Lie Detectors (Polygraphs) should not be used in court

"A polygraph is an instrument that records certain physiological changes in a person undergoing questioning in an effort to obtain truth or deception. A polygraph simultaneously records a minimum of respiratory activity, galvanic skin resistance/conductivity and cardiovascular activity. In 1961 Davis presented three hypotheses to explain the effectiveness of the polygraph technique. One of these concepts related to fear of consequences. When a subject recognises that he or she faces negative consequences for their actions i.e. imprisonment, financial loss or embarrassment if a deception is discovered, he or she becomes fearful of that outcome. This emotional reaction activates the Autonomic Nervous System (ANS) and such changes are monitored and subsequently recorded. Polygraphy or psychophysiological detection of deception is based upon a scientific theory that can be tested with the methods of science. Any conscious effort at deception by a rational individual causes involuntary and uncontrollable physiological responses which include measurable reactions in blood pressure, peripheral pulse-amplitude, breathing and electrodermal response. The most commonly used techniques for the psychophysiological detection of deception are control/comparison question tests. The control question test (CQT) assesses a person's credibility by looking for a differential reaction between two questions: the relevant and comparison questions. It has been shown that a person will develop a "psychological set" and direct their attention to the question that posses the greatest anxiety, concern or threat to his/her well being. Current Usage Polygraph testing is currently being used in more than 50 countries in the fields of corrections, criminal investigations, intelligence/counter intelligence and civil matters. In the United States alone all federal law enforcement agencies either employ their own polygraph examiners or use the services of examiners employed in other agencies. Examiners and quality control programs exist in the FBI, US. Secret Service, US Army CID, US Marine Corps CID, Air Force OSI, Navy NCIS, US Customs, US Marshals, Defence Criminal Investigation Service, Internal Revenue Service, US Capitol Police, Food & Drug Administration, Department of Energy, Central Intelligence Agency, Police & County Sheriff's departments, sex therapists and numerous other investigative bodies. Law enforcement agencies using the polygraph do so predicated on the basis that it is an important investigative aid, but not a substitute for standard investigative techniques. For decades the law enforcement community has used polygraph testing as an investigative aid to: verify the statements of victims; establish the credibility of witnesses; evaluate the truthfulness of suspects and to help exonerate the innocent who is surrounded by circumstantial or uncorroborated evidence. During 1996, the US Department of Defence conducted over 12,000 polygraph examinations. In recent years the US Department of Defence has used the polygraph in 95% of criminal investigations pertaining to crimes for which the maximum penalty is 15 years or more. Such use accounted for the army solving 64.7% of felony cases compared with the national average of 19.5% Polygraph technology is now also gaining acceptance in Sex Offender Treatment Programs when testing convicted serial sex offenders whilst on parole or probation. Today a very high number of pedophiles on probation in the states of Oregon and Washington are currently under polygraph surveillance and maintenance programs as part of their parole conditions. The success of the Jackson County Sex Offender Treatment Program (JCSOTP) in Oregon has been so great that other states including California, Texas, Tennessee, Florida, Massachusetts, Indiana and Colorado have adopted the use of polygraph examinations in the supervision, treatment and monitoring of sex offenders on parole and probation. Legal Aspects The polygraph examination is, and can only be, a voluntary process. Major technical and computerised advances in technology have been made in the field of polygraphy in the last decade. The development of Zone of Comparison Testing (ZCT) formats, control questions, and validated testing procedures together with ongoing training and research into the validity and reliability of such testing has continued to enhance the utility of the science. This has led to the admission of polygraph results into evidence in all Federal Circuit Courts in the USA, and into 36 of the 50 US States on a stipulated bases (where defence and prosecuting attorneys agree to its admission). In 1989, the US Eleventh Circuit Court of Appeals stated "…based on what it considers to be significant progress in the field of polygraphy in recent years, …it now takes the position that such evidence is generally accepted in the scientific community." Supporting the legal use of the polygraph in criminal investigations, legal author and expert on the common law, Wigmore (1970), noted three probative uses of the polygraph with respect to criminal investigation, namely: The observer may use it as a clue to obtaining external data which can otherwise be used in evidence; The disclosure of the lie may impress the subject with the apparent futility of trying to conceal the facts, and may thus lead to a voluntary confession before trail; and The recorded curves may reveal a general emotional consciousness of guilt… and can serve to guide police investigators in their hypotheses. The United States Supreme Court has held that a Miranda warning before a polygraph examination is sufficient to allow admissibility of a confession that follows an examination. In most courts in the United States that admit polygraph evidence under stipulation the trier of fact has to weigh up the probative value of the matter against the prejudicial effect upon the defendant. Professor David Lykken PhD from the University of Minnesota has written that "Judicious use of the polygraph in the criminal investigation context not only can improve the efficiency of police work but could also serve as a bulwark to protect the innocent from false prosecution. In fact, I believe that the police use the polygraph too infrequently… if used wisely, polygraphing can greatly facilitate police work." Within the Australian context there are no legal impediments to the use of polygraph testing as an investigative tool other than the Lie Detectors Act NSW 1983 which prevents testing in certain circumstances. Validity and Reliability In the past 75 years over 250 studies have been conducted on the accuracy of polygraph testing. Since 1980, 10 separate studies based on 1,909 real cases showed that the accuracy rate for truthful subjects was 97% and for deceptive subjects, 98%. There have been more published studies done on polygraph accuracy, validity and reliability than on handwriting analysis which is routinely admitted into evidence on a daily basis. Although sceptics of polygraph techniques have expressed concern that polygraph testing is not 100% accurate one needs to consider that there is no one scientific technique in dealing with humans that is 100% accurate including psychiatry and psychological assessments regarding clinical diagnosis. Classification of psychological disorders, although subjective, are often challenged by other experts and, at times, incorrectly diagnosed. Cross contamination has occurred in DNA testing, fingerprints have been wrongly classified, handwriting evidence has been misinterpreted and eye witnesses make mistakes. Furthermore, admissibility does not necessarily mean that evidence is valid. Note how invalid eyewitness and psychiatric findings can be, and often are, legally and judiciously recognized as admissible evidence." http://www.nettrace.com.au...