The Lie Detectors by Ken AlderIn May 1922, a wealthy family of four was driving home to San Francisco from a day trip in the Santa Cruz mountains when a second car forced them off the road. A gunman stuck a revolver through the drivers window and demanded money. The father, Henry Wilkins, handed him three $100 bills, but the bandit lunged for Anna Wilkinss diamond rings. Enraged, Henry reached for a gun stowed in his glove compartment, his two young children bunkered in the backseat, but the robber shot first, killing Anna Wilkins and disappearing before Henry could respond. My daddy loved my mother, the Wilkinses eight-year-old son testified. She died to save the bandits bullet from hitting him.

The machine, a Rube Goldberg contraption of tubes, pumps, wires, and meters designed to monitor the subjects vital signs and record on smoke-blackened paper telltale jumps in blood pressure and breathing rate, was then chiefly known for finding thieves among honest sorority sisters in a series of breathlessly reported penny-ante Berkeley capers. Wilkins submitted and, as the city watched, passed the test; the police dropped the investigation, and Wilkins was invited to leave the courthouse unmolested. From there he went to meet one of the convicts he had earlier failed to identify. Money changed hands, and Wilkins was heard boasting about his performance on the polygraph. A month later, the other brother, already in jail on other charges, admitted that Wilkins had indeed paid the men to kill his wife and orchestrated the incident on the road. Furious and humiliated, San Francisco police vowed never to employ the lie detector again; at the next meeting of the International Association of Chiefs of Police, their captain declared that future use of the polygraph could not be countenanced.

Since its American debut, the lie detector has been a persistent but extralegal feature of our juridical culture, not much evolved from the faulty contraption employed in San Francisco in 1922. The device has been derided by teams of experts as junk science, hardly more reliable than methods of pure chance, barred from the courts, a favorite tool of overzealous investigators and an instrument of state-sponsored vigilantism, a handmaiden to McCarthyism, an accomplice to the pink scare, and a nightmare vision of justice as arbitrary and expansive as the judgment of a totalitarian court, in a box no bigger or more conspicuous than the briefcase of a company man. And yet, as Ken Alder shows in his revealing, colloquial social history The Lie Detectors, by the time scientific scrutiny finally caught up to the scientistic ambition of the device in the late 1980s, generations of Americans had been seduced by it. For decades, the polygraph was a trusted tool of justice, treasured by beat cops and internal affairs investigators alike, celebrated across popular culture as an unerring arbiter of honesty and public virtue, used to test patients in psychiatric hospitals and job applicants in corporate interviews, and entrusted with some of the most valued secrets of the atomic age, the twitchy mechanical conscience of the cold war era. How did this happen?

The Lie Detectors is a shaggy dog, unruly with anecdotes and built loosely around the narratives of two outsize Jazz Age personalities: Leonarde Keeler, an avid amateur polygraph enthusiast, a charmer, a womanizer, and a drunk; and John Larson, a psychologist and Americas first doctoral cop, who adapted and refined the lie detector from an earlier model assembled by the creator of Wonder Woman. In ascribing the power of the polygraph to the charismatic salesmanship of a huckster playboy and a starry-eyed psychologist, Alder suggests that the device represents neatly the scientific hubris and human folly of the machine age. The polygraph, he writes, belonged to the American strain of the Enlightenment project to replace personal discretion with objective measures, and political conflict with science, and transform the central moral questions of our society into simple matters for scientific inquiry. A tall order.

One field that could legitimately benefit from such a scientific approach was law enforcement. At the time, rural justice in America could still resemble the lynch mob, and many cities were policed by corrupt departments rife with patronage and mob influence, and willing to countenance even the most brutal forms of interrogation. In some quarters, Alder writes, critics were so outraged by the methods employed by city cops that they called on courts to reclaim from police departments the long-lost monopoly on interrogating suspects.

At first blush, the polygraph appeared to offer an alternative. The device came to prominence in Berkeley, California, where a legendary cop ran a small station house as a laboratory for progressive police methods. August Vollmer was the first chief in America to employ squad cars, install radio systems, and map area crimes to study the efficacy of various police methods. He introduced merit-based promotion, opened a police school for his officers, and invented a system for filing evidence that became the model for the state of California, and later, under J. Edgar Hoover, the nation. The lie detector, which John Larson developed and Leonarde Keeler publicized for Vollmer, was the most vaunted product of his program of police professionalization, and it arrived on the national stage bearing his imprimatur.

The device appealed to police as a potent interrogatory tool, to reformers as a way to replace the ugly human science of law enforcement with an objective science of criminology, and ultimately to government officials who hoped to police the inner lives of citizens in the name of national security. By the early 1950s, Alder reports, the lie detector had become the de facto police force in Oak Ridge, Tennessee, where federally managed plants produced much of the nuclear fissile material used in the early atomic era. In 1951, the New York Times reported that polygraph testing had become commonplace within the CIA, and by 1953 the Army routinely tested its ranks on the device for hints of treasonous sentiment.

Unfortunately, the device did not work. The polygraph can be an aid in interrogation, helping guide inquisitors in their questioning, but it fails, by leagues, any reasonable standard of reliability for determining guilt. The lie detector does not pierce the opacity of the human psyche or solve the mind-body problem, as early proponents insisted, but merely measures metabolic functions, which detectives can then interpret for signs of anxiety. In 1951, Larson estimated the error rate of polygraph readings as high as 40 percent. In 2003, the National Academy of Sciences found that no scientific study of any rigor had yet been published demonstrating the validity of the polygraph test.

Polygraph testing is a placebo science, then, and as Alder points out, the first step in staging such a test must always be convincing the subject that the machine does, in fact, work; only then will the stakes seem high enough to produce anxiety levels in the suspect elevated enough to suggest deception. (Keeler, for one, always boasted of his ability to beat the machine, though he trusted it enough to strap himself in during psychoanalysis.) As a placebo, the polygraph can often be exchanged for a prop. In the last several decades, Alder reports, cops have taken to placing the suspects head in a colander with wires attached. Baltimore police have extracted confessions by placing suspects hands on a copying machine filled with paper preprinted with the word LIE! The polygraph ultimately fell out of favor not when detectives lost faith in its reliability, but only when DNA evidence replaced the confession as the Holy Grail of investigative work. As heightened public scrutiny cleared cobwebs from the final shadowy corners of American police work in recent decades, the resilient lie detector has been relegated to a cherished tool of celebrity culture, part of a standard plea to regain the trust of the American people.

Not surprisingly, despite its remarkable American appeal, the lie detector has never caught on abroad. In his lifetime, Leonarde Keeler sold only one polygraph outside the country. Canadians dismissed the device as sham pseudoscience, and the French had a substitute fetish for the subtler superstition of handwriting analysis. Machines resembling polygraphs were seen in space-age Russia only in spy movies, when captured KGB agents routinely outsmarted them.