How to Pass a Lie Detector Test

How to Pass a Lie Detector Test

A polygraph test or lie detector test is designed to analyze physiological reactions to questions to determine whether or not a subject is being truthful. The accuracy of the test has been widely contested by groups including the National Academy of Science, the US Congress Office of Technology Assessment, and the American Psychological Association. Even so, the test is routinely used to screen employment applicants and interrogate criminal suspects.

While a person may be told to answer all questions honestly, the test is designed to measure responses to "white lies," which means truly honest people run the risk of generating a false positive on the test. Other people may wish to conceal answers to certain questions, whether guilty of wrongdoing or not. Fortunately for them, it's not that hard to beat a lie detector test. The first step to passing the test is understanding how it works.

How a Lie Detector Test Works

A lie detector test includes more than the time spent hooked up to the polygraph machine. The tester will start making observations the instant a person enters the test center. A skilled polygrapher will notice and record nonverbal cues associated with lying, so it's a good idea to know your "tells".

The polygraph machine records breathing rate, blood pressure, pulse rate, and perspiration. More sophisticated machines include magnetic resonance imaging (MRI) of the brain. Physiological responses to irrelevant, diagnostic, and relevant questions are compared to identify lies. Questions may be repeated two to three times. The subject may be asked to intentionally lie to help the examiner establish baseline values. The test typically requires one to three hours to complete, including the background assessment, medical history, explanation of the test, actual polygraph, and follow-up.

Most Advice Isn't Very Effective

The internet is filled with advice on ways to beat a lie detector test, but many of these ideas aren't very effective. For example, biting your tongue or putting a tack in your shoe to use pain to affect blood pressure won't affect perspiration levels. Similarly, imagining a lie when telling the truth and imagining the truth when telling a lie won't work because it establishes differences between lies and truth. Remember, differences between the truth and lies are the basis for the test!

2 Ways to Beat the Test

Basically, there are two good ways to beat the test:

  1. Be completely zen, no matter what you're asked. Note: Most people can't master this.
  2. Be completely distraught throughout the entire test.


on Yo Joe!