9-13 重压之后记忆力会丧失（在线收听）

Memory Fails You after Severe Stress

People are woefully¹ bad at recalling details of their own traumatic² experiences. When military personnel were subjected³ to threatening behaviour during mock⁴ interrogations⁵, most failed to identify the questioner a day or so later, and many even got the gender⁶ wrong. The finding casts serious doubt on the reliability of victim testimonies⁷ in cases involving psychological trauma.

Numerous studies have questioned the accuracy of recall of traumatic events, but the research is often dismissed as artificial and not intense enough to simulate⁸ real-life trauma. Other studies have suggested that intense, personal experiences might produce near photographic recollection, something that prosecutors⁹ and juries in legal cases often assume.

But some researchers think this is an illusion. “People come away from these experiences feeling they will never forget what happened,” says Gary Wells, an expert on eyewitness testimony at Iowa State University in Ames, “but they confuse that with thinking they remember the details.”

Now Andy Morgan at Yale University and his colleagues have evidence from truly stressful situations. They studied over 500 soldiers, sailors and pilots at “survival schools”--three mock POW¹⁰ camps run by the US military, who partly funded the study. The subjects, whose mean age was 25, were being trained to withstand the mental and physical stresses of capture.

After 48 hours without food or sleep, they were subjected to intense interrogation. Half of the subjects were physically threatened, and this caused them to show all the signs of intense physiological stress--very high heart rate and levels of adrenalin¹¹ and cortisol¹², combined with plummeting¹³ sex hormones¹⁴.

Twenty-four hours after release from the camps, the subjects were asked to identify their interrogators. Some of the mock interrogators were shown a live line-up of 15 people, others were shown a photo-spread, and a third group was shown single photos sequentially¹⁵. Most of the mock interrogators dressed in standard military garb¹⁶, but some were shown dressed exactly as they had been during the questioning. Using a scale of 1 to 10, participants were asked to say how confident they were that they had chosen the right person.

The performance of all groups was abysmal¹⁷. Only 30 per cent could find the right person in a line-up, 34 per cent from a photo-spread and 49 per cent from sequential photos -- though the clothing cue¹⁸ boosted correct identification to 66 per cent. Thirty people got the gender wrong, and those subjected to physical threats were the worst at recognising their interrogator.

Elizabeth Loftus, a psychologist at the University of California, says the study is unique because the stresses were intense and real. “I think people will pay attention to this,” she adds. “What it illustrates is that stress does not help memory.”

注释：

1. woefully [5wEufuli] ad. 悲惨地，令人痛苦地

2. traumatic [trC:5mAtik] a. 创伤（性）的，令人痛苦而难忘的

3. subject [5sQbdVikt] vt. 使经受，使遭受

4. mock [mCk] a. 模拟的，演习的

5. interrogation [in7terE5^eiFEn] n. 讯问，审问

6. gender [5dVendE] n. [口]（生理上的）性，性别

7. testimony [5testimEni] n. 证据，证明，证词

8. simulate [5simjuleit] vt. 模拟

9. prosecutor [5prCsikju:tE] n. 检察官，公诉人，原告，起诉人

10. POW abbr. prisoner of war 战俘

11. drenalin [E5drenElin] n. [生化] 肾上腺素

12. cortisol [5kC:tisCl] n. [生化] 考的索

13. plummet [5plQmit] vi.（价格、水平等）骤然下跌，陡然变差

14. hormone [5hC:mEun] n. [生化] 激素，荷尔蒙

15. sequentially [si5kwinFEli] ad. 连续地，相继地，顺序地

16. garb [^B:b] n.（尤指特种）服装，装束

17. abysmal [E5bizmEl] a. [口] 极坏的，糟透的

18. cue [kju:] n. 暗示，信号

重压之后记忆力会丧失

人们一般都难以详细地回忆起自己遭受过的创伤。在模拟审讯中，多数受测军人在百般恐吓下，一两天后无法辨别出审讯他们的人到底是谁，很多人甚至将审讯者的性别搞错。这一发现使人们对受害者在心理重创下提供的证词的可靠性产生了强烈的怀疑。

多项研究已经对遭受创伤的记忆的准确性提出了质疑，但是这类研究常被认为是人为的，而且强度不够，不能模拟真实生活中的创伤。其他研究表明，紧张的亲身经历或许能产生摄影般的回忆，在司法案件中控方和陪审团往往持此观点。

然而，一些研究人员却认为这只是一个错觉。“有这些经历的人感觉他们永远也不会忘记所发生的事，”在埃姆斯的艾奥瓦州立大学研究证人证词的专家加里·韦尔斯说，“但是他们又把这个与感觉记得细节混淆起来。”

耶鲁大学的安迪·摩根和他的同事们通过对真实的强压处境的调查找到了证据。该研究的对象是在“生存学校”学习的500名士兵、水手和飞行员。这些学校是美国军方管理的模拟战俘营。美国军方也对此项研究提供了部分资助。试验对象平均年龄25岁，当时正在接受被俘后如何忍耐精神和肉体压力的训练。

受测者在经过了48个小时没吃没睡的折磨后，受到了高强度的审讯。他们当中的一半受到了肉体上的恐吓，以致出现了在高度生理压力下的种种征兆——心率过快，肾上腺素和考的索指标过高，同时伴随性激素水平的急剧下降。

受测者在从营中获释24小时后，被要求指认出审讯者。有些模拟审讯者站在15人一排的队伍中出现在受测者面前；有些审讯者本人未露面，其照片被混在其他照片中散乱地展现在受测者面前，还有的照片是一张张地展示给受测者。大多数的模拟审讯者穿着标准军服，而有些人穿着的则是与审讯时一样的服装。研究者采用1～10等级让受测者说出自己辨别审讯者时的自信度。

所有测试组的表现都糟糕得很。只有30％的人能够从站立的一排人当中找出正确的对象；34％的人可以从散乱展开的照片中做出正确的识别；而49％的人能从依次展示的照片中进行正确的判断(虽然有了衣着提示后的正确识别率上升到66％)。30人将性别搞错，而饱受肉体恐吓的受测者在识别审讯者时的表现最差。

加利福尼亚大学的心理学家伊丽莎白·洛夫特斯称这次研究是独特的，因为受测者所受到的压力非常大而且十分真实。“我想人们对此会加以留意，”她补充说。“该研究表明压力无助于记忆。”