DECEPTION DETECTION TECHNIQUES USING POLYGRAPH IN TRIALS: CURRENT STATUS AND SOCIAL SCIENTIFIC EVIDENCE

Abstract

1. IntroductionAlthough not every state in U.S admits polygraph examination as evidence in trial, results of polygraph examination have been presented in some trials as evidence under certain conditions. The results of polygraph examination are given to jury usually through expert testimony, or sometimes, jury hears about defendant taking polygraph test at some point of a trial. Generally, in U.S, polygraph evidence is not admissible in court, but jury could be given information related to polygraph in various ways. In U.S, 18 states1 admit polygraph evidence only when certain conditions are met and rest do not admit such evidence to jury or at all with any purposes. Since there are cases in which polygraph evidence is presented to jury with a certain safeguard (e.g., a stipulation and judge's instructions), even though it is not generally admissible, it is necessary to learn about uses of polygraph evidence in trial and status of social scientific evidence that has accumulated over last several decades. Furthermore, there needs to be novel research fitted to situation where polygraph evidence is encountered, based on legal decision and social scientific evidence. In this article, therefore, 1) uses of polygraph in each state in U.S will be summarized, and 2) status of social scientific evidence dealing with polygraph itself and its effects in trial will be synthesized. Finally, 3) I will provide an outline of what kinds of research have to be done in cooperation will be suggested. For researchers working on detection and jury decision making, this study would provide synthesized information to conduct more qualified and practical studies. Thus, it would contribute to improvement of related policies, ultimately.2. The Uses of Polygraph in Trials: Analysis by State LevelThe aim of first section is to summarize reasons why some states admit polygraph evidence, and, if a state admits evidence in trial, what requirements are. The polygraph is, actually, a device for measuring various types of physiological activity, such as electrodermal activity, blood pressure, and respiration, but it is known more commonly as lie detector. This is misleading because a polygraph does not detect lies, but only records physiological activity that each polygraph technique assumes to be along with telling a lie. Regarding validity, polygraph proponents argue that a polygraph technique (CQT) has over 85% of accuracy (e.g., Abrams, 1989; Ansley, 1983; Honts & Quick, 1996; Raskin, Honts, & Kircher, 1997), while Lykken (1979) asserts that in real-life situations, polygraph test has a slightly above chance level of accuracy (64% to 71%). Moreover, APA (American Psychology Association) members estimated validity of polygraph test at about 61% (Iacono & Lykken, 1997). The results of research regarding validity of polygraph techniques are extremely polarized, which gives rise to controversies about admissibility of polygraph evidence in trial.The first decision related with polygraph technique (e.g., systolic blood pressure deception technique) was made in Frye v. United States (1923), which stated that the thing from which deduction is made must be sufficiently established to have gained in particular field in which it belongs. At that time, technique had not yet met standard that is known as general acceptance and therefore Court concluded that evidence would have been rejected. Seventy years later, in Daubert v. Merrell Dow Pharm., Inc. (1993), court ruled that general acceptance is not a necessary precondition to admissibility of scientific evidence under Federal Rules of Evidence, but Rules of Evidence, especially Rule 702, do assign to trial judge task of ensuring that an expert's testimony both rests on a reliable foundation and is relevant to task at hand. …