Poor child, brain development may fall behind? Brain, child-IT information

Children who grow up in poverty, their brains would be portrayed like that? Neurobiologist working on related research.

Children living in poverty of brain and common difference is the most obvious parts of the hippocampus and the prefrontal. 3D perspective view, blue for the hippocampus, red and yellow zones for frontal lobe.

Cognitive neuroscientist Masha·falahe (Martha Farah) is interested in the early development of the brain, is not due to the birth of his daughter, but because she hired a nanny for her daughter. Most of these nannies are mothers, most of them single, in order to prevent to make ends meet, receiving government subsidies but also as domestic servants. Farah feel getting into their lives: she ate with the Babysitting, tutoring their children would also lend money to their relatives. But as time went by, Farah found their children and their children are on a different track, for which she felt powerless.

"When I first started, the kids and my daughter show the same potential: love their mothers, learning writing, playing games, asking questions," Farah, Director of the Center for Neuroscience and sociology at the University of Pennsylvania said, "but I do not know why they gradually embarked on a different path: a decline in academic performance, and less choice. ”

These observations troubled Farah, so she set out to study this phenomenon. A lot of social science research shows that child's socio-economic status (socioeconomic status,SES) may affect their health, academic performance, and mental health, but no one has yet to prove the child's socio-economic situation and there is a clear link between brain development. Farah began to wonder, poverty limits the opportunities of children out of poverty at the same time, will also affect brain development, so as to change their whole life?

Farah produced the idea is before 15, starting from that, sociologists, psychologists and economists to incorporate brain research into social sciences the idea produces a high degree of enthusiasm. But the irony is, Farah studied neuroscience colleagues are not interested in her new-found problems and project fund review also believes she is to equate poverty with a brain disease, poor children as "sick", such research is irresponsible.

In the Farah team published the first paper on the topic after 10 years, neuroscientists and Cognitive psychologists have begun to enter the relevant studies. 6 study found the family's socio-economic status and child childhood hippocampus volume is related to a large number of studies have shown that poor children also have different brain structures in other parts, and their brain development trajectory will be different . Recent studies have begun to look for these different links with the real-life performance, such as achievement test scores. Even so, these early results exactly what it means to be a problem, and most people agreed that this area has just begun.

The broader significance of the study can't help but worry. If you grow up poor childhood brain will leave a mark, then this can be reversed, in extent reversible? Leads to the root cause of this is what? Critics have also questioned if we all know social projects to help poor families improve the lives of poor families, then from the perspective of neuroscience, you sure it functioned as really necessary?

"Our study does have some discovery. I do think poverty can affect a child's brain development, "a saisi·bolake, a psychology professor at the University of Wisconsin (Seth Pollak) said," but we have to be very careful, because this area is easy to involve some controversial policy implications . ”

Visible difference

In developed countries, the United States children's poverty level is the highest, a total of 15 million children, out of every 5 children there will be a live below the Government's poverty line (family of four earning less than $24250 can be defined as poverty). Farah said that economic constraints not just lack of money simply for poor children, the economic constraints on the child's nutrition, prenatal care level, family, neighbors, and other environmental stress factors affecting. One of the worst affected is the achievement gap: overall, compared with the children of middle-class and affluent families, children from poor families even worse score lower on standardized tests, and the number entering University is also relatively small. Moreover, this gap continues to grow [4].

" After the introduction of neuroscience research methods, you will find many new perspective can explain the effects of poverty on children . "Farah said. For example, compared with the rich kids of the same age, poor children have less memory, neuroscience explanation is that this could grow up in poor families will take more pressure. The hippocampal region of the brain has a strange design: it is not only the consolidation of key structures of the memory, happened to be full of stress-related Hormone receptors.

Early study results reveal some interesting contradictions. Farah and her colleagues found that socio-economic status is not all cognitive functions of the brain, but concentrated in the considered functions associated with specific brain circuits, such as language, memory capacity, and the ability to regulate thought and emotion. Her collaborators included then her student jinbaili·nuobeier (Kimberly Noble), now is the Colombia Institute of education, University Professor of neuroscience and education, and neonatology at the University of Pennsylvania expert halemu·hete (Hallam Hurt).

