Shankar VedantamHost, Hidden Brain · Journalist, Writer, Science Correspondent

The Psychologist Who Became the Monster He Studied

4 Aug 2026 · 1 min

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1:12

In this Hidden Brain segment narrated by Shankar Vedantam, the 1971 Stanford Prison Experiment conducted by psychologist Philip Zimbardo is recounted. Young male volunteers were placed in a mock prison, with some assigned as prisoners and others as guards, in a study intended to run two weeks but halted after six days due to escalating abuse. The guards quickly adopted cruel, dehumanizing behaviors, stripping and humiliating prisoners, while Zimbardo, acting as prison superintendent, became immersed in his role and allowed the mistreatment to continue, losing his scientific perspective. The episode highlights the central lesson that powerful situational forces can compel ordinary, well‑meaning people to commit terrible acts, and it underscores that even researchers studying vulnerability are themselves vulnerable to those same forces. Over five decades, the experiment has sparked ongoing debate about ethics and methodology, cementing its place as a cautionary cornerstone in psychology. Listeners are invited to explore more about the science of the mind on Hidden Brain via Apple, Spotify, or hiddenbrain.org.

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In 1971, the psychologist Philip Zimbardo recruited young men for an experiment at Stanford University. The volunteers would learn they were taking part in a mock prison scenario with jail cells set up in the basement of the psychology building. Some of the volunteers were assigned to be prisoners. Others were guards. The study was supposed to last 2 weeks. It was shut down after 6 days. The guards became cruel. They stripped prisoners and forced them into humiliating exercises. Phil believed the experiment proved that bad situations can make good people do terrible things. During the study, Phil himself got swept up in his role as prison superintendent. He let the abuse continue. He lost perspective. He became a poster child for the very human weakness he was trying to study. Over the past 5 decades, the Stanford Prison Experiment has become one of the most infamous and debated studies in the history of psychology. The lesson cuts both ways. We are all more vulnerable to circumstance than we want to believe, including the people who study vulnerability for a living. For more insights about the science of the mind, tune into Hidden Brain on Apple, Spotify, or hiddenbrain.org.