Stanford psychologist behind the controversial ‘Stanford Prison Experiment’ dies at 91

SAN FRANCISCO– Philip G. Zimbardo, the psychologist behind the controversial “Stanford Prison Experiment” designed to explore the psychological experiences of captivity, has died. He was 91.

Stanford University announced Friday that Zimbardo died Oct. 14 at his home in San Francisco. A cause of death was not provided.

In the 1971 prison study, Zimbardo and a team of graduate students recruited middle-aged men to spend two weeks in a mock prison in the basement of a building on the Stanford campus.

The study was ended after six days because the students who played guards became psychologically abusive and those who played prisoners became anxious, emotionally depressed and enraged, the Stanford statement said.

Zimbardo was criticized for taking on the role of chief inspector and becoming an active participant in the investigation and no longer a neutral observer.

“The outcome of our research was shocking and unexpected,” Zimbardo later wrote along with one of the graduate students who was part of the project.

The experiment is now used in psychology classes to study the psychology of evil and the ethics of psychological research with human subjects, Stanford said.

Zimbardo’s research also included persuasion, hypnosis, cults, shyness, time perspective, altruism and compassion, Stanford said.

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