Early language expert at the University of Washington patelixia·KUER (Patricia Kuhl) function magnetic resonance imaging (MRI) studies have shown that low levels of socio-economic conditions of 5-year-olds, their reading ability as reflected in important areas of the cerebral cortex showed a relatively low level of specialization [6]. Hailun·neiweier University of Oregon (Helen Neville) 's team measured brain responses were measured of event-related potential (event-related potentials), results show that the 3~8sui children of low socio-economic status for a specific sound input are relatively slow to react.

In the past few years, most of the focus was centered on structural differences in the brain, including early on the amygdala in fear and other emotions found in, as well as the role of prefrontal cortex in decision making, and control of related research. These findings are the most consistent part of, is the child of lower socio-economic status of the hippocampus generally relatively small.

First reports on the size of the hippocampus from Pollack's laboratory. The study is based on brain magnetic resonance imaging (MRI) data, as well as from the United States national development 317 families of 4~18sui children of a database extract population data. Two years later, the University of Washington Qiong·Lubi (Joan Luby) as well as her colleagues for 145 poor children starting from pre-school 6~12sui implemented a continuous observation, found that compared with non-poor children, children living in poverty significantly smaller hippocampus of the brain.

RS team marks the beginning of the research was not intended to explore how poverty affects and changes the brain, they track to explain depression and other mental illness occurs in the study of variability . But in the statistical data, they found very informative, RS said. "It's not our intention, but the data drives what we pursued. "The researchers asked children and their parents about the pressure thing, in order to assess the child's mother told them to encourage and support role. Through statistical analysis, the researchers found, mothers caring for children or larger family life under pressure, impact of poverty on their brains become more evident .

In terms of brain structure and socio-economic ties the largest study in March 2015. Nobel, who came from a national database of over 1000 3~20sui of individual brain magnetic resonance imaging (MRI) scan results are analyzed, they [10] finds from affected by level of education (this is a commonly used alternative indicators of socio-economic conditions) families of the hippocampus of low capacity is relatively small. More importantly, they found that these children also varied in the surface region of the cerebral cortex. In childhood and adolescence, started building the myelin in the brain, neurons gradually formed the right connections, thickness of the cerebral cortex in the process will be reduced, increased surface area, previous research has shown that these results and intelligence. In Nobel's study, on average, with the increasing length of parent to child education, child and this will increase the surface area of the cortex of the brain, particularly in language learning, reading and self-adjustment ability of cortical areas. These effects are also related to and revenue, particularly in low-income families.

According to Hanson, who researches, with the increase of age, socio-economic situation of the family is positively associated with gray matter volume.

Results of the complex

Farah said, observable changes in brain structure, has the advantage that it does not like the image, you need to know in advance which cognitive functions are affected. However, in the study of structure, how to interpret structural changes difficult. Although differences in the hippocampus in the brain of the child has on a number of studies is confirmed by exact, but in adults do not get consistent results, does this mean that the children's brain in adulthood and to catch up? But researchers for the uncertain time difference. Pollack and her colleagues compared the low socio-economic status (low-SES) and middle socio-economic status (mid-SES) family children brain growth rates, they found poor children brain growth rate started to fall from the toddlers, wait until 4 years old already has a lot of differences. In a longitudinal comparison of very poor children, Farah and his colleagues found that in just a few months after birth, brain cortex gray matter volume has shown a different, this may mean some poverty-related changes in the brain before birth, have been produced.

Development of the human brain is very complex, and that in this process there are interactions between genes and environment, so how to make sense of these structures is still a very difficult issues . Pollack and others emphasized that these results were obtained by average, thus removing many errors caused by individual differences. We cannot only look at a particular low socio-economic status (low-SES) family of children, and then only the data collected on her brain. To understand long-term environmental effects, and to find out if child is developing in the brain (or how) compensation impact of poverty, need more experiments to reflect the child's reaction in the face of poverty and where individual differences, Professor of psychology and Neuroscience at the University of California, Berkeley xierweiya·bangqi (Silvia Bunge) said. Such reactions include cultural or individual traits under pressure and have a protective reaction, which produces what psychologists call the "recovery (resilience)".

