Rough justice

 作者:薛饿     |      日期:2019-03-08 07:15:00
By Nell Boyce EARLIER this month, Connecticut resident Jay Black and his lawyer used an unprecedented defence in a paternity suit filed by the mother of a three-year-old child. Although two DNA tests identified Black as the father, he claims infection with human papilloma virus could have altered his DNA, skewing the test results. Gordon Carmichael, a microbiologist at the University of Connecticut Health Center in Farmington, agreed to testify that the virus would damage the DNA of cells it infected, and that genetic tests on these cells could be unreliable. “The people that do the genetic testing say it’s absolutely ridiculous,” says assistant state attorney general Wilbur Ward Dinegar, who is acting for the child. He points out that no one has ever shown that human papilloma virus can alter the results of paternity tests. “Right now, it’s a pretty far-out theory. If Dr Carmichael is right, we’re looking at a Nobel laureate.” Nonetheless, the judge admitted this testimony as evidence, and is expected to return a verdict in August. In child cases of this type no jury is present. This particular judge has a scientific background so Dinegar feels confident in his ability to make a critical assessment of the evidence. But what would happen if the judge knew nothing about science? From the birth defects allegedly caused by the morning sickness drug Bendectin to the case of nanny Louise Woodward, accused of killing a baby, juries have found themselves facing two or more expert witnesses who confidently contradict each other. Growing concern about the courts’ handling of science has recently led to reforms on both sides of the Atlantic that are designed to curtail the number of experts-for-hire and to promote the use of independent witnesses. One of the most contentious “junk science” problems in recent years has been the thousands of silicone breast implant cases coming to trial in the US. Last week, the National Academy of Sciences in Washington DC concluded that breast implants did not cause cancer, immune disease or neurological problems. Yet since 1984, when experts first appeared in court backing theories of a link between implants and damage to the immune system, juries have considered the evidence and come to exactly the opposite conclusion, awarding women millions of dollars in damages. Because the immunology in these cases was so complex, three judges took the unusual step of appointing a panel of independent experts in 1996 to review the evidence. These experts concluded last December that there was no link between silicone and immune disease. Although federal judges have had the power to appoint outside experts for decades, they rarely do so. Several other court cases in recent years, especially the 1993 Supreme Court ruling on expert testimony in the Bendectin case, have established that US judges have a responsibility to keep dubious science out of the courtroom. Now the American Association for the Advancement of Science in Washington DC has announced that, for the next five years, it will provide federal judges with neutral experts. “Our expert comes in without any allegiance to a particular side,” says project leader Mark Frankel, who believes fringe testimony by partisan scientists “gives a bad name to all of science”. English judges may also be rejecting the adversarial system when it comes to scientific testimony. On 26 April, new procedural rules governing all civil litigation in England and Wales came into force, after an inquiry by Lord Woolf concluded that the old system was too slow and costly. “One of the things that can happen, and may happen far more, is the appointment of court experts [by the judge],” says Chris Hughes of the British Medical Association. In the past, the plaintiff and defendant had to find their own expert witnesses, explains Matt Kelly, a specialist in personal injury law from the General Council of the Bar in London. Now all expert witnesses will be obliged to explain the reasoning behind their opinions and highlight prominent issues where scientists disagree. Judges can restrict the number of experts who are called, or insist that both parties agree on one shared expert. Janine Collins, with the Medical Defence Union in London, says that the new rules should “eliminate those experts who have given opinions for one side over the other”. Many lawyers and scientists welcome the prospect of a shift away from experts who serve opposing parties. “Scientific testimony has become a recognised issue that judges have to deal with,” says Peter Huber, whose 1991 book Galileo’s Revenge: Junk Science in the Courtroom sharpened the debate about science in the courts. “A judge with no axe to grind can go out and choose a name and is much more likely to get neutral feedback. The mere threat of a judge appointing an expert gives a big impetus towards settlement.” Those who support reform believe juries should be protected from “junk science” because it’s easy for expert witnesses to pull the wool over the eyes of scientifically illiterate jurors. Not everyone agrees. Neil Vidmar of Duke University in Durham, North Carolina, is a leading researcher on jury behaviour. “There is a body of evidence rejecting these claims about juries,” he says. His studies show that more often than not, independent doctors and judges agree with juries’ verdicts when it comes to malpractice cases. Some critics say, however, that a fundamental cultural clash will always make the courts dissatisfied with scientists and vice versa. Scientists like to reserve judgment until other studies confirm their findings, while juries and judges are required to pass judgment based on the available information. Sometimes the science central to a case is genuinely in dispute: well-qualified experts looking at the same data can reach different conclusions. In those cases, critics argue, turning to an independent expert might potentially usurp the jury or judge’s fact-finding role in the courtroom. Studies with mock juries suggest juries find court-appointed experts highly convincing and tend to go along with their views. “There is experimental evidence that neutral experts’ opinions are taken very seriously by the jury,” says Joseph Saunders at the University of Houston Law Center. Vidmar agrees that “the neutral expert is likely to have more weight than an individual from the adversary system”. Carlton Carl, who is spokesperson for the Association of Trial Lawyers of America in Washington DC, believes that juries should be especially wary of experts who purport to be neutral. “Experts, by their very nature, have biases.” His association opposes the appointment of outside experts, and believes “juries are intelligent enough to receive information from both sides and make an informed decision”. Though courts might welcome greater involvement of neutral scientists, no one knows whether scientists will be prepared to leave their labs for the courtroom. Finding neutral experts for the breast implant panel proved a time-consuming task. “These experts did not want to participate,” says Vidmar. Unfortunately, those scientists who are least willing to spare time from their cutting-edge research are the ones whose opinions would be most valued by the court. Frankel is betting that the AAAS will be able to find scientists who are prepared to heed the call. “We see this as a public service that gives them an opportunity to serve the court, not one side or the other,