When it comes to a lie detector, a lot of what we know is taken from the television. Shows which feature lie detector tests are sadly not always accurate or realistic. Therefore, it is not uncommon for people to have an insufficient idea of how the lie detector test works. We’re going to be taking a look at the procedure for identifying if people are telling the truth.

The pre-test

This is the first part of a lie detector test. The pre-test is where the person who is being tested, known as the subject, and the person who is giving the test, known as the examiner, get properly acquainted with one another. The inspector will show the subject all of the equipment which will be used during the test, and explain to them how everything works so that the subject is fully informed on what is going to happen. There will also be a discussion where the questions which are going to be asked will be decided upon and then agreed on by both the subject and the examiner. This is, in fact, the longest part of the entire process, and usually takes an hour on average to complete.

The polygraph test

From there, it is time to move onto the main part of the lie detector test, and this is called the polygraph test. It involves the subject being attached to the apparatus, which measures respiration and breathing levels. These are continuously recorded, and when they change the machine is notified and records the changes, which can be then matched up with a specific question. The subject is also attached something called a GSR. This is referred to as the Galvanic Skin Response and measures the level of perspiration on the skin. As most people tend to have an elevated standard of perspiration when they are in situations which cause anxiety, the machine is placed on strategic points on the body to best capture the increase of perspiration and record it.

From there, a series of questions are asked. These questions are designed to try and ascertain if the person is telling the truth or if they are not. These will be questions about an event, questions about their own private lives, and they all serve to try and identify if what the subject has said previously is true or not.

The post-test

This is where the polygraph test is over, and the end is in sight. The results will be given back to the subject, and any identified falsehoods will be identified and will require explanation. After that, the subject needs to sign all of the papers involved to confirm that they undertook the test and prevented their records from being confused for other subjects.

Overall, this is how the lie detector test works out in real life. A lie detector is a powerful tool which can be used to discern if people are truthful and is a relatively straightforward process. If you’re a liar, then you will be caught out. If you are not, then the test will reveal nothing new.