.”

Last year Blum, a computer-science Ph.D. who’s now a full-time writer, published a book about Alex, Ranger Games: A Story of Soldiers, Family, and an Inexplicable Crime. With his personal story told, he started looking into the story behind Zimbardo’s study.

The result was a lengthy exploration of the Stanford Prison Experiment that Blum published online in June, “The Lifespan of a Lie.” The piece concludes that the experiment had been, in many ways, an exercise in deception. Blum was no longer just wrestling with what drove his cousin; now he was asking the field of psychology to take a long, hard look at part of its bedrock.

His investigation has cast a shadow on an entire discipline. “The very best case for me was the opening of a true scientific debate about these fundamental questions of how wrongdoing arises in institutional settings that the Stanford Prison Experiment tried to answer, and that seems to be exactly what’s happened,” Blum said.

Blum’s exposé had another effect: It angered one of psychology’s longtime stars, Zimbardo, who has since published a defiant 6,855-word rebuttal and portrayed the writer as an ambitious troublemaker. Zimbardo insists that the attack on his work is without merit, and that Blum’s motivations are suspect.

And Zimbardo is determined to fight back and protect his legacy.

“It’s not that I ever did him anything wrong. I just think he was fishing around for some way to make him a more notable figure,” Zimbardo said of Blum in an interview. “And he hit on this.”

It was 1971. Philip G. Zimbardo, a psychologist at Stanford University, had just earned tenure, and he had completed a study he wanted the world to know about.

For six days that August, Zimbardo and his student collaborators had transformed the basement of Stanford’s psychology department into a mock prison, filling it with college-age men who had responded to an ad seeking volunteers for a “psychological study of prison life.” The men were randomly assigned to be either prisoners or guards. For the duration of the study, they would act out those roles, and Zimbardo would observe how much the artificial hierarchy affected their behavior. Zimbardo cut the experiment short when his girlfriend, Christina Maslach, a psychologist who is now his wife, visited and was horrified by the conditions she found.

Even in 1971, Zimbardo suspected his study could have staying power. “I wanted this research to be not just for psychologists buried in the library,” Zimbardo said. “I wanted it to be in the general public.” So to share his findings, he turned not to an academic journal, but to The New York Times Magazine.

In its pages, Zimbardo wove a story, now cited in introductory psychology textbooks the world over, about how his volunteer “prisoners” were cowed by the influence of the sadistic “guards,” some to the point of breakdown. “Prisoners” were forced to participate in simulated sodomy, and one was even made to clean a toilet bowl with his bare hands. The experiment became a “cautionary tale,” as the social psychologist Scott Plous, a former doctoral student of Zimbardo, put it, about how “good people, well-adjusted people, the sort of person that we would meet on the street, might be capable, under certain situations, of treating other people with cruelty or with brutality.”

Zimbardo’s feature on the Stanford Prison Experiment ran in The New York Times Magazine under the headline “A Pirandellian prison.” The nod was to Luigi Pirandello — an Italian playwright who shared Zimbardo’s Sicilian roots — and his 1921 play “Six Characters in Search of an Author,” a metatextual drama.

“Essentially, what he’s saying is, we all play roles,” Zimbardo said. “You get on a stage and there’s an audience and you do your thing for an hour or two. You get your applause and you finish. The problem is, what happens when there’s no audience?

“You start off as an actor playing a role, and after a while, you become the role. That’s what happened in the Stanford prison study.”

Just as powerful as the prisoners’ and guards’ behavior in those six days was the way Zimbardo has told their story in the 47 years since — in a book, documentary and feature film, and in testimonies he provided on real-life prisoner abuse at Abu Ghraib. That narrative approach has made the Stanford Prison Experiment the rare work of social psychology that punctures the mainstream consciousness.

It’s made Zimbardo a household name, too — and paved his professional success. Along with writing over 300 articles, chapters, and books over a 50-year career, Zimbardo served as president of the American Psychological Association in 2002.

“He happens to be an extremely gifted storyteller, and he told that story in a variety of mediums to a variety of audiences,” Blum said. “That’s a wonderful trait. It’s made him a fabulous educator. It’s made him a very valuable popularizer of psychology.

“But I think it also made it quite difficult to overturn his story of the experiment, since it just had such amazing narrative heft.”

