In 1961, Yale University psychology professor Stanley Milgram placed an advertisement in the New Haven Register. “We will pay you $4 for one hour of your time,” it read, asking for “500 New Haven men to help us complete a scientific study of memory and learning.”
Only part of that was true. Over the next two years, hundreds of people showed up at Milgram’s lab for a learning and memory study that quickly turned into something else entirely. Under the watch of the experimenter, the volunteer—dubbed “the teacher”—would read out strings of words to his partner, “the learner,” who was hooked up to an electric-shock machine in the other room. Each time the learner made a mistake in repeating the words, the teacher was to deliver a shock of increasing intensity, starting at 15 volts (labeled “slight shock” on the machine) and going all the way up to 450 volts (“Danger: severe shock”). Some people, horrified at what they were being asked to do, stopped the experiment early, defying their supervisor’s urging to go on; others continued up to 450 volts, even as the learner pled for mercy, yelled a warning about his heart condition—and then fell alarmingly silent. In the most well-known variation of the experiment, a full 65 percent of people went all the way.
Until they emerged from the lab, the participants didn’t know that the shocks weren’t real, that the cries of pain were pre-recorded, and that the learner—railroad auditor Jim McDonough—was in on the whole thing, sitting alive and unharmed in the next room. They were also unaware that they had just been used to prove the claim that would soon make Milgram famous: that ordinary people, under the direction of an authority figure, would obey just about any order they were given, even to torture. It’s a phenomenon that’s been used to explain atrocities from the Holocaust to the Vietnam War’s My Lai massacre to the abuse of prisoners at Abu Ghraib. “To a remarkable degree,” Peter Baker wrote in Pacific Standard in 2013, “Milgram’s early research has come to serve as a kind of all-purpose lightning rod for discussions about the human heart of darkness.”