经济学人下载:测谎仪 谎话连篇

Polygraphs
测谎仪

Lies, damn lies
谎话连篇

Scientifically dodgy lie-detector tests may prove surprisingly useful
科学的测谎仪可能惊人的有用

POLYGRAPHS, or “lie detectors”, make frequent appearances on “The Jeremy Kyle Show”, a television programme that resembles nothing so much as bear-baiting, but with humans. Guests are fond of the tests as a means of proving their loved ones' philandering ways, or their own innocence. Now the government seems to be growing similarly keen.
测谎仪，经常出现在跟逗熊游戏差不多的“逗人节目”杰瑞米·凯尔脱口秀。嘉宾很喜欢用测试来检测他们所爱慕的对象或者证明他们是否无辜。如今政府似乎也和这个节目一样越发喜欢用测谎仪了。

In May a small number of probation officers began training as polygraph examiners. From October around 1,000 sex offenders released from prison on licence in England and Wales but deemed to be at high risk of reoffending will be required to undergo polygraph tests. The checks will help to determine whether offenders have breached the conditions of their licences, such as restrictions on visiting children's playgrounds. Failing a test will not result in a return to prison but could prompt closer supervision or surveillance.
在5月，一小部分缓刑监督官开始训练使用测谎仪。自10月份约1000名性犯罪者从英格兰和威尔士的监狱假释，但那些被视为高犯罪风险者且将会被要求接受测谎仪测试。检测将有助于鉴别罪犯是否违反了假释的条件，如限制访问儿童游乐场。没有通过测试并不意味着要回到监狱，但意味着要受到更强监督或监视。

Polygraphs are used widely in America, including on sex offenders, but in Britain many remain sceptical. Polygraphs do not detect lies. They measure changes in physiology, such as breathing rate, sweating and blood pressure. Telling lies is often stressful and can prompt jumps in the readings. But other things–fear, embarrassment, worries about being wrongfully accused–can do the same. Enthusiasts say that polygraphs accurately detect lies 80-90% of the time. The British Psychological Society cites studies showing similar figures but cautions that problems in the research mean that the real rate is probably much lower. And “false positive” rates (dubbing a truthful person a liar) can be as high as 47%.
测谎仪在美国被广泛使用，其中也会用在性犯罪者身上，但在英国很多人都对测谎仪持怀疑态度。测谎仪并不能检测谎言。它们只是测量生理变化，例如呼吸频率。但其它会引起恐惧的事物、尴尬、对误判的焦虑也会在测谎仪上有相同的体现。热心人称测谎仪当时准确率可高达80%-90%。英国心理学会引用的研究得出了相似的数据，但同时也告诫我们实际成功率比这要低得多的问题。并且“假阳性”比率（误指一个诚实的人撒谎）可以高达47%。

Boosters of the government's scheme say the point is that using polygraphs encourages sex offenders to reveal more information, before, during and after the test. In a 2010-11 pilot study offenders who took polygraph tests made more than twice as many “clinically significant disclosures”–information that could prompt changes in the way they are managed–as those that did not. Many said they would not have done so without undergoing the test. Jane Wood, a forensic psychologist at the University of Kent who co-authored the report on the pilot, says that some offenders found the tests helpful as way to convince their families they were being honest about their behaviour. Others said that the discussions prompted when they failed the test helped them better to understand the conditions of their licence.
政府计划的支持者称使用测谎仪的核心目的是为了诱使性犯罪者在测试前后以及期间透露更多信息。在一个2010-11初步研究中，接受测谎仪测试的罪犯与没有接受测试的罪犯相比，多做出了两倍多的“临床上的重要披露”，这些披露是促使他们改变的重要信息。很多罪犯称若没有接受测谎仪的测试，他们不会做出这么多的改变。肯特大学的法庭心理学家简·伍德合着了一篇关于初步研究的报告，称一些罪犯发现测试是说服他们家人自己言行可信的一个有效方式。其他人认为当罪犯没有通过测试时，争议就产生了，但这也帮助罪犯更好地了解他们假释的条件。

Polygraph tests do not stand on their own, argues Don Grubin, a professor of forensic psychiatry at Newcastle University who is leading the probation officers' training; they should be one of a number of tools used to assess offenders. Nonetheless some remain uneasy. Those using the tests may become complacent, worries Anne-Marie McAlinden of Queen's University, Belfast, and give them undue weight. In the government's study, the more tests offenders took, the fewer lies were flagged. That might indicate that they became more truthful, or it might suggest that they were getting better at gaming the test.
测谎仪测试并不能独立存在，纽卡斯尔大学的法医精神病学教授，同时也带头进行缓刑监督官训练的唐·格鲁宾争论道；测谎仪应该只是评估罪犯的众多工具中的一个。尽管如此情况仍旧不易。贝尔法斯特皇后大学的安妮·玛丽·麦卡林登担心那些使用测试的人可能会变得自满，然后因而过于依赖测谎仪。政府研究显示，罪犯接受的测试越多，被标记的谎言越少。这或许可以说明罪犯变得越来越诚实，不过这也可能说明这些罪犯越来越会在测视力耍花招了。

The polygraph's power may rely on offenders' inflated belief in the accuracy of its tests. But getting more information from sex offenders about their behaviour–even on this basis–is still a good thing, suggests Professor Grubin. Instead of Mr Kyle, the government might look to “The Wire”, an American TV drama about murderous gangs, where detectives hooked suspects up to photocopiers, claiming they were polygraphs.
测谎仪的能力依赖于罪犯过于相信测试的准确性。但是即使是以此为基础从性犯罪者那里得到更多关于他们行为举止的信息仍是一件好事。格鲁宾教授如是说。与凯尔的脱口秀不同，政府似乎更倾向于美剧《火线》，这部美剧是关于警探们将凶残的帮派嫌疑人连接上了类似影印机的工具，并宣称这些是测谎仪。