演讲MP3+双语文稿:收入是如何影响儿童大脑发育的

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【演讲者及介绍】Kimberly Noble

Kimberly Noble，神经科学家、儿科医生，医学博士，研究社会经济不平等与儿童认知和大脑发育的关系。

【演讲主题】收入是如何影响儿童大脑发育的

How does income affect childhood brain development?

【中英文字幕】

翻译者Nancy Cai 校对者Yolanda Zhang

00:17

What I'm about to share with you are findings from a study of the brains of more than 1,000 children and adolescents. Now, these were children who were recruited from diverse homes around the United States, and this picture is an average of all of their brains. The front of this average brain is on your left and the back of this average brain is on your right. Now, one of the things we were very interested in was the surface area of the cerebral cortex, or the thin, wrinkly layer on the outer surface of the brain that does most of the cognitive heavy lifting. And that's because past work by other scientists has suggested that in many cases, a larger cortical surface area is often associated with higher intelligence. Now, in this study, we found one factor that was associated with the cortical surface area across nearly the entire surface of the brain. That factor was family income.

我要和你们分享 一项研究的成果， 这项研究是关于 1000个儿童和青少年的大脑。 这些参与研究的儿童 来自美国不同的家庭， 这张图片代表了 一个普通的大脑， 图片中大脑的前面 相当于你的大脑左侧， 后面相当于你的大脑右侧。 我们想要研究的事情之一 就是大脑皮层的表面积， 就是大脑外表面 薄薄的皱巴巴的一层， 它主要负责认知功能。 曾经有科学家的研究表明， 在许多情况下， 皮层的表面积越大， 代表着智商越高。 在这次的研究中，我们发现 有一个因素 和整个大脑表面的 皮层表面积有关联， 这个因素就是家庭收入。

01:16

Now, here, every point you see in color is a point where higher family income was associated with a larger cortical surface area in that spot. And there were some regions, shown here in yellow, where that association was particularly pronounced. And those are regions that we know support a certain set of cognitive skills: language skills like vocabulary and reading as well as the ability to avoid distraction and exert self-control. And that's important, because those are the very skills that children living in poverty are most likely to struggle with. In fact, a child living with poverty is likely to perform worse on tests of language and impulse control before they even turn two.

这上面，你看到的每一个 彩色的点都代表着 较高的家庭收入和 较大的表层面积是相关联的， 还有一些区域， 这些黄色的， 是这种关联 尤其明显的地方， 这些区域也是据我们所知 负责一些特定的认知功能的区域： 语言能力，词汇和阅读， 避免分心的能力， 还有进行自我约束的能力。 这个很重要， 因为这些能力 恰恰是贫困的孩子 最有可能欠缺的。 事实上，一个贫困的孩子， 在两岁之前，就有可能在 语言测试和控制冲动的测试中 显现出劣势。

02:02

Now, there are a few points I'd like to highlight about this study. Number one: this link between family income and children's brain structure was strongest at the lowest income levels. So that means that dollar for dollar, relatively small differences in family income were associated with proportionately greater differences in brain structure among the most disadvantaged families. And intuitively, that makes sense, right? An extra 20,000 dollars for a family earning, say, 150,000 dollars a year would certainly be nice, but probably not game-changing, whereas an extra 20,000 dollars for a family only earning 20,000 dollars a year would likely make a remarkable difference in their day-to-day lives.

关于这项研究，我想强调几点。 第一， 家庭收入和儿童 大脑结构之间的这种关联， 在最低收入水平人群中 是最明显的， 这意味着，在同一个标准下， 在最贫困的家庭中， 家庭收入相对较小的差异， 会带来大脑结构上较大的差异。 直觉上，这是有道理的，对吧？ 假设一个家庭年收入是15万美元， 再有额外的2万美元 当然会更好， 但是可能不影响大局。 但是假设一个家庭 年收入只有2万美元， 那么这额外的2万美元， 就很可能给他们的生活 带来显著的改变。

02:43

Now, the second point I'd like to highlight is that this link between family income and children's brain structure didn't depend on the children's age, it didn't depend on their sex and it didn't depend on their race or ethnicity.

