Polygraph was often used to request for resignation to the dishonest job applicants in those days (Barland, 1978). Later, an important addition in law in 1988 in the US disapproved the firing of employees based on polygraph results. However, several US government agencies practice the applicability of polygraph in the detection of lie (American Polygraph Association, 1983a; 1983b; American Psychological Association, 1974; 1983). Amongst several government sectors, the police investigators of US also hold the practice of polygraph applicability. The US Supreme Court has left it to the decision of individual jurisdictions whether or not the inclusion of polygraph test should take place in the court cases. On the other hand, in European jurisdictions, the application of polygraph is considered as an unreliable and invalid means of approaching the truth.
The procedure for the application of polygraph instrument for lie detection has its beginning with a pre-test interview designed to establish a connection between the tester and the testee. The information gained by this step is called "Control Questions." We might say that just as in a good research design of an experiment a control group exists so in the practical application of polygraph the first step can be considered as the control step. The tester makes it very clear to the subject that the machine being used in connection with his answers holds the efficiency to detect lie. Thus, the subject is being requested to answer truthfully. Next step in lie detection in many cases is the practical application of slim test. In this step, the subject or the testee is requested for deliberately lying and then the tester reports that he was able to detect his/her lie. We might state that the initial tests helps in gaining control reading and acquaintance with the essential biological and mental aspects of the testee.
After these initial crucial steps begins the procedure of actual test for lie detection using polygraph. During the actual test, some of the questions are irrelevant and others are probable-lie. In addition, there are certain control questions that are inscribed in the actual test. The remaining questions are those that hold relevance with the actual area of investigation. We might state that a randomized approach to the application of several types of questions is being used to detect lie in the testee. The testee passes the test if the physiological responses as observed in his body during the probable-lie control questions are larger than those during the relevant questions. However, if the testee fails to pass the test, attempts to elicit admissions to the post-test interview are made. These admissions form the most prominent goals of the test.
Polygraph- validity and reliability is existent or inexistent
The validity and reliability of the results obtained by the administration of polygraph test is an area of great controversy and dispute (Abrams, 1973; Ansley, 1983; Barland, 1981; 1982; 1973). There are some who project the accuracy of polygraph test to the level of 70%-90% of the cases (this might be an overly optimistic view of the instrument). However, others play the essential role of critics and thereby question the scientific base for the application of