Science and Technolgy
科技
Forensic science
司法科学
Ignorance is bliss
无知即是福
Forensic scientists know too much about the cases they investigate
法医科学家对他们调查的案子知道得太多
AS ALL fans of crime fiction know, DNA is the gold standard of forensic science. Or is it? Itiel Dror, a cognitive psychologist at University College, London, thinks this doctrine of infallibility needs to be questioned. His problem is not with the technology itself, but with the way it is deployed. For he has gathered evidence that DNA examiners' interpretations of their results are, at least in complex cases, open to subjectivity and bias.
所有的罪案小说迷都知道,DNA是司法科学的黄金标准。它到底是么?一位伦敦的大学认知心理学专家Itiel Dror认为这个说法的正确性有待考验。他的问题不是针对技术本身而是它进行的方式。因为他已经搜集了证据证明DNA鉴定者对他们结果的解释至少在复杂的案子里易受主观性和偏差的影响。
When America's National Academy of Sciences produced a report on the state of forensic science in 2009, it criticised many of the methods then in use. Citing earlier research by Dr Dror, the report's authors stated, for example, that fingerprint examiners' claims of zero error rates were scientifically implausible. DNA, however, was spared their criticism. Now Dr Dror and Greg Hampikian, a forensic biologist at Boise State University in Idaho, have published a study in Science & Justice that suggests all is not shipshape in the domain of the double helix either.
当美国国家科学院在2009年发表了一片关于司法科学现状的报告时,它批判了很多当时正在应用的鉴定方式。引用这篇报道的作者Dror博士早前做的研究,例如,指纹鉴定者宣称的零误差在科学上是不合理的。然而DNA省去了他们的批判。现在,Dror博士和博伊西的爱达荷州立大学的法医学生物学家Greg Hampikian在"科学与正义"上发表了一篇研究,表明所有的东西都不是井然有序的,在双螺旋线的领域里也不是。
Dr Dror's and Dr Hampikian's experiment presented data from a real case to 17 DNA examiners working in an accredited government laboratory in North America. The case involved a gang rape in the state of Georgia, in which one of the rapists testified against three other suspects in exchange for a lighter sentence, as part of a plea bargain. All three denied involvement, but the two DNA examiners in the original case both found that they could not exclude one of the three from having been involved, based on an analysis of swabs taken from the victim.
Dror博士和Dr Hampikian博士的实验提供一个真实案例的数据给17个在一家受认可的北美政府实验室里工作的DNA鉴定员。这起案件涉及到一宗乔治亚州的轮奸案,其中一名强奸犯为了让自己获得轻判做了不利于其它三名嫌疑者的证言,作为认罪辩诉协议的一部分。其他三名嫌疑人全部否认参与强奸,但是根据从受害者处提取的药签分析,原案中有两位DNA鉴定师都发现他们无法排除三名中的其中一名参与了强奸。
As is almost always true in forensic-science laboratories, these examiners knew what the case was about. And their findings were crucial to the outcome because in Georgia, as in many other states, a plea bargain cannot be accepted without corroborating evidence. However, of the 17 examiners Dr Dror and Dr Hampikian approached—who, unlike the original two, knew nothing about the context of the crime—only one thought that the same suspect could not be excluded. Twelve others excluded him, and four abstained.
来源:经济学人
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