Frederick Schauer, University of Virginia School of Law, has published Can Bad Science Be Good Evidence: Lie Detection, Neuroscience, and the Mistaken Conflation of Legal and Scientific Norms at 95 Cornell Law Review 1191 (2010). Here is the abstract.
As the capabilities of cognitive neuroscience, in particular functional magnetic resonance imaging (fMRI) 'brain scans,' have become more advanced, some have claimed that fMRI-based lie-detection can and should be used at trials and for other forensic purposes to determine whether witnesses and others are telling the truth. Although some neuroscientists have promoted such claims, most aggressively resist them, and arguing that the research on neuroscience-based lie-detection is deeply flawed in numerous ways. And so these neuroscientists have resisted any attempt to use such methods in litigation, insisting that poor science has no place in the law. But although the existing studies have serious problems of validity when measured by the standards of science, and true as well that the reliability of such methods is significantly lower than their advocates claim, it is nevertheless an error to assume that the distinction between good and bad science, whether as a matter of validity or of reliability, is dispositive for law. Law is not only about putting criminals in jail, and numerous uses of evidence in various contexts in the legal system require a degree of probative value far short of proof beyond a reasonable doubt. And because legal and scientific norms, standards, and goals are different, good science may still not be good enough for some legal purposes, and, conversely, some examples of bad science my, in some contexts, still be good enough for law. Indeed, the exclusion of substandard science, when measured by scientific standards, may have the perverse effect of lowering the accuracy and rigor of legal fact-finding, because the exclusion of flawed science will only increase the importance of the even more flawed non-science that now dominates legal fact-finding. And thus the example of neuroscience-based lie detection, while timely and important in its own right, is even more valuable as a case study suggesting that Daubert v. Merrill-Dow Pharmaceuticals may have sent the legal system down a false path. By inappropriately importing scientific standards into legal decision-making with little modification, Daubert confused the goals of science with those of law, a mistake that it is not too late for the courts to correct.
Download the essay from SSRN at the link.
Professor Schauer says in part:
Because the criteria that judges and juries traditionally employ to evaluate the veracity of witnesses have been notoriously unreliable, the quest for a scientific way of distinguishing the truth teller from the liar has been with us for generations. Indeed, the Frye test, which for many years was the prevailing legal standard for determining the admissibility of scientific evidence, arose in 1923 in the context of an unsuccessful attempt to admit into evidence a rudimentary lie-detection machine invented by William Moulton Marston -- perhaps better known as the creator of the comic book character Wonder Woman, whose attributes included possession of a magic lasso, forged from the Magic Girdle of Aphrodite, which would make anyone it encircled tell the truth without fail. The device at issue in Frye was a simple polygraph and not a magic lasso, but Frye did not just set the standard for the admission of scientific evidence for more than a half-century; its exclusion of lie-detection technology also paved the way for the continuing exclusion, with few exceptions, of lie-detection evidence in American courts.