2022年经济学人 目击者的证据比想象的更可靠（在线收听）

Science & Technology

科技版块

The psychology of justice

公平的心理学

First impressions

第一印象

Eyewitness evidence is more reliable than thought

目击者的证据比想象的更可靠

The “satanic panic” that swept through America in the 1980s and 1990s held that thousands of ordinary people up and down the country were secretly members of devil-worshipping cults which were abusing, raping and murdering children on an industrial scale.

20世纪80年代和90年代席卷美国的“撒旦恐慌”认为，全国上下数以千计的普通人是崇拜魔鬼邪教的秘密成员，这些邪教以工业规模虐待、强奸和谋杀儿童。

Alleged victims made detailed allegations, often after therapy designed to “recover” memories that had supposedly been buried in the aftermath of trauma.

所谓的受害者往往在接受了旨在“恢复”创伤后被埋藏的记忆的治疗后，提出了详细的指控。

Many people went to prison.

很多人进了监狱。

None of it was true.

这一切都不是真的。

One after-effect of the panic was to cement in the minds of both the public and the justice system the idea that eyewitness testimony is unreliable.

恐慌的一个后遗症是：在公众和司法系统看来，目击者证词是不可靠的。

That fitted with experiments by psychologists such as Elizabeth Loftus, which demonstrated just how malleable memories can be.

这与伊丽莎白·洛夫图斯等心理学家的实验相吻合，这些实验证明了记忆可塑性的强大。

The Innocence Project, an American charity, examined 375 cases of wrongful conviction for all sorts of crimes, and found misidentification of suspects by witnesses was a factor in around 70% of them.

美国慈善机构“清白计划”审查了375起各种罪行的误判案件，发现其中70%的误判都是由于证人对嫌疑人的误认。

But at the annual meeting of the American Association for the Advancement of Science, John Wixted, a psychologist at the University of California, San Diego, argued that this institutional distrust has gone too far.

但在美国科学促进会的年度会议上，加州大学圣地亚哥分校的心理学家约翰·威克斯特表示，这种制度性不信任太过分了。

Eyewitness memories, he said, can in fact be very reliable—if they are tested in the right circumstances.

他说，如果在正确的环境下进行测试的话，目击者的记忆实际上可以非常可靠。

The key to reliability, said Dr Wixted, is the confidence of witnesses in their assessments.

威克斯特博士说，可靠性的关键在于证人对其评估的信心。

Experiments suggest that when witnesses to a simulated crime are confident of having identified the suspect in a later photo line-up, they are almost always correct.

实验表明，模拟犯罪中，目击者确信在随后的照片中认出了嫌疑人时，他们几乎总是正确的。

Similarly, if they are sure the suspect is not present, that is likely to be right too.

同样，如果他们确定嫌疑人没有出现，这也很可能是正确的。

Only when a witness is unsure does a risk of misidentification arise.

只有当目击者不确定时，才会出现误认的风险。

A field study conducted in 2016 by Houston’s police came to similar conclusions.

休斯顿警方在2016年进行的一项实地研究也得出了类似的结论。

The problem is that this confidence is trustworthy only the first time the question is asked.

问题是，这种信心只有在第一次提问时才值得信任。

One of the unavoidable frustrations of quantum mechanics is that measuring a particle’s position or energy irretrievably alters it.

量子力学一个不可避免的问题是，测量粒子的位置或能量会不可逆转地改变它。

Something similar, said Dr Wixted, happens with memories.

威克斯特博士说，类似的情况也会发生在记忆中。

The very act of testing them contaminates every other test that comes after.

测试它们的行为本身就影响了随后进行的所有其他测试。

Assessing people’s faces for a possible match, for example, lodges them in a witness’s memory.

例如，通过评估人们的面孔来寻找可能的匹配，就能将他们保存在目击者的记忆中。

Once that has happened, anything from police encouragement to the high-pressure environment of a courtroom can twist subsequent attempts at recollection.

一旦这种情况发生，从警察的鼓励到法庭的高压环境，任何事情都可能扭曲随后的回忆尝试。

Dr Wixted drew a comparison with evidence such as dna samples.

威克斯特博士将其与DNA样本等证据进行了比较。

Improper handling can contaminate these.

处理不当可能会污染这些。

That does not mean dna tests are inherently unreliable, but it does mean the technology must be used carefully.

这并不意味着DNA测试本身不可靠，但它确实意味着这项技术必须谨慎使用。

The same, he says, is true of witnesses.

他说，目击者也是如此。

The answer, as he and Dr Loftus argue in a recently published paper, is to test a witness’s memory as fairly as possible, and—crucially—to do so only once.

正如他和洛夫特斯博士在最近发表的一篇论文中指出的那样，要尽可能公平地测试证人的记忆，而且至关重要的是，只测试一次。

Decades after the Satanic panic, the matter remains important.

在撒旦恐慌过去几十年后，这件事仍然很重要。

Dr Wixted cited the case of Charles Don Flores, a prisoner awaiting execution for a murder committed in 1998.

威克斯特博士引用了查尔斯·唐·弗洛雷斯的案例，他是一名因1998年犯下谋杀罪而等待处决的囚犯。

Initially, when shown a line-up that included Mr Flores, a crucial witness said none of the people matched her recollection.

最初，当展示包括弗洛雷斯在内的名单时，一名关键证人表示，没有一个人与她的记忆相匹配。

(She had recalled a white man with long hair.

(她回忆起一个留着长发的白人男子。

Mr Flores is of Latin American extraction, and had short hair then.)

弗洛雷斯有拉美血统，当时留着短发。

By the time the case came to trial a year later, she had changed her mind, and Mr Flores was convicted.

一年后案件开庭审理时，她改变了主意，弗洛雷斯先生被判有罪。

His appeal on the basis of the witness’s change of mind has been denied.

他以证人改变主意为由提出的上诉已被驳回。

Dr Wixted, however, suggests she was likely to have been right the first time and wrong the second.

然而，威克斯特博士认为，她很可能第一次是对的，第二次是错的。