The polygraph is commonly referred to as a lie detector, but it does not recognize lies. A specific physiological lie response has never been demonstrated and is unlikely to exist (NRC, 2003). The responses it measures are not unique to deception nor are they always provoked by it. The aim of the polygraph examiner is to establish a psychological set in the examinee that will increase the likelihood that any observed arousal to specific questions is the result of deceptive responses (Kleiner, 2002; Grubin, 2010; Senter et al, 2010).
Use of polygraph examination in criminal investigations, employee screening and security vetting where the emphasis is on whether or not the individualhas passed the test is an area of much controversy (NRC, 2003). In the event-related investigation polygraph performed well above chance level, an unacceptable level of false positive results during the screening, precluding its usage in employment and pre employment screening procedures (NRC, 2003). Confessions or disclosure of the individual as the result of either possibility or being a subject of polygraph testing is considered the highest proof of polygraph validity and reliability by the polygraph examiner and the polygraph community at large. Such a situation does not address the effect of Bogus Pipeline.
The effect of Bogus Pipeline is the expectation that subjects will answer more honestly if they believe that the truth can be tested for accuracy even in the absence of such a test. Since 1971, when Jones and Sigall described a new paradigm for measuring affect and attitude and named it “The Bogus Pipeline” attempts to quantify its effect were undertaken. Damphousse et al. (2007) reported that in the study, where subjects were informed that their answers would be analysed by a lie detector, only 14% lied about recent drug use compared to 40% in the study where no lie detector was used or mentioned. Both studies participants were the subjects of urinary drug testing. It is important to point out that the remarkable outcome is the effect of informing the subjects about the use of a lie detector only.
Whether the lie detector actually does anything or is even physically present is irrelevant. Telling the subjects that a lie detector will be used, but without actually using one, will have the same effect as long as the subjects believe that a lie detector is used. Future scientific validation of the basic principles of polygraph testing cannot be considered without factoring in the Bogus Pipeline effects of such testing.