The film, a remake of the 2001 German film "Das Experiment," is a dramatic retelling of the infamous Stanford Prison Experiment. For those of you who aren't pointed-heady, New Yorker magazine reading elitists, in 1971 a team of psychiatrists at the august university decide to construct a make-believe prison in a basement and gathered some two dozen subjects to take the roles of prisoners and guards.
It's a great conceit for a film.
U.S. & World
As the poster makes clear, Brody stars as a prisoner, while Whitaker plays one of the guards. You can see stills of the film over at Bloody Disgusting.
Things got so ugly so fast, with "guards" subjecting the "prisoners" to a level of abuse so far beyond what anybody could have anticipated that the whole thing was called off after six days.
If the atrocities committed at Abu Ghraib didn't convice you, check out the documentary below (warning: adult language) about the horrors of the fake prison to get a handle on just what terrible monsters we all are.