本文选自《北外网院》的博客，点击查看博客原文

　　How poverty passes from generation to generation is now becoming clearer. The answer lies in the effect of stress on two particular parts of the brain。

　　贫困是怎样代代相传的问题现在已经越来越清楚了。答案就在于压力对大脑两个部分的影响。

　　Children of the poor underachieve in later life, and thus remain poor themselves, is one of the enduring problems of society。

　　贫困的儿童在以后的生活里表现不佳，之后便一直贫困，这是一个持续的社会问题。

　　The crucial breakthrough was made three years ago, when Martha Farah of the University of Pennsylvania showed that the working memories of children who have been raised in poverty have smaller capacities than those of middle-class children。

　　三年前，这个问题取得到了突破性的进展。宾夕法尼亚大学的马萨·法哈表明，贫困儿童的工作记忆体相比出生中产阶级的儿童要小。

　　Working memory is the ability to hold bits of information in the brain for current use--the digits of a phone number, for example. It is crucial for comprehending languages, for reading and for solving problems. Entry into the working memory is also a prerequisite for something to be learnt permanently as part of declarative memory--the stuff a person knows explicitly, like the dates of famous battles, rather than what he knows implicitly, like how to ride a bicycle。

　　工作记忆是能够在大脑中把握信息而用于现实的能力，就像从头脑中调出数字打电话一样。它对语言的理解，阅读和解决问题都至关重要。进入工作记忆也是一个先决条件，它是一种将明确认知变为大脑永久记忆部分的能力，如毫不含糊地记住著名战役的日期以及如何骑自行车等。

　　Since Dr Farah's discovery, Gary Evans and Michelle Schamberg of Cornell University have studied the phenomenon in more detail. As they report in this week's Proceedings of the National Academy of Sciences, they have found that the reduced capacity of the memories of the poor is almost certainly the result of stress affecting the way that childish brains develop。

　　由于法哈博士的这一发现，康奈尔大学的加里·埃文斯和米歇尔·尚博格对此进行了更详细的研究。正如他们在本周美国国家科学院发布的报告，他们发现，由于贫困而致的记忆能力下降几乎可以肯定是影响儿童大脑发育的原因。

　　Dr Evans's and Dr Schamberg's volunteers were 195 participants in a long-term sociological and medical study that Dr Evans is carrying out in New York state. At the time, the participants were 17 years old. All are white, and the numbers of men and women are about equal。

　　埃文斯博士和尚博格博士对195名志愿者进行了长期的社会跟踪和医学研究。埃文斯博士负责在纽约州开展调查，参与者都是17岁，全部为白种人，男性和女性的人数大约相等。

　　To measure the amount of stress an individual had suffered over the course of his life, the two researchers used an index known as allostatic load. This is a combination of the values of six variables: diastolic and systolic blood pressure; the concentrations of three stress-related hormones; and the body-mass index, a measure of obesity. For all six, a higher value indicates a more stressful life; and for all six, the values were higher, on average, in poor children than in those who were middle class。

　　这两位研究人员使用了称为适应负荷的方法来衡量一个人在遭受压力过程中显出的各项指数。它由六个变量构成：舒张压和收缩压；三种与荷尔蒙有关的浓度，体质指数，肥瘦程度。数值越高显示承受越多的生活压力。大体来说，贫困儿童的各项指数要高于那些中产阶级儿童。

　　Moreover, because Dr Evans's wider study had followed the participants from birth, the two researchers were able to estimate what proportion of each child's life had been spent in poverty. That more precise figure, too, was correlated with the allostatic load。

　　此外，由于埃文斯博士对参与者从出生开始进行了更广泛地跟踪研究，使得两个研究人员能够依据每个儿童在贫困中度过的时间长短进行衡量，从而更准确地描绘了以此相关的负荷状况。

　　The capacity of a 17-year-old's working memory was also correlated with allostatic load. Those who had spent their whole lives in poverty could hold an average of 8.5 items in their memory at any time. Those brought up in a middle-class family could manage 9.4, and those whose economic and social experiences had been mixed were in the middle。

　　一个17岁大的工作记忆状况同样也与负荷相关。那些一直生活在贫困中的人，记忆体的容量一直在8.5 左右，而生活在中产家庭的则可以达到9.4。中间缺失的部分，就是经济的和社会的混合经验。