How to cheat a lie detector?

There are a variety of instances in which you may be subjected to a polygraph, or lie detector examination. These tests can be a source of tremendous anxiety, especially since it is all too common for innocent people to fail them for no reason, resulting in the denial of employment or false criminal accusations. Why? Because polygraphs are far from perfect. In fact, many experts consider them a farce, and almost all scientists who have studied them (and even some polygraph administrators) understand that polygraphs are seriously limited. Fortunately, for this very reason they are easy to trick. So whether you don’t want your potential employer to know about your youthful mistakes or you want to make sure you don’t fail a polygraph just because you’re nervous, follow these steps to take control of your interrogation.

Steps to follow:

  1. Refuse a polygraph test if you can. For pre-employment screenings this will almost certainly ensure that you don’t get hired, but it probably will not get you fired in most circumstances. In the U.S., private sector employers may not terminate employment or take other such adverse actions based solely on a polygraph refusal (this protection usually does not cover government employees). If your polygraph is part of a criminal investigation, you have a right to refuse (in the U.S., at least), and you should refuse, even if you are innocent, because of the possibilities of a “false positive.” Refusal to submit to a polygraph is generally not admissible in court, and polygraphs themselves are always inadmissible.
  2. Learn about polygraphs. Since you’re reading this article, you’re on the right track, but if your career or court case depends on it, wouldn’t you do as much research as you can? Answer truthfully, now. The most important thing to know is that polygraph is not an exact science. In fact, to the extent that it is a science at all, it is one in its infancy and one which frequently produces incorrect results.
  3. Find out what the tester is seeking. A polygraph examination is administered to help find out specific information, such as whether you’re a spy or whether you’ve used drugs. Prepare yourself in advance by thinking about what confessions they are looking for, what things you cannot admit. The polygrapher will ask you many uncomfortable questions, but only certain ones are important. If your test is prompted by a specific incident, you probably know what the examiner is looking for, but for pre-employment screening tests and the like, research the company or agency’s policies to determine what you can and cannot admit.
  4. Approach your whole “polygraph day” as a test. Treat the polygraph examination as an extreme job interview.
  5. Identify the types of questions you are being asked. There are three basic types of questions you will be asked: relevant, irrelevant, and control. Irrelevant questions are those that are obvious, such as “What is your name” or “Have you ever eaten pasta?” Relevant questions are the important ones, such as “Did you leak that memo to the media?”, “Have you ever stolen money from an employer?”, or “Have you ever sold drugs?”
  6. Don’t admit anything relevant. The job of polygraphers is to extract confessions, and in one way, the whole examination is a complex ruse to trick you into confessing something. Never confess relevant information. No matter what the lines on the chart look like, nothing is more certain or damaging than your confession.
  7. Say only what you need to say. “Yes” or “No” answers should be all you need for most of the test. Resist the temptation to explain your answers or to go into details, although the polygrapher may try to get you to do so. Be courteous and cooperative, but do not offer any more information than is absolutely necessary.
  8. Conceal your knowledge of polygraphy. The polygrapher may ask you, often before or after the test, if you’ve done any research on polygraph tests or what you know about them. Do not disclose that you’ve done extensive research, and act as though you don’t know much about polygraph examinations but that you do believe polygraphy to be a science and polygraphs to be reliable (or at least do not exhibit any doubt as to their reliability). The polygrapher may try to trick you by mentioning certain technical terms and acronyms, such as, “Your test came back NDI.” While you know (or will now know) that “NDI” means “no deception indicated,” you need to act as though you have no idea what it means. Too much knowledge of the process may make the polygrapher think you’ve got something to hide, even if you don’t.
  9. Throw off the machine’s reading of the control questions by changing your blood pressure and heart rate. Do some of the following when replying to control questions:
    • Develop a breathing strategy. Throughout the test (except during control questions) maintain a normal breathing rate of 15-30 breaths per minute. Do not breathe too deeply. Then alter breathing rate with control questions. You can make it faster or slower, you can hold your breath for a couple of seconds after an exhalation, or you can breathe more shallowly, for example. Do this for 5-15 seconds, and return to your normal breathing pattern before the next question. As explained above, the polygrapher will compare your physiological responses to control questions to your responses to relevant questions. If the deviation from normal during control questions exceeds the deviation from normal during relevant questions, you will pass. If, however, you react more to a relevant question than to control questions, the polygrapher will perceive (rightly or wrongly) that you are lying in response to something relevant—you will fail the polygraph.
    • Do math in your head. During control questions do something mentally complex. For example, count backwards in your head as quickly as possible or do some quick long division, as you are answering the question.
    • Think about something exciting or frightening; think of things that make you ecstatic, fearful, or frustrated.
    • Bite your tongue. Bite the side of your tongue hard enough to cause pain, but not so hard as to draw blood. Practice this in a mirror to be sure the polygrapher cannot detect it. This is highly effective, but may be detectable if you have to speak for an extended period, because you can’t bite while you’re speaking. Only use this method if you can give a quick “yes” or “no” response, which, luckily, will be most of the time.
    • Insert a small nail or tack in the toe area of your shoe and press down on this during the control questions to elicit a pain response. This is a sound method, but it is easily defeated if the polygrapher asks you to remove your shoes.
    • Contract your anal sphincter muscle when a control question is asked. While also highly effective, this method may (or may not) be discovered with the use of pressure-sensitive seat pads that are now commonly used.
  10. Handle the post-test interview. After you’re disconnected from the machine, the polygrapher may leave you in the room for a while and come back. The polygrapher may then claim to “know” that you are lying about something.


