It is an uncertain fact that no human in this world who speak truth in all situations, but the reaction of people always depend on the circumstance they face. Especially, the victims in the hand of police need to speak truth and when they ignore it and tell lie, they will be punished. However, no human being is born to identify another’s mind to ensure whether he is speaking truth or lie. Fortunately, the technological advancements have brought a solution to it. Yes, the polygraph test or lie detector test is now used for detecting when the person speaks lie.
Why lie detector test is used?
This lie detector testing is used in various situations to explore whether the person speaks true or lie. It becomes so popular cultural icon from the crime dairies to the advertisements. In fact, this lie detector test is a kind of instrument which is used for conducting the polygraph test. This test consists of physiological recorder that can assess three kinds of the indicators of the autonomic arousal.
It is very important to have an idea about how this system works. Actually, it is a natural thing that we get sweat, increased heart beat and eyes changes when we speak lie. Based on these changes in our body, the detector finds the result. Therefore, this recorder instrument analyses the following aspects.
- Blood pressure
- Pulse rate
- Skin conductivity
Here, depth of the respiration and pulse rate is measured by the pneumographs which are wrapped around the chest of the subject. Moreover, cardiovascular activity is monitored through the blood pressure. Additionally, the skin conductivity can be measured through the electrodes that are joined to the fingertips of the subject.
During the lie detector test, questions will be asked to the subjects. While they answering to the questions, their body changes are monitored. If there are any abnormal changes in the body, then the subject will be handled exclusively. This is the main work of the lie detector test and it is used in various places like investigation to know the truth from victims.