George W. Maschke sent this letter to the members of the West Virginia House of Delegates Judiciary Committee on 6 May 2003. For discussion of the proposed legislation that is the subject of this letter, see the message board thread, West Virginia Sex Offender Polygraph Bill.

Dear Chairman Amores, Vice-Chairman Armstead, and Members of the West Virginia House of Delegates Judiciary Committee:

I am a co-founder of, a non-profit, public interest website dedicated to exposing and ending polygraph waste, fraud, and abuse. I am writing to provide you with important information about polygraphy that you should be aware of before taking action on House Bill 2780, which would require that sex offender probationers and parolees be subjected to polygraph examinations.

While many Americans believe that polygraphy is an admittedly imperfect but nonetheless science-based diagnostic technique, it actually has no scientific basis whatsoever and is completely unreliable. The dirty little secret of the polygraph community is that polygraph testing actually depends on trickery, not science, and that polygraph tests are easily beaten by those who understand how the test "works" (and doesn't).

The trickery on which polygraph testing depends, while increasingly well-known to criminals, is little understood by the American people. Let me briefly explain it. While numerous deceptions are employed in the polygraph process, the key element of trickery is this: the polygrapher must mislead the examinee into believing that all questions are to be answered truthfully, when in reality, the polygrapher is counting on the examinee's answers to certain of the questions (dubbed "probable-lie control questions") being untrue.

One commonly-used probable-lie control question is, "Did you ever lie to get out of trouble?" While the examinee may at first make minor admissions, the polygrapher will strongly discourage any further admissions, warning the examinee, for example, that anyone who would lie to get out of trouble is fundamentally untrustworthy. But in reality, the polygrapher assumes that the examinee's denial will be a lie, or that the examinee will at least experience considerable doubt about the truthfulness of his or her denial.

The second category of questions are termed "relevant" questions. In post-conviction polygraph screening (such as that envisaged by H.B. 2780) these questions are typically about the examinee's compliance with the conditions of probation or parole.

A third category of questions are termed "irrelevant" questions, the true answers to which are obvious, such as, "Is today Tuesday?" or, "Are you in West Virginia?" The polygrapher falsely explains to the examinee that these questions provide a "baseline" that shows what it looks like when the examinee is telling the truth. But in reality, the irrelevant questions are not scored at all. They merely serve as a buffer between sets of relevant and "control" questions.

The polygrapher connects the examinee to the polygraph instrument, which records breathing, heart rate, blood volume, and perspiration rate (as a function of skin conductance or resistance), and asks a series of relevant, irrelevant, and "control" questions (all of which are reviewed with the examinee beforehand).

The polygrapher then compares the examinee's physiological responses while answering the "control" questions to those while answering the relevant questions. If reactions to the "control" questions are greater, the examinee is deemed truthful. If reactions to the relevant questions are greater, the examinee is deemed deceptive, and a post-test interrogation will follow. If responses to both the "control" and the relevant questions are about the same, the test will be deemed inconclusive.

Perversely, the more honestly one attempts to answer the "control" questions, and as a consequence experiences less stress when answering them, the more likely one is to fail.

Conversely, deceptive persons who understand the theoretical assumptions of the procedure may covertly augment their physiological responses to the "control" questions, producing a "truthful" chart and beating the test. This may be accomplished by doing mental arithmetic, biting the side of the tongue, or constricting the anal sphincter muscle. It is a common misperception that one must believe one's own lies or be a sociopath to beat a polygraph test. As the FBI's top expert on polygraphy, Dr. Drew C. Richardson of the Laboratory Division, testified at U.S. Senate Hearing 105-431 in 1997, "If this test had any validity (which it does not), both my own experience, and published scientific research has proven, that anyone can be taught to beat this type of polygraph exam in a few minutes." You might wish to seek Dr. Richardson's testimony in any hearing(s) you hold on H.B. 2780. He may be reached by phone at [contact information deleted].

Detailed information on how to pass or beat a polygraph test is available in's popular free e-book, The Lie Behind the Lie Detector. While we made this information available to help truthful persons to protect themselves against the significant risk of a false positive outcome, and not to help criminals escape detection, this same information could also be used by recidivist sex offenders to beat the polygraph.

Note that while polygraphers frequently claim that they can detect countermeasures (techniques for beating the polygraph), no polygrapher has ever demonstrated any such ability, and peer-reviewed research suggests that even experienced polygraphers cannot detect the kinds of countermeasures described in The Lie Behind the Lie Detector.

You should also be aware that the National Academy of Sciences (NAS), agreeing with Dr. Richardson, has recently determined that polygraph screening is completely invalid, and that reliance on it even poses a danger to national security. While the NAS focused on the polygraph screening of federal employees, the same principles apply to post-coviction polygraph screening. Indeed, in its report, The Polygraph and Lie Detection, the NAS even went so far as to compare the polygraph community with a shamanistic priesthood that keeps its rites secret to protect its power.

See also Professor William G. Iacono's recent article, "Forensic 'Lie Detection': Procedures Without Scientific Basis," Journal of Forensic Psychology Practice, Vol. 1 (2001), No. 1, pp. 75-86.

H.B. 2780 is no doubt well-intentioned, but it is clearly ill-advised, and I urge you to reject it.


George W. Maschke