how accurate is lie detect machine - 测谎仪有多准.docx

How accurate are lie detector machineFrom a perspective of psychology, telling lies is the reflection of human defending incentive just like eating when feeling hungry. As an inevitable product of the history development, technology of psychology detecting keeps developing at the pattern of society civilization as well as scientific technology. With the emerge of trial procedure since class society, the psychological battle between the judge and the judged is always the key point, which is the primary condition that lie detector machine is invented and widely used in juridical practice. Just like any new invention, lie detector machine is always being doubted in terms of its accuracy since emerging. Based on the past statistics together with some real cases, this essay is focused on discussing whether lie detector machine is reliable. Before it starts, there is an introduction on the development and the principle of lie detector machine. In the end, there is a brief conclusion to sum up the whole essay. As a kind of psychology test technology, lie detecting is process that combine bioelectronics and psychology to analyze the metal world of characters with the help of computer (Kozel, Padgett & George, 2004). According to the theory of psychology, without exception there will be indelible stamp in characters mental world after they get through a certain of special incident. After being recorded by detecting machine, these wispy reactions can come to a series references for conclusion. With the increasing development of lie detecting technology, lie detecting machine plays a significant role in many doubtful cases or serious cases. Italian criminologist Cesare Lombroso is the first person to apply lie detect machine to legal cases. In 1985, Lombroso successfully detected several cases with the help of a “hydraulic pulse recorder” which is to judge whether criminal suspects are involved in the case through recording the flucuation of their pulse and blood pressure. Since then, psychology test with multiple parameters developed prosperously all around the world and widely used in various fields. At present, lie detect machine is the ordinary equipment in many station police institutions such as America, Canada, Japan, Turkey, Korea, Israel, Russia, Poland and so on (Lykken 2001). When a person is telling lies, there are some physical changes that can be seen macroscopically such as scratching head or ears, or shaking legs. On the other hand, there are some changes that cannot be checked easily, which is why machines are needed. Usually, these mental parameters are controlled not by characters awareness but by nervous system, and a series of conditioned reflex phenomenon are aroused under external stimulation. Modern lie detect machine is composed of sensors, mainframe and microcomputer which is mainly to detect four aspects of characters physical changes: blood pressure, heart rhythm, breath and skin resistance (National Academy of Sciences, 2002). The sensor is connected with characters body surface to collect the change information of his or her physical parameters. The mainframe is electronic components to transfer the collected analog signals into digital signals. The microcomputer is to store and analyze the input signal and arrive at the lie detecting result. The university expert, Jaume Masip, indicated that the principle of lie detecting technology is that it takes more energy for people to describe an event which is not real and this can be reflected into his word and the difference can be caught by detecting machine. Based on the word analysis, the lie detecting technology can be extended to observe the expressions when the tested character try to recall an event such as the reality degree of his description or whether including ordinary smell, voice the like details in a practical real event (Saxe 1991). Ever since the invention of lie detecting technology, scholars from America and other countries have made many researches on the accuracy. According to the result, the accuracy of the testing conclusion conducted by well trained professionals is 85% - 98% (Saxe & Ben, 1999). The chief editor of American Criminal Psychological Test, Norman Anslie collected all the test conclusions of practical cases from 1980 1990 and compared 2042 cases according to their testimony, physical evidence and the judgment, and his conclusion is: when characters are lying, the accuracy of the testing conclusion is 97%; when characters are telling the truth, the accuracy is 98% (Lykken 2001). After studied 3030 past literature cases from six countries, the American Polygraph Association found that the lie detecting accuracy is 98% under the process of investigaton and verification (Adelson 2004). A criminal psychological test expert from China, Wu Boxin summed up his ten year career which involved with 900 plus cases in 23 case types and concluded that more than 80% cases got breakthrough after the testing and some of the rest has excluded existed suspects (Bellin 2007). In terms of distinguishing innocent person and guilty person, the lie detecting technology can makes accuracy to be 98%, and the 2% mainly results to mistaking the guilty into innocent people (ibid). Based on the statistics above, lie detecting technology has a high accuracy in excluding innocent person and is very helpful in case detecting. The supporters argue that the lie detecting machine is to record the physical reactions of the tested characters when answering relevant questions. And thus, as long as the lie detecting machine is well equipped and involved experts are experimental enough, the analyzed conclusion is reliable. On the other hand, there is always some doubt that the lie detecting conclusion has a low accuracy and the result cannot act as meaningful evidence in judicial process. Even though modern lie detecting technology is becoming more and more mature, and many statistics has shown the accuracy is not lower than 90% or even higher, some experts question that even if the accuracy rate can be 99%, who can buy for the 1% mistake. There are many unjust case occurred because of wrong lie detecting conclusion, which brings more doubt on lie detecting technology. There is case that an innocent person are judged to be guilty after lie detecting analysis, which happened to the 36 year - old defendant, David Jay Ivy (Alfred 2014). He was accused to steal USD 500 from the safe case of his employers room. At the court duration of