经济学人28:司法科学 无知即是福

 　　Science and Technolgy

　　科技

　　Forensic¹ science

　　司法科学

　　Ignorance is bliss²

　　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, DNA³ is the gold standard of forensic science. Or is it? Itiel Dror, a cognitive⁴ psychologist at University College, London, thinks this doctrine⁵ of infallibility needs to be questioned. His problem is not with the technology itself, but with the way it is deployed⁶. For he has gathered evidence that DNA examiners' interpretations⁷ of their results are, at least in complex cases, open to subjectivity⁸ and bias⁹.

　　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 fingerprint¹⁰ 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 domain¹¹ 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 accredited¹² government laboratory in North America. The case involved a gang rape¹³ in the state of Georgia, in which one of the rapists testified against three other suspects in exchange for a lighter¹⁴ 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 corroborating¹⁵ 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 abstained¹⁶.

　　由于在司法科学实验室里总是什么都是对的，这些鉴定师们知道这个案子到底是怎么回事了。而且他们的手指对于出来的结果是至关重要的，因为在乔治亚，同时也在很多其它州，认罪辩诉如果没有确实的证据是无法被接受的。然而，在Dror博士和Hampikian接触的17个鉴定师中——他们不像开始两位鉴定师那样，对犯罪内容一无所知——只有一位认为一样的嫌疑不能被排除。另外十二位把他排除了，而四位弃权。

　　Though they cannot prove it, Dr Dror and Dr Hampikian suspect the difference in contextual information given to the examiners was the cause of the different results. The original pair may have subliminally¹⁷ interpreted ambiguous information in a way helpful to the prosecution¹⁸, even though they did not consciously realise what they were doing.

　　尽管他们无法证明，Dror博士和Hampikian博士怀疑鉴定师得到的上下文信息的区别是引起这些不同结果的原因。开始的两个人也许已经在下意识里以某种有益于控方的方式破译了模棱两可的信息，即使他们没有清楚地意识到当时他们在做什么。

　　And DNA data are ambiguous more often than is generally realised. Dr Dror thinks that in about 25% of cases, tiny samples or the mixing of material from more than one person can lead to such ambiguity¹⁹. Moreover, such is DNA's reputation that, when faced with claims that the molecule²⁰ puts a defendant²¹ in a place where a crime has been committed, that defendant will often agree to a plea-bargain he might otherwise not have accepted.

　　而且DNA数据往往比普遍了解的要模棱两可。Dror博士认为在大约25%的案子里，小样本或者从不止一人身上取来的混合物质可能导致这样的二义性。此外，DNA的好名声就是这样，当面临宣称用DNA分子证明被告所犯的罪的时候，被告通常会同意认罪辩诉，否则他也许不会接受。

　　This one example does not prove the existence of a systematic²² problem. But it does point to a sloppy²³ approach to science. According to Norah Rudin, a forensic-DNA consultant²⁴ in Mountain View, California, forensic scientists are beginning to accept that cognitive bias exists, but there is still a lot of resistance to the idea, because examiners take the criticism personally and feel they are being accused of doing bad science. According to Dr Rudin, the attitude that cognitive bias can somehow be willed away, by education, training or good intentions, is still pervasive²⁵.

　　这个例子没有证明系统性问题的存在。但是它确实指出了一个科学上草率的方法。根据一位加利福尼亚州芒廷维尤的法庭DNA顾问Norah Rudin，法庭科学家正在开始接受那种认知性偏差的存在，但仍然有很多阻力，因为鉴定师个人会接受批评，觉得自己被谴责说自然科学学得差。根据Rudin博士，认知偏差可以通过某种方式意识性去除的态度是普遍的，比如通过教育、训练或好意的方式。

　　Medical researchers, by contrast, take great care to make drug trials "blind", so that neither the patient nor the administering doctor knows who is receiving the drug being tested, and who is getting a control drug or placebo²⁶. When someone's freedom—and, in an American context, possibly his life, as well—is at stake, it surely behoves forensic-science laboratories to take precautions that are equally strong.

　　相比之下，医学研究者非常注意使药物试验"不透明"，所以病人和用药的医生都不知道接受药物测试的是谁，和控制药物和安慰剂的是谁。在美国环境中，当某人的自由和他的生命也危在旦夕的时候，法医科学实验室应当采取相当的强预防措施。

1 forensic   

adj.法庭的，雄辩的

参考例句：

• The report included his interpretation of the forensic evidence.该报告包括他对法庭证据的诠释。
• The judge concluded the proceeding on 10:30 Am after one hour of forensic debate.经过近一个小时的法庭辩论后，法官于10时30分宣布休庭。

2 bliss   

n.狂喜，福佑，天赐的福

参考例句：

• It's sheer bliss to be able to spend the day in bed.整天都可以躺在床上真是幸福。
• He's in bliss that he's won the Nobel Prize.他非常高兴，因为获得了诺贝尔奖金。

3 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

4 cognitive   

adj.认知的，认识的，有感知的

参考例句：

• As children grow older,their cognitive processes become sharper.孩子们越长越大，他们的认知过程变得更为敏锐。
• The cognitive psychologist is like the tinker who wants to know how a clock works.认知心理学者倒很像一个需要通晓钟表如何运转的钟表修理匠。

5 doctrine   

n.教义；主义；学说

参考例句：

• He was impelled to proclaim his doctrine.他不得不宣扬他的教义。
• The council met to consider changes to doctrine.宗教议会开会考虑更改教义。

