The dirty little secret behind the polygraph is that the "test" depends on trickery, not science. The person being "tested" is not supposed to know that while the polygraph operator declares that all questions must be answered truthfully, warning that the slightest hint of deception will be detected, he secretly assumes that denials in response to certain questions -- called "control" questions -- will be less than truthful. An example of a commonly used control question is, "Did you ever lie to get out of trouble?" The polygrapher steers the examinee into a denial by warning, for example, that anyone who would do so is the same kind of person who would commit the kind of behavior that is under investigation and then lie about it. But secretly, it is assumed that everyone has lied to get out of trouble.

The polygraph pens don't do a special dance when a person lies. The polygrapher scores the test by comparing physiological responses (breathing, blood pressure, heart, and perspiration rates) to these probable-lie control questions with reactions to relevant questions such as, "Did you ever commit an act of espionage against the United States?" (commonly asked in security screening). If the former reactions are greater, the examinee passes; if the latter are greater, he fails. If responses to both "control" and relevant questions are about the same, the result is deemed inconclusive.

The test also includes irrelevant questions such as, "Are the lights on in this room?" The polygrapher falsely explains that such questions provide a "baseline for truth," because the true answer is obvious. But in reality, they are not scored at all! They merely serve as buffers between pairs of relevant and "control" questions.

The simplistic methodology used in polygraph testing has no grounding in the scientific method: it is no more scientific than astrology or tarot cards. Government agencies value it because people who don't realize it's a fraud sometimes make damaging admissions. But as a result of reliance on this voodoo science, the truthful are often falsely branded as liars while the deceptive pass through.

Perversely, the "test" 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 covertly augmenting their physiological reactions to the "control" questions. This can be done, for example, by doing mental arithmetic, thinking exciting thoughts, altering one's breathing pattern, or simply biting the side of the tongue. Truthful persons can also use these techniques to protect themselves against the risk of a false positive outcome. Although polygraphers frequently claim they can detect such countermeasures, no polygrapher has ever demonstrated any ability to do so, and peer-reviewed research suggests that they can't.

Educate yourself. Before playing Russian roulette with your reputation, learn how to protect yourself against this invalid test. Download AntiPolygraph.org's free book:

The Lie Behind the Lie Detector

Polygraph Countermeasure Challenge Clock On 28 January 2002, retired FBI polygraph expert Dr. Drew C. Richardson reiterated his challenge to the polygraph community to prove their claimed ability to detect countermeasures (techniques for passing -- or beating -- the polygraph). This clock figure shows the number of weeks Dr. Richardson's challenge has gone without takers. What are the polygraph operators afraid of? (Listen to a personal message from Dr. Richardson.)

328 weeks

The Port-A-Poly Goes to Afghanistan
Some two weeks after MSNBC investigative reporter Bill Dedman broke the story of the Department of Defense's new hand-held lie detector, formally dubbed the "Preliminary Credibility Assessment Screening Tool" (PCASS), Mike A. Glasch who writes for the weekly Reader, the official newspaper of Fort Jackson, South Carolina, picked up on the story in the 24 April 2008 issue.

The Polygraph Interrogation of Kevin Jones: Another case of polygraph abuse
Discussion of the use of the polygraph in the investigation of the murder of Nona Dirksmeyer of Russellville, Arkansas.

U.S. District Judge Jed Rakoff Derides Polygraphy as "Junk Science"
"[The use of a polygraph] is not remotely scientific and, when it creeps into the courtroom, can create great mischief."

The Crystallynn Girard Murder Case: Yet Another Failure of the Polygraph
On Valentine's Day 1993, 13-year-old Crystallynn Girard was found dead in her bedroom, apparently strangled. Days after the death, a suspect, Dennis Donohue, passed a polygraph "test," was granted immunity, and provided grand jury testimony that helped indict the victim's innocent mother, Lynn DeJac, of the crime.

According to Polygrapher: Irregular Breathing Must Mean Countermeasures
Like many here I just had a horrific experience with a polygraph while trying to gain employment at a police department. In this case I passed the test with no indications of deception, only to be told I was being kicked out because I was using countermeasures....

