This movie is a remake of a movie based on a book that was inspired by the real-life Stanford prison experiment. The experiment at Stanford ended early as both the guards and prisoners took their respective roles too seriously. The experiment will never be redone because, although it was deemed ethical at the time under the later-amended rules of the American Psychiatric Association, any research done must not physically or mentally harm the participants.
While this film is based on actual experimentation performed by psychologists on college students. Some of the experiment's findings have been called into question. The experiment has been criticized for unscientific methodology, possible fraud bordering on a hoax. Results are believed to have been forced and manipulated to fit the researchers motives.
There has been controversy over both the ethics and scientific rigor of the Stanford prison experiment since nearly the beginning, and it has never been successfully replicated. French academic and filmmaker Thibault Le Texier, in a 2018 book about the experiment, Histoire d'un mensonge ("Story of a lie"), wrote that it could not be meaningfully described as an experiment and that there were no real results to speak of.
The trivia items below may give away important plot points.
Although some similarities exist with the real Stanford Prison Experiment - e.g. it was really terminated after only six of 14 days due to the guards going power mad etc. - there are many more wildly different events. Subjects were harmed after the first day without being stopped. Though they were not murdered, raped, savagely beaten, etc.