6 deployed   

（尤指军事行动）使展开( deploy的过去式和过去分词 )； 施展； 部署； 有效地利用

参考例句：

• Tanks have been deployed all along the front line. 沿整个前线已部署了坦克。
• The artillery was deployed to bear on the fort. 火炮是对着那个碉堡部署的。

7 interpretations   

n.解释( interpretation的名词复数 )；表演；演绎；理解

参考例句：

• This passage is open to a variety of interpretations. 这篇文章可以有各种不同的解释。 来自《简明英汉词典》
• The involved and abstruse passage makes several interpretations possible. 这段艰涩的文字可以作出好几种解释。 来自《现代汉英综合大词典》

8 subjectivity   

n.主观性（主观主义）

参考例句：

• In studying a problem,we must shun subjectivity.研究问题，忌带主观性。
• 'Cause there's a certain amount of subjectivity involved in recreating a face.因为在重建面部的过程中融入了太多的主观因素？

9 bias   

n.偏见，偏心，偏袒；vt.使有偏见

参考例句：

• They are accusing the teacher of political bias in his marking.他们在指控那名教师打分数有政治偏见。
• He had a bias toward the plan.他对这项计划有偏见。

10 fingerprint   

n.指纹；vt.取...的指纹

参考例句：

• The fingerprint expert was asked to testify at the trial.指纹专家应邀出庭作证。
• The court heard evidence from a fingerprint expert.法院听取了指纹专家的证词。

11 domain   

n.(活动等)领域，范围；领地，势力范围

参考例句：

• This information should be in the public domain.这一消息应该为公众所知。
• This question comes into the domain of philosophy.这一问题属于哲学范畴。

12 accredited   

adj.可接受的；可信任的；公认的；质量合格的v.相信( accredit的过去式和过去分词 )；委托；委任；把…归结于

参考例句：

• The discovery of distillation is usually accredited to the Arabs of the 11th century. 通常认为，蒸馏法是阿拉伯人在11世纪发明的。
• Only accredited journalists were allowed entry. 只有正式认可的记者才获准入内。

13 rape   

n.抢夺，掠夺，强奸；vt.掠夺，抢夺，强奸

参考例句：

• The rape of the countryside had a profound ravage on them.对乡村的掠夺给他们造成严重创伤。
• He was brought to court and charged with rape.他被带到法庭并被指控犯有强奸罪。

14 lighter   

n.打火机，点火器；驳船；v.用驳船运送；light的比较级

参考例句：

• The portrait was touched up so as to make it lighter.这张画经过润色，色调明朗了一些。
• The lighter works off the car battery.引燃器利用汽车蓄电池打火。

15 corroborating   

v.证实，支持（某种说法、信仰、理论等）( corroborate的现在分词 )

参考例句：

• Neither can one really conclude much from a neat desk, unless there is further corroborating evidence. 实际上，我们也无法从一张整洁的办公桌中得出什么结论，除非还有其它证据进一步证实。 来自互联网

16 abstained   

v.戒（尤指酒），戒除( abstain的过去式和过去分词 )；弃权（不投票）

参考例句：

• Ten people voted in favour, five against and two abstained. 十人投票赞成，五人反对，两人弃权。
• They collectively abstained (from voting) in the elections for local councilors. 他们在地方议会议员选举中集体弃权。 来自《简明英汉词典》

17 subliminally   

adv.下意识地

参考例句：

• I have read many books, perhaps they influenced me subliminally. 我读过很多书，也许受到了它们潜移默化的影响。 来自柯林斯例句

18 prosecution   

n.起诉，告发，检举，执行，经营

参考例句：

• The Smiths brought a prosecution against the organizers.史密斯家对组织者们提出起诉。
• He attempts to rebut the assertion made by the prosecution witness.他试图反驳原告方证人所作的断言。

19 ambiguity   

n.模棱两可；意义不明确

参考例句：

• The telegram was misunderstood because of its ambiguity.由于电文意义不明确而造成了误解。
• Her answer was above all ambiguity.她的回答毫不含糊。

20 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

21 defendant   

n.被告；adj.处于被告地位的

参考例句：

• The judge rejected a bribe from the defendant's family.法官拒收被告家属的贿赂。
• The defendant was borne down by the weight of evidence.有力的证据使被告认输了。

22 systematic   

adj.有系统的，有计划的，有方法的

参考例句：

• The way he works isn't very systematic.他的工作不是很有条理。
• The teacher made a systematic work of teaching.这个教师进行系统的教学工作。

23 sloppy   

adj.邋遢的，不整洁的

参考例句：

• If you do such sloppy work again,I promise I'll fail you.要是下次作业你再马马虎虎，我话说在头里，可要给你打不及格了。
• Mother constantly picked at him for being sloppy.母亲不断地批评他懒散。

24 consultant   

n.顾问；会诊医师，专科医生

参考例句：

• He is a consultant on law affairs to the mayor.他是市长的一个法律顾问。
• Originally,Gar had agreed to come up as a consultant.原来，加尔只答应来充当我们的顾问。

25 pervasive   

adj.普遍的；遍布的，(到处)弥漫的；渗透性的

参考例句：

• It is the most pervasive compound on earth.它是地球上最普遍的化合物。
• The adverse health effects of car exhaust are pervasive and difficult to measure.汽车尾气对人类健康所构成的有害影响是普遍的，并且难以估算。

26 placebo   

n.安慰剂；宽慰话

参考例句：

• The placebo has been found to work with a lot of different cases.人们已发现安慰剂能在很多不同的病例中发挥作用。
• The placebo effect refers to all the observable behaviors caused by placebo.安慰剂效应是指由安慰剂所引起的可观察的行为。