Analysis of the Stanford Prison Study of 1971

In 1971, the United States Navy commissioned Stanford University’s psychology department to conduct an experiment on the human responses to captivity (Stanford..,2007). The specific purpose was to resolve conflictions within the naval prison system as well as the Marine Corps. Dr. Philip  Zimbardo led a team of researchers composed of healthy male students. They would be paid fifteen dollars per day to participate in the experiment ($76/day adjusted according to inflation rates for 2006)(Stanford.., 2007). They simulated a prison environment by converting the bottom floor of one of the psychology buildings into the mock institution (Maxfield ; Babbie, 2005).  Randomization was employed for the selection of “guard” vs. “prisoner”. Zimbardo instructed those who would serve as “guards” in methods to depersonalize the “prisoners”; to take away their very identities. He wanted to promote “disorientation, depersonalization, and deindividuation” (Stanford.., 2007). Specific focus was placed prisoners’ reactions to hopelessness and of having no control over personal decisions. They wanted to witness the traits exhibited by the “guards” as well; surprising acts of sadism and ruthlessness were demonstrated by some. There was cooperation from the Palo Alto Police Department in the form of actually charging, arresting, booking, and delousing “prisoners”. This added to the perceived authenticity of the experiment. The experiment has been and is still heavily criticized for having been inhumane and bordering on unscientific (Stanford.., 2007).


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It was the United States Navy that funded the project. Their intent was to learn to understand human reactions to captivity. Zimbardo and his team constructed a hypothesis based on the assumption that prisoners and prison guards self-selectively create adverse conditions by assuming characteristics that would naturally lead to poor conditions (Stanford..,2007). They wanted to test the power of the social situation to determine certain behaviors (Psychology Matters, 2004).

“They wanted to determine what prison-like settings bring out in people that are not confounded by what people bring into prisons. They sought to discover to what extent the violence and anti-social behaviors often found in prisons can be traced to the “bad apples” that go into prisons or to the “bad barrels” (the prisons themselves) that can corrupt behavior of even ordinary, good people (Psychology Matters, 2004)”.


The study induced psychological trauma on the participants through a number of varying vehicles. Zimbardo conceptualized the variables to include effective degradation as their outcome. Collaboration with long-time convicts and other prison-related individuals enabled Zimbardo and his cast of actors to induce dominating control over the group of non-hardened young students (Psychology Matters, 2004). The important variables included in the study are composed of the numerous methods employed by the controllers: removal of clothing/blankets; bouts of forced physical exercise; sexually humiliating “prisoners”; denial of personal hygiene items; forced standing still for hours in a closet; blasts with fire extinguishers and many other acts. Zimbardo and his minions assaulted the mock prisoners with varying methods of dehumanization to force behaviors associated with hopelessness, disorientation, and powerlessness (Maxfield & Babbie, 2005).



An important aspect of the experiments drastic results is the cooperation of the Palo Alto Police Dept. Actual charges, arrests, and incarceration from real police personnel jump started the process for the “prisoner” participants; it helped to quickly bring about the reality of the situation. Other measures taken to provide authenticity to the environment were numerous. Redesigning the basement floor of the psychology building to capacitate the experiment was important for the development of a believable scenario. Likewise, the instruction (permission) given by Zimbardo to the “guards” concerning methods of degradation was a significant aspect in the development of sadistic traits; it is as if he desired the guards to act hatefully. There were also times when he admittedly allowed unethical proceedings to be prolonged (Stanford, 2007). These are all important factors in making the conceptualizations predetermined by Zimbardo into operational components of the experiment. Combined efforts of everyone involved helped to operationalize the study conceptions.



The independent variables in the Stanford Prison Experiment are the many situational characteristics induced upon the prisoners and guards. The prisoners were stripped of everything, while the guards were given free reign. These manipulations and restrictions of basic life freedoms are the independent variables here that catalyze behaviors in the participants. It is this set of behaviors or reactions that are the dependent variables. The highly emotional reactions from some prisoners are no more significant than the epitomized conformity shown by others. All reactions and behaviors were dependent upon the induction of trauma in one form or another in the case of the prisoners. The guards’ behaviors and actions/reactions were also dependent upon underlying constructs of the experiment. It is argued that their sadistic characteristics were a product of being granted the authority to exhibit them in the first place (Psychology Matters, 2004).



The selection process for this cross-sectional study is not sufficiently valid. The sample size was quite small; hardly able to represent the masses (Psychology Matters, 2004). While attention was given to ensure that all seventy-something applicants were physically healthy and not abnormal in a mental sense, the twenty-four that were ultimately selected to participate were by no means similar to real convicts. These were inexperienced, middle-classed, predominately white college students (Stanford, 2007); almost total opposites of those who were/are incarcerated in any prison system. The knowledge that, at the very worst, the experiment would be over in two weeks would seemingly alleviate the real stressors that must come with a real sentence to prison. The knowledge that there is really no difference between “prisoners” and “guards”, in the minds of the “prisoners”, would seemingly yield non-cooperation. The dreams of spending the fifteen dollars per day to be earned soon paled in comparison with the thought of a joyous reunion with freedom; they wanted out.



