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Polygraphy Is Quackery

Make-believe science yields make-believe security.

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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 tracings 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 polygraph operators 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.

Latest News:

S.F. Chronicle Publishes Investigative Report into Use of CVSA by Law Enforcement Agencies
On Tuesday, 4 June 2024, the San Francisco Chronicle published a well-researched investigative article by Susie Neilson and Matthias Gafni on the use of the Computer Voice Stress Analyzer (CVSA) by law enforcement agencies, especially in the state of California.

Confessed Spy Alexander Yuk Ching Ma Evidently Did Not Beat the Polygraph
On 18 August 2020, reported that Alexander Yuk Ching Ma, a former CIA officer and FBI contract linguist charged with espionage, had evidently beaten the polygraph to penetrate the FBI. It now seems clear that this was not the case.

California Department of Corrections and Rehabilitation Phasing Out CVSA has confirmed with the California Department of Corrections and Rehabilitation (CDCR), that its Office of Peace Officer Selection, which in 2016 began using Computer Voice Stress Analysis (CVSA) to screen applicants, terminated this practice in May of 2023.

Dr. Wes Boyd on Physicians Being Forced to Submit to Polygraph "Testing"
Some state physician health programs are compelling physicians with or suspected of having substance use disorders to submit to polygraph "testing."

Polygraph Evidence at Issue in Alex Murdaugh's Federal Sentencing
Federal prosecutors are attempting to revoke a plea agreement based on an allegedly failed polygraph "test."

Government-controlled Reddit Community for Border Patrol Applicants Bans Discussion of Polygraphs
Talk about polygraphy is now verboten on r/borderpatrolapplicant.

Virginia Polygraph Board Unanimously Rejects CVSA
It appears that CVSA will not be approved for use in the state of Virginia. Co-founder George Maschke Interviewed on Publicly Buzzed Live Stream
On Friday, 15 September 2023, brothers Steve and Dan, the hosts of Publicly Buzzed, a YouTube channel focused on crime, mystery, and comedy, spoke about polygraphs with co-founder George Maschke

Voice-Based "Lie Detector" Marketer Offers $2,000 for Success Stories
In a 29 June 2023 mass emailing addressed to "All CVSA Examiners," NITV Federal Services, which markets a putative "lie detector" called the Computer Voice Stress Analyzer (CVSA), offered $2,000 for any success stories that it accepts for publication on its website.

No, Ted Bundy Didn't Pass a Polygraph "Test"
It is often claimed that notorious serial killer Ted Bundy (1946-1989) passed a polyraph test….

Espionage Act Conviction of Former FBI Intelligence Analyst Kendra Kingsbury Raises Questions About the FBI's Personnel Security Polygraph Program
On Wednesday, 21 June 2023, U.S. District Judge Stephen R. Bough sentenced former FBI intelligence analyst Kendra D. Kingsbury, 50, of Kansas to 46 months in prison to be followed by 3 years of supervised release.

EyeDetect Marketer Converus Spends Hundreds of Thousands of Dollars Lobbying Federal Agencies
Intercept investigative reporter Daniel Boguslaw reports on lobbying efforts by Converus Inc., which is attempting to market its EyeDetect “lie detector” to the federal government.E

Polygraph Statement of Wais Ahmad Ahmadzai
Wais served as a combat interpreter with the U.S. Army in Kandahar province in 2008. In 2017, he re-applied, but this time was branded as a liar during a polygraph screening test, despite telling the truth. He remains in Afghanistan where he and his family are in imminent danger from the Taliban.