The Reliability and Accuracy of Polygraph

There are 4 main aspects of Voodoo science: pathological science, junk science, pseudoscience, fraudulent science. A polygraph falls under the category of pseudoscience. This is because it is based on the psychological manipulation of those under questioning, who are under the notion that a polygraph is grounded in science. However, it is my opinion that polygraphs are simply a complicated scare tactic used by law enforcement to extract a confession.

Polygraphs are often used by law enforcement, the military and even during job screenings. It measures one’s heart rate, breathing, and galvanic skin response. However, there are many factors that may affect the reliability of the polygraph.

Firstly, polygraphs may elicit false positives. Based on the United States Department of Energy’s (US DOE) experiments, polygraphs have been shown to have a false positive rate of approximately 2%. While 2% may appear to be a negligible amount, this still indicates that the results are not fully accurate, and cannot be entirely relied upon. Thus, it is my opinion that polygraphs can only serve as an indication that further investigation is required, rather providing a definitive result.

Secondly, a polygraph depends on the state of mind of the subject. The polygraph can be wholly inaccurate when an individual believes what they are saying. The truth is subjective to an individual – if the subject believes in their statements bona fide, regardless of how wrong their information may be, the polygraph would be unable to detect the “truth”, rendering the test useless. Furthermore, it fails to consider the issue of a psychopath that may not have any anxiety over their crimes and therefore escape detection.

Moreover, there are individuals that feel guilty at the mere mentioning of various acts, so that they fail the polygraph despite being innocent. Subjects may not be lying, but the polygraph might pick up on their anxiety resulting from worry and panic. This would generate inaccurate results that would place the innocent subjects at a detriment.

Lastly, the results of a polygraph can be easily rigged. This has been proven by Doug Williams, who sells a manual teaching one how to beat polygraphs. As claimed by Williams, “the polygraph test has a built-in bias against a truthful person. It is certainly not capable of determining truth or deception. It can be beaten rather easily”. The knowledge of how to beat a polygraph renders the test entirely useless. What good is a lie detector if it is unable to detect lies?

In conclusion, it is my take that the only value of a polygraph test is as a basic interrogation tool to weed out answers from a suspect. However, the results cannot be taken as completely reliable and accurate, as many factors can affect the test’s results. This view has been cemented by the Judiciary in Singapore and the majority of the United States, with most States’ Courts ruling the inadmissibility of polygraphs as evidence.