This area has gradually begun to explore more complex associations. In 2015, two explicitly underprivileged children in the study, published in brain structure changes and their associated together. Through the small study of 58 youth, MIT yuehan·jiabuliaili (John Gabrieli) team will for the first time of the cerebral cortex volume touch with math and reading scores up. This work was published in April last year. Pollack and his colleagues analyzed in an article published in July last year 398 4~22sui children and adolescents an MRI scan results, taking into account other influencing factors, after adjusting the data, found that differences in brain structure are underprivileged children and middle economic level or affluent children exists 20% causes of the achievement gap . Measurements and the results of the brain associated with importance, our brain structure can be measured as a marker means or alternative indicators to help us identify the effectiveness of community interventions for poor families, Gabrieli said.

However, some people do not need to use these tags to describe poverty or for the solution of poverty problems. "In-depth research on how poverty affects the neurological development is an interesting question," sangdela·weikesiman, a Professor of psychology at Northwestern University (Sandra Waxman) said, "but even if the poor child's brain capacity and structure identical to intermediate levels of economic families, we still need interventions to help poor families and children. "Waxman explained that if low-income pregnant women's access to education has a positive effect on their children, then it would not need additional determination of the child's brain nerves. The Institute's message is also problematic: differences in biology to describe the problem may make policymakers mistakenly believe that the effect is permanent. But in fact the brain is extremely malleable, especially children. "We need special care on this issue," bunch said, "does not deepen or strengthen any negative impressions about the poor. ”

But supporters of this study, it is because of the biology of trust, they should be introduced into the political field of neuroscience. "Discussing social justice do not always attract attention," Pollack said, "but if you say, ' look, this can affect a child's brain ', people's attention will quickly move on to the subject. "He insisted that the change is effective. "Once you know the research in this area, you're going to think, ' my God, this is a bio-medical issues. ' Really will change on the biology of poverty and hinders a child's development, and brought a high price. ”

Looking for a causal relationship

How poverty affects brain structure? Because before birth and early life stress? Because do you feel slim chance of getting rich? Because of parental pressure and did not give them sufficient care? Because of toxic substances such as lead or pesticide? Or because of malnutrition? Though scientists have no way to test pay on rats will impact or monkey, but using animal model studies have found many poverty-related environmental factors can affect the brain. Rupees and other scientists ' research shows that stress and love-poverty needed to produce the effect of media – has a strong role in animal models.

To some extent, this is a problem without solution, Pollack said. He explained, "the human brain has a strong ability to recover and we can, I think it can withstand a lot of pressure and will not affect the normal development of the brain. Long interaction of many factors, however, may affect a child's brain, which belongs to such a situation. ”

Researcher aims to clarify mechanisms, or for further confirmation of the links between poverty and brain development, now doing those observational studies alone are not enough. At the University of California, Irvine Professor of education geleige·dengken (Greg Duncan) said, on the issue of causation can only be solved through the experimental intervention. Income Dynamics research program as a Government researcher, Duncan in the first 25 years of career, the tens of thousands of families are economic levels, health status, and tracked many social factors. The project was launched in 1968 and is still running today, to assess the Lyndon Johnson presidency, an anti-poverty effect of [15]. This project later Duncan and developmental psychologists and neuroscientists to cooperate like Nobel, studying the effects of family poverty on the behavior and the brain.

In the past few years, Duncan and the Nobel Prize has been as a randomized controlled trial of funds and start running, the experiment will be able to clearly answer the income levels are associated with cognitive ability and brain development in children. Researchers experiment is envisaged, to 1000 in the United States for babies born in four different locations of the debit card for low-income mothers for a period of three years. Those randomly assigned to the experimental group of debit card every month in $333, some studies have shown that this amount can affect the older child's cognitive development [16], and the level of benefits is also provided with certain items, such as the federal income tax imposed on the working poor tax credit projects (the Federal Earned Income Tax Credit). Control group of Cary only monthly token in $20. These families can use this money in any form they wish. To the child's second birthday, researchers will have on their family atmosphere, literary activities, family stress and parental mental health assessments. When three years old, children will receive a comprehensive set of cognitive tests.

