“Problem Polygraphs”

The Chicago Tribune published a letter from AntiPolygraph.org’s George Maschke regarding its 19 Nov. editorial, “Polygraphing students, sensibly.” The following is the text of the letter as published (it was edited for length):

Problem Polygraphs

George W. Maschke, Co-founder, AntiPolygraph.org

December 1, 2001

The Hague, The Netherlands — In “Polygraphing students, sensibly” (Editorial, Nov. 19), you characterize as “ingenious” Dunlap, Ill., school Supt. Bill Collier’s decision to give student athletes accused of violating a pledge not to drink, or remain in the presence of those who do, the opportunity to prove their innocence. Mr. Collier’s intent to avoid wrongly punishing the innocent is laudable, but his decision to rely on polygraph tests is hardly ingenious.

Your observation that “polygraphs are not foolproof” is an understatement. Polygraph “testing” has no scientific basis; it is, instead, fundamentally dependent on trickery. The polygrapher, while admonishing the examinee to answer all questions truthfully, secretly assumes that denials in response to certain questions–called “control” questions–will be untrue, or that the examinee will at least have doubts.

An example of a control question is, “Did you ever cheat in school?” The polygrapher steers the examinee into a denial by suggesting that someone who would cheat in school would also cheat outside of school.

The polygrapher scores the test by comparing physiological reactions to these probable-lie control questions with reactions to relevant questions such as, “Did you drink alcohol at that party?” If the former reactions are greater, the examinee passes; if the latter are greater, he fails.

This simplistic methodology has never been validated by peer-reviewed scientific research and is inherently biased against the truthful, because the more honestly one answers the control questions, and as a consequence feels less stress when answering them, the more likely one is to fail!

Conversely, liars can beat the test by subtly augmenting their physiological reactions to the control questions. This can be done by constricting the anal sphincter muscle, biting the side of the tongue or merely thinking exciting thoughts.

While polygraphers claim that any experienced examiner can easily detect countermeasures, peer-reviewed research has shown that they cannot.

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