Lie detectors are instruments that use the involuntary physiological changes of a subject’s heart rate, blood pressure, and respiration to assess whether the subject is lying. Most commonly, this involves using a polygraph, but there are many other lie detection methods.
Getting the Answer
Although lie detectors have been popularized by television programs and movies, they are often inaccurate and should not be used as evidence in court. In fact, they may even present an innocent person as guilty. This link https://liedetectors.co.uk
A Lie Detector Test
A polygraph, which measures the involuntary physiological changes of he subject’s heart rate, blood pressure, respiration, and perspiration, is the most common and widely used form of lie detector. It is based on the premise that, when the subject is asked questions or made to respond to statements, his or her breathing rate, heartbeat, blood pressure, and skin conductivity are all likely to increase as a result of apprehension, fear, or emotional excitement.
The Science behind Lie Detection: Exploring the Physiology of Deception
Polygraphs are also susceptible to a number of countermeasures that can be employed by subjects to ‘beat’ the test. These include intensifying emotions when answering questions, biting the tongue, or making physical movements that cannot be seen by the examiner.
The NAS Report stated that, “[a]lmost a century of research in scientific psychology and physiology provides little basis for the expectation that a polygraph test could have extremely high accuracy.” It also noted that efforts to improve accuracy would be difficult, if not impossible, given the lack of a better theoretical understanding of how deception works. Moreover, many scientists believe that the fundamental premise of lie detection is flawed.