Skip Webb Admits PCASS Is Easy to Beat
In another thread Skip Webb made some rather damning admissions. I think it will be worthwhile to review them. He has freely admitted that: (1) It is easy to beat the PCASS; and (2) It is reasonable to suppose that the people the PCASS is supposed to detect know how to beat it.

New religion: Church of the Polygraph (satire)
"The American Polygraph Association has founded it's own religion, the Church of the Polygraph (COP), Adherents, called Cops, believe that the polygraph is divine and worship it as the one true God and creator of the universe...."

Mr. Mascke's [sic] Act of Treason
Federal polygrapher and American Polygraph Association Past President Skip Webb accuses AntiPolygraph.org co-founder George Maschke of treason for revealing how the Defense Academy for Credibility Assessment's new hand-held lie detector can be fooled.

Warning to U.S. Troops on Hand-Held Lie Detector
AntiPolygraph.org's George Maschke addresses members of the U.S. armed forces who are being asked to rely on DoD's new hand-held lie detector, the "Preliminary Credibility Assessment Screening System" (PCASS).

How to Beat the Preliminary Credibility Assessment Screening System (PCASS)
The U.S. Government's new hand-lie detector, the Preliminary Credibility Assessment Screening System or PCASS, can be easily defeated through the use of simple countermeasures.

Preliminary Credibility Assessment Screening System: U.S. Deploys Hand-Held Lie Detector
MSNBC has released a major investigative report on the Department of Defense's adoption of a hand-held lie detector to be used by U.S. forces deployed in Afghanistan and Iraq. The device is to be used to screen local nationals, who will be questioned through the use of interpreters.

Unlawful Referral Scheme Alleged in Dallas-Fort Worth Metroplex Post-Conviction Sex Offender Polygraph Testing
A lawsuit filed in January 2008 alleges the existence of an illegal referral scheme whereby sex offender therapists and probation officers of the Community Supervision and Corrections Department of Tarrant County, Texas (which includes Fort Worth) directed sex offenders subject to mandatory polygraph screening to go to specific polygraph examiners, rather than allowing them to go to any appropriately credentialed polygraph examiner.

Polygraph Operator Eric J. Holden Sanctioned for Sexual Harassment
In July 1999, polygraph examiner Eric J. Holden of Texas, a past president of the American Polygraph Association and prominent advocate for the post-conviction polygraph screening of sex offenders, was accused of sexually harassing a female student at the Texas Department of Public Safety Polygraph School.

Seeking Information from Registered Sex Offenders on Probation in the Dallas-Fort Worth, Texas Area
If you are a convicted sex offender on probation or deferred adjudication and are subject to mandatory polygraph screening in the Dallas-Fort Worth area, AntiPolygraph.org's George Maschke would be interested in communicating with you privately regarding polygraph practices in the Metroplex.

Nebraska Polygrapher Charles O’Callaghan Named in Federal Lawsuit
Charles O'Callaghan, a polygraph examiner and Nebraska State Patrol investigator, has been named as a defendant in a lawsuit filed in the United States District Court for the District of Nebraska by Matthew Livers, from whom investigators coerced a false confession after an allegedly failed polygraph examination conducted by O'Callaghan, who is also a member of the Nebraska Association of Polygraph Examiners.

Larry Sinclair and the Polygraph
As noted earlier on the blog, Larry Sinclair, who claims (thus far without evidence) to have used cocaine with, and performed fellatio on, Barack Obama in 1999 has accepted a $100,000 polygraph challenge from one-time Internet pornographer Dan Parisi, who runs the website WhiteHouse.com....

Politics, Publicity Stunts, and Polygraphs: Obama Accuser Larry Sinclair Accepts WhiteHouse.com's $100,000 Polygraph Challenge
On 18 January 2008, a Mr. Larry Sinclair of Duluth, Minnesota posted to YouTube a video statement entitled "OBAMA'S LIMO SEX & DRUG PARTY" in which he made sensational allegations against Democratic presidential hopeful Barack Obama and challenged him to a polygraph showdown....

 

 

 

 

 

 

 

 

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