In my opinion, there are many threats to the validity of the experiment beginning with the aforementioned lack of authentic street characteristics in the participants. It was no different than playing “cops and robbers” except that the game didn’t end, and there was no reward for the robbers; no catalyst besides fifteen bucks every twenty-four long hours to stay in the game. The guards demonstrated great enthusiasm and offered extra unpaid cooperation; the prisoners in contrast offered to forfeit their pay for the privilege of leaving (Stanford.., 2007).

Some attention was given to the redesign of the corridor of offices into the “prison” This is another threat to the validity of the experiment due again to the lack of authenticity. I believe Zimbardo knew this as well. The ecological validity of this experiment has been under fire from its onset (Stanford.., 2007). The conditions were simply not authentic enough to induce accurate responses from participants. Another problem is the very nature of the words: participant and volunteer. These college students were voluntary participants. Voluntary participants are rare in real prisons, I hear. Further threats to the validity of the experiment are (Stanford.., 2007):

* Men made to wear women’s clothing (short dresses);

* Disallowing the use of given names;

* Not allowing prisoners to look out of windows;

* The fact that the prisoners knew they were innocent.



A popular argument for the result of the Stanford Prison Experiment is that it exposed the “impressionability and obedience (Stanford.., 2007)” of people in a situation where they feel that they have no control; such as that of a governmental institution. It is also credited with advances in the understanding of the concept of authority. Further, it has been used to illustrate cognitive dissonance theory; the perception of incompatibility between two cognitions (Stanford.., 2007). It certainly seems to demonstrate components of conformity and rebellion simultaneously. It also strongly exhibits traits of abusing authoritative powers. These observations serve as a predictor for guard behavior worldwide, at least as far as Guantanamo Bay anyway. The results of the experiment represent situational attributions, not dispositional attributions; the behaviors were a result of the situation at hand and not caused by personality traits alone. It can be further argued that there is in fact some correlation between a person being predisposed to sadistic behavior patterns and exhibiting them more profoundly than others in a situation of granted authority (Psychology Matters, 2004).



There are many possible cause and effect scenarios that could be derived from the Stanford Prison Experiment. It would need to incorporate several components. The dual natures of rebellion and conformity, dictating and being dictated, quitting and following through (as with a job), accepting the role of a lesser – if only temporarily, dealing with the loss of one’s freedom to represent himself in life, and so many more issues. As for an overall cause and effect statement concerning the entire experiment, one might say: When authoritative powers are granted to individuals from a governing body, that individual must be more than “screened” for the position; he must be monitored. When authoritative powers are abused, it can evoke many deep-rooted emotional patterns in the repressed. If an individual is stripped of identity and degraded for long enough, that individual will have to either shut down their will and accept an existence of unworthy conformism, or collect strength internally until an explosive rebellion occurs. Although the rebellion will probably be extinguished, it may serve as a way to preserve personal integrity. It is worthy to note the increasing population percentage that finds itself incarcerated. It is worthy to note because it could be any of us next in a real life situation of personal incarceration. Human error dictates that some prisoners are in fact innocent. It is hoped that the guards will be humane.



The Stanford Prison Experiment provides the world with an example of how not to conduct research. Some believe that the whole group of “administrators” and “guards” were involved in an immature power trip; growing increasingly enveloped in their own fantasies to achieve real power someday. The sample suffered from minuscule size from the onset. It cannot be considered a generally representative sampling. There were so few similarities between the simulation and a real prison setting that it is hardly comparable at all. Even if the experiment lasted the full two weeks, it would still have proved non-representational of a real prison setting. A convict facing a real sentence would not even be marginally adapted to prison life after such a short time. It is obvious that a totally different mindset would result from true exposure. What about prison rape? What about prison murders? What about the very real prison hierarchies and pecking orders that exist? What about the fact that most prison inmates are not necessarily of healthy bodies and minds? None of this was represented in the experiment, as well as so many other issues that would be needed for a true simulation. Policy makers would be wise to study the totality of the Stanford project and avoid many of the obvious mistakes discussed within this document. Perhaps Zimbardo should have called it the Stanford Small Town Overnight Jail Stay Experiment.


Research Methods in Criminal Justice and Criminology by Michael Maxfield & Earl Babbie Fourth Edition 2005

Cognitive dissonance. (2007, January 30). In Wikipedia, The Free Encyclopedia.      Retrieved 21:44, February 1, 2007, from    241203

Psychology Matters: Demonstrating the Power of Social Situations via a Simulated             Prison Experiment, June 8, 2004, American Psychological Association,         Available at:

Stanford prison experiment. (2007, February 1). In Wikipedia, The Free         Encyclopedia. Retrieved 16:59, February 1, 2007, from    d=104871837