Now, though, Blum is trying to do just that.

Blum’s critique draws on interviews with several of the Stanford Prison Experiment’s participants and evidence culled from the Stanford archives. Some scholars say Blum’s piece, along with new recordings posted to Stanford’s digital repository and a book — History of a Lie — recently published in French by the academic Thibault Le Texier, has dealt a damning blow to the experiment’s standing in psychology and society.

In an interview with Blum, a prisoner who’d supposedly had a mental breakdown in the middle of the experiment said he had been faking it, hoping to be released from the experiment so he could study for his GREs.

Another concern lies in the behavior of the guards, which Zimbardo has maintained was organic — they were provided no instructions on how to treat the prisoners, he has said. But in a recorded conversation in the Stanford archives, Zimbardo’s student “warden” is heard telling a guard that “every guard is going to be what we call a tough guard.” When the guard demurs, the warden tells him that “you have to kind of try and get it in you.”

This isn’t the first time the experiment has come under fire. The psychologists Alexander Haslam and Stephen Reicher were unable to replicate its results in a 2002 BBC documentary, leading them to speculate about experimenter interference. And because the study had no control group or impartial observers — Zimbardo doubled as principal investigator and “prison superintendent” — some have questioned whether it can be rightfully called an experiment.

David M. Amodio doesn’t think it can. Amodio, a social neuroscientist at New York University, wrote in June on Twitter that “The SPE was never considered to be scientific. It’s typically presented in classrooms as a demonstration, not an experiment, and as a notorious case of ethical malfeasance.” Instead, Amodio wrote, “The serious fraud seems to have occurred between Zimbardo and a complicit audience in the media, policy makers, and general public. Zimbardo couldn’t convince his scientific peers in social psychology, so he circumvented the field and went straight to the people.”

In his published rebuttal, Zimbardo said he has published several peer-reviewed articles about the experiment before and after the Times essay. He has also said, though, that “experiment” is something of a loaded term. This week, according to a tweet from the psychology professor Russell T. Warne, Zimbardo said at an American Psychological Association conference that “It shouldn’t have been called the Stanford Prison Experiment. It should have been called the Stanford Prison Experience.”

Whether an experiment or experience, the Stanford Prison Experiment has been caught squarely in the midst of a whirlwind of self-reckoning in the field of social psychology.

As many experiments performed in the past decade have failed to replicate, the field has struggled to define how such experiments should be judged.

The re-examination epidemic has now reached the discipline’s touchstones, including the Stanford Prison Experiment and the work of many of Zimbardo’s contemporaries — Stanley Milgram’s obedience study, for example, and Walter Mischel’s work on self-control and gratification. Because the work of psychology’s giants has influenced decades of research, the field must also contend with the ripple effect that has ensued.

For Zimbardo, now 85, it’s a difficult pill to swallow.

“The idea of having to go back and validate the Stanford Prison Study, it’s challenging and it’s draining,” Zimbardo said. “‘Challenging’ is a positive word. ‘A drag’ is a more appropriate way to get at it. It’s a drag on my time and my efforts to do more important things.”

Zimbardo doesn’t buy the talk about storytelling or showmanship. The narrative he espouses has never been about his own opinion of the experiment, he said, but about the evidence itself.

“In science, it’s not your personal opinion that matters. The only thing that matters is verifiable evidence,” Zimbardo said. “I thought we had enough verifiable evidence of the prison study to indicate that it was a very powerful, unique situation for everybody involved.”

Not so, say some scholars of social psychology.

“The bottom line is that conformity isn’t natural, blind, or inevitable,” Jay Van Bavel, a social neuroscientist at New York University, wrote on Twitter in June. “Zimbardo was not only deeply wrong about this — but his public comments misled millions of people into accepting this false narrative about the Stanford Prison Experiment.”

When Blum published his piece, Zimbardo was hesitant to engage publicly. Maybe, he hoped, the scrutiny of his work would blow over soon enough.

“That’s the last thing I want to do at this point, is to promote his career more widely,” Zimbardo said.

But Scott Plous, the former student who now helps maintain the experiment’s official website, encouraged his mentor to draft a formal response. “At the end of the day, it’s inevitable that there are certain areas in which reasonable people can draw different conclusions. And in some cases those areas of disagreement are fruitful areas for exploration,” Plous said in an interview.

