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Landmark Stanford Prison Experiment Criticized as a Sham

by Steve Horn

It’s a study widely taught in high school and college psychology textbooks as a prime example of how, as Lord Acton put it, “Power tends to corrupt; absolute power corrupts absolutely.” It’s also a study whose findings may very well have been falsely represented.

The study – the 1971 Stanford Prison Experiment carried out by Prof. Philip Zimbardo – had already been called into question over the years, yet maintained legitimacy in mainstream psychology as a landmark piece of research. Zimbardo’s study revolved around a mock prison created at Stanford University, with 24 students randomly assigned the roles of “guards” or “prisoners.” The purpose was to observe the psychological effects on the participants; expected to last two weeks, the experiment ended after just six days due to the apparent trauma that some of the students experienced.

The conclusion, both at the time the study was conducted and as it was subsequently taught for decades, was that the subjects of the mock prison experiment quickly embraced their assigned roles, with the “guards” becoming authoritarian and sadistic, and the “prisoners” accepting the abusive authority of the guards and experiencing psychological trauma. The study was funded by the U.S. Office of Naval Research.

Over the past 47 years, though, the experiment has been criticized on the grounds of both its lack of generalizability and flawed methodology. Generalizability is defined as extending research findings and conclusions from a small sample population to the larger, general population.

“Prison Study” Advertisement Flawed

The Stanford Prison Experiment has been critiqued for the fact that it involved all white men except for a single Asian-American male. It was also advertised as a “prison study” in classified ads at the time, in order to attract volunteer participants. That, critics have said, would tend to attract people already interested in the authoritarian nature of prison settings.

“Individuals high in social dominance may be drawn to volunteer for the prison study due to the explicit hierarchical structure of the prison system, and such individuals are unconcerned about the human costs of their actions,” psychologists Thomas Carnahan and Sam McFarland explained in a 2007 article published in the Personality and Social Psychology Bulletin, an academic journal.

Just as problematic, others have argued, is the issue of generalizability. That is, could this same experiment be recreated in other settings using a random sample of participants? If not, in the world of social science, big picture takeaways should not be drawn from such a small-scale study.

In this case, the students who participated did not represent a solid cross-section from the general population due to the way the experiment was advertised. Thus, critics say, general conclusions should not be drawn from the results.

Accusations of Coaching

The generalizability critiques were made before the latest round of objections to the study. The newest volley of critiques center around the implementation of the study itself. While academic research typically includes an in-depth explanation of the methodology used, Professor Zimbardo was not fully transparent about his methods, and the study was not peer-reviewed – the gold standard in academia. The full scope of those methods finally came to light almost a half-century later, in the form of audio recordings and other documentation in historical archives housed at Stanford.

The first person to track down those materials was Le Texier Thibault, a French academic and filmmaker, who wrote up his findings in a book titled Histoire d’un Mensonge (History of a Lie). His book came out in April 2018, but did not become a news story in the U.S. until June, when author Ben Blum wrote an extensive blog post about Thibault’s conclusions. In the aftermath of that post, the “sham” of Zimbardo’s study – as Blum called it in his article – made international headlines. The article, titled “The Lifespan of a Lie,” went beyond Thibault’s archival findings by interviewing several of the students who participated in the study, as well as Prof. Zimbardo himself.

“Anybody who is a clinician would know that I was faking,” Douglas Korpi, one of the original student volunteers, told Blum in an interview. “If you listen to the tape, it’s not subtle. I’m not that good at acting. I mean, I think I do a fairly good job, but I’m more hysterical than psychotic.”

Zimbardo was accused of telling the students how to act before and during the study. Those were not new critiques, as they had been aired in a 2005 article by a consultant to the Stanford Prison Experiment who had spent 17 years incarcerated at San Quentin. But they had a new level of gravitas due to the fact that they came via the lens of primary archival materials and interviews, not merely hearsay.

For example, in a recording, one of Zimbardo’s assistants, David Jaffe, was heard telling a “guard” to be tougher with the “prisoners” – indicating that the participants were coached. “We really want to get you active and involved because the guards have to know that every guard is going to be what we call a ‘tough guard,’” Jaffe said in the recorded conversation.

“Serious Fraud”

The timing of Prof. Zimbardo’s study was important, as it was conducted in 1971 – the same year as both the Attica and San Quentin prison riots. His research offered a simple explanation for such incidents: the prison environment created monsters of everyone involved and it was the nature of the carceral system itself that should bear the blame. Not long after his study came out, Zimbardo was invited to testify before Congress at a special hearing in San Francisco, applying his findings to the recent riots.

“In the wake of the prison uprisings at San Quentin and Attica, Zimbardo’s message was perfectly attuned to the national zeitgeist,” wrote Blum. “A critique of the criminal justice system that shunted blame away from inmates and guards alike onto a ‘situation’ defined so vaguely as to fit almost any agenda offered a seductive lens on the day’s social ills for just about everyone.”

According to a 2017 academic paper, 95 percent of criminologists have cited Zimbardo’s study without skepticism since 1971. Further, the Stanford Prison Experiment is often taught in most entry-level psychology and criminology courses with little critique, and as a seminal study in the field. It has also been made even more famous via the release of a movie, “The Stanford Prison Experiment,” which won two awards at the 2015 Sundance Film Festival.

Zimbardo’s colleagues in the psychology community have called the recent critiques of his research a watershed moment not only within academia, but for the impact on psychological research more generally.

“The Stanford Prison [Experiment] – as it is presented in textbooks – presents human nature as naturally conforming to oppressive systems. This is a lesson that extends well beyond prison systems and the field of criminology – but it’s wrong,” wrote Jay Van Bavel, a professor of neuroscience and psychology at New York University.

Van Bavel’s colleague at NYU, psychology professor David Amodio, further examined the real-world effects that Zimbardo’s famous study has had.

“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,” Amodio stated. “This, to me, is a very different kind of fraud – it’s not about a breach in scientific practice, but in how science is communicated and consumed....”

Queensland University psychologist Alex Haslam had tried to recreate the study in 2002, but the subjects in his study who assumed the roles of “guards” did not become brutal or abusive. “We didn’t reproduce that core finding” from the Stanford Prison Experiment, he said. “The standard account [of the research] has no credibility whatsoever now.”

Zimbardo’s Response

Prof. Zimbardo, now 85 years old, posted a lengthy rebuttal to the latest round of critiques on the study’s website,

“For whatever its flaws, I continue to believe that the Stanford Prison Experiment contributes to psychology’s understanding of human behavior and its complex dynamics,” he wrote. “Multiple forces shape human behavior: they are internal and external, historical and contemporary, cultural and personal. The more we understand all of these dynamics and the complex way they interact with each other, the better we will be at promoting what is best in human nature.”

The renewed debate about Zimbardo’s scholarship, should it extend beyond the walls of academia and into the world of public policymaking, could have profound impacts on the future of policies concerning incarceration for years to come. 



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