In an ongoing experiment contains 30 New York City family, the team tested monthly $100 and $20, two smaller amounts will produce different effects. "Some people think the salary is very high in New York, the small amount paid nothing for them," Duncan said, "so I want to know how important is $ 20 for these families is not realistic. ”

Many psychologists question directly without using the restricted cash on cognitive ability is really helpful. "According to previous studies, researchers found that testing would family is not always the way we want to spend the cash," bunch said, "instead of directly giving them money, I prefer projects that help people to stand on their own feet. ”

But the Nobel believes that these families can take they think is the right way to use this money, this poverty is used to study scientific and feasible. If poverty is the main cause of impaired cognitive abilities, then cash is likely to be the most effective solution. "The impact of poverty on family mechanism is likely to be different," Nobel said, "in a poor economic situation, they can buy more books for children, whether shorter working hours and more with the children, or could reduce the pressure of paying rent, which is different in different families. ”

穷人家的孩子，大脑发育会落后？ - 大脑,孩子 - IT资讯

在贫穷中长大的孩子，他们的大脑会被塑造成什么样子呢？神经生物学家正在进行相关研究。

生活贫困的孩子的大脑与普通人差别最明显的部位是海马体以及大脑前额叶。3D透视图中，蓝色区域为海马体，红色和黄色区域为大脑前额叶。

认知神经生物学家玛莎·法拉赫（Martha Farah）之所以对大脑的早期发育产生兴趣，并非源于女儿的出生，而是因为她为女儿雇佣的保姆。这些保姆大部分也是母亲，她们大多单身，为了防止入不敷出，在接受政府补贴的同时还要做家庭佣人。法拉赫感觉自己渐渐融入了她们的生活：她与保姆一起吃饭、辅导她们的孩子，也会借钱给她们的亲戚。但是随着时间的流逝，法拉赫发现自己的孩子和她们的孩子渐渐还是走上了不同的生活轨道，对此她感到无能为力。

“刚开始的时候，这些孩子和我的女儿表现出相同的潜力：爱他们的母亲、学习写字、玩游戏、问问题，”宾夕法尼亚大学神经学和社会学中心的主任法拉赫说，“但是不知为何他们渐渐走上了不同的生活轨迹：学业成绩下降，选择权也越来越少。”

这些观察结果困扰着法拉赫，所以她开始着手研究这个现象。大量社会科学研究表明，孩子的社会经济状况（socioeconomic status，SES）可能影响着他们一生的健康状况、学业成绩以及心理健康，但是还没有人证明孩子的社会经济状况和大脑发育之间有明确的联系。法拉赫则开始琢磨，贫穷在限制了孩子脱离贫穷的机会的同时，会不会还影响了大脑发育，从而改变了他们的整个人生？

法拉赫产生这一想法是在15年之前，从那开始，社会学家、教育心理学家以及经济学家对将大脑的研究纳入社会科学领域这个想法产生了很高的热情。然而讽刺的是，法拉赫研究的神经科学的同事们都对她新发现的研究问题不感兴趣，而且项目基金评审还认为她这是将贫穷等同于一种大脑疾病，将贫困的孩子视为“有病”，这样的研究很不负责任。

在法拉赫团队发表第一篇关于这个话题的论文后的10年里，神经科学家和认知生理学家也开始进入相关研究。有6项研究发现家庭的社会经济状况和孩子童年时期的海马体容量有关；大量的研究指出贫穷的孩子大脑结构在其他部位也有差别，而且他们的大脑发育轨迹也会不同。近期，有研究开始寻找这些不同点与真实生活中的表现的联系，比如学业测试的成绩。即使这样，这些早期的研究结果到底意味着什么始终是个问题，而且大部分人一致认为这个领域才刚刚起步。

这项研究更广泛的意义不免让人担忧。如果在贫困的环境中成长会给童年时期的大脑留下印记，那么这是可以逆转的吗，在多大程度上可逆？导致这个结果的根本原因是什么？批评者也提出疑问，如果大家都知道帮助贫困家庭的社会项目能够改善贫困家庭的生活，再从神经科学的角度确认它起了作用真的有必要吗？

“我们的研究的确有了些发现。我认为贫穷确实会影响孩子的大脑发育，”威斯康星大学的一位心理学教授赛斯·波拉克（Seth Pollak）说，“不过在这方面我们必须要非常小心，因为这个领域很容易牵涉到一些争议性的政策含义。”

