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Acing the Lie Detector Test:  7 Helpful Tips, As Well As Things, To Watch Out For Before The Exam

In order to establish whether or not a person is telling the truth, a polygraph or lie detector exam analyses physiological responses to queries. Several organisations have raised concerns about the test's validity, including the National Academy of Sciences, the US Congress Office of Technology Assessment, and the American Psychological Association. Nonetheless, the exam is commonly used to vet job candidates and question suspected criminals.

Though test takers are instructed to answer every question truthfully, the exam is really intended to gauge reactions to "white lies," increasing the likelihood that those who are completely forthright may provide a bogus result. Even if they are innocent, others may prefer to keep quiet about your replies to certain inquiries. It's not too difficult to find ways to fool a lie detector, which is good news for them. Learning the test's structure is the first step toward success.

Lie detector test on a school boy
source: howstuffworks

A Lie Detector's Inner Workings

There is more to a lie detector exam than just using polygraph equipment. As soon as a candidate enters the testing facility, the tester will begin collecting data. Knowing your "tells" will help you avoid being caught by a polygraph examiner who is trained to look for and document nonverbal signs that are linked with lying.

The polygraph monitors physiological data including heart rate, blood pressure, and sweat. Magnetic resonance imaging (MRI) of the brain is one application of newer technology. The physiological reactions to leading, diagnostic, and leading queries are compared to detect deception. There may be a two- or three-question repetition. In order to help the examiner determine appropriate ranges, the subject may be instructed to knowingly provide inaccurate data. Background check, medical history, test explanation, polygraph, and possible follow-up might easily eat up two or three hours.

Most pieces of advice aren't worth taking.

Many of the suggestions for how to fool a lie detector test that may be found online are, unfortunately, not particularly reliable. You won't be able to control your perspiration rate by, say, biting your tongue or sticking a tack in your shoe in order to raise your blood pressure. Similarly, pretending to imagine a falsehood while saying the truth or the truth while pretending to tell a lie is ineffective since it reveals the distinction between the two. To review, the test will be based on your ability to distinguish between truth and falsehoods.

How to Pass Any Exam: Two Strategies

There are essentially two viable strategies for succeeding on the exam:

Stay calm and collected no matter what comes your way. Keep in mind that the vast majority of individuals will never be able to grasp this.

Act dejectedly during the entire examination.

Experiment with These Seven Suggestions

1. It doesn't matter if a person intends to deceive or not, taking a lie detector exam makes them uneasy. No lie detector is going to be fooled by the physiological effects of anxiety. If you want to make them feel truly terrified, you have to elevate your game. This is because, in order to succeed in test taking, one must engage in mental manoeuvres, which in turn influence behavioural reactions. What follows is a list of suggestions to consider trying:

2. If you want to do well on the exam, your best chance is to remain agitated, afraid, and bewildered the entire time. The objective is to project an air of serenity and confidence despite whatever anxiety or unease one may be experiencing on the inside. Try to put yourself in a condition of persistent excitement and stress by recalling your worst event or by mentally completing tough arithmetic problems. If you're nervous about answering a certain question, pretend like it's the only one you're being asked.

3. Be thoughtful about your response. Choose if it is unimportant, useful, or diagnostic (control). Asking you to repeat your name or if the lights are on are examples of irrelevant queries. The key questions are the ones that are directly relevant. Do you know about the crime? is an example of such a question. Most people will lie in response to diagnostic inquiries that they should honestly say "yes" to. Questions like, "Have you ever stolen something from your workplace?" or "Have you ever lied to get out of trouble?" are examples of this type.

4. While answering the control questions, breathe in a different manner, but get back to your regular breathing pattern before answering the following question. The choice to reveal any of these tangential details is yours.

If asked a question, answer it confidently, without laughing it off. Be helpful without going overboard with jokes or friendliness.

5. Be as definitive as possible with your responses. Do not elaborate on your replies or provide any justifications for your choices. There's really nothing to say about it; what more do you want me to say?

6. Don't believe someone who accuses you of lying. On the contrary, let the accusation feed your anger and confusion. Even though you answered the examiner's diagnostic questions truthfully, you may have gotten contradictory information.

7. Get plenty of test-day practises with your countermeasures. Make use of someone else's questioning skills by having them probe for likely answers. Pace yourself and watch how you respond to various queries by tuning into your breathing.

Remember that while these strategies may help you to invalidate the test, they won't help you much if you're taking a lie detector exam to gain a job. Most of the time, being truthful is the best strategy for passing a lie detector exam.

Substances That May Impair Diagnostic Accuracy

An inconclusive polygraph result is common when drugs or health issues are involved. This is why a screening questionnaire and/or a drug test are typically administered prior to a lie detector test. Heart rate and blood pressure medications can alter the results of a polygraph.

Pills like heroin, marijuana, cocaine, and methamphetamine are among those that fall into this category, along with over-the-counter pharmaceuticals including antihypertensives and anti-anxiety drugs. Some drugs and supplements, such as caffeine, nicotine, sleep aids, and cough medicines, may potentially have an impact on test results.

The Test May Not Be Permitted If You Have...

It's possible that people with diagnoses of sociopathy or psychopathy could manipulate their responses on the test, but it's also possible that people with certain medical conditions couldn't take it.

Do not take the exam if you suffer from epilepsy, neurological damage (including essential tremor), cardiovascular illness, stroke, or excessive exhaustion. People who are mentally unfit should not take the exam. Women who are pregnant are not required to take the test unless their obstetrician grants prior written consent.

A person's ability to deceive a lie detector test is not impacted by the use of drugs or medical conditions, with the exception of mental illness. This makes the findings less trustworthy.


  • Board on Behavioral, Cognitive, and Sensory Sciences and Education (BCSSE) and Committee on National Statistics (CNSTAT) (2003). "The Polygraph and Lie Detection". National Research Council (Chapter 8: Conclusions and Recommendations), p. 21.

  • "Scientific Validity of Polygraph Testing: A Research Review and Evaluation". Washington, D. C.: U.S. Congress Office of Technology Assessment. 1983.

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