On Wednesday, 3 June 2015, Business Insider published a story by reporter Christina Sterbenz titled “The one thing you need to know to pass a polygraph test.”1 AntiPolygraph.org co-founder George Maschke and American Polygraph Association president Raymond Nelson were interviewed for this report.
A few points in the article merit special note. Sterbenz writes:
Most jurisdictions, including the government, have also forgone the use of probable-lie comparison, Nelson said, and now rely on “directed lie comparison,” which doesn’t require any manipulation when asking control questions.
It is AntiPolygraph.org’s understanding that the probable-lie control question test remains the primary technique relied upon by federal, state, and local governmental agencies in the United States. It is true that the U.S. Departments of Defense and Energy have adopted the directed-lie Test for Espionage and Sabotage, but to the best of our knowledge, these agencies are outliers, and the CIA and NSA continue to rely on the Relevant/Irrelevant technique while federal law enforcement agencies rely on the probable-lie CQT as embodied in the Law Enforcement Pre-Employment Test. Moreover, even the directed-lie technique entails numerous instances of examiner deception of the examinee, as explained by retired FBI polygraph expert Dr. Drew Richardson more than a decade ago.
“It’s less scientifically, ethically, legally, and socially complicated,” Nelson said.
The directed-lie technique is arguably less ethically complicated than the probable-lie technique, but it has no stronger scientific or legal basis. It’s still pseudoscience.
In 2002, the National Academy of Sciences published one of the most comprehensive studies of polygraph accuracy, concluding that while the tests could “differentiate lying from telling the truth at rates well above chance,” they weren’t accurate enough for security purposes.
Regrettably, Sterbenz’s citation of the National Academy of Sciences’ report omits crucial caveats. What the NAS report actually states, at p. 214, is:
Notwithstanding the quality of the empirical research and the limited ability to generalize to real-world settings, we conclude that in populations of examinees such as those represented in the polygraph research literature, untrained in countermeasures, specific-incident polygraph tests for event-specific investigations can discriminate lying from truth telling at rates well above chance, though well below perfection.
Accuracy may be highly variable across situations. The evidence does not allow any precise quantitative estimate of polygraph accuracy or provide confidence that accuracy is stable across personality types, sociodemographic groups, psychological and medical conditions, examiner and examinee expectancies, or ways of administering the test and selecting questions. In particular, the evidence does not provide confidence that polygraph accuracy is robust against potential countermeasures. There is essentially no evidence on the incremental validity of polygraph testing, that is, its ability to add predictive value to that which can be achieved by other methods.
AntiPolygraph.org notes with respect to the foregoing conclusion (in Chapter 1 of The Lie Behind the Lie Detector):
Some in the polygraph community have attempted to hang their hat on the first sentence of the above citation to support the claim that polygraphy “works.” But note that the Committee’s conclusion that “specific-incident polygraph tests for event-specific investigations can discriminate lying from truth telling at rates well above chance” is conditioned upon the subject population being similar to “those represented in the research literature,” that is, ignorant of polygraph procedure and countermeasures. Such ignorance cannot be safely assumed, especially with information on both polygraph procedure and countermeasures readily available via the Internet.
It follows from the Committee’s conclusion that “the evidence does not allow any precise quantitative estimate of polygraph accuracy” that software algorithms peddled by polygraph manufacturers such as Axciton and Stoelting that purport to determine with mathematical precision the probability that a particular individual is lying or telling the truth are unreliable. And because, as the Committee concludes, “the evidence does not provide confidence that polygraph accuracy is robust against potential countermeasures,” it is not safe to assume that anyone passing a polygraph “test” has told the truth.
The last sentence of the above-cited passage is the key one with respect to polygraph validity (as opposed to accuracy): “There is essentially no evidence on the incremental validity of polygraph testing, that is, its ability to add predictive value to that which can be achieved by other methods.” What this means is that there is no evidence that polygraph “testing” provides greater predictive value than, say, interrogating a subject without the use of a polygraph, or with a colander-wired-to-a-photocopier that is represented to the subject as being a lie detector.
Indeed, in the first chapter of their report, in a subsection titled, “The Lie Detection Mystique” (pp. 18–21), the Committee members compare polygraphy with superstitious lie detection rituals in primitive societies, likening the polygraph community to a shamanistic priesthood “keeping its secrets in order to keep its power.”
A discussion thread regarding this article has been opened on the AntiPolygraph.org message board.
- The less click-baity title suggested by the article URL, “How to pass a polygraph test,” would have been more appropriate. There are numerous things that anyone hoping to pass a polygraph “test” should know. [↩]