The Polygraph: A Critical Appraisal BY CATHERINE ANN MENARD Truth, for judicial purposes, has above assumptions fail, the long been sought by man. Its elusive polygraph's results are invalidated. nature has prodded him to develop The machine records a change in numerous exploratory devices such breathing by the use of a hose as the wheel and the rack for the strapped around the subject's purpose of determining facts abdomen or chest. A medical blood quickly and effectively. A prevalent pressure cuff measures the subject's current method purporting to blood pressure and pulse. The C separate truths from falsehoods is Galvanic Skin Reflex records the the polygraph. skin's electrical resistance by As early as the third century B.C., passing a small current through two Erasistratus observed that emotions electrodes which are placed on the accelerate the pulse rate. In 1895, subject's hands. Each sensing Cesare Lombroso experimented device is connected to a pen which with pulse rates and blood pressure records the responses on a moving while questioning suspected graph. Upon completion of the criminals and initiated the examination, the operator makes his development of the modern determination on the basis of an instrument. 1 The polygraph is an interpretation of the graph and his electrically energized device personal observations of the which, upon application to the exam1nee. body, records blood pressure, perspiration, respiration, and pulse Role of Examiner rate on a moving graph. It is evident, then that the polygraph operator plays the Theory of Polygraph crucial role. His duty is to observe Underlying the polygraph's use and analyze the subject's as an investigative technique are psychological makeup. Thus, the four assumptions: ( 1) lying gives examiner should be educated and rise to conflict; (2) conflict, in tum, trained in clinical psychology. creates fear and anxiety; (3) the Furthermore, the examiner resulting mental state brings about observes and interprets the subject's measurable physical changes physiological responses during the capable of being accurately examination. Thus the operator recorded on the polygraph; (4) by should be skilled and trained in the studying the graph, the examiner is medical sciences. However, he is able to separate the subject's true rarely so trained. Polygraph statements from his false ones. 2 examiners usually have a police Hence, the underlying theory background. 4 The question is assumes that fear of detection therefore raised as to whether or not causes specific involuntary these examiners can be expected to responses if the subject is have the needed professional attempting to conceal the truth expertise. during questioning. 3 If any of the In addition, the possibility for VOLUME 50, NUMBER 3, MARCH 1976 147 "The polygraph has failed to receive judicial acceptance ... " distortion is increased by the The first reported case denying decision is old, but rather whether individual examiner's own admissibility to polygraphic its logic is still persuasive. psychological bias. Precautions are evidence was Frye v. U.S., 293 Fed. almost never taken to off set the bias 1013 (D.C. Cir. 1923), due to lack of Arguments of Opponents of the polygraph examiner. 5 This "general acceptance in the scientific The first line of attack by lack of control over examiner bias is community ." Largely since then, opponents of the polygraph has in direct contrast to the procedures results of the polygraph have been generally been upon the validity of fallowed in most social science ruled inadmissible by jurisdictions the theoretical premises upon studies and experiments. considering the issue. which the polygraph procedure is Essentially, the examiner has a Proponents view the current based. As Jerome Skolnick three-step approach to each exclusion of such evidence as based observed: "The scientific basis for subject. First, the operator on outdated precedent. While other lie detection is questionable." He interviews the examinee in order to areas of the forensic sciences have doubts the existence of a constant reassure the subject, to familiarize received judicial acceptance, such relationship between lying and him with the questions which will as fingerprint and firearms emotion, and asserts that: " [ there is be asked, and to observe the identification, the polygraph has a] failure to recognize that 'truth' examinee's behavior. Second, failed to be accorded such and 'falsity' are not absolute, and based upon the operator's recognition. One proponent that deviations in autonomic knowledge of the facts and complains that such rejection by the responses do not always reflect circumstances of each case, he courts "has been a thorn in the sides conscious deviations from the designs the questions to be asked of of polygraph exponents for over truth." Moreover, no proof exists the subject during the examination. two generations. "9 Commenting on demonstrating a measurable Lastly, the operator evaluates and this topic, one writer contends that relationship between emotional interprets the polygram. stare decisis is inherently variation and autonomic response. 