我想强调的第二点， 就是家庭收入和儿童大脑结构 之间的这种关联， 并不取决于儿童的年龄， 性别， 种族，或是民族。

02:58

And the final point -- and this one's key -- there was tremendous variability from one child to the next, by which I mean there were plenty of children from higher-income homes with smaller brain surfaces and plenty of children from lower-income homes with larger brain surfaces. Here's an analogy. We all know that in childhood, boys tend to be taller than girls, but go into any elementary school classroom, and you'll find some girls who are taller than some boys. So while growing up in poverty is certainly a risk factor for a smaller brain surface, in no way can I know an individual child's family income and know with any accuracy what that particular child's brain would look like.

最后一点， 这点很重要， 每两个孩子之间都有 很大的个体差异， 也就是说， 很多高收入家庭的孩子， 也有较小的大脑表面积， 而很多较低收入家庭的孩子， 也有较大的大脑表面积。 打个比方， 我们都知道，在童年时期， 男孩一般比女孩高一些， 但是任何一个小学的班级里， 都有一些女孩比 一些男孩要高。 所以即使在贫困中成长 会有一定的风险 导致较小的大脑表面积， 我也并不能由 一个儿童的家庭收入， 准确地判断出 这个儿童的大脑长什么样子。

03:41

I want you to imagine, for a moment, two children. One is a young child born into poverty in America; the other is also an American child, but one who was born into more fortunate circumstances. Now, at birth, we find absolutely no differences in how their brains work. But by the time those two kids are ready to start kindergarten, we know that the child living in poverty is likely to have cognitive scores that are, on average, 60 percent lower than those of the other child. Later on, that child living in poverty will be five times more likely to drop out of high school, and if she does graduate high school, she'll be less likely to earn a college degree. By the time those two kids are 35 years old, if the first child spent her entire childhood living in poverty, she is up to 75 times more likely to be poor herself.

现在，想象有两个孩子， 一个孩子来自美国一个贫困家庭， 另外一个也是美国的孩子， 但他的家庭经济境况更好一些。 我们并没有发现 他们出生时的大脑有任何区别， 但当两个孩子到了 上幼儿园的年龄时， 我们知道那个贫困中长大的孩子， 平均会比另一个孩子的认知能力 低60%。 后来，那个贫困中长大的孩子， 从高中辍学的几率要高5倍， 假设她真的从高中毕业， 她获得大学学位的可能性也更低， 等两个孩子都35岁了， 那个在贫困中长大的孩子 依然贫困的概率要高出75倍。

04:38

But it doesn't have to be that way. As a neuroscientist, one of things I find most exciting about the human brain is that our experiences change our brains. Now, this concept, known as neuroplasticity, means that these differences in children's brain structure don't doom a child to a life of low achievement. The brain is not destiny. And if a child's brain can be changed, then anything is possible.

但是这种情况不是必然的， 作为一个神经科学家， 最令我兴奋的一个发现就是， 我们的经历会改变我们的大脑。 这个概念叫做神经可塑性， 它意味着，儿童 大脑结构的这些区别， 并不意味着一个孩子的 一生都会碌碌无为， 大脑并不决定命运。 而如果一个孩子的大脑能被改变， 任何事都是有可能的。

05:09

As a society, we spend billions of dollars each year, educating our children. So what can we tell schools, teachers and parents who want to help support kids from disadvantaged backgrounds to do their best in school and in life? Well, emerging science suggests that growing up in poverty is associated with a host of different experiences and that these experiences in turn may work together to help shape brain development and ultimately help kids learn. And so if this is right, it begs the question: Where along this pathway can we step in and provide help?

我们的社会每年都会花费 几十亿美元教育孩子， 学校，家长，和老师， 都想帮助弱势背景的孩子 在学校和生活中过得更好， 那么我们能告诉他们什么呢？ 最新的科学研究证明， 在贫困中长大代表着 很多不同的经历， 这些经历放在一起可能会 决定大脑的发育， 并最终帮助孩子学习。 如果真的是这样， 那么问题就来了： 我们能在这个过程中的 哪一步进行干预并提供帮助呢？

05:40

So let's consider first intervening at the level of learning itself -- most commonly through school-based initiatives. Now, should we be encouraging teachers to focus on the kinds of skills that disadvantaged kids are most likely to struggle with? Of course. The importance of high-quality education based in scientific evidence really can't be overstated. And there are a number of examples of excellent interventions targeting things like literacy or self-regulation that do in fact improve kids' cognitive development and their test scores. But as any intervention scientist doing this work would tell you, this work is challenging. It's hard to implement high-quality, evidence-based education. And it can be labor-intensive, it's sometimes costly. And in many cases, these disparities in child development emerge early -- well before the start of formal schooling -- sometimes when kids are just toddlers. And so I would argue: school is very important, but if we're focusing all of our policy efforts on formal schooling, we're probably starting too late.

