Lie detector tests are used for different purposes. The first thing that comes to most people’s mind when they hear about a polygraph test is something that is connected to a crime. However, polygraphs are often taken for personal reasons or simply to entertain people i.e. like on the Jeremy Kyle’s TV show. The accuracy of the lie detector tests has always been a subject of discussion. Some people believe that the results of the polygraph are 90% accurate, whereas others believe that the polygraph cannot be trusted. Both claims have their supporters; both sides are right up to a point.


Polygraph Tests In Court

The results from the polygraph tests can’t be used as evidence in court, simply because there is no way to prove whether they are accurate or not. The polygraph is just a machine. It picks up peoples’ reactions on certain questions that are considered to be true and questions that need to be confirmed and it creates a pattern. This pattern then helps the private investigators to read what is true and what is not. The machine controls the blood pressure/heart rate, respiration and skin conductivity. The problem is that the test causes stress to people. That stress makes the body react very unusual. If the body reacts unusual, then the machine thinks you are hiding something. If the needle jumps more than expected then it registers your answer with a probability that it’s a lie. However, if you are too stressed about the polygraph, the results can be falsely positive. This doesn’t mean that you are hiding something, but it means that it is just the way your body reacts to stressful situations. In addition, people who are generally very calm can easily cheat the system. If they are able to focus on something else during the test and isolate the body from the mind, then the results can be falsely negative. It is very difficult to determine who is telling the truth and who is not.


Two Types Of Questions

During the testing the private investigator who is conducting the test uses two types of questions, control questions and relevant questions. The person who is truthful will react more to the control questions, as those questions refer to something that is familiar to them. They will not react to the relevant questions connected to the crime, as they have nothing to do with it. The person who is lying will not pay attention to the control questions, but it will show greater concern over the relevant questions that are connected to the crime they are trying to hide. That is how the test works. If the person reacts in a similar way both to the control questions and to the relevant questions that the test is considered to be inconclusive.

Whether or not the polygraph is accurate will highly depend on the circumstances. Sometimes it is a good tool to find out the truth; sometimes it can be very misleading. In conclusion we can say that anyone is innocent until proven guilty, and you are always telling the truth until proven otherwise.