Polygraph Test Reliability

Technology
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From ChatGPT:

"Polygraph tests, commonly known as lie detector tests, measure physiological responses such as heart rate, blood pressure, respiration, and skin conductivity while a person answers a series of questions. The underlying assumption is that deceptive answers will produce distinctive physiological responses that can be detected by the polygraph.

Reliability and Accuracy

  1. Scientific Consensus: The reliability and accuracy of polygraph tests are highly debated within the scientific community. Many experts argue that there is no consistent, reliable physiological response specific to lying. As a result, polygraph results are often considered scientifically controversial.
  2. False Positives and False Negatives: Polygraph tests can produce false positives (innocent people being labeled as deceptive) and false negatives (deceptive people being labeled as truthful). Factors such as anxiety, nervousness, fear, or even the skill of the examiner can influence the results.
  3. Control Questions: Polygraph tests often use control questions to establish baseline physiological responses. However, the interpretation of these responses can be subjective, leading to potential inaccuracies.

Legal and Professional Use

  1. Legal Admissibility: In many jurisdictions, polygraph results are not admissible as evidence in court due to their questionable reliability. For example, in the United States, the results are generally inadmissible in federal courts, though some states may allow them under specific circumstances.
  2. Employment Screening: Polygraph tests are sometimes used in employment screening, particularly in law enforcement and security agencies. However, their use is regulated and controversial. In the U.S., the Employee Polygraph Protection Act (EPPA) of 1988 significantly restricts the use of polygraphs for most private employers.

Alternatives and Advances

  1. Technological Advances: There have been efforts to improve lie detection technology, including the use of functional magnetic resonance imaging (fMRI) and other brain imaging techniques. However, these methods are still under research and have not yet proven to be reliably effective for widespread use.
  2. Behavioral Analysis: Some experts advocate for behavioral analysis techniques, which involve observing and analyzing a person’s verbal and non-verbal behaviors for signs of deception. While potentially useful, these methods also lack consistent reliability and are subject to interpretation.

In summary, while polygraph tests can provide some insight, their reliability and accuracy are questionable, and they are not universally accepted as a definitive measure of truthfulness."

I find it interesting that according to a true crime show I watched tonight titled Criminal Confessions one person who passed a polygraph test was Gary Ridgeway aka The Green River Killer who killed 49 women and is the second most prolific serial killer in American history.

He was eventually identified when DNA from the victims was linked to him.

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Polygraphs measure how nervous you are, period.

Some people are so trusting and goody two-shoed that the needles would jump no matter what question they were asked.

It’s a garbage tool built on the incorrect assumption that nobody will be nervous unless they are lying.

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I once took a voice analysis lie detector.
One of the answers the at showed “deception “ was if I had ever belonged to a group that would like to overthrow the country.
And yes, this was pre January 6th, 2021.

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Actually not how the test works.

The assumption is the person will think they were caught and admit or tell more of their story.

It’s a prop for the most part

My buddy was a polygraph examiner for 30 years.

There are all sorts of what’s ifs with one but the general stance is people think the machine works

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In one of his shows Lt Joe Kendra in Homicide Hunter said he has no faith in lie detectors working but they were useful because criminals think they work.

In addition to that because cops can lie to suspects the cops can tell the suspect they failed even when they passed and hope that leads to a confession.

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Back in the late 70’s I worked for a dairy in Dallas as a dock supervisor. The owners were concerned about supervisors and route drivers stealing product. So they sent us to monthly polygraph exams. I had one every month for a year. The first ones I was nervous, but pretty soon they became routine. They changed companies that were giving the test and the operator was interviewing me to give me the standard once over. He asked if I had ever had a polygraph and I told him I have taken about a dozen. The guy sat back in his chari and said “your shitting me”…then said they were throwing their money away becsause they had become too common. But he administered the test. For his last question he stood up, slammed his hands on the table and almost shouted “Do you believe that I know what I’m doing with this test”. I blandly answered “yes”. The needle barely moved at all. They eventually stopped the practice. And the only supervisor who WAS doing something like that was the owner’s nephew, who was the only one who didn’t have to get tested.

I basically went in and closed my eyes, pretty much meditating, but listening to the question. Damn near flat-lined a polygraph.

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