清晰可见的差别

在发达国家中，美国儿童的贫困水平相对来说是最高的，总共1500万个孩子，每5个孩子中就会有一个生活在政府制定的贫困线以下（四口之家的年收入低于$24250就会被定为贫困）。法拉赫说，经济的拮据不仅仅是缺钱这么简单，对于贫困儿童来说，经济的拮据会对孩子的营养、产前护理、家庭教育水平、邻居以及其他环境压力因素造成影响。最严重的影响之一就是成绩差距：总体来讲，与中产阶级以及富裕家庭的孩子相比，贫困家庭的孩子成绩更差，在标准化测试中得分较低，而且进入大学的人数也相对较少。而且，这种差距还在持续增长[4]。

“引入神经科学的研究方法以后，你会发现许多新的角度可以解释贫困对孩子的影响。”法拉赫说。比如，和富裕的同龄孩子相比，贫困孩子的记忆力要差一些，神经科学的解释是，这可能因为在贫困家庭中成长会承担更多生活压力。大脑的海马区有个奇怪的设计：它既是巩固记忆的关键结构，又恰巧布满了压力相关的激素受体。

早期的研究结果揭示了一些有趣的矛盾。法拉赫和同事发现社会经济状况并非影响大脑所有的认知功能，而是集中在被认为与特定大脑回路相关的功能上：比如语言、记忆容量以及调节思维和情感的能力。她的合作者包括当时还是她学生的金柏丽·诺贝尔（Kimberly Noble），现在是哥伦比亚大学教育学院神经科学与教育方向的教授，还有宾夕法尼亚大学的新生儿学专家哈勒姆·赫特（Hallam Hurt）。

华盛顿大学的早期语言专家帕特里夏·库尔（Patricia Kuhl）的功能核磁共振（MRI）研究显示，社会经济状况水平较低的5岁孩子，其大脑皮质区中反映阅读能力的重要区域表现出了较低水平的特化[6]。俄勒冈大学海伦·内维尔（Helen Neville）的团队测量了衡量大脑反应情况的事件相关电势（event-related potentials），结果表明社会经济状况较低的3~8岁孩子对特定的声音输入反应相对较慢。

在过去的几年里，大多数的工作重点都集中在大脑结构差异上，包括早期关于杏仁核在处理恐惧和其他情感中的相关发现，以及前额皮质在决策制定和自控能力中作用的相关研究。在这些发现中最一致的部分，是社会经济状况较低的孩子的海马体普遍相对较小。

第一个关于海马体大小的研究报道来自波拉克的实验室。该研究基于大脑核磁共振（MRI）数据以及从美国国家发展数据库中提取的317个4~18岁孩子的家庭人口数据。两年之后，华盛顿大学的琼·卢比（Joan Luby）以及她的同事对145个6~12岁的贫困儿童从入学前开始实施了持续的观察，发现和非贫困儿童相比，贫困儿童大脑的海马体明显要小很多。

卢比的团队刚开始的研究目的并不是探索贫穷如何影响并改变大脑，他们的跟踪研究只是为了解释在抑郁症和其他精神疾病的研究中出现的多变性。但在统计数据时，他们发现信息量很大，卢比说。“这虽然不是我们本意，但是这些数据推动着我们继续研究下去。”研究人员还问了孩子以及他们的父母一些有关生活压力的事情，以便评估孩子的母亲对他们起到了多少鼓励和支持作用。经过统计学分析，研究人员发现，对于缺乏母亲关爱或者承受的家庭生活压力较大的孩子，贫困对他们大脑的影响会更明显。

在大脑结构与社会经济学联系方面规模最大的研究来自2015年3月份。诺贝尔等人对来自国家数据库的超过1000个3~20岁的个体的大脑核磁共振（MRI）扫描结果进行了分析,他们[10]发现来自受教育水平（这是社会经济状况常用替代指标）较低的家庭的孩子的海马体容量相对较小。更重要的是，他们发现这些孩子在大脑皮质的表面区域也有差异。在童年时期以及青春期，大脑中的髓磷脂开始生成，神经元逐渐形成正确的连接，这个过程中大脑皮质厚度会降低，表面积增加，此前的研究已经显示这些结果和智力有关。在诺贝尔的研究中，平均来看，随着父母对孩子教育年限的增加，孩子的大脑皮质区的表面积也会相应的增加，特别是在与语言学习、阅读以及自我调节能力相关的皮质区域。这些影响也和收入有关，特别是在那些低收入的家庭中。

