演講MP3+雙語文稿:收入是如何影響兒童大腦發(fā)育的

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【演講者及介紹】Kimberly Noble

Kimberly Noble，神經(jīng)科學家、兒科醫(yī)生，醫(yī)學博士，研究社會經(jīng)濟不平等與兒童認知和大腦發(fā)育的關系。

【演講主題】收入是如何影響兒童大腦發(fā)育的

How does income affect childhood brain development?

【中英文字幕】

翻譯者Nancy Cai 校對者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.

我要和你們分享 一項研究的成果， 這項研究是關于 1000個兒童和青少年的大腦。 這些參與研究的兒童 來自美國不同的家庭， 這張圖片代表了 一個普通的大腦， 圖片中大腦的前面 相當于你的大腦左側， 后面相當于你的大腦右側。 我們想要研究的事情之一 就是大腦皮層的表面積， 就是大腦外表面 薄薄的皺巴巴的一層， 它主要負責認知功能。 曾經(jīng)有科學家的研究表明， 在許多情況下， 皮層的表面積越大， 代表著智商越高。 在這次的研究中，我們發(fā)現(xiàn) 有一個因素 和整個大腦表面的 皮層表面積有關聯(lián)， 這個因素就是家庭收入。

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.

這上面，你看到的每一個 彩色的點都代表著 較高的家庭收入和 較大的表層面積是相關聯(lián)的， 還有一些區(qū)域， 這些黃色的， 是這種關聯(lián) 尤其明顯的地方， 這些區(qū)域也是據(jù)我們所知 負責一些特定的認知功能的區(qū)域： 語言能力，詞匯和閱讀， 避免分心的能力， 還有進行自我約束的能力。 這個很重要， 因為這些能力 恰恰是貧困的孩子 最有可能欠缺的。 事實上，一個貧困的孩子， 在兩歲之前，就有可能在 語言測試和控制沖動的測試中 顯現(xiàn)出劣勢。

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.

關于這項研究，我想強調幾點。 第一， 家庭收入和兒童 大腦結構之間的這種關聯(lián)， 在最低收入水平人群中 是最明顯的， 這意味著，在同一個標準下， 在最貧困的家庭中， 家庭收入相對較小的差異， 會帶來大腦結構上較大的差異。 直覺上，這是有道理的，對吧？ 假設一個家庭年收入是15萬美元， 再有額外的2萬美元 當然會更好， 但是可能不影響大局。 但是假設一個家庭 年收入只有2萬美元， 那么這額外的2萬美元， 就很可能給他們的生活 帶來顯著的改變。

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.

我想強調的第二點， 就是家庭收入和兒童大腦結構 之間的這種關聯(lián)， 并不取決于兒童的年齡， 性別， 種族，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.

最后一點， 這點很重要， 每兩個孩子之間都有 很大的個體差異， 也就是說， 很多高收入家庭的孩子， 也有較小的大腦表面積， 而很多較低收入家庭的孩子， 也有較大的大腦表面積。 打個比方， 我們都知道，在童年時期， 男孩一般比女孩高一些， 但是任何一個小學的班級里， 都有一些女孩比 一些男孩要高。 所以即使在貧困中成長 會有一定的風險 導致較小的大腦表面積， 我也并不能由 一個兒童的家庭收入， 準確地判斷出 這個兒童的大腦長什么樣子。

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.

現(xiàn)在，想象有兩個孩子， 一個孩子來自美國一個貧困家庭， 另外一個也是美國的孩子， 但他的家庭經(jīng)濟境況更好一些。 我們并沒有發(fā)現(xiàn) 他們出生時的大腦有任何區(qū)別， 但當兩個孩子到了 上幼兒園的年齡時， 我們知道那個貧困中長大的孩子， 平均會比另一個孩子的認知能力 低60%。 后來，那個貧困中長大的孩子， 從高中輟學的幾率要高5倍， 假設她真的從高中畢業(yè)， 她獲得大學學位的可能性也更低， 等兩個孩子都35歲了， 那個在貧困中長大的孩子 依然貧困的概率要高出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.

但是這種情況不是必然的， 作為一個神經(jīng)科學家， 最令我興奮的一個發(fā)現(xiàn)就是， 我們的經(jīng)歷會改變我們的大腦。 這個概念叫做神經(jīng)可塑性， 它意味著，兒童 大腦結構的這些區(qū)別， 并不意味著一個孩子的 一生都會碌碌無為， 大腦并不決定命運。 而如果一個孩子的大腦能被改變， 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?

我們的社會每年都會花費 幾十億美元教育孩子， 學校，家長，和老師， 都想幫助弱勢背景的孩子 在學校和生活中過得更好， 那么我們能告訴他們什么呢？ 最新的科學研究證明， 在貧困中長大代表著 很多不同的經(jīng)歷， 這些經(jīng)歷放在一起可能會 決定大腦的發(fā)育， 并最終幫助孩子學習。 如果真的是這樣， 那么問題就來了： 我們能在這個過程中的 哪一步進行干預并提供幫助呢？

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.

