Philip Zimbardo - Social Psychology - The Canon

Psychology: Essential Thinkers, Classic Theories, and How They Inform Your World - Andrea Bonior 2016

Philip Zimbardo
Social Psychology
The Canon


BORN 1933, New York City, New York


Educated at Brooklyn College and Yale University



For several decades, Philip Zimbardo has been a colorful presence in social psychology. He is best known as the principal investigator in the Stanford Prison Experiment, a 1971 study whose extreme results are still breathlessly discussed some 45 years later.

The experiment and Zimbardo’s analysis of the results are stark examples, like Stanley Milgram’s experiments, of just how far environmental conditions can go in shaping our behavior. While Milgram’s work highlighted obedience to authority, Zimbardo showed the importance of social roles—how taking on the persona of someone in power, or someone without any power at all, seems to drastically affect behavior. Like Milgram, Zimbardo showed that even the most seemingly psychologically healthy people can act with extreme cruelty, and that people with a wide range of personality traits are prone to such behavior. Zimbardo found that participants who were given the role of prison guard began to act inhumanely and, as some would argue, even sadistically. Those in the role of prisoner grew distressed, disconnected, and angry. Conflict between the two groups grew so severe that Zimbardo had to cancel the experiment after six days, even though it had been planned to last for two weeks.

By contrast with Milgram’s experiments, which used the authoritative figure of an experimenter to prod cruel behavior, in Zimbardo’s experiment there was no powerful authority demanding obedience and instructing participants to behave inhumanely. On the contrary, it seemed that the mere opportunity to wield power was sufficient to cause inhumane behavior.

Zimbardo argued forcefully that social roles and environmental conditions can bring out devastatingly cruel behavior. Taking his findings to the mainstream media, and even to congressional hearings on prison conditions, Zimbardo theorized that we can all too easily assume the roles we are given, letting them merge with our identities and give us permission to act in extreme ways. Power can be irresistible, and it can seemingly bring out bad behavior as easily as good.

Zimbardo’s findings also say something about group dynamics. It’s hard to imagine that the conflict would have escalated so dramatically if the experiment had involved just one guard and one prisoner. But pitting group versus group appeared to increase the severity of the conflict and the immoral behavior, in several ways. It was probably easier for any individual guard to justify his behavior when he could observe other guards doing the same things. And the fact that the prisoners were identified only by their assigned numbers, not by their names, probably encouraged the perception that they were an amorphous blob of objects, not individual human beings. They were conceptualized as a threat that needed to be controlled, not as individuals with thoughts, experiences, and emotions.

As reports of the experiment’s results ignited the public conscience, Zimbardo’s name recognition grew significantly. He used this platform to make his psychological findings more accessible to the public, and he encouraged the field of social psychology to take more interest in applying the results of its scientific work to the world at large. Zimbardo himself has shown interest not only in the applicability of his results to societal issues but also in the public’s ability to have access to the education that experimental results can provide.

More recently, Zimbardo, relying in part on theories developed by other social psychologists, has summarized what he believes to be the seven forces that make the descent into evil behavior more likely:

”Mindless taking of the first small step

”Dehumanization of others

”Anonymity/deindividuation of the self

”Diffusion of personal responsibility

”Blind obedience to authority

”Uncritical conformity to group norms

”Passive tolerance of evil through inaction or indifference

KEY EXPERIMENT The 1971 Stanford Prison Experiment involved 24 male undergraduates at Stanford University. Each of them had been screened and selected for stable emotional traits. Thus the participants were not likely to be hotheads or people overly sensitive to stressful situations, though it is worth noting that they all responded to a newspaper advertisement asking for participants in a study of prison life, which has been suggested by critics to mean that they were not a randomized, typical group to begin with.

The students were randomly assigned to be either prisoners or guards for the duration of the experiment. Of course, random assignment was key because it all but assured that there would be no meaningful, systematic differences in personality between the prisoners and the guards at the start of the experiment.

Though they had all, of course, agreed in advance to participate in the experiment, the actual booking of those who were to become prisoners was sprung on them as a surprise, and it was performed by members of the Palo Alto police department. Processing of the prisoners was conducted very much as in real life, with fingerprinting, mug shots, and rap sheets as well as actual jail cells. The prisoners were then transferred to a mock prison in the basement of Stanford’s psychology department. At any given time, there were nine prisoners and nine guards (some of the participants were alternates).