  • Practice countermeasures in advance. The countermeasures listed here can almost guarantee that you “pass” the polygraph examination, but only if you do them right. Once you read about the measures, be sure to practice them well before the test so that you’re thoroughly prepared.
  • The needles on the machine chart physiological changes, such as breathing and heart rate, over time. While this sort of machine is still frequently used, computer-based polygraph machines are becoming more common.
  • Remember that you are being watched closely during the test. When you use countermeasures, use them discreetly.
  • There are several subtle variations on the polygraph test. Be sure to research these thoroughly before your test to be prepared for anything they might throw at you.
  • If you do not feel comfortable employing countermeasures from a moral standpoint, you are probably better off not taking the test. Even if this means, for example, that you will not get a job. In almost all circumstances, “passing” a polygraph cannot help you get a job, nor can it exonerate you from an alleged crime.
  • Understand that polygraphs do not detect lying. They detect physiological responses when you are thinking of a topic.
  • So, if you were to hook up a polygraph to yourself in your basement and have your buddy ask you questions, it would likely not show any such anticipation/relief responses. However, the nervousness in employment interviews and police questioning is your give away. You are expected to be nervous and that is accounted for. The polygraph takes your baseline, which is your base physiological response when you are nervous.
  • Remember that the Polygraph is nothing more than a complex trick to get you to make an admission. Never make a relevant admission! The polygrapher only knows what you tell them and nothing more. Many honest people fail the polygraph, and they will take this into consideration. But make an admission, and you will not pass.
  • Think to yourself that the answer you are giving is the truth this will calm down anything the the polygraph will detect as a lie.
  • Do not rely on the truth to prevent positive indications. The most important factor is your state of mind. You need to be relaxed.


  • The polygrapher is not your friend. Beware pretest tricks. Polygraphers will frequently attempt to instill fear in the subject or convince the subject of the accuracy of the polygraph machine.
  • Don’t take this article as the bottomline, but you can always view this as a guiding light…

About theultimaterenaissance

I am an Engineer and a Management Graduate. I love writing poetry and research reports on cars. Surfing, listening to music, and Reading and writing Technical & Research papers are among my most savored hobbies.
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4 Responses to How to cheat a lie detector?

  1. Cameron says:

    im taking a test sometime this month and ive done many things against my probations like drink,smoke underage,have sex go to underage clubs,be out past curfiew.etc. so explain on my situation how do i pass this thing im 2 for 2 i need to pass this next one and i will be off probation finaly after 5 years

  2. Pingback: I have book marked you

  3. Clare says:

    I lost my husband to a lie detector on the jeremy Kyle show 😥
    I swear I wad lying

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