我们首先考虑一下 在学习阶段干预， 这通常是通过 学校的活动实现的。 我们是否应该鼓励教师着重关注 贫困孩子最容易欠缺的技能呢？ 当然， 以科学证据为基础的高质量教育的 重要性不容小觑。 而且有很多干预成功的例子， 针对识字能力或自我约束， 成功地提高了孩子的 认知能力和测试分数。 但是所有从事这类研究的 科研者都会告诉你， 这项工作很有挑战性， 以科学证据为基础的 高质量教育很难实施， 有可能需要很大的人力投入， 有时费用高昂。 并且在许多情况下，这些儿童 发育的差距很早就显现了—— 早在他们开始正式的 学校教育之前， 有时甚至在幼儿时期。 所以我的观点是， 学校很重要， 但如果我们把所有的政策工作 都集中在正规学校教育上， 可能为时已晚了。

06:41

So what about taking a step back and focusing on trying to change children's experiences? What particular experiences are associated with growing up in poverty and might be able to be targeted to promote brain development and learning outcomes for kids? Of course, there are many, right? Nutrition, access to health care, exposure to second-hand smoke or lead, experience of stress or discrimination, to name a few. In my laboratory, we're particularly focused on a few types of experiences that we believe may be able to be targeted to promote children's brain development and ultimately improve their learning outcomes.

那么我们能不能退后一步， 着眼于改变儿童的成长经历呢？ 有哪些经历是 与在贫困中成长有关， 并且能被干预，以促进孩子的 大脑发育和学习效果呢？ 当然，有很多，对吧？ 营养，医疗资源， 二手烟污染或铅污染， 有压力的环境或者受到歧视， 等等。 在我的实验室里， 我们特别关注几种类型的经历， 我们认为这些经历 也许能够被干预 以促进儿童大脑发育， 并最终提升他们的学习成果。

07:19

As one example, take something I'll call the home language environment, by which I mean, we know that the number of words kids hear and the number of conversations they're engaged in every day can vary tremendously. By some estimates, kids from more advantaged backgrounds hear an average of 30 million more spoken words in the first few years of life compared to kids from less advantaged backgrounds. Now, in our work, we're finding that kids who experience more back-and-forth, responsive conversational turns tend to have a larger brain surface in parts of the brain that we know are responsible for language and reading skills. And in fact, the number of conversations they hear seems to matter a little bit more than the sheer number of words they hear. So one tantalizing possibility is that we should be teaching parents not just to talk a lot, but to actually have more conversations with their children. In this way, it's possible that we'll promote brain development and perhaps their kids' language and reading skills. And in fact, a number of scientists are testing that exciting possibility right now.

举一个例子， 有一样东西叫做家庭语言环境， 我们知道，孩子们 听到的词汇的数量 和他们每天 进行的对话数量 可能差异很大。 据估计， 来自更有优势背景的孩子们， 在前几年中， 与较弱势群体的孩子相比， 平均会多听到 3000万个口语词汇。 在我们的研究中发现， 进行更多双向对话的孩子， 大脑控制语言 和阅读能力的区域 有更大的表面积。 事实上，他们 听到的对话的数量， 比他们听到的词汇的数量， 似乎还更重要一些， 所以有一种令人欣喜的可能， 就是我们要教给父母们， 不仅要多说话， 而且要和他们的孩子 多进行对话。 这样有可能促进孩子的大脑发育， 并提高孩子的语言和阅读能力。 事实上，许多科学家现在正在测试 这个令人振奋的方法是否可行。

08:24

But of course, we all know that growing up in poverty is associated with lots of different experiences beyond just how many conversations kids are having. So how do we choose what else to focus on? The list can be overwhelming. There are a number of high-quality interventions that do try to change children's experience, many of which are quite effective. But again, just like school-based initiatives, this is hard work. It can be challenging, it can be labor-intensive, sometimes costly ... and on occasion, it can be somewhat patronizing for scientists to swoop in and tell a family what they need to change in order for their child to succeed.

