The Stanford University prison experiment was abruptly ended 44 years ago after treatment of pseudoprisoners by pseudoguards, both played by students, escalated too far for the researchers to tolerate.

The study has since found a hallmark place in Psych 101 and AP Psychology courses as books and documentaries on the topic have been created. And this summer, a feature film on the experiment was released, cementing an already well-established place in popular culture.

The Stanford Prison Experiment has received positive reviews from critics, echoing reactions to the film’s first screening at Sundance Film Festival last year. But the timing for a movie revolving around the ethics of psychology could not be more relevant, as reports on the involvement of top officials at the American Psychological Association being complicit in the torture of others by U.S. agencies emerge.

During the experiment in the summer of 1971, 24 young men were assigned the role of either a prisoner or a guard and quickly adapted to their roles, maintaining the appearance of a 24-hour prison in the basement of a hall on Stanford's campus. The guards, who worked in eight-hour shifts, took advantage of their power, and the prisoners rebelled within 36 hours of the start of the experiment, but each individual soon forgot that they were subjects in an experiment and not people in a prison.

The movie is no different. The first half of the movie is completely dedicated to describing the setup of the study and the first 48 hours. Tensions run high, prisoners attempt to escape and the psychologists running the show find themselves more deeply intertwined in the process than they had anticipated.

Philip Zimbardo, the Stanford University psychology professor who oversaw the original experiment, said he has been trying to make the film a reality for 35 years. Today at 82, an emeritus professor of psychology at the university, he said he closely collaborated with the screenwriter and director of the movie to make the film as accurate as possible.

Zimbardo said that as he was writing his 2007 book on the experiment, The Lucifer Effect, he would send chapters to the screenwriter, Tim Talbott, to help develop the script. He also said all dialogue between the prisoners and the guards was taken straight from the recordings of the experiment, which was filmed in its entirety.

Only one scene in the film didn’t sit well with Zimbardo. At one point in the film, Zimbardo's character is approached by another Stanford professor, who asks what the independent variable in the experiment was. Zimbardo said the scene came across as if he didn’t know what the experiment was about, and he asked for it to be removed, but it was too late in production to do so.

“Of all of the things in the movie, this is probably the most negative because it looks like I didn’t know the answer,” Zimbardo said.

The experiment itself has come under fire over the years. Peter Gray, a research professor at Boston College, decided not to include the Stanford prison experiment in his psychology textbook because he didn’t believe the study, which was never published in a peer-reviewed journal, was a legitimate experiment and that it was essentially fabricated by Zimbardo.

Gray, whose book is now in its sixth edition, called the study “an embarrassment to the field of psychology.”

“He got a bunch of college kids to pretend they’re prisoners and another group to pretend they’re guards, told them what they’re supposed to do and then they did it,” he said.

Gray has not seen the movie, but said so many people have asked him about it that he may watch it in the future.

And a paper co-authored by Sam McFarland, now an emeritus professor of psychology at Western Kentucky University, found that there could have been bias in the selection of those who participated in the experiment because the word “prison” was included in the advertisement for subjects. The film opens with the writing and printing of the advertisement.

McFarland said that individuals could have been encouraged or deterred from joining a “psychological study of prison life” by the word “prison.” His paper found that individuals who responded positively to the original wording were more likely to be aggressive and narcissistic and less empathetic than those who would have signed up for only a psychological study with no mention of prison life in the wording.

Zimbardo stood by his experiment, saying that it’s still “the most powerful demonstration in psychology,” even if other psychologists didn’t believe it was a true experiment.

As for the ethics of the experiment, Zimbardo said he believed the experiment was ethical before it began but unethical in hindsight because he and the others involved had no idea the experiment would escalate to the point of abuse that it did.

The movie ends with Zimbardo’s character and some of the prisoners and guards describing how they felt throughout the experiment and some of its findings. There is also a disclaimer, saying that none of the subjects suffered any long-term or negative effects from their involvement in the study.

And as the ethics of the experiment are once again discussed with the release of the film, so is the current state of ethics in psychology. Three top officials of the American Psychological Association stepped down last month after a 542-page report described how members of the organization who worked with the Department of Defense were complicit in the torture of individuals by federal agencies.

Zimbardo, a former president of the APA who was traveling to the association’s annual conference at the time of this interview, said he hoped the film would help contribute to a conversation about ethics by psychologists.

“It raises those basic questions -- these people who are Ph.D.s in psychology, who understand human nature, whose job it is to develop a set of ethical guidelines to help psychologists deal with these very difficult issues. It’s hard to perceive the whole process,” Zimbardo said.

McFarland, whose study criticized Zimbardo’s methods, said it was important to understand the experiment, and has included the study in his psychology courses, following it with readings on massacres in Vietnam and findings of torture and severe mistreatment in Abu Ghraib prison.

“It’s a matter of balancing points and balancing perceptions, and the perception that human beings have a great capability for good and also a great capability for evil -- I think there’s certainly enough real-world experience to show that,” he said.

Melissa Smith, a fourth-year doctoral student at George Mason University studying human factors and applied cognition, had an opportunity to meet Zimbardo and the film’s director, Kyle Patrick Alvarez, before she saw the movie a few weeks later. She described the film as “gripping” and “brutal.”

She said she had first learned about the experiment in middle school but had the opportunity to see some of the actual footage of the study later. She said that juxtaposing the actual footage with the movie’s depiction might teach students about the study and the evolution of views about it.

“No one really knew the extent of the experiment because it was just another experiment,” Smith said. “I think being able to show them that and be like, ‘hey, this is real, what do you guys think?’ … I think you can show that this is a true example of people being put in a prison that still impacts daily perception of life.”