hearings, the police caught the real thief. Surprisingly, this chief passed the lie detecting machine, while Ivy did not. Another mistaking case is the murder case occurred in Ohioan State in 1979. The suspect Fred Fay was accused of murder and was sentenced to life imprisonment because the lie detecting machine found he told lies. After two years, however, the real criminal culprit was caught. What interesting in this case is that five experimental lie detecting experts tested Fred and analyzed the results in five different ways, among which two experts decided he was guilty, one could not decide and the fourth expert thought that psychological test was invalid, the fifth expert decided Frey was telling the truth (Eitan & Gershon, 2009). Based on these mistakes, opposed people argue that lie detecting machine can only record the subjective reactions and there are many mistakes may occurring. For example, when an innocent person behaves like a criminal, he may feel very nervous in his confession because of fear, which is very likely to be judged as guilty person by lie detecting machine. To put it in another word, if character has no reason to lie but gets a result that he tell lies, that means the lie detecting machine is lying. The lie detecting machine seems to be very objective, but it can make very serious mistakes. There was research report showing that the lie detect machine had a low accuracy, only 35%, and even after meeting all the test requirements the accuracy can only be 64% - 71% (Mark et al., 2009). It is true that lie detecting machine is not able to detect the inner hear of character, but has to test characters with a series of prepared questions which are made according to investigation content. Professor Jon R Waltz from Yale University law school indicated that the statistics show that the accuracy of lie detecting tests is around 90% (Iacono 2008). In his book, he said if testing 1000 people including 10 liers, 9 of the liers can be correctly detected out by lie detecting machine. However, if testing 990 people who are all telling the truth, 99 people will be detected incorrectly to telling lies. Furthermore, even the lie detect machine can reach accuracy to be 99% (actually is impossible for now), there are still 10 people who tell the truth to be detected as liers. Therefore, due to the imperfection of lie detecting machine, it is still too early to include it into criminal litigation evidence system (ibid). Even if in America where lie detecting error is lower than 1% (except 5% cases that cannot be detected because of physical or mental defect), lie detecting conclusions have to be supported with physical evidence in court hearing or put proof by the evidence providers, otherwise the conclusion cannot be adopted by the judge (National Research Council 2003). Just like all other new inventions, the lie detecting machine is always under critics and doubt. But just like all other useful and meaningful inventions, it is widely used and keeps developing constantly. In addition to America, there are many countries now using lie detecting technologies especially Israel, Canada, Japan and India. Despite the fact that the domestic culture diversity in Israel and India is quite huge, lie detecting machine is widely used there (Langleben 2008). Furthermore, there are more countries that research and develop new technology of lie detecting machine, and there are even countries that consider lie detecting as the legal means of evidence in judicial process. It is an inevitable tendency that lie detecting machine is going to become more and more accurate, and more and more automatic as well as intelligent. Based on previous programs for detecting examination cheating, an American student from Arizona named Judee Burgoon invented a computer lie detecting program called “Policeman 99”. He planned to invent a computer video analytical program so as to observe the gestures and expressions of tested characters when they are describing an event (Mohamed, 2014). Another scientist from University of Pennsylvania named Britton Chance invented a new remote lie detection equipment which can be used in public places such as airport (ibid). As a relatively subjective judgment, conclusions from lie detecting machine cannot reach 100% like the DNA or finger print detecting technology. Actually, the detecting technologies that reach that high accuracy is very limited and most technologies in the detecting process are judged subjectively by experimental professionals according to their previous experience and knowledge to the case. So making mistakes can be considered to be very common and tolerated, let alone lie detecting machine usually has a higher accuracy than most professionals. Based on the process of detecting lies, the key point lies not in the machine itself, but lie in the expertise level of professionals as it is them that make the criterion from the questions design to the conclusion orientation. In addition, no detecting technology can avoid being interfered and lie detecting machine is making progress on its antijammingcapability to act as a helpful evidence for professionals. In conclusion, there is no lie detect machine that can be 100% reliable, but it has already been an accurate detecting machine to help professionals in many aspects. The activity from human brain is extremely complex and the human psychological activity cannot totally be in line with the atlas from scientific data. The conclusion from psychological test is sure to be imperfect, but as it is made by human and operated by human, the main factor to decide the result is human. Therefore, lie detecting machine can be considered as a scientific tool and accurate enough comparing with many other detecting tools. Based on this, lie detector machine is promising in the future, which is indeed in line with the reality of lie detector machine development. Reference Adelson, R. (2004). The polygraph in doubt. APA Monitor, 13(2), 35, revived from Alfred, C.(2014). Polygraph Use by the Department of Energy: Issues for Congress.Congressional Research Service, 13(2), 45-48.Bellin, J. (2007). The Significance (If Any) for the Federal Criminal Justice System of Advances in Lie Detector Technology.Temple Law Review,80(1), 711-742.Eitan, E. & Gershon, B.S. (2009). Countering Countermeasures in the Concealed Information Test Using Covert Respiration Measures,Applied Psychophysiology and Biofeedback34(1), 197208.Mark. H et al. (2009), Integration of Pre-Employment Polygraph Screening int