The familiar complaints also gloss over the deep tensions between science and the law that are at the root of these problems. The culture of the law is adversarial, and its goal is case-specific, final answers. The culture of the sciences, by contrast, is investigative, speculative, generalizing, and thoroughly fallibilist: most scientific conjectures are sooner or later discarded, even the best-warranted claims are subject to revision if new evidence demands it, and progress is ragged and uneven. Science doesn’t always have the final answers the law wants, or not when it wants them; and even when science has the answers, the adversarial process can seriously impede or distort communication. It’s no wonder that the legal system often asks more of science than science can give, and often gets less from science than science could give; nor that strong scientific evidence sometimes falls on deaf legal ears, while flimsy scientific ideas sometimes become legally entrenched. Here’s the first part of Ashoka’s in-depth research article, in the weekly column, of Different Truths.
Justice requires just laws, of course, and just administration of those laws; but it also requires factual truth. And in determining factual truth, in both criminal and civil cases, courts very often need to call on scientists: on toxicologists and tool mark examiners, epidemiologists and engineers, serologists and psychiatrists, experts on PCB’s and experts on paternity, experts on rape trauma syndrome and experts on respiratory disorders, experts on blood, on bugs, on bullets, on battered women, etc. For, as science has grown, so too has the legal system’s dependence on scientific evidence; it has been estimated that by 1990 around 70 per cent of cases in the United States involved expert testimony, most of it scientific. Such testimony can be a powerful tool for justice, but it can also be a powerful source of confusion – not to mention opportunities for opportunism.
Who could have imagined, when DNA was first identified as the genetic material more than half a century ago, that DNA analysis would by now have come to play so large a role in the criminal justice system, and in the public perception of the law? Even twenty years ago, forensic scientists could tell only whether a blood sample was animal or human, male or female, and, if human, of what type (the least common blood type being found in 3 per cent, and the commonest in 43 per cent, of the U.S. population). Then, in the mid-1980s, DNA fingerprinting made vastly more accurate identification possible, to probabilities of the order of a billion to one; and by now new techniques have made it possible to amplify and test the tiniest samples.
At first, such evidence was strenuously contested in court; but as its solidity, and its power to enable justice, became unmistakable, the ‘DNA wars’ gradually died down. By the spring of 2002, DNA testing had exonerated more than a hundred prisoners, including a significant number on death row, and helped convict numerous rapists and murderers. In at least one instance, it both exonerated and convicted the same person: after serving nearly eleven years of a twenty- five-to- fifty-year sentence for rape, Kerry Kotler was released, in 1992, when newly conducted DNA tests established his innocence; less than three years after his release, he was charged with another rape, and this time convicted on the basis of DNA analysis identifying him as the perpetrator.
Even so, DNA evidence can present problems of its own: police officers and forensic technicians make mistakes – and have been known deliberately to falsify or misrepresent evidence; juries may misconstrue the significance of expert testimony about the probability of a random match with the defendant, or of information about the likelihood that a sample was mishandled – and attorneys have been known to contribute to such misunderstandings; criminals devise devious ways to circumvent DNA identification – and at least one prisoner, apparently hoping to exploit the potential for confusion, has petitioned for a DNA test that, as he must have anticipated, confirmed his guilt.
Law and Experimental Psychologists
And who could have imagined, when Hugo Münsterberg urged in his On the Witness Stand: Essays on Psychology and Crime (1908) that the law avail itself of the work of experimental psychologists on the reliability of memory, perception, and eyewitness testimony, that less than half a century later psychological evidence would play a significant role in such landmark constitutional cases as Brown v. Board of Education (1954), or that by now it would have come to play so large a role in the criminal justice system – or that it would be the focus of seemingly endless controversy? For while the work of experimental psychologists on eyewitnesses, memory, etc., has indeed proved useful, clinical psychologists’ and psychiatrists’ diagnoses of this syndrome and that, and especially their theories about the repression and recovery of traumatic memories, have been the subject of heated battles in the courtroom, in the press, and in the academy.
