Social psychologist Philip Zimbardo, who died October 14, is best remembered for six days of his nearly 60-year career: the 1971 Stanford Prison Experiment, a planned two-week study cut off early because students portraying guards began to abuse those portraying prisoners. It became a common case study in textbooks, a catalyst for changes in research ethics guidelines, and the topic of a 2015 film and a 2024 docuseries. “The prison study will be my legacy,” Zimbardo said in 2012. It was not a hope; it was a fear, says his wife, psychologist Christina Maslach, PhD ’71.
The SPE was a dramatic illustration of a larger point central to Zimbardo’s work and to the field of social psychology, says UC Santa Cruz psychology professor Craig Haney, MA ’71, PhD ’78, JD ’79: that people’s thoughts and actions are oftentimes determined not by their individual psychological makeup but by the situations in which they find themselves. Haney’s own career analyzing the U.S. criminal justice system sprang from his grad student experience with the SPE.
Zimbardo will be remembered for those six days, sure, but also for the subsequent avenues of research he pursued, the generations of grad students he mentored, and the thousands of undergraduates he captivated in Psych 1, which Haney calls “more of a phenomenon than a class.” There is a philosophy in the field of psychology that knowledge should be given away to the people who need it—that is, all of us. Zimbardo’s legacy also includes more than 500 articles and books, including 12 editions of the textbook Psychology and Life and the New York Times bestseller The Lucifer Effect, as well as the award-winning PBS series Discovering Psychology. “He never stopped sharing ideas,” says Haney. Here are some of them.
Bad barrels can rot good apples
The SPE demonstrated how intensely institutional forces could alter behavior. “The system creates the situation that corrupts the individuals,” Zimbardo said in his 2008 TED Talk, The Psychology of Evil. In subsequent years, he would contribute his efforts to a law requiring prisons to house pretrial juveniles separately from adult inmates and to the defense of the highest-ranking officer court-martialed for abuse at Abu Ghraib Prison in Iraq. Zimbardo didn’t believe that situational forces absolved individuals of their bad acts, but he was clear that fault lay not with “bad apples” but “bad barrels.” He himself had succumbed to such a barrel during the SPE, where he held the dual role of lead researcher and prison superintendent. When Maslach visited the simulation on day 5, she didn’t recognize him as the person she had just begun dating, and she persuaded him to terminate it. “By the end, it was not what it had started to be, and they were being swept along with it,” she says. The SPE and other experiments of the time contributed to changes in research ethics guidelines, including fuller evaluation of potential participant risks and protocols for objective oversight.
Shyness can be a prison
In a classroom discussion in the early 1970s, Zimbardo used the guard-prisoner example to describe power differentials in other areas of life. For example: Was shyness a condition of self-imprisonment in which people restrict their own freedom and then comply with those limits? After class, students went to Zimbardo to disclose their shyness and ask for help. Research-wise, “there was pretty much a black hole,” Maslach says. Meanwhile, popular culture treated shyness as a childhood affliction—one that kids would grow out of. Zimbardo’s uncovering of its nuances (it can be situational; it is not restricted to introverts or children; it can be changed) translated into applications for treating adults and, later, kids. Today, research abounds on social anxiety, which can develop from shyness.
Systems can also promote good
At the end of The Lucifer Effect, Zimbardo introduced the idea that a system might influence people not to do evil but to do good. In 2010, he launched the Heroic Imagination Project to bring insights from the study of heroism to an international audience, typically in the form of trainings on how to counter bullying, overcome pressure to conform to group norms, and combat the bystander effect. “It’s taking a little action day by day that makes the world better,” Zimbardo said in 2019.
Everything is psychology
In a 2000 Psychology Today interview, Zimbardo touched on his teaching tactics, which included special demonstrations, experiments, and guest speakers ranging from 49ers coach Bill Walsh to the Stanford Band to cult recruiters. “All of these are ways of communicating that the joy of being a psychologist is that almost everything in life is psychology, or should be, or could be,” he said. Zimbardo became the closest thing to a rock star that academia had to offer. At conferences, he could be mobbed for selfies. But he also supported his students’ ideas and answered emails from strangers asking for advice. It was all part of his desire to contribute to the world and to share insights, says Maslach: “We’ve learned things. There’s more to learn. Here’s more to think about; here’s more to use. This is not the end of the story.”
Summer Moore Batte, ’99, is the editor of Stanfordmag.org. Email her at summerm@stanford.edu.
