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The effectiveness of polygraphs

A polygraph, more commonly known as a lie detector, measures and takes record of a number of physiological indicators such as pulse, blood pressure, respiration, and skin conductivity while a subject is asked to answer a sequence of questions. The belief supporting the use of the polygraph is that misleading or deceptive answers will produce physiological reactions that can be distinguished from those related to non-deceptive responses; the polygraph is one of numerous devices that can be used in lie detection.

The effectiveness of polygraphs is widely debated in the community of scientists. In 2001, a noteworthy segment of the scientific community deliberated that polygraphy to be pseudoscience. In 2002, a review by an American agency known as the National Academies of Science found that in populaces of untrained in countermeasures, lie detection can differentiate between lying and truth-telling at levels above chance, yet below perfection. These outcomes apply only to particular events and not to the screening where it is of popular assumption that polygraph would work less effectively. Efficacy may also be degraded by countermeasures. Some countries make use of polygraphs as a tool for the interrogation of criminal suspects or applicants for certain public or private sector employment. American law enforcement and federal control agencies such as the FBI (Federal Bureau of Investigation) or the CIA (Central Intelligence Agency) and several other police departments, for example, the LAPD, use polygraph tests to interrogate suspects and examine new employees. Within the United States federal government, a lie detection exam is also known as a psychophysiological detection of deception (PDD) examination.

Lie detection testing is designed to analyse the physiological reactions of those being tested. However, studies have indicated that there aren’t really any specific physiological reactions connected with lying and the brain activity and mechanisms linked with lying are actually indefinite, creating some difficulty in identifying aspects that differentiate liars from truth tellers. Polygraph testers also prefer using their own individual method of scoring, rather than computerised techniques, as they can more simply support their own evaluations.

The probable lie test was developed to contest the issues with the relevant-irrelevant testing method debate. Even though the relevant questions asked in the probable lie test are employed to spark a reaction from liars, it can also gain a reaction from the innocent subject who is afraid of false detection. The physiological reactions that "distinguish" liars, may also occur in individuals who fear a false detection, or feel passionately that they did not commit the crime. Therefore, although a physiological reaction may be occurring, the reasoning behind the response may be different. Further examination of the probable lie test has shown that it is partial towards innocent subjects. Those who are incapable of thinking of a lie in relation to the relevant question will inevitably fail the test.

Despite the debate around the validity of the polygraph, it has proven to do more good than bad. Life Crusader Polygraph Services offers quality polygraph testing services for the corporate as well as private sector. Life Crusader Polygraph Services uses the well-known AVSAPRO, which is a leader in fully automated voice polygraph technology.

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