How to Cheat a Polygraph Test (Lie Detector)

Apply Polygraph Countermeasures

1. 
   Say only what you need to. '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.
2. 
   Don't admit anything relevant. No matter what the lines on the chart look like, nothing is more certain or damaging than your confession. The polygrapher will most likely try to convince you that he or she can 'see' a lie in your polygraph, even if there's nothing abnormal there. Don't fall for it. However, you want to appear honest, so don't be afraid to make minor admissions to control questions. Just make sure you don't admit anything in these that can invite further questioning or that may be construed as relevant.

   1. Remember that the job of polygraphers is to extract confessions. In many ways, the whole examination is a complex ruse to trick you into confessing something.
3. 
   Answer questions firmly, seriously, and without hesitation. This is no time to joke around or try to be crafty. You want to appear earnest, cooperative and resolute.
4. 
   Breathe normally. Except during control questions, you should try to maintain a breathing rate of 15-30 breaths per minute. Do not breathe too deeply.^[1]
5. 
   Alter breathing rate with control questions.^[2] 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 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 and you will likely fail the polygraph.

   1. Change your breathing pattern when a control question is asked. You can make it faster or slower, hold your breath for a couple seconds after an exhalation, or breathe more shallowly. Do this for 5-15 seconds and return to your normal breathing pattern before the next question.
6. 
   Answer control questions strangely.^[3] When you are asked a question that is obviously a control question, answer in a vague or odd fashion. For instance, if you're asked what year it is, you might respond with, "the year of the snake" or such an answer. Your goal is to make it difficult for the tester to get a bead on what a "normal" response is for you.
7. 
   Think of something mentally stressful when answering a control question.^[4] If you can artificially worry yourself when answering a control question, you can modify the results of your test so that your "normal" responses appear the same as the responses that actually worry you. For instance, you might try doing mental arithmetic when a control question is asked. Count backwards by 7s in your head as quickly as possible or do some quick long division. This will help change your blood pressure and heart rate to a level that's similar to that which occurs during actual stressful situations - like answering a revealing question. Alternatively, you can mentally picture a frightening scenario, like, for instance, drowning, as this typically will also increase your heart rate and breathing.^[5]
8. 
   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. This is a trick. Remain calm and firmly but politely repeat your denial. Don't change or augment your answers and decline extended post-test interviewing if possible.