So within a month, Zimbardo mounted a self-defense. On an email list for the Society for Personality and Social Psychology, a leading academic professional society, he wrote that critics were “impugning my honesty and professional integrity.” On the experiment’s website, he posted a point-by-point response to the criticisms leveled by Blum and others, including Vox’s Brian Resnick, alongside five statements of support from colleagues and collaborators.

“None of these criticisms present any substantial evidence that alters the SPE’s main conclusion concerning the importance of understanding how systemic and situational forces can operate to influence individual behavior in negative or positive directions, often without our personal awareness,” Zimbardo wrote. “The SPE’s core message is not that a psychological simulation of prison life is the same as the real thing, or that prisoners and guards always or even usually behave the way that they did in the SPE.”

But he thinks it should have never come to that. Zimbardo felt he should’ve been approached for comment by Blum before the piece’s publication and been given a chance to respond, which he said is “a scientific courtesy, but it should also be a media courtesy.”

Now Zimbardo, the scientist accused of going “straight to the people,” is accusing a critic of doing much the same. In fact, Zimbardo feels Blum isn’t even qualified to critique his work. In interviews with The Chronicle, he and Plous both repeatedly referred to Blum and Resnick as “bloggers.”

“This is called damage control,” Zimbardo said. “I couldn’t ignore the criticism, because it wasn’t from one person. I mean, the fact that there were at least three bloggers and one author that makes it seem more true. It’s not just one person against Zimbardo. It’s now four against Zimbardo.”

But the criticism still came — and so did criticism of the criticism.

On the social-psychology email list, several scholars waded into the fray in Zimbardo’s defense, touching off a debate on how their field should be refereed. According to screenshots posted in a Twitter thread by Patrick Forscher, an assistant professor at the University of Arkansas, one Zimbardo supporter expressed a need to “clamp down” on unrefereed sources, while another referred to replication efforts as “slapstick” psychology. A third wrote that Blum’s article “doesn’t fit within the critical and civil discourse we should be striving for — but rather fits in a partisan climate that is currently spoiling so much of public discourse.”

The infighting demonstrates how, in the psychology community, the crisis of replication and re-examination has turned into a debate about climate. The discipline has grappled with issues of civility and constructive discourse: Is it better to openly air concerns about research methods and results, as a way to push the field to improve? Or are conversations that could derail careers, damage legacies, and potentially discourage future researchers better had in quieter forums?

The conversations unfolding on the email list alarmed Forscher. “I worried that they might have a chilling effect, particularly for young scholars who are seeing these very eminent psychologists say kind of rude things on this very public listserv,” he said. “It’s important to know that it’s OK to critique past work, even if it’s rather well-established.”

So Forscher drafted a response of his own, which he invited other scholars to revise and sign via an open Google Doc. The result, which he sent to the email list on behalf of almost 150 signatories, reads as an effort to turn down the temperature of what was becoming a bitter intradisciplinary dispute. It stresses that “social scientists, all of us, are united by one common goal: to accumulate knowledge about human nature.”

“There are no sides,” the letter pleaded, “in the quest toward truth.”

Where does that leave the Stanford Prison Experiment?

Forscher thinks that should be a matter of individual interpretation. He champions the motto of Britain’s Royal Society, the world’s oldest national scientific institution — nullius in verba, Latin for “take no one’s word for it.” The response he sent to the email list adopts no formal position on the experiment’s merits; it merely encourages readers to “critically examine the evidence as it stands.”

Ben Blum thinks that evidence is overdue for critical examination.

“Whether the Stanford Prison Experiment needs a major reconsideration,” he said, “I don’t know that there is much to debate there from my view. But I do think that there is a very interesting debate to be pursued about what that reinterpretation should look like and what new questions open up.”

Those questions might be uncomfortably large in scope, given the Stanford Prison Experiment’s social impact. How, for instance, should we interpret another of Zimbardo’s court testimonies, this one in the defense of former U.S. Army Reserve Staff Sergeant Chip Frederick, who pled guilty in 2004 to abusing prisoners at the Abu Ghraib prison in Iraq? Zimbardo argued in a TED talk that the abuses at Abu Ghraib were the result not of a few “bad apple” soldiers, but rather of a “bad barrel” — or systemic forces in the U.S. military.