根据汉森等人的研究工作，随着年龄的增长，家庭的社会经济状况与大脑灰质的容量成正相关。

复杂的结果

法拉赫称，研究大脑结构中可观测的变化，有一个好处就是它不像功能成像那样，需要提前知道哪些认知功能会被影响。但是，在结构研究中，如何解释结构变化也是一个难题。虽然在儿童大脑中海马体的差异已经在不同的研究中被确切证实了，但是在成人中却得不到一致的结果，难道这意味着这些孩子的大脑在成人时期又追上来了？而且研究人员对于这些差异出现的时间也不确定。波拉克和她的同事对比了低社会经济状况（low-SES）和中等社会经济状况（mid-SES）家庭孩子的大脑生长速率，她们发现贫困孩子大脑的生长速率从学步时期就开始下降，等到4岁的时候就已经有很大的差异了。在一项对极贫困的儿童的纵向比较中，法拉赫和同事发现在刚出生后的几个月，大脑皮质区灰质的容量就已经表现出了不同，这可能意味着一些与贫困有关的大脑变化在出生前就已经产生了。

人类大脑的发育是非常复杂的，而且在这个过程中还有基因和环境之间的相互作用，所以怎样去理解这些结构的改变依然是个很棘手的问题。波拉克以及其他一些人强调这些结果是通过人口平均得到的，因而消除了许多由个体差异导致的误差。我们不能只看某一个特定的低社会经济状况（low-SES）家庭的孩子，然后只收集关于她大脑的数据。要理解长期的环境效应，并弄清孩子发育中的大脑是否（或者如何）补偿贫困带来的影响，还需要更多实验以体现孩子在面对贫困时的反应有何个体差异，加州大学伯克利分校的心理学及神经科学教授西尔维娅·邦奇（Silvia Bunge）说。这类反应包括了文化或个体特质面对压力而产生的保护性反应，正是它们产生了心理学家所说的“恢复力（resilience）”。

这个领域已经逐渐开始探索更复杂的关联。2015年，两项发表的研究明确将贫困家庭孩子的大脑结构变化和他们的成绩联系在了一起。通过对58个青少年的小规模研究，麻省理工大学约翰·加布里埃利（John Gabrieli）的团队首次将大脑皮层的容量和数学以及阅读课成绩联系了起来。这项工作已于去年4月份发表。波拉克和同事在去年7月份发表的文章中分析了398个4~22岁儿童以及青少年的核磁共振扫描结果，在考虑了其他影响因素、对数据进行调整之后，发现大脑结构的差别是造成贫困家庭孩子和中等经济水平或者富裕家庭孩子存在20%成绩差距的原因。将大脑测量与其结果联系在一起具有重要意义，从此我们就能够将大脑结构测量作为一种生物标记手段或者替代指标，用以帮助我们识别针对贫困家庭的社会干预手段是否有效，加布里埃利说。

但是，有些人却认为并不需要用这些标记来描述贫困问题或者针对贫困问题的解决方法。“深入研究贫困如何影响神经发育是一个很有意思的问题，”西北大学的心理学教授桑德拉·韦克斯曼（Sandra Waxman）说，“但是即使贫困儿童的大脑容量和结构与中等经济水平家庭孩子的一模一样，我们依然需要使用干预手段来帮助贫困家庭和儿童。”韦克斯曼解释说，如果让怀孕的低收入妇女接受教育对她们的孩子有积极的影响，那么这样做并不需要额外对孩子的大脑做神经方面的测定。该研究所传递出的信息也存在问题：用生物学方面的差别来描述这个问题可能会让决策者错误地认为这种影响是永久的。而实际上大脑是极具可塑性的，尤其是儿童。“对于这个问题我们需要特别谨慎，”邦奇说，“不能加深或者强化任何有关穷人的负面印象。”

