Introduction
Recent court cases in the U.S. showed the contradictory nature of scientific evidence in law enforcement. Many legal problems concern the issue of polygraph evidence admissibility in U.S. Federal and State courts. For instance the famous case of U.S. vs. Scheffer that took place in 1998 made evident the existence of two crucial questions concerning polygraph evidence. The first deals with a problem of defendant’s ability to give polygraph evidence to the court if he wishes to do so as was in this particular case. Is this right must be regarded as his inalienable constitutional right? Secondly, can polygraph evidence be regarded as admissible at all? As this particular trial showed the defendant managed to force the court to admit his polygraph evidence referring to the Sixth Amendment, his basic constitutional rights in trial and previous court cases that admitted polygraph evidence (like Daubert- Merrell Dow Pharmaceuticals. Inc case, which is regarded by many as precedent case). Other cases where the issue of polygraph evidence was raised show that there is no definite answer to the question of admissibility. Some courts admitted polygraph evidence, some strictly prohibited it, and others admitted it but regarded as secondary evidence.
This paper suggests that polygraph evidence should not be admissible and proves this claim in the number of successive paragraphs dealing with different facets of the polygraph evidence issue. The paper relies on various research of this problem and supports the argument with the actual court cases that occurred in the U.S. during last 15 years. Apart from this the paper deals with opposite viewpoints, attempting to assess their legitimacy. Eventually, drawing on the findings on the paper my personal perspective on the admissibility of the polygraph evidence is outlined.
The scientific premises behind polygraph examination are not adequate
The underlying premise of polygraph examination refers to that a person produces different psychological reactions when he/she lies. The polygraph test equipment includes instruments which are attached to the subject and transferring his psychological reactions on the special chart list. Then the polygraph examiner is required to examine the results of the test and make assessment of “lie-truth” results.
Among special instruments utilized during the polygraph test one should mention various cardiographs, cardio-cuffs and numerous sensitive electrodes (Henseler, 1997). These tools measure deviation in person’s respiration, blood flow, skin galvanic resistance.
The scientific premises of the polygraph test is in my view are false. That doesn’t mean that I regard the instruments utilized during the test such as mentioned above not sufficient for assessing various psychological reactions of the subjects and can easily assess physiological values as blood pressure and skin resistance. The central question concerns not this but the problem of whether various psychological changes in subject may be related to lying and saying truth, or in contrary may be indicative of other psychological responses such as anxiety, fear, nervousness, confusion or other reactions that may easily result in changes of psychological response (Davis,1992).
Apart from these problems the examiner may also come across with other difficulties concerning the attempts of the subject under test to consciously change its results which may cause the abnormal psychological data, irrationality and difference arisen from the different subjects’ cultural backgrounds. These issues can not be understated since irrationality for instance is inherent in every human being behavior. Think for example of the person who is innocent and knows that he/she is telling truth but due to the fear that his/her nervousness may alter the results of the test leads to the examination results that may be interpreted as lie. This assumption is justified from all standpoints in my view. Another issue is difference in different cultural background or psychological stability that may lead to sometimes contradictory perception of guilt. Moreover, such socio-cultural differences as gender, race and the level of intelligence may also influence the results of the polygraph test (McCall, 1996). So, polygraph machine can not provide examiner with sufficient data that could provide the basis of adequate interpretation. If the process is reduced to mechanistic cause-effect approach to psychology based on the “common stereotypes” peculiar to rational and scientist mindset of modern civilization, then formally rationalistic interpretation may lead to false results. Thus, if scientific parameters of the polygraph test do not provide us with accurate empirical knowledge of defendant psyche (the kind of accuracy that can be achieved in physical and mathematical calculations), they can not be applied to this kind of the object. More over, I regard this application unjustified and dangerous since its claim of scientific accuracy hides totally obscurantist nature.
Polygraph test and the issue of prejudice.