In the mid-1980s, testimony of allegedly repressed and recovered memories came to public attention in the McMartin Preschool case–the longest U.S. criminal trial ever (six years), and one of the most expensive (around $15 million). But in 1990 the seven defendants were acquitted of the ritual sexual abuse that, under the influence of therapists, numerous children at the school had claimed to remember. George Franklin spent nearly seven years in prison for the murder of nine-year- old Susan Nason, convicted on his daughter’s supposed memory of the event, recovered under hypnosis twenty years afterward; he was released in 1996, after his daughter also ‘remembered’ his committing two other murders, with respect to one of which he could be unambiguously ruled out. (Franklin later sued prosecutors and the experts who testified against him for wrongful prosecution and violation of his civil rights.) By the late 1990s, it began to seem that critics such as experimental psychologist Elizabeth Loftus, who had maintained all along that supposedly repressed and recovered ‘memories’ could be the result of therapists’ suggestive questioning, were vindicated. But recently the ‘memory wars’ have flared up all over again, this time in legal claims filed against Catholic priests accused of sexual abuse of children and young people.
Why has the legal system found scientific testimony hard to handle? Ever since there have been scientific witnesses, lawyers and legal scholars–like Eliot’s Mr. Chichely – have had their doubts about them. The commonest complaint has been that venal scientists brought in by unscrupulous attorneys will testify to just about anything a case demands. In 1858, the Supreme Court observed that “experience has shown that the opposite opinions of persons professing to be experts may be obtained in any amount”; in 1874, John Ordronaux wrote in the American Journal of Insanity, “If Science, for a consideration, can be induced to prove anything which a litigant needs in order to sustain his side of an issue, then Science is fairly open to the charge of venality and perjury, rendered the more base by the disguise of natural truth in which she robes herself.” More than a century later, in Galileo’s Revenge (1991), Peter Huber was sounding a similar theme: junk science – “data dredging, wishful thinking, truculent dogmatism, and, now and again, outright fraud” – was flooding the courts. Some scientists concur. In her study of the silicone breast implant fiasco, Science on Trial (1996), Marcia Angell complains that “[e]xpert witnesses may wear white coats, be called ‘doctor,’ purport to do research, and talk scientific jargon. But too often they are merely adding a veneer to a foregone, self-interested conclusion”; in Whores of the Court (1997), an exposé of flimsy psychiatric and clinical testimony, experimental psychologist Margaret Hagen writes of “charlatans and greedy frauds.”
There surely are venal and incompetent scientific witnesses, and there surely are scientifically ignorant and credulous jurors, attorneys, and judges; but the familiar complaints gloss over many complexities. Scientific testimony may be flawed by outright fraud, or, more often, by the overemphatic presentation of scanty or weak evidence; it may be solid science misapplied by a poorly run laboratory, or serious but highly speculative and controversial science, or sloppily conducted scientific work, or pseudoscientific mumbo jumbo. The motive may be an expert’s greed, or his desire to feel important, or his anxiety to help the police or a sympathetic plaintiff, or it may be a scientist’s conservatism about new and radical-sounding ideas; or a plaintiff’s attorney’s interest in keeping disputes long settled in science legally alive. Failures of understanding may be due to jurors’ or judges’ or attorneys’ inability to follow complex statistical reasoning, or to their ignorance of the kind of controls needed in this or that type of experiment or study, or to their excessive deference to science, or their resentment of its perceived elitism. Or the problem may simply be jurors’ sense that someone should compensate the victim of an awful disease or injury, or that someone should be punished for a horrible crime.
And the familiar complaints also gloss over the deep tensions between science and the law that are at the root of these problems. The culture of the law is adversarial, and its goal is case-specific final answers. The culture of the sciences, by contrast, is investigative, speculative, generalising, and thoroughly fallibilist: most scientific conjectures are sooner or later discarded, even the best-warranted claims are subject to revision if new evidence demands it, and progress is ragged and uneven. Science doesn’t always have the final answers the law wants, or not when it wants them; and even when science has the answers, the adversarial process can seriously impede or distort communication. It’s no wonder that the legal system often asks more of science than science can give, and often gets less from science than science could give; nor that strong scientific evidence sometimes falls on deaf legal ears, while flimsy scientific ideas sometimes become legally entrenched.
