您能控制自己的身體反應騙過機器嗎(下)

A common strategy examiners employ involvesasking a combination of both relevant (Did you rob the bank?) and irrelevantquestions (Have you ever taken anything that didn’t belong to you?). Since noone can really answer ‘no’ to the irrelevant questions without lying somewhat,the theory is that the physiological response to the irrelevant questionsserves as a type of baseline. The idea is to get a decent profile of what itlooks like when you’re lying when unstressed – this helps the person readingthe machine to be more confident that they are observing a response to astressed lie than if they were only comparing with obvious truths (such as ‘are you aman?’).

測謊人員一個常見的策略是同時提出相關問題（你是否搶了銀行？）和無關緊要的問題（你是否拿過不屬於自己的東西？）。由於沒有人能做到對無關緊要的問題不撒謊就回答“否”，理論上，將受試者對無關緊要問題的生理反應充當測試基準。這種思路是，得到受試者在無壓力狀態下撒謊的合理情況，與僅對照明顯事實（如‘你是男性嗎？’）相比，這樣做這有助於測謊人員更相信自己對有壓力狀態下撒謊反應的判斷。

George Maschke, who has since 2000, says the strategy for beating a polygraph is torecognise the control questions and augment your reactions to them.

喬治·馬施克（George Maschke）自2000 年起經營一家網站，他表示，戰勝測謊儀的策略是，承認對照問題，並放大自己對它們的反應。

“When you’re asked a control question, like ‘Did you ever lie to getout of trouble?’ you can try to solve a math problem as quickly as you can inyour head and that mental activity will tend to raise your sweating, yourbreathing, et cetera,” he says. “If you have a stronger reaction to the controlquestions than the relevant questions you will pass the test.”

他說，“在被問到像‘你是否曾爲了擺脫困境而撒謊？’這樣的對照問題時，你可以試着在大腦中儘快解答一個數學題，這種心理活動會促使你出汗增加、呼吸加速，還有其他一些指標也會提高。如果回答對照問題時你的反應要比回答相關問題時還要激烈，那麼你就能通過測謊測試。”

Goodson says that although he cansuccessfully defeat a polygraph against novice students, defeating anexperienced examiner is harder. “Altering human physiology is not difficult,and there are many anti-polygraph websites that teach this. What these websitescan’t teach is how to alter one’s physiology that appears to a polygraphexaminer as a genuine or natural response to a polygraph exam question,” hesays. “When polygraph examinees try to alter or control their bodies’ normalreactions, it creates abnormal data that is easily recognisable by a polygraphexaminer trained to detect these unnatural physiological responses.”

古德森表示，儘管他面對新手能成功騙過測謊儀，但欺騙有經驗的測謊人員卻並不容易。“改變人的生理反應並不難，有許多對付測謊儀的網站教人怎樣做。但這些網站卻無法教給人怎樣在回答測謊問題時改變生理反應的同時，面對測謊人員還能做出真實或自然的反應，”他這樣表示。“當受試者試圖改變或控制身體的正常反應時，會產生異常數據，訓練有素的測謊人員很容易就能發現這種不自然的生理反應。”

Some researchers are also concerned thatwhen wrong, the tests produce more false positives (meaning innocent people whowrongly fail) than false negatives (meaning guilty people who wrongly pass), aphenomenon that can be seen in a 2004 report on the validity of polygraphs bythe British Psychological Society.

有些研究人員也會擔心，測試有誤時，測試生成的錯誤陽性結果（意思是，無辜者錯誤地未通過測謊）多於錯誤的陰性結果（意思是，有過錯的人錯誤地通過測謊），這種現象在2004 年英國心理學學會驗證測謊儀有效性的報告中就可以看到。

According to Goodson, some people who aretelling the truth can fail polygraph tests by trying too hard to control theirbody’s responses. “When truthful persons alter their physiology, thinking theywill help themselves pass the polygraph, polygraph literature suggests thatmany of these truthful examinees are classified as deceptive when they do so,”he says.

據古德森說，有些人說真話時過於努力控制自己的身體反應也通不過測謊測試。他說，“說真話的人也會改變自己的生理反應，以爲這會有助於自己通過測謊，而測謊文獻表明，許多這種說真話的受試者在試圖這樣做的時候也會被歸入欺詐行列。”

Many scientists are concerned that thetheory behind lie detectors is faulty, since a physiological response is notnecessarily linked to lying. A 2011 meta-analysis by the American PolygraphAssociation found that polygraph tests using comparison questions had incorrectoutcomes about 15% of the time.

許多科學家擔心，測謊儀背後的理論是錯誤的，因爲生理反應與撒謊並不具有必然聯繫。美國測謊協會2011 元分析報告（A 2011 meta-analysis by the American Polygraph Association）發現，當時測謊測試使用的對照問題約15% 都會得到錯誤的結果。

The type of test I’m trying to pass howeveris sounder, and slightly more difficult to cheat. Since I’m doing this for astory, Mordi has devised a way for me to test the system that doesn’t requirecomparison questions. He asks me to write a number between one and seven on apiece of paper and will monitor my physical response as I try to lie my way througheach number, as if I didn’t write anything at all.

我試圖通過的測試比較可靠，想騙過測謊器會更難。由於我是爲了寫報道才這樣做的，所以穆爾迪爲我設計了一種測試系統的方法，無需使用對照問題。他讓我在紙上寫出1 到7 之間的一個數字，然後在我試圖隱瞞每個數字，好像我什麼也沒有寫的時候，監控我的生理反應。

It’s a simplified version of the GuiltyKnowledge Test, which is used in investigations after a known crime. Anexaminer presents a potential suspect with specific information unrelated andrelated to a crime to test whether examinees have a response to the relevantitems. Take a bank robbery for instance. You could present the amount of moneythat was stolen from the bank among other figures, or a genuine ransom notethat was passed to the bank teller among other notes created by the police.

這是犯罪知識測試的簡單版本，這種測試用於已知犯罪後進行的調查。測謊人員會給一名潛在疑犯出示與犯罪無關緊要的特定信息和有關聯的特定信息，然後測試受試者對有關信息是否有反應。以搶劫銀行爲例。你可以給疑犯出示若干數字，其中有銀行被盜的金額；或者出示若干交給銀行櫃員的勒索信，其中有真正的勒索信，也有警方製作的假勒索信。

Though Maschke says it’s still possible tocheat through it, the Guilty Knowledge Test is considered more theoreticallysound than the comparison strategy and less controversial by scientists,according to the report by the British Psychological Society. The 2011meta-analysis conducted by the American Polygraph Association found that GuiltyKnowledge type tests were incorrect closer to 10% of the time.

儘管馬施克表示，還是有可能騙過犯罪知識測試，但根據英國心理學會的報告，在理論上，這種測試要比對照策略更爲可靠，科學家對此的爭議要少一些。美國測謊協會2011 元分析報告發現，當時，犯罪知識類測試的錯誤率接近10%。

Far from perfect –but still,it caught me out. I failed spectacularly. There is a screenshot of myphysiological reactions below. See if you can tell when I lied.

雖然這種測試離完美還相差甚遠，但也足以抓住我這樣的人了。我沒有通過測試，結果還很糟。下面是顯示我的生理反應的截圖。試試看，您能否發現我在撒謊。

If you look at the thick black line inparticular, you can probably guess that I lied about the number six. And Mordispotted it too.

如果您仔細觀察黑色粗線，可能就會發現我對數字6 撒了謊。這點穆爾迪也發現了。