Is it possible to beat a lie detector test?

Aug 29, 2022 | News & Science

Searching Google for how to beat a lie detector test will produce some interesting results. There are lots of suggestions, without proof, as to how you can fool the polygraph.

Here are some of the methods recommended:

  • Taking cannabis, cocaine or other recreational drugs will confuse the results
  • Respond to every question with a lie
  • Alter your respiration pattern all through the test
  • Those who have recovered from a stroke, have nerve damage or suffer from epilepsy don’t test accurately

So, virtually every recommendation involves deliberate deception to beat a lie detector test! However the reality is very different.

Facts about trying to beat a lie detector test

A lie detector test, when administered by a qualified, accredited polygraph examiner is both authentic and reliable.  We don’t argue that mistakes have never been made but they are not usually made by experienced, highly trained examiners. But comprehensive scientific research has revealed that polygraph tests are infinitely more reliable than expert or eye witness testimony.  Verification of scientific studies can be found in a number of resources including the Journal of Criminal Law and Criminology, Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques and Polygraph among many others.

Human beings possess an SNS (Sympathetic Nervous System).  The sympathetic nervous system activates what is often termed the fight or flight response.” according to Science Daily,

The SNS works with the ANS (Autonomic Nervous System), CNS (Central Nervous System) and PNS (Peripheral Nervous System). This network of neurons functions independently of cognizant thought. For example, when you are sleeping you continue to breathe and your lungs and heart function irrespective of your slumbers.

Contrary to common belief, the polygraph examination doesn’t test for truth or lies. It records the physiological responses of a subject when questions are posed. When the test is over, the examiner analyses the results and creates a detailed report of known and verifiable responses.

Medical conditions

If you have a medical condition you must be honest about it.  We will not conduct a test on anyone or verify results without this being disclosed. Some medical conditions and medications can influence a polygraph examination. There is no point in taking the test without being up front about such conditions. Often those who brag that they beat a lie detector test have not been truthful about their health.

Drugs taken for hypertension, blood and heart conditions can influence a lie detector test, as can anti-depression/anxiety drugs. However state of the art polygraph technology can pick up on the most minor changes when a subject responds to questions. An experienced examiner will be able to determine whether a person is on medication.  If you are on drugs of any type you should disclose this during the pre-test screening. If you are, depending on your condition, an examiner may require your doctor to approve the test if you still want to take it.


Humans are able to control neurological responses to a minor extent. However, a trained polygraph examiner is usually able to recognise attempts to do this. Whilst it is possible that outcomes can be affected, it is highly unlikely that you will beat a lie detector test.

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