How to pass a lie detector test


The purpose of a lie detector test is to analyse bodily changes in response to questions to detect deception to determine whether or not an examinee is telling the truth or lying. 

The accuracy of polygraph testing has been the subject of controversy and question amongst bodies in the United States of America where polygraph test results are used within criminal courts and the prison service, such as  the National Academy of Science, the US Congress Office of Technology Assessment, the American Psychological Association and The American Polygraph Association. Even so, in the US lie detector testing is regularly utilised to screen employment applicants and when questioning suspects of a crime within policing.

The generally accepted rate of accuracy for lie detector testing is 87% but this does depend on factors such as the examiner and the equipment used.

Can you beat a lie detector test?

Many people argue that it is possible to “beat” a lie detector test and the internet is full of “helpful” tips to pass a lie detector test when you are lying and not have your deception detected. Below are some examples of internet suggestions to beat a polygraph test:

  1. A lie detector test is not just about the time that you are connected to sensors attached to the polygraph machine; the polygraph examiner will start observing your non-verbal cues and body language and the narrative you provide of the reason for the test. You can learn how you behave and what body language and non-verbal cues indicate deception to the examiner and focus on changing your behaviour to not indicate deception through your general presentation, speech and actions. This is not easy and quite often the effort you are putting in to change your whole natural demeanour will just come across as inauthentic to an experienced examiner and immediately raise alarm bells for deception.
  1. The polygraph machine records breathing rate, blood pressure, pulse rate, and perspiration. Try to be completely relaxed and calm to prevent any spikes in your bodily responses. Breathe deeply and focus on keeping your breathing and heart rate steady and rhythmical. Most people are not capable of doing this however, especially when they are attached to a machine and having to answer questions which repeatedly remind them of the event they are trying to lie about. It’s a lot for one brain to cope with and, contrary to popular belief, human brains cannot consciously multi-task; they can just switch very quickly from one focus to the next. A momentary drop in concentration will give the game away!
  1. Biting your tongue – this is a ridiculous suggestion as the examiner will hear you are doing this when you respond and record non-cooperation which is interpreted as deception so an instant fail!
  1. Think about lying when you tell the truth and telling the truth when you lie; only a small part of the human brain is available to the awareness of our conscious self. We are not in control of everything we do on a conscious level. Plus, the lie detector test is not looking for standard responses to lying and truth telling; it is just looking for significant responses or changes so showing any difference between your presentation lying and being honest will indicate deception so, sorry, but this won’t work either!
  1. Try winding yourself up and remaining upset, fearful and confused throughout the entire test. Keep yourself in a stressed and agitated state. If there is one particular question you’re worried about, imagine every question is that question before answering. This tip is designed to make you present as just uniformly stressed and reactive so that any spikes are not standing out in response to certain questions as you are just spiking all the time. An experienced and knowledgeable examiner will pick up on this behaviour and delay the test to spend time helping you to calm down and settle so that you are in an appropriate psychological state to focus. If they can’t calm you, they will ask you to come back on another day to sit the test when you are more settled so, unlucky, this won’t save your bacon either if the examiner knows their stuff!
  1. Practice the expected questions before the test; you are in most situations quite likely to know what the questions are going to be regarding in the polygraph test so think about and talk about these issues regularly to desensitise yourself to the subject matter and reduce the chance of your physiological responses being peaked in the test. Polygraph testing, unfortunately, is one step ahead of you here! The tests are not just cobbled together; the wording and question order is carefully considered and formulated to prevent any desensitisation from being able to influence the results and to enhance the tension and physiological response when the relevant questions are asked. You can’t prepare for this.
  1. Keep fidgeting and moving so that it is impossible to record your responses consistently. This wont work: the examiner will warn you a couple of times to sit still. If you don’t, they will stop the test due to you being in-cooperative and this indicates deception so an automatic fail.
  1. Think of other things, meditate, take your mind elsewhere, solve complex maths problems in your head….. um, so the examiner will be in the room with you and isn’t stupid. They are closely observing you. They will notice if you are not focused on the questions, listening fully and paying attention and will stop the test. You are also even more like to have a significant response when the examiner mentions the hot topics and rips you out of your happy daydream so no, this won’t work.
  1. Say the word “dream” inside your head over and over. Really?! No. Just no. This will not work. 
  1. Give the examiner a sob story when you enter the test environment; act distraught and like this test means the whole world to you and that you are the most innocent and hurt individual ever for being accused in this way. Cry. Make the examiner feel sorry for you so they believe your story and are on your side. So, polygraph examiners are lovely people and they do want to support you and help you through the test and appreciate it can be a nerve-wracking experience. However, they see this every day and deal with emotional human beings every day. They are there to get the answers and an accurate result. Whilst they will sympathise and understand how you are feeling, they know better than to be influenced by displays of distress or dramatic statements of innocence. Sorry!

Methods for beating a polygraph test

Essentially there are a whole load of suggested methods and top tips for beating a lie detector test all over the internet and the majority of people know someone who, when you say you are taking a polygraph test, will be able to give you all kinds of hints and “scientifically proven” ways to pass it. The thing to remember is that polygraph examiners live in the same world you do and know about these things; polygraphy has been developed in full awareness of all of this and countermeasures provided to prevent people from being able to influence their results.

Admittedly there are some very unique people in the world who just do not produce physiological responses when they lie. However, they are extremely rare, and you are extremely unlikely to be one of them!

The simple answer: if you are going to lie it’s probably best just not to agree to sit the test. End of.

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