我們首先考慮一下 在學習階段干預， 這通常是通過 學校的活動實現(xiàn)的。 我們是否應該鼓勵教師著重關注 貧困孩子最容易欠缺的技能呢？ 當然， 以科學證據(jù)為基礎的高質量教育的 重要性不容小覷。 而且有很多干預成功的例子， 針對識字能力或自我約束， 成功地提高了孩子的 認知能力和測試分數(shù)。 但是所有從事這類研究的 科研者都會告訴你， 這項工作很有挑戰(zhàn)性， 以科學證據(jù)為基礎的 高質量教育很難實施， 有可能需要很大的人力投入， 有時費用高昂。 并且在許多情況下，這些兒童 發(fā)育的差距很早就顯現(xiàn)了—— 早在他們開始正式的 學校教育之前， 有時甚至在幼兒時期。 所以我的觀點是， 學校很重要， 但如果我們把所有的政策工作 都集中在正規(guī)學校教育上， 可能為時已晚了。

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.

那么我們能不能退后一步， 著眼于改變兒童的成長經(jīng)歷呢？ 有哪些經(jīng)歷是 與在貧困中成長有關， 并且能被干預，以促進孩子的 大腦發(fā)育和學習效果呢？ 當然，有很多，對吧？ 營養(yǎng)，醫(yī)療資源， 二手煙污染或鉛污染， 有壓力的環(huán)境或者受到歧視， 等等。 在我的實驗室里， 我們特別關注幾種類型的經(jīng)歷， 我們認為這些經(jīng)歷 也許能夠被干預 以促進兒童大腦發(fā)育， 并最終提升他們的學習成果。

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.

舉一個例子， 有一樣東西叫做家庭語言環(huán)境， 我們知道，孩子們 聽到的詞匯的數(shù)量 和他們每天 進行的對話數(shù)量 可能差異很大。 據(jù)估計， 來自更有優(yōu)勢背景的孩子們， 在前幾年中， 與較弱勢群體的孩子相比， 平均會多聽到 3000萬個口語詞匯。 在我們的研究中發(fā)現(xiàn)， 進行更多雙向對話的孩子， 大腦控制語言 和閱讀能力的區(qū)域 有更大的表面積。 事實上，他們 聽到的對話的數(shù)量， 比他們聽到的詞匯的數(shù)量， 似乎還更重要一些， 所以有一種令人欣喜的可能， 就是我們要教給父母們， 不僅要多說話， 而且要和他們的孩子 多進行對話。 這樣有可能促進孩子的大腦發(fā)育， 并提高孩子的語言和閱讀能力。 事實上，許多科學家現(xiàn)在正在測試 這個令人振奮的方法是否可行。

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，我們當然都知道， 在貧困中長大代表著 很多不同的經(jīng)歷， 不僅僅是孩子 進行了多少對話， 那么我們如何選擇 別的關鍵點呢？ 各種因素可能太多了。 有很多更高質量的干預方法， 試圖改變孩子的經(jīng)歷， 其中不乏相當有效的方法。 但是，就像學校主導的方式一樣， 它并不容易， 有很多挑戰(zhàn)， 需要人力投入， 有時費用高昂… 而且有時， 科學家們介入一個家庭， 告訴他們需要怎么改變 才能讓他們的孩子成功， 會顯得有些冒昧。

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?

所以我想和你們分享一個想法， 我們能不能僅僅通過 給貧困孩子的家庭捐款 來幫助他們呢？

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.

我有幸和一些經(jīng)濟學家， 社會政策專家和神經(jīng)科學家一起合作 共同負責“孩子的最初階段”這個實驗， 這是首個探究減輕貧困 能否改變孩子的大腦發(fā)育的隨機實驗。

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.

這項研究的目標很大， 但它的前提實際上很簡單。 從2018年5月起， 我們開始在美國的各個醫(yī)院 招募1000名剛剛生過孩子的 生活在國家貧困線以下的母親。 在參與我們的實驗后， 所有的媽媽在孩子 出生后的前40個月， 每個月都會收到一筆 無條件的現(xiàn)金禮物， 她們可以任意支配這筆錢。 但有一點很重要， 這些媽媽是隨機挑選的， 有些媽媽每個月會 收到很少的一筆錢， 而其他的媽媽則被隨機挑選為 每個月收到幾百美金， 我們覺得這筆錢足夠 給她們的日常生活帶來改變， 在多數(shù)情況下，這會使她們的 月收入提高20%到25%。 通過這種方式， 我們希望能跳脫出 貧困是否和兒童發(fā)展相關聯(lián)的問題， 而是真正探究在兒童三歲前， 減輕貧困能否引起 兒童的認知、情感 和大腦發(fā)育的改變， 我們認為，這三年 發(fā)育中的大腦 最容易被不同的經(jīng)歷塑造。

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?

這項研究在幾年之內 都不會有明確的結果， 但最起碼 1000個新生兒和他們的 媽媽能在每個月 拿到一些他們 迫切需要的額外的錢。 但如果研究證明， 給媽媽們更多錢 是幫助在貧困中的孩子的 一種更加節(jié)省財力的方式呢？

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.

如果我們的假設被證實， 那么我們希望這次實驗的成果 能啟發(fā)我們對社工服務的思考， 這將有可能改變 幾百萬個有孩子的家庭。 雖然收入并不是決定 兒童大腦發(fā)育的 唯一的或最重要的因素。 從政策角度來說， 它卻有可能是 最容易被解決的。

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.

簡單來說， 如果我們能證明 減輕貧困能改變兒童大腦的發(fā)育， 從而引起政策上的 有意義的改變， 那么今天一個貧困家庭的孩子， 就有可能有一個 更加美好的未來。