但是这项研究的支持者表示，正是因为人们对生物学如此信任，神经科学才更应该被引入政治领域。“讨论社会公平并不总能引起人们的注意，”波拉克说，“但是如果你说‘看，这能影响孩子的大脑’，人们的关注点就会迅速转移到这个话题上。”他坚持认为这种改变是有效的。“一旦了解了这方面的研究，你就会想‘我的天呐，这是个生物医学问题。’贫穷真的会在生物学上改变并阻碍孩子的发展，并给社会带来了高昂的代价。”

寻找因果关系

贫穷到底是怎样影响大脑结构的呢？是因为出生前和幼年时期的生活压力吗？是因为感觉变得富有的机会渺茫吗？是因为父母压力大而没有给与孩子足够的关爱吗？是因为铅或者农药等有毒物质吗？亦或是因为营养不良？虽然科学家没有办法测试薪水对大鼠或者猴子会有什么影响，但是利用动物模型研究发现许多与贫困相关的环境因素可以影响大脑。卢比以及其他科学家的研究表明，压力和母爱——贫穷产生影响所需的介质——在动物模型中有很强的作用。

在一定程度上这是个无解的问题，波拉克说。他解释道，“人类的大脑有极强的恢复能力和多能性，我认为大脑可以承受许多压力而不会影响正常发育。然而诸多因素长时间的共同作用可能会影响孩子的大脑，而贫穷正属于这样的情况。”

无论研究人员的目的是理清作用机制，还是为了进一步证实贫困与大脑发育之间的联系，仅凭现在所做的那些观测性研究是不够的。加州大学欧文分校教育学教授格雷格·邓肯（Greg Duncan）说，关于因果关系的问题只能通过实验干预来解决。作为政府收入动态研究项目组的研究员，邓肯在前25年的职业生涯中，对成千上万的家庭进行了经济水平、健康状况以及许多社会因素的跟踪调查。该项目于1968年启动，现今仍然在运行，目的是评估林登·约翰逊总统任内开展的一项抗贫活动的效果[15]。这个项目促使邓肯后来与发育心理学家，以及像诺贝尔这样的神经科学家进行合作，研究家庭贫困对行为和大脑的影响。

在过去的几年中，邓肯和诺贝尔一直在为一项随机对照试验的经费和启动奔走，这项实验将能明确地回答收入水平是否与孩子的认知能力和大脑发育有关。研究人员设想的实验方式是，给1000个在美国四个不同地点出生的婴儿的低收入母亲发放为期三年的借记卡。这些随机分配给实验组的借记卡每月会存入$333，一些研究表明这个数额能够影响较年长孩子的认知发展[16]，并且也同某些项目提供的福利水平相当，比如对有工作的穷人实行的联邦所得税抵免项目（the Federal Earned Income Tax Credit）。对照组的卡里则只会每月象征性的存入$20。这些家庭可以以他们希望的任何形式使用这些钱。到孩子的第二个生日时，研究人员将对他们的家庭氛围、文学活动、家庭压力以及家长的心理健康进行评估。到三岁的时候，孩子们将会收到一套全面的认知测试题。

在一项正在进行的包含30个纽约市家庭的预实验中，团队测试了每月发$100和$20这两个较小的数额会产生怎样不同的影响。“有些人认为在纽约薪水是相当高的，这些小金额报酬对他们来说不算什么，”邓肯说，“所以想要知道20美元对这些家庭有多重要也不太现实。”

许多心理学家怀疑直接发没有使用限制的现金对研究认知能力是否真的有帮助。“根据先前的研究，研究人员发现测试家庭并不会总是按照我们希望的方式消费这些现金，”邦奇说，“与其直接给他们钱，我更看好那些帮助人们自食其力的项目。”

但是诺贝尔认为，这些家庭完全可以以他们认为正确的方式使用这些钱，用这种做法研究贫穷是科学可行的。如果贫穷是认知能力受损的主要原因，那么提供现金就可能是最有效的解决方法。“贫穷对不同家庭的影响机制极有可能是不同的，”诺贝尔说，“在贫穷的经济状况下，父母能否为孩子买更多的书，能否缩短工作时间从而更多的陪陪孩子，又或者是能否降低支付租金的压力，这些因素在不同家庭是不同的。”