Top 10 Strategies for Outsmarting a Lie Detector

There are various situations in which you may be asked to undergo a polygraph, or lie detector test. These examinations can be extremely stressful, particularly since it's not uncommon for innocent individuals to fail them, which could result in job rejection or false criminal charges. Why is this the case? Because polygraphs are far from flawless. In fact, many specialists view them as unreliable, and nearly all scientists who have researched them (along with some polygraph examiners) acknowledge their significant limitations. Luckily, due to these flaws, they can often be easily manipulated. So, here are the top 10 strategies for beating the lie detector test.

10. Decline

If possible, decline a polygraph test. While refusing such a test during pre-employment screenings will likely lead to rejection, it typically won’t result in dismissal in most cases. In the United States, private employers cannot terminate or take punitive actions based solely on a polygraph refusal (though this protection doesn't usually extend to government employees). If the polygraph is part of a criminal investigation, you are entitled to refuse (in the U.S., at least), and you should decline, even if you are innocent, due to the risk of a “false positive.” Refusing a polygraph generally cannot be used as evidence in court, and polygraphs themselves are inadmissible as well.

Familiarize yourself with polygraphs. Since you're reading this article, you're already on the right path, but if your career or legal situation is on the line, wouldn't you want to do as much research as possible? Be honest with yourself. The most crucial thing to understand is that polygraphy is not a precise science. In fact, if it can even be considered a science, it is still in its early stages and often produces inaccurate results.

Understand what the examiner is trying to determine. A polygraph test is designed to uncover specific information, such as whether you're a spy or have used illegal substances. Prepare ahead by considering what confessions they might be fishing for and what you're unwilling to admit. The polygraph examiner will ask you a series of uncomfortable questions, but not all of them hold significance. If your test is tied to a particular event, you likely know what the examiner is seeking, but for routine pre-employment screenings or similar tests, research the organization's policies to know what you can and cannot reveal.

Approach the entire polygraph process as if it's a job interview. Treat the polygraph test like an intense interview. Dress appropriately and conservatively, make a strong first impression before the test, and be punctual—avoid rescheduling or attempting to delay the exam unless absolutely necessary. You wouldn't fidget, behave oddly, or do anything inappropriate during a job interview, right? The polygraph is even more intense, as your every move is likely being watched the moment you enter the test area. There may be hidden cameras in waiting rooms and restrooms, and it's almost certain there’s a camera or two-way mirror in the testing room. Your polygraph assessment starts long before you're hooked up to the machine and finishes only after you leave the facility.

Recognize the different types of questions you'll face. There are three main categories: relevant, irrelevant, and control questions. Irrelevant questions are obvious and unrelated, like 'What is your name?' or 'Have you ever had pasta?' Relevant questions are the critical ones, such as 'Did you leak that memo?' 'Have you ever stolen from your employer?' or 'Have you ever dealt drugs?' Control questions are used to compare your responses to the relevant ones. These are usually uncomfortable but non-threatening questions everyone can answer 'yes' to, like 'Have you ever cheated in a game?' or 'Have you ever lied to your spouse?' Before the test, the polygrapher will typically go over all the questions with you, which is a good opportunity to mentally categorize them.

Avoid admitting anything important. The purpose of polygraph examiners is often to extract confessions, and the whole process is designed to trick you into revealing something. Never admit to anything relevant. Regardless of the chart readings, nothing is more damaging than your own confession. The polygrapher will likely try to convince you they can 'see' lies in the results, even when nothing is out of the ordinary. Don't fall for this. That said, you should still try to appear truthful overall, so it's okay to make minor admissions during control questions—just ensure these don't lead to further probing or seem relevant to the test.

Only provide necessary information. In most cases, simple 'Yes' or 'No' answers will suffice. Resist the urge to elaborate or give extra details, even if the polygrapher tries to prompt you. Be polite and cooperative, but don't give out any more information than what is absolutely required. Answer each question clearly, seriously, and without delay. This isn't the time for jokes or clever tactics. You should appear sincere, cooperative, and firm in your responses.

Keep your knowledge of polygraphy concealed. The examiner may ask if you’ve studied polygraph tests or know anything about them, either before or after the test. Do not admit to having researched them extensively. Instead, act as though you're not well-versed in polygraphs but believe in the science behind them, and in their reliability (or at least do not show any skepticism). The polygrapher may attempt to trick you by using technical terms or acronyms like 'Your test came back NDI.' Even though you know that 'NDI' stands for 'no deception indicated,' pretend you don't understand what it means. Revealing too much knowledge may make the polygrapher think you're hiding something, even if you're not.

Distract the machine from accurately reading your control questions by adjusting your blood pressure and heart rate. This can be challenging, but with practice, the following strategies will help you achieve this. Try some of these methods when answering control questions:

Create a breathing pattern. Maintain a normal breathing rate of 15-30 breaths per minute during the test (except for when answering control questions). Avoid deep breathing. Then, alter your breathing rate when you answer control questions. You can either speed it up or slow it down, hold your breath briefly after exhaling, or breathe more shallowly. Do this for 5-15 seconds, then return to your normal breathing pattern before the next question. As previously explained, the polygrapher will compare your physiological responses to control questions and your answers to relevant questions. If your reaction to control questions deviates more than your response to the relevant questions, you will pass. If, however, you react more strongly to a relevant question than to control questions, the polygrapher will assume (correctly or incorrectly) that you're lying about something relevant, and you will fail the polygraph.

Engage in mental calculations. While responding to control questions, perform a mentally challenging task. For instance, mentally count backwards as quickly as you can or perform some rapid long division calculations.

Focus on something intense or unsettling; consider things that excite you, terrify you, or frustrate you.

Bite your tongue. Apply enough pressure on the side of your tongue to cause discomfort, but not so hard that it draws blood. Practice this technique in front of a mirror to ensure the polygrapher cannot notice it. This method is very effective, but may be detectable if you have to talk for a long time, as you can't bite your tongue while speaking. Use this technique when you're only required to give brief 'yes' or 'no' answers, which will usually be the case.

Place a small nail or tack inside the toe area of your shoe and press it down during control questions to trigger a pain response. This technique works well, but can be thwarted if the polygrapher requests that you remove your shoes.

Tighten your anal sphincter muscle when a control question is asked. This method is highly effective, but may or may not be detected if pressure-sensitive seat pads are used during the test.

Navigate the post-test interview. Once you’ve been disconnected from the machine, the polygrapher might leave you alone in the room and return later. When they do, they might claim to ‘know’ that you’re lying about something. This is a tactic to unsettle you. Stay composed and calmly, but firmly, reiterate your denial without altering or debating your answers in any way. If possible, avoid extended post-test questioning.

This article is licensed under the GFDL. It utilizes material from the WikiHow articles: How to cheat a lie detector