11 retrospective and is especially Arguments of Proponents pernicious with respect to the A. Reliability Statistics The basic justification of evaluation of scientific evidence. In The polygraph test is not a admitting polygraph test results short, "Does justice prevail when precise quantitative test. It is not a into evidence is the alleged the judiciary ignores proven routinized procedure predicated accuracy of such examinations. scientific reliability and permits a upon well established relationships Numerous studies conducted by decision of fifty years ago to control whereby any researcher under­ 10 polygraph examiners and institutes a decision of today?" The issue, taking to replicate the experiment have resulted in extremely high however, is not whether the would reach the same conclusion on levels of accuracy. A typical study the same facts. But rather, it is a test conducted by Horvath and Reid The Author . .. which leads to results which are resulted in an overall 89 percent subject to diverse interpretation accuracy rating. 6 Testimony by and open to influence fro witnesses in favor of admitting uncontrolled variables. It does not polygraph results in U.S. v. Zeiger, appear that reliability statistics with 350 F. Supp. 685 (D .C. 1972), respect to diagnostic procedures claimed test results with levels of will be obtainable since it seems accuracy upwards of 95 percent. 7 conceded that one examiner cannot Less supporting, but more neutral, "make a diagnosis from another was a study conducted in 1958, by examiner's test data," 12 because the Chicago Bar Association's there has not been developed any Committee on Criminal Law, standardization in test design and which found a 5-30 percent error in procedure. It might be possible to test results, depending upon the test reliability of conclusion by ability of the operator, in addition having multiple examiners dealing to other factors. 8 Catherine Ann Menard holds a B. A. with the same subject, but no such In defense against the charge that degree in Political Science from California test on any substantial scale seems State University , Long Beach, and will polygraph evidence tends to exert receive her J. D. degree from Whittier to have been undertaken. an improper influence on the jury, C allege, Beverly School of Law in June , As a result of the above, the the advocates contend that it is only 1976. She is the 1973-74 winner in the I. H. scientific community does not place an expert's opinion which is being Prinzmetal legal essay competition much credence in the polygraph as considered as admissible evidence. sponsored by the Beverly Hills Bar Association , and currently does free-lance a means of distinguishing truth from In effect, the proponents visualize legal writing. mendacity. Scientists cannot be the polygraph expert as being on a This article was originally published in the expected to accept a machine par, for instance, with the medical Beverly Hills Bar Journal (Nov.-Dec. 1974) which has as its purpose the or engineering expert. and is reprinted with permission . detection of truth from falsity when 148 THE FLORIDA BAR JOURNAL the technique employed is would agree that the polygraph has imprecision of these criteria and the ~- unsophisticated and imprecise. The improved its procedure, technique, deficiency of the existing accuracy machine has been attacked as not and accuracy figures since its data must be recognized. having progressed from the inception in 1895. But unless and B. Lack of Cross Examination experimental to the demonstrable until accuracy reaches 100 percent, In the Kansas case of State v. stage. Little has been done toward the polygraph's use in the Lowry, 163 Kan. 622, 185 P.2d 147 the end of gaining scientific courtroom must be consistently (1947), the court denied the acceptance. Since the first decision challenged. It would seem that admissibility of polygraph results in 1923, most courts have implied since no method will ever be 100 on the ground that they were not that its unacceptability to the percent effective, such challenge subject to cross-examination. scientific community makes it would be untenable. But upon Several subsequent courts 16 agreed similarly unacceptable to the analysis it will be seen that if the that the vital role of cross­ judicial process. polygraph is 95 percent accurate, it examination would be impaired by The argument over the accuracy will have contained within it a 5 admitting such evidence. A figures has been a battleground of percent guarantee of injustice. machine cannot be examined or contention. Statistical studies show Regardless of which accuracy cross-examined. Its "testimony" is a broad range in reported test figures a person believes, the way in interpreted by the operator. results . There is a 25 percent range which these figures are reached Proponents took up the challenge in the published statistics, with should be examined.