Lie Detectors (Polygraphs) should not be used in court

The accuracy of polygraphs My primary argument will be based around the unscientific and inaccurate results produced by the polygraph, the negative effects of a misreading in a court case being obvious. Polygraphs work by measuring blood pressure, pulse, skin conductivity and respiration during an interrogation scenario. The more modern version of the polygraph is the CQT test, so I'll argue against the validity of this one. It works by using a 'control question' which asks a vague question about a past misdeed and intends to garner a concerned reaction or if possible a lie. (1) An example could be “Have you ever taken an illegal drug? ” Or “Have you ever lied to a person in a position of authority? ” The idea is that it is highly likely that you have committed one of these misdeeds in the past and the control question will provide an example of what your physiological reactions to lies look like. Itfurther assumes that innocent people, because they are being truthful when they answer relevant questions "no," will be relatively unaroused by these questions. Guilty individuals, even though presumably lying to both questions, are expected to respond more strongly to the relevant question because it carries greater significance. (1) Therefore, for this method to hold two assumptions must be made, an innocent individual must give a greater response to control than relevant questions and guilty individuals must respond more intensely to relevant than control questions. It is obvious that both of these assumptions could be challenged, either intentionally or unintentionally. A major limitation of this method is that it does not offer an adequate psychological control for the emotional impact of being asked the accusatory relevant question and most innocent individuals are savvy enough to understand that whether they pass or fail the test will depend on how they respond to the relevant questions rather than to the trivial issues covered by the control questions. (1) One of the main factors behind the polygraph is the belief that lying is associated with anxiety and the accompanying physiological arousal, however it fails to take into account the fact that manyinnocent people will respond with the same arousal when accused, even if they are telling the truth. This is the primary reason why the polygraph is biased against innocent individuals. The idea that a guilty person would be aroused more with relevant questions than control questions is unlikely due to the fact that a guilty individual can artificially augment their responses to control questions. Countermeasures which have been shown to achieve this include curling your toes, lightly biting your tongue, or performing mental arithmetic when control questions are asked. (2) Due to the fact that these techniques cannot be observed they can't be regulated either and they therefore remain unknown to the examiner. Websites such as (3) and many others provide these methods for anyone curious enough to look. The work of Honts et al (1994) show that more than 50% of guilty individuals defeat the polygraph when using similar methods. A short list of famous polygraph-related miscarriages of justice: US spy and double agent Aldrich Ames passed two polygraphs while working for the Soviet Union. He described how he passed as “There's no special magic. .. Confidence is what does it. Confidence and a friendly relationship with the examiner. .. rapport, where you smile and you make him think that you like him. ” (4) Karl Koecher (5) Ana Belen Montes (5) Leandro Aragoncillo (5) Nada Nadim Prouty (5) Serial Killer Gary Ridgeway passed a polygraph in 1984, confessing 20 years later when confronted with DNA evidence. (6) Bill Wegerle was forced to live under the suspicion of killing his wife for twenty years after he failed two polygraphs (one police administered and the other given by an expert. ) The real killer, Dennis Rader, was found in 2004 thanks to DNA evidence. (7) Scientific Opinion The scientific community widely holds the polygraph in a poor light as an extremely flawed and unscientific way of ascertaining guilt. In 1978 Richard Helms, the 8th Director of Central Intelligence, stated that: "We discovered there were some Eastern Europeans who could defeat the polygraph at any time. Americans are not very good at it, because we are raised to tell the truth and when we lie it is easy to tell we are lying. But we find a lot of Europeans and Asiatics who can handle that polygraph without a blip, and you know they are lying and you have evidence that they are lying. ” (8) The New Scientist describes them as “notoriously unreliable” and “the world's most inappropriately named technology. ” (9) A 2003 review by the US National Academy of Sciences came to the conclusion that lie detectors are better than the toss of a coin but fall far short of the accuracy required. (9) The former Supervisory Special Agent of the FBI Laboratory DivisionDr. Drew C. Richardson described polygraph screenings as “completely without any theoretical foundation and has absolutely no validity. .. the diagnostic value of this type of testing is no more than that of astrology or tea-leaf reading. " (10) According to a comprehensive 2002 review by a federal panel of distinguished scientists. The study found that if polygraphs were administered to a group of 10,000 people, nearly 1,600 innocent people would fail the test. (11) These studies, articles and cases clearly demonstrate that the polygraph is a deeply flawed machine which is extremely prone to mistakes. There are still many more articles and studies out there that I do not have the character count to mention, but I happily will next round. Now all there is left to say is the very obvious point that what we do not want is for this problematic and poorly designed machine to be used to determine the innocence/guilt of a defendant. In 1998 Supreme Court Case 'United States vs Scheffer' it was stated that "Unlike other expert witnesses who testify about factual matters outside the jurors' knowledge, such as the analysis of fingerprints, ballistics, or DNA found at a crime scene, a polygraph expert can supply the jury only with another opinion. .. " (12) This conveys the accurate point that the polygraph is just that, a subjective opinion. If a juror is undecided the polygraph may nudge them in its own direction, which may well be the wrong one, it provides an opinion which seems definitive and objective, but in reality is misleading. Imagine for a moment if in the Bill Wegerle case I mentioned above he had been convicted due to the faulty polygraph reading, he would've been in prison for twenty years before they found the real killer. Then imagine this repeated thousands of times with other innocent individuals. Thanks for reading. I look forward to Con's response and I hope he won't only use statistics from advocacy websites or ones which sell polygraphs. Sources (1) . http://antipolygraph.org... (Forensic "Lie Detection": Procedures Without Scientific Basis by William G. Iacono, PhD) (Honts, Raskin, & Kircher, 1994) . http://www.police-test.net... . http://articles.dailypress.com... . http://en.wikipedia.org... . http://en.wikipedia.org... . http://www.cbsnews.com... . http://mcadams.posc.mu.edu... . http://www.newscientist.com... . http://www.police-test.net... . http://www.washingtonpost.com... United States v. Scheffer. March 31 1998