In my view the admission of lie-detector test as evidence in legal proceeding must be regarded as highly prejudicial for the defendant. The thing is that if admitted the polygraph results will unconditionally speak to the innocence or guilt of defendant without any necessary stipulations. As some specialist claim, “the potential prejudicial effects of permitting a jury to consider a polygraph examination are enormous and thus rather disturbing” (Gallai, p. 34).
The scientific status of polygraph test has a strong prejudicial effect both on jury and judges and thus must be excluded from the legal proceedings.
Another problem occurs when examination specialist presenting his evidence before the court claim that the polygraph test shows that there is 70-90% chance that the defendant is lying. Without necessary instruction the juror can’t decide on the adequateness of this evidence. So, we see that giving such evidence before the court may lead to the confusion of the jury and as result to unjustified decisions on the case. As other cases show, “with the lack of standardization of polygraph procedure and a lack of agreement as to necessary qualifications of examiners, the jury would have very little basis to evaluate the conflicting expert testimony.” (United States v. Duque, p. 6). The evaluation of the guilt on the basis of probability is highly prejudiced, because if for instance there is 10% probability of the polygraph test deviation, the jury may falsely convict innocent person.
Polygraph procedures are time-consuming and replace jury
It is easy to see that polygraph test replaces or alters the role of jury in legal proceeding. Scientific claims of the polygraph test that as I showed above are unjustified tend to replace the jury’ role in dealing with case. Those arguments and evidence that jury has to evaluate and based on them come forth with its decisions are no longer necessary if there is one legitimate statement based on the polygraph test’s results. If this occurs, the traditional and discursive character of legal proceeding would be completely ruined, transforming court into formalistic and scientist place for automatic productions of decisions. Of course, it reminds Orwellian metaphors of authoritarian state and it would be morally wrong to introduce such changes to our democratic society. Apart from this the universal admissibility of polygraph evidence may make legal procedures time-consuming and routine, which by no means meet the constitutional rights of their participants.
Opposite viewpoints and arguments.
There are some opposite opinions concerning the admissibility of polygraph test in legal trial. These can be divided into two categories. The first suggests that the scientific premises underlying the utilization of polygraph machines and examination are perfect and accurate and can be regarded as necessary tools for defining person’s guilt or innocence. Based on various psychological and physiological researches the defendants of this standpoint claim that the polygraph machine should become the inherent part of legal procedures and the process of evidence base formulation. According to this stance, polygraph test should be made necessary and obligatory for all defendants.
Another current in polygraph machine apologetics ground its claims on the premise that the decision to utilize polygraph test in evidence must be determined by a defendant and should be regarded as his/her inalienable constitutional right. The supporters of this position suggest that this requirement should not be obligatory.
In my view neither of these two approaches is adequate and scientifically grounded.
The first as was showed above proceeds from the ungrounded premises of scientific correlation between saying truth or lie and psychological reactions registered by polygraph machine.
The second opinion claims that the utilization of polygraph test must be regarded as constitutional right. But if it is the case, then it suggests that U.S. citizen’s constitutional right is to lie before the court since no one can claim that polygraph test provides with accurate evidence of defendant innocence or guilt. So as we see this apologetics are interrelated and based on the same wrong grounds.
References
- Davis L., (1992). A Doubtful Device: Polygraph Machine, HEALTH, 92
- Gallai, D. (1999). Polygraph Evidence in Federal Courts: Should It Be Admissible? American Criminal Law Review, 36(1), 87-123.
- Henseler T. B. (1997). A Critical Look at the Admissibility of Polygraph Evidence in the Wake of Daubert: The Lie Detector Fails the Test. 46 CATH. U. L. REV. 1251-52
- McCall J. R. (1996). Misconceptions and Reevaluation–Polygraph Admissibility After Rock and Daubert, U. ILL. L. REV. 363,410 n.333.
- United States v. Duque (1998). 176 F.R.D. 691,695 N.D. Ga.