An extreme psychological study of the way confinement and mental torture degrades both the jailed and the jailer, the 1971 Stanford Prison Experiment was a disturbing look at the outer edges of human nature. (Thanks Reddit.)

A description from the Believer of the experiment, which was conducted by a Stanford psychologist: “Dr. Zimbardo wanted to study the effects of a prison environment on human behavior. He gathered a group of college students, randomly divided them into ‘prisoners’ and ‘guards,’ and placed them in a simulated prison at Stanford University. What followed is discussed at some length below; for now, it’s enough to say that the behavior was so unexpectedly brutal and dehumanizing that the experiment—designed to last two weeks—had to be cut short after only six days.”