Psychologist Who Conducted Infamous 1971 'Stanford Prison Experiment' Passes Away at 91

SAN FRANCISCO — Philip G. Zimbardo, the psychologist renowned for the “Stanford Prison Experiment,” has passed away at the age of 91. His death occurred on October 14 at his residence in San Francisco, as confirmed by Stanford University.

The controversial study, conducted in 1971, aimed to explore the psychological impacts of imprisonment. Zimbardo’s team recruited college males to participate in a simulated prison environment located in the basement of a university building. Initially intended to last two weeks, the experiment was halted after just six days due to the severe psychological effects it had on participants. Those assigned the role of guards exhibited abusive behavior, while the prisoners experienced heightened anxiety, depression, and anger.

Critics have pointed to Zimbardo’s involvement as the prison superintendent, arguing that he compromised the study’s neutrality by becoming an active participant. He later acknowledged the unanticipated and distressing nature of the experiment’s outcomes.

Today, the experiment serves as a critical case study in psychology courses, illustrating themes of authority, the psychology of evil, and ethical considerations in human research. Beyond this infamous study, Zimbardo also explored topics such as persuasion, hypnosis, and altruism throughout his career.

Zimbardo is survived by his wife, Christina Maslach Zimbardo, along with three children and four grandchildren.