Literature is full of invented words, and we’re accustomed to these coinages making the leap into everyday usage. The words nerd and gargantuan, for example, made their first appearances in works of fiction. The same is true of lie detector. However, lie detector differs from many other literary neologisms, because mystery novelists of the early twentieth century didn’t just come up with its name—they also came up with the very invention itself.
Geoffrey C. Bunn’s recent book The Truth Machine (Johns Hopkins, 2012) gives an in-depth account of how the modern-day polygraph sprung from the literary imagination. In the last decades of the nineteenth century and early years of the twentieth, the most trusted science viewed criminality as an inherent trait, detectable through phrenology and other means of pseudo-genetic testing. In the words of one prominent surgeon, commenting in the late nineteenth century, criminals constituted “a variety of the human family quite distinct from civil and social men.”
Because criminals were thought to belong to an actual human subspecies, there was no law enforcement interest in having a machine that could detect lying in the ordinary person. Scientists did conceptualize some technological means of rehabilitating serial liars and otherwise stemming the progress of criminal development, but these efforts were always predicated on the idea that an individual person was either inherently law-abiding or inherently degenerate.
That’s where fiction comes in. This harsh conception of human predisposition caused problems for the burgeoning genre of the whodunit, which derives its suspense from the premise that anyone at all could be the culprit. In order to justify the suspicions thrown on each and every character, mystery writers of the early twentieth century had to embrace a new, equal-opportunity model of criminality. The detective novel, Bunn writes, presupposed the shift in attitude that came in the 1930s, when many people in the U.S. and the U.K. rejected a eugenics-oriented approach to eradicating crime and began to think of criminality as a behavior rather than an identity. To go with this new conception of crime, several detective novels of the day imagined a new kind of sleuthing technology: the lie detector, which could be strapped to any ordinary person and distinguish his moments of earnestness from his moments of deception.
Over the first few decades of the twentieth century, as the scientific view of criminality caught up to the literary one, lie detector prototypes emerged in police stations across the country. Once subjects of literature, lie detectors were now positioned as a readership, scrutinizing suspects whose “secret knowledge can be read like print.” Bunn writes that the use of these machines was widely celebrated by critics of the brutal police interrogation tactics of the time. Reformers welcomed the polygraph as expedient, sterile, accurate, and humane. Unfortunately, though, the machines’ extreme unreliability and resulting potential to do harm wasn’t fully acknowledged until decades later. Today, the results of lie detector tests are usually inadmissible in court.
It’s hard to read this book and not think of the analogous argument of the twenty-first century, of our own mysterious black box trotted out to replace the unpleasantness of hands-on investigation. Of the black box sold to us as faster, smarter, and less harmful than the alternative. Of the black box that also turned out, in its own way, to be capable of overzealousness. Earlier this month, the Transportation Security Administration announced that it was suspending its contract with the manufacturer of its airport body scanners, in large part because of the privacy concerns that civil rights advocates have been raising for two years. As we wait to see whether the new scanners will, in fact, avoid the harms of the old ones, The Truth Machine is a nice reminder, in general, that some black boxes may best be left to the realm of the imagined.