但是，我们当然都知道， 在贫困中长大代表着 很多不同的经历， 不仅仅是孩子 进行了多少对话， 那么我们如何选择 别的关键点呢？ 各种因素可能太多了。 有很多更高质量的干预方法， 试图改变孩子的经历， 其中不乏相当有效的方法。 但是，就像学校主导的方式一样， 它并不容易， 有很多挑战， 需要人力投入， 有时费用高昂… 而且有时， 科学家们介入一个家庭， 告诉他们需要怎么改变 才能让他们的孩子成功， 会显得有些冒昧。

09:01

So I want to share an idea with you. What if we tried to help young children in poverty by simply giving their families more money?

所以我想和你们分享一个想法， 我们能不能仅仅通过 给贫困孩子的家庭捐款 来帮助他们呢？

09:14

I'm privileged to be working with a team of economists, social policy experts and neuroscientists in leading Baby's First Years, the first-ever randomized study to test whether poverty reduction causes changes in children's brain development.

我有幸和一些经济学家， 社会政策专家和神经科学家一起合作 共同负责“孩子的最初阶段”这个实验， 这是首个探究减轻贫困 能否改变孩子的大脑发育的随机实验。

09:29

Now, the ambition of the study is large, but the premise is actually quite simple. In May of 2018, we began recruiting 1,000 mothers living below the federal poverty line shortly after they gave birth in a number of American hospitals. Upon enrolling in our study, all mothers receive an unconditional monthly cash gift for the first 40 months of their children's lives, and they're free to use this money however they like. But importantly, mothers are being randomized, so some mothers are randomized to receive a nominal monthly cash gift and others are randomized to receive several hundred dollars each month, an amount that we believe is large enough to make a difference in their day-to-day lives, in most cases increasing their monthly income by 20 to 25 percent. So in this way, we're hoping to finally move past questions of how poverty is correlated with child development and actually be able to test whether reducing poverty causes changes in children's cognitive, emotional and brain development in the first three years of life -- the very time when we believe the developing brain may be most malleable to experience.

这项研究的目标很大， 但它的前提实际上很简单。 从2018年5月起， 我们开始在美国的各个医院 招募1000名刚刚生过孩子的 生活在国家贫困线以下的母亲。 在参与我们的实验后， 所有的妈妈在孩子 出生后的前40个月， 每个月都会收到一笔 无条件的现金礼物， 她们可以任意支配这笔钱。 但有一点很重要， 这些妈妈是随机挑选的， 有些妈妈每个月会 收到很少的一笔钱， 而其他的妈妈则被随机挑选为 每个月收到几百美金， 我们觉得这笔钱足够 给她们的日常生活带来改变， 在多数情况下，这会使她们的 月收入提高20%到25%。 通过这种方式， 我们希望能跳脱出 贫困是否和儿童发展相关联的问题， 而是真正探究在儿童三岁前， 减轻贫困能否引起 儿童的认知、情感 和大脑发育的改变， 我们认为，这三年 发育中的大脑 最容易被不同的经历塑造。

10:41

Now, we won't have definitive results from this study for several years, and if nothing else, 1,000 newborns and their moms will have a bit more cash each month that they tell us they very much need. But what if it turns out that a cost-effective way to help young children in poverty is to simply give their moms more money?

这项研究在几年之内 都不会有明确的结果， 但最起码 1000个新生儿和他们的 妈妈能在每个月 拿到一些他们 迫切需要的额外的钱。 但如果研究证明， 给妈妈们更多钱 是帮助在贫困中的孩子的 一种更加节省财力的方式呢？

11:03

If our hypotheses are borne out, it's our hope that results from this work will inform debates about social services that have the potential to effect millions of families with young children. Because while income may not be the only or even the most important factor in determining children's brain development, it may be one that, from a policy perspective, can be easily addressed.

如果我们的假设被证实， 那么我们希望这次实验的成果 能启发我们对社工服务的思考， 这将有可能改变 几百万个有孩子的家庭。 虽然收入并不是决定 儿童大脑发育的 唯一的或最重要的因素。 从政策角度来说， 它却有可能是 最容易被解决的。

11:26

Put simply, if we can show that reducing poverty changes how children's brains develop and that leads to meaningful policy changes, then a young child born into poverty today may have a much better shot at a brighter future.

简单来说， 如果我们能证明 减轻贫困能改变儿童大脑的发育， 从而引起政策上的 有意义的改变， 那么今天一个贫困家庭的孩子， 就有可能有一个 更加美好的未来。

11:43

Thank you.

谢谢。

11:44

(Applause)

（鼓掌）