One response to the difficulties has been to try to tame scientific testimony by devising legal rules of admissibility to ensure that judges don’t allow flimsy stuff to be presented to juries. But, as the tortuous history of efforts to frame such formal rules suggests, no legal form of words could guarantee that only good enough scientific testimony is admitted. Another response has been, instead, to adapt the culture of the law, bringing it more into line with science by compromising adversarialism or the concern for finality. But these pragmatic and piecemeal strategies, though in some ways more promising, raise hard questions about why we value trial by jury, why we want finality, and whether the adversarial process is really an optimal way of ensuring–in the words of the preamble to the Federal Rules of Evidence –“that the truth be ascertained.”
The present practice of relying on experts proffered by the parties not to report on what they saw but rather to give their informed opinion, evolved only gradually, along with the growth of the adversary system, cross-examination, and formal rules governing the admissibility of evidence. For a long time it was required only that a scientific witness, like any other expert witness, establish his qualifications as an expert–until 1923, when the Frye ruling imposed new restrictions on the proffered testimony itself.
In Frye, excluding the testimony of a then new blood pressure deception test, the D.C. court ruled that novel scientific evidence was admissible only if it had gained “general acceptance in the field to which it belongs.” At first cited only quite rarely, and almost always with regard to lie-detector evidence, the Frye rule gradually came to be widely followed in criminal trials, and by 1979 had been adopted in a majority of states. (It remains officially the law today in a number of states). Of course, general acceptance is a better proxy for scientific robustness when the field in question is a mature, established scientific specialty than when it is a highly speculative area of research – or, worse, the professional turf of a trade union of mutually supportive charlatans. Moreover, the rule is highly manipulable, depending, among other things, on how broadly or narrowly a court construes the field in question. Nevertheless, a main focus of criticism was that the Frye test was too restrictive.
Federal Rules of Evidence
The Federal Rules of Evidence (1975) in the United States seemed to set a less restrictive standard: the testimony of a qualified expert is admissible provided only that it is relevant, and not legally excluded on grounds of unfair prejudice, waste of time, or potential to confuse or mislead the jury. In line with the Federal Rules’ apparently liberal approach, in Barefoot, a 1983 constitutional case, the Supreme Court affirmed that the rights of a Texas defendant were not violated by the jury’s being allowed, in the sentencing phase, to hear psychiatric testimony predicting his future dangerousness – even though an amicus brief filed by the American Psychiatric Association reported that two out of three psychiatric predictions of future dangerousness are mistaken. Justice White, writing for the majority, observed that the Federal Rules anticipate that courts will admit relevant evidence and leave it to juries, with the help of cross-examination and presentation of contrary witnesses, to determine its weight.
In dissent, however, noting that a scientific witness has a special aura of credibility, Justice Blackmun averred that “it is extremely unlikely that the adversary process will cut through the facade of superior knowledge.”
By the late 1980s, as legal scholars debated whether the Federal Rules had or hadn’t superseded Frye, and whether a more or a less restrictive approach to scientific testimony was preferable, there was rising public and political concern that the tort system was getting out of hand; a crisis due in large measure, Huber argued in his influential book, to scandalously weak scientific testimony that would have been excluded under Frye but was being admitted under the Federal Rules. Then in 1993, with proposals before Congress to tighten up the Federal Rules, the Supreme Court issued its ruling in the landmark Daubert case–the first case in the Court’s 204- year history where the central issue was the standard of admissibility of scientific testimony.
Daubert was a tort action against Merrell Dow Pharmaceuticals brought by parents who claimed that their children’s severe birth defects had been caused by their mothers’ taking the company’s morning sickness drug, Bendectin, during pregnancy. In excluding the plaintiffs’ expert testimony, the lower court had cited Frye (which up till then, contrary to Huber’s diagnosis, had almost always been cited in criminal, not civil, cases). Remanding the case, the Supreme Court held that the Federal Rules had superseded Frye, but added that the Rules themselves required judges to screen proffered expert testimony not only for relevance, but also for reliability.
(To be continued)
Pix from Net.