Let’s start with what we know: In the summer of 1971, Stanford psychology professor Philip Zimbardo (Billy Crudup) paid two dozen students $15 a day to participate in his prison experiment. The roles of prisoner and guard were chosen at random, but it didn’t take long for the participants to settle into their new positions. On the first day, the guards started verbally abusing the prisoners; within two days, at least one prisoner was on the verge of a breakdown and had to be released. Ultimately, the proposed two-week experiment was canceled after six days to protect the subjects.

That’s the plot of The Stanford Prison Experiment, but the social and political implications of the study spiral out toward infinity. It must have been tempting for the filmmakers to tease out some topical context, but they don’t, and their restraint pays off. The film is less an interpretation of its chilling real-life events and more of a straightforward re-enactment, and the lack of overt directorial comment allows the audience to draw their own conclusions.

Still, simply documenting these proceedings on film, even without comment, sets up a dizzyingly complex dynamic for the viewer. In addition to watching the young male characters play the roles of prisoner and guard, we are also watching young male actors play those characters playing those roles. This kaleidoscopic relationship between film and audience could be distracting in lesser hands, but director Kyle Patrick Alvarez seamlessly integrates it into the story as a subtle implication of guilt directed at the audience. When the first prisoner breaks down and screams at the camera (the one used by Zimbardo to record their actions), “You have no right to fuck with my head,” it’s hard to disavow yourself of the unsettling notion that he’s talking to you.

The young actors are all terrific, though it is difficult to name a standout since they sort of blend together. Of course, that’s the point: Their treatment by the guards breaks down their identities until each is more prisoner than person. But Zimbardo is an integral standalone character. As the atrocities unfold, the film frequently cuts to him watching on his own screen, tugging on viewers’ sympathies. A subtle, charismatic actor who never quite broke through, Crudup does important work here, creating a flawed, relatable character whose actions seem at once both reasonable and deplorable.

Cinematographer Jas Shelton does wonders with the enclosed space, eliciting claustrophobia without letting the film stagnate. Inside the prison, he leans on close-ups, focusing our attention on the characters’ inner anguish or (in the guards’ case) lack of feeling. When filming Zimbardo and his associates as they deal with the consequences of their actions, Shelton zooms out a little, giving us room to breathe—and think.

There’s plenty to think about. The Stanford Prison Experiment could easily be read as a comment on the dehumanizing effects of prison, but there are also implications on race (would we react differently if any or all of the subjects were black?) and gender (would women behave differently under the same circumstances?). Ultimately, this is what makes it a near-perfect allegory: It’s a compelling human drama that can be read as metaphor or simply taken on its own terms. Sometimes, a filmmakers’ best choice is to get out of the way so viewers can let themselves in.

The Stanford Prison Experiment opens July 31 at E Street Cinema.