Polygraphs and Lie Detectors: Determining Who is Telling the Truth or Lying

Lie detector test

What is a Polygraph Test?

A polygraph (commonly referred to as a lie detector) is an instrument that measures and records several physiological responses such as blood pressure, pulse, respiration and skin conductivity while the subject is asked and answers a series of questions, on the basis that false answers will produce distinctive measurements.

The polygraph machine measures physiological changes caused by the sympathetic nervous system during questioning.

Within the U.S. federal government, a polygraph examination is also referred to as a psychophysiological detection of deception (PDD) examination. Several other technologies are also used in the field of lie detection, but the polygraph is the most famous.

Some private investigators offer polygraph examination services. Visit our Private Investigator Directory to find a polygraph examination provider in your area.

Following are resources for polygraphs, testing, and related resources.

American Polygraph Association – The largest organization for truth verification specialists in the world. Represents the interests of examiners in government, law enforcement and in private business. Provides access to helpful resources, publications and training resources.

Federation of American Scientists: Polygraph Policy – An extensive list of official documents, articles and other resources on polygraph testing.

How to Pass a Polygraph Test – Prepare to pass the test by knowing how to always produce a truthful chart. Almost half of the time, if you’re nervous when you take the test, you’ll end up being branded as a liar. This is why the tests are often inadmissible because it is not a true lie detection test.

National Polygraph Association – Organization whose goal is to promote and advance public acceptance of the polygraph and to urge the members active participation in civic and community affairs where the polygraph is concerned. Includes helpful resources links and tools and allows you to search for a certified examiner. Also provides membership for existing examiners.

Polygraph Evidence in Court – Examining lie detection results as a sensible approach to the problem of wrongful convictions due to perjury by police, jailhouse informants, and co-operating prosecution witnesses. A somewhat helpful website, yet contains a lot of text, long pages and a lot of links. May take you a while to sift through to find what you need.


Please enter your comment!
Please enter your name here