The Stanford Prison Experiment Was Based on a Pilot Study With Similar Results


Do many people know that the infamous Stanford Prison Experiment was based on a preliminary study that was terminated prematurely? And yet the main experiment was conducted anyway? This would certainly exacerbate the ethical breach of subjecting unwitting participants to such brutal conditions.

A friend gave me a tip on this Letter to the Editor in the Stanford Alumni Magazine:

‘Prison’ Perspectives

“It began with an ad in the classifieds.” With all due respect to Professor Zimbardo, it actually began several months earlier when David Jaffe, ’72, an undergraduate research associate of his, recruited a number of students for a pilot “prison program” conducted in the basement of Toyon Hall. As one of the guards, I can attest to the same feelings of desensitization and turmoil experienced by participants in the subsequent larger study. I remember well denying medication to a student who had forgotten to list it on her medical requirements form. I remember, too, that Jaffe’s experiment was called off well before the target date, as prisoners and guards alike began to fray at the edges. It was the startling results of this pilot project of David’s that I believe provided the impetus for the larger Stanford Prison Experiment.

Tom Jordan, ’71
Eugene, Oregon

Here’s how Professor Philip Zimbardo explains it in the Acknowledgments to his book, The Lucifer Effect:

It all began with the planning, execution, and analysis of the experiment we did at Stanford University back in August 1971. The immediate impetus for this research came out of an undergraduate class project on the psychology of imprisonment, headed by David Jaffe, who later became the warden in our Stanford Prison Experiment.

Mr. Jordan’s account suggests the results were not exactly a surprise, which undermines the claim that “no one knew what, exactly, they were getting into.”

There are other major discrepancies in the storyline. In addition to thanking his massage therapist, Zimbardo acknowledges the assistance of a former prison inmate:

In preparation for conducting this experiment, and to better understand the mentality of prisoners and correctional staff, as well as to explore what were the critical features in the psychological nature of any prison experience, I taught a summer school course at Stanford University covering these topics. My co-instructor was Andrew Carlo Prescott, who had recently been paroled from a series of long confinements in California prisons. Carlo came to serve as an invaluable consultant and dynamic head of our “Adult Authority Parole Board.”

Mr. Prescott has a grimmer recollection of this collaboration, and a much different view on the ultimate outcome of the experiment:

The lie of the Stanford Prison Experiment

. . .

Regrettably, the gulf between verisimilitude and real prison life is a huge leap of faith that still raises serious issues of validity from the get-go. Nevertheless,ideas such as bags being placed over the heads of prisoners, inmates being bound together with chains and buckets being used in place of toilets in their cells were all experiences of mine at the old “Spanish Jail” section of San Quentin and which I dutifully shared with the Stanford Prison Experiment braintrust months before the experiment started. To allege that all these carefully tested, psychologically solid, upper-middle-class Caucasian “guards” dreamed this up on their own is absurd.

Hmm. Here’s a 2003 interview with Zimbardo:

HS: Did you encounter any opposition from the administration at Stanford University when you proposed the idea of conducting the SPE? 

PZ: None. The study was  readily approved by the Human Subjects Research committee because it seemed like college kids playing cops and robbers, it was an experiment that anyone could quit at any time and minimal safeguards were in place. You must distinguish hind sight from fore sight, knowing what you know now after the study is quite different from what most people imagined might happen before the study began.

In the same interview, Zimbardo acknowledges the pilot project but doesn’t discuss the disastrous outcome:

HS: When did you first conceive the idea of observing the behavior of mock prisoners and guards in a simulated prison?

PZ: During a class the previous spring when I got students interested in the intersection of psychology of individuals and the sociology of institutions, and doing a mock prison for a weekend was part of the class exercise for one group of social psychology students.

The mere existence of a pilot project for the infamous Stanford Prison Experiment was news to me. I also found it interesting that the Stanford Alumni Magazine initially refused to publish Mr. Jordan’s letter. Has anyone else heard about Jaffe’s pilot study?