Jay Van Bavel thinks the Stanford Prison Experiment still has a place in the world of social psychology — just not the one we thought it did.

“Many psychologists would like to toss this experiment into the scrap heap and erase it from our textbooks,” Van Bavel wrote in an email to The Chronicle. But despite its faults, he says, the experiment has provided a useful lens for understanding atrocities, “which is why the public cares so much about how we should properly interpret what happened in the basement of the Stanford Psychology Department in the summer of 1971.”

A proper interpretation, according to Van Bavel and his collaborators, Alexander Haslam and Stephen Reicher, who have studied the Stanford Prison Experiment for 20 years, may lie in a theory they call identity leadership.

“We are trying to understand how Zimbardo and his team created a sense of shared group identity among the guards and licensed them to abuse the prisoners,” Van Bavel said. “Most people don’t just blindly adopt social roles and mistreat others unless they believe they are serving some social purpose or working towards the vision of their leaders.”

Reicher said that the Stanford Prison Experiment has become so famous in part because of its realism. Most studies consist of “beautifully constructed but rather pallid exercises in which phenomena like prejudice and discrimination are measured by ticks on a questionnaire” that can seem distant from the real-life applications of those phenomena, he wrote in an email to The Chronicle. “By contrast the SPE seems to produce real brutality, humiliation and sadism. That is what makes it important conceptually and empirically and also what makes it so toxic ethically.”

It’s that indelibility that has made it somewhat of a calling card within the profession, he added.

“If social psychologists want to provide examples to the wider world of why social psychology matters, the SPE seems to do the job,” Reicher wrote. “On top of that, the SPE delivers a very simple and clear message that, perversely, also seems redemptive. If ordinary people do terrible things, we cannot blame them for they cannot help it. We seem absolved of our sins by the fragile nature of the human psyche.”

For the experiment’s architect, its utility still stands. The U.S. military, Zimbardo says, plays footage from Quiet Rage, his documentary about the study, as part of training for its SERE (Survival, Evasion, Resistance, and Escape) program, which teaches military personnel not to compromise classified information as prisoners of war. As a call to think critically about power structures and hierarchies, the experiment’s message can be powerful. In a reconception of the study, on which Zimbardo consulted, staff at a mental-health center role-played as patients for a weekend. After observing that staff members assigned to be “patients” displayed behavior akin to that of actual patients, personnel at the center convened a team of staff members and current and former patients to change their treatment procedures.

The Stanford Prison Experiment, in his telling, has transcended the research itself.

“Aside from the details of what happened on each hour, each day, each guard shift, the prison study is still a demonstration of the power of social situations to change the way people think and feel and act in those situations,” Zimbardo said.

It’s been a trying summer for Phil Zimbardo. He feels as though the scientific community has turned against him, and he worries that his more recent work won’t be taken seriously as a result.

“Hopefully this will be the end,” he said, “so that when the 50th anniversary comes of the prison study in three years, I can enjoy it — hopefully, if I live that long — rather than have some body of new critics jump up.”

Yes, he’s proud of the Stanford Prison Experiment. What happened in the basement of Jordan Hall in August 1971 is an inextricable part of his life and his discipline. “The study had a dramatic impact,” he says. “But it’s really a minimal part of my career. It’s a six-day investment of my time.”

He’d rather be remembered for his other work. There’s the clinic he established for treating shyness. There’s the scale that measures time perspective, or “the extent to which you are focused on the past, present, or future in positive and negative ways.” And there’s the Heroic Imagination Project, which he founded to teach youth how to act courageously in challenging situations.

He worries that the new scrutiny on his most famous study will cast that other work in a darker light, too. “It’s not simply an attack on the validity of the Stanford Prison Experiment. After 47 years, you know, I can say, ‘Who cares?’” Zimbardo said. “But the implication is, if the Stanford Prison Experiment is a lie, then Zimbardo is a liar. And so my professional integrity is being attacked.”

“I don’t want it to be my albatross,” he now says of the study that made him a psychology star. “I don’t want it to pull me down.”

Follow Megan Zahneis on Twitter at @meganzahneis, or email her at megan.zahneis@chronicle.com.