Soon after their arrival, the prisoners, identified solely by number, were put into garments resembling dresses, with no undergarments, and were made to wear something akin to a hairnet. The guards, who wore dark sunglasses and carried sticks, were given few specific instructions for handling the prisoners other than being told that they were to keep order and that corporal punishment was not allowed. At first the mood was somewhat light, with the prisoners mocking the guards. But several of the guards soon grew frighteningly power-hungry, commanding the prisoners to do repeated push-ups and denying trips to the bathroom. They even sprayed fire extinguishers to break up a prisoner rebellion that arose as early as the second day, and extra guards, in the person of alternates, had to come in because of the uprising and the resulting escalation on both sides.

Before long, some guards began stripping prisoners naked and imposing solitary confinement for longer than they were supposed to. Their behavior became frankly and increasingly sadistic, but it did nothing to unite the prisoners, who began to turn on each other. The prisoners became more and more depressed and less and less autonomous, and the guards became more and more hostile. Zimbardo finally stopped the experiment, even though it officially still had eight days to go.

Zimbardo himself served as superintendent of the prison, and another researcher with the experiment served as prison warden. These arrangements have generated some controversy, and there are different ways to view them. Critics say that because Zimbardo was not an unbiased observer, he probably created certain expectations for how people were supposed to behave, as he had a vested interest in seeing things spin somewhat out of control so as to prove just how dehumanizing the conditions in a prison can become. Perhaps this led to a sense of performing among some of the guards. Zimbardo himself has said that his role actually helped, scarily, underscore the results of the experiment itself—he got sucked in like all the rest, and perhaps he let the experiment go on too long because he was failing to view the participants as real people in distress and was dehumanizing them because of his desire to see the research go on. “I lost my sense of compassion,” he has said. “I totally lost that.”


Zimbardo’s findings have been used in many political and legal arenas, including the prison reform movement, as well as in the study of modern examples of extreme and cruel behavior, such as the torture of prisoners at Abu Ghraib. He has also used his findings to support antibullying education and initiatives. His additional work in social psychology has led to further study of shyness, for which he established a treatment clinic, and his most recent research has looked at the differences in how individuals perceive the passage of time and at how those perceptions affect the way time is used.


When even randomly assigned power is liable to be so extremely abused, it is not hard to imagine how certain roles in real life—which are not random, and which we think we actually deserve to play—can provide justification for our poor treatment of others. Do you know anyone who treats restaurant servers like underlings? If you have such a friend, chances are that he or she is not rotten to the core and has some redeeming qualities; otherwise you probably wouldn’t go out to dinner together. But something inherent in the social role of being served causes this person to lose a bit of his or her compassion and sense of fellowship.

As we’ve seen, anonymity can also contribute to problematic behavior. Why, for example, are online comment forums such cesspools of hatred? There is evidence that the veil of anonymity encourages people to act more callously than they would if they were identified by name. Or maybe you’ve been the recipient of an anonymous, passive-aggressive note in your workplace, one with a derisive tone that you wouldn’t have guessed could come from any of your coworkers. And have you ever seen a public restroom stall that was absolutely covered in graffiti? Maybe you even added to the mix—other people were there first, so you didn’t feel fully responsible for what you did personally to deface the stall.


It is worth noting that even the criticisms leveled at Zimbardo’s methodology—that his presence in the prison created expectations for the guards to perform; that the participants’ self-selection may have meant that those who became guards already had too much interest in prison dynamics and were perhaps power-hungry—actually support the idea that what goes on in real-life prisons can be harrowing and horrifying. The guards in those facilities are self-selected, too, and it’s reasonable to assume that at least some of them would like to become acquainted with what it feels like to have ultimate power over others. Guards in actual prisons may also be constantly observed and supervised by others who have an order-above-all-else mentality. So, from a methodological stand point, Zimbardo’s prison experiment may not have been as unbiased as it could have been, and the behaviors that emerged may not have done so in a pure way. But this actually strengthens the argument that what is going on in real prisons, where conditions are less randomized, is even worse.

So perhaps it’s not absolutely true that any given person can turn sadistic in the right circumstances. But it likely is true, heartbreakingly so, that the right circumstances exist in very numerous and extreme ways outside the laboratory. And the people who have chosen to put themselves in those circumstances may be particularly prone to sadistic behavior.