A lie detector, also known as a polygraph, uses physiological indices blood pressure, pulse, respiration, and skin conductivity during the interview. When the interview is on, some of the reactions represent that the person is lying. This is formed on the hypothesis that if a person is knowingly lying, then it produces some reaction in the person’s body and this is used as an indicator. But the anomaly is that there are no particular physiological reactions that the person may show when the person is lying. More importantly, similar physiological reactions may also occur when a truthful person is afraid to be caught and misunderstood.
Some Facts about Lie Detectors
Sometimes the examiner uses a pretest by going through all the questions before time actual examination, but at times it is a general conversation that the examiner has with the person to be tested with the lie detector. This is done so that the person knows the baseline for the examination and understands what to expect. The examiner also tends to test the machine before starting the actual test by asking very obvious questions like whether the person has ever lied before or not.
Uses of Lie Detectors
Lie detectors are used in multiple places even today. Though in the US it is not legal to be used for employment purposes, it is used there for the federal investigations. Especially in UK police has started using lie detectors. The lie detector testing has proven to be an advantageous asset in arresting criminal offenders. But they also have to adhere to the national standards of interviewing as set by the College of Policing by which the police can only use it in certain cases in a certain manner beyond which it is not permitted.
There is the UK lie detector test agencies in multiple locations who provide services, but the usage of such services are governed. Some of the offices of these agencies are at Sussex, Suffolk, and London. Thus the trend of using the lie detector services is increasing by the day. But on the other hand it is speculated that lie detectors do not help to understand that a person is definitely lying, but is rules out cases where there are probably cases that the person is lying, hence it is an additional tool that helps in interrogation and not the ultimate judge of the fact that the person is lying.