Lie detector tests belie the truth
Polygraph measurements — derived from changes in blood pressure, breathing depth, and skin conductivity of an electric current — have never been proved to be reliable indicators of deception. Not only is genuine emotional turmoil hard to reproduce in laboratory studies, but such emotional responses are not uniform among humans and can be imitated by countermeasures (such as pinching yourself before giving a response). In large screening tests, significant numbers of “false positives” (innocent people being labeled deceptive) are unavoidable.
In addition, the question of whether deception during a polygraph test indicates a person is unsuitable for employment transcends merely technical issues. In the final analysis, American security agencies never arrived at a definition of what personal characteristics a model employee should have. Instead, the polygraph provided reasons for dismissing a person as a security risk or denying him or her employment.
Since shortly after its creation in 1947, the CIA has used the polygraph as part of its personnel security procedures to ascertain the truthfulness of job applicants and employees and to confirm the bona fides of agents. At the height of McCarthyism, utilizing a machine known by the public as a “lie detector” made sense, especially for a brand-new agency that had to be staffed quickly. To its proponents, the polygraph represented a promise of objectivity and fairness along with effective deterrence of spies and traitors. As a CIA inspector general report from 1963 emphasized, “We do not and could not aspire to total security. Our open society has an inherent resistance to police-state measures.”
When challenged by Congress, which investigated federal polygraph use repeatedly beginning in the mid-1960s, the CIA defended the polygraph aggressively. Yet internally, CIA bureaucrats admitted that the practice of sorting out job applicants and employees based on their test results was questionable at best. Even after decades of polygraph practice, the CIA could not define what exactly it meant by elusive terms such as “routine” and “voluntary” in its polygraph program.
A 1974 list of questions from polygraph examiners to the general counsel included the following query: “What can a polygraph officer say in response to the question: ‘Do I have to take this test to get a job with the Agency?’ or ‘What happens if I don’t take the test?’” The relevance of the evidence produced during most polygraph tests was also unclear. “The precise yardstick for the measuring of security reliability of an individual continued to be elusive,” an internal CIA history on personnel security concluded in 1973.
Other questions haunted the polygraph throughout the Cold War, and the oftentraumatic experience of the test provoked fierce protests from Americans across ideological lines. Journalists Joseph and Stewart Alsop, two otherwise unrelenting Cold War boosters, compared the polygraph to the embrace of an octopus whose “electric tentacles” produced an “overwhelming impulse to tell all … in order to appease the octopus machine.” Even former chief of CIA counterintelligence James Olson called polygraph exams “an awful but necessary ordeal. We all hate them. … It’s a grueling process.” Whether the sheer unpleasantness of the exam did more to deter potential traitors, or kept otherwise upstanding citizens from joining the agency, is impossible to determine.
Ultimately, there is the question of whether the polygraph ever caught Soviet spies. Certainly no major communist spy was ever caught by the machine, and the most damaging one, Aldrich Ames, passed two routine polygraph exams after he had delivered deadly information about U.S. activities in the Soviet Union to his handlers.
While the Ames case almost fatally damaged the polygraph’s reputation, the technology was rekindled in the wake of the 9/11 attacks and the subsequent wars in Afghanistan and Iraq, because, once again, it gave the appearance of a scientific way to test such elusive values as loyalty when doing the inherently risky jobs of screening employees and counterintelligence work. As the history of the polygraph makes clear, American policy makers place great trust in technological fixes to thorny political problems — even though they themselves question those fixes privately.
John Baesler is a professor of history at Saginaw Valley State University and the author of Clearer Than Truth: The Polygraph and the American Cold War. This essay was initially published on Zocalo Public Square.