Behind the Shock Machine

In 1963, Yale psychologist Stanley Milgram reported an appalling discovery: 65 percent of volunteers would deliver electrical shocks to another person at levels they believed were lethal if an experimenter asked them to. Ordinary people, it seemed, could easily be convinced to do monstrous things by authority figures.

The famous obedience experiment resonated in postwar America, where the trials of Nazi officers were fresh in the public mind. Milgram’s work lent scientific credibility to fears about the human capacity for cruelty, says science writer Perry.

But in the 50 years since, much of Milgram’s science has been lost in the sensationalism. Perry examines notes and archived audio tapes to piece together an accurate account of the experimenter’s methodology. Milgram selected his data carefully and downplayed inconsistencies in his publications, she says. For instance, he performed not one but 24 versions of the shock machine scenario, altering variables such as whether screams were audible or asking people to shock family members. In many of these variations, more than 60 percent of subjects disobeyed the experimenter’s directions.

Perry offers no easy answers as to what Milgram’s work can or can’t teach about human nature. But she does present a more complete picture of a captivating and often misunderstood experiment. The book also provides an unflinching biography of Milgram himself: a scientist who eagerly promoted his controversial research but who may have understood the limitations of his findings better than anyone.

“Whether all of this ballyhoo points to significant science or merely effective theater,” he once wrote, “is an open question.”

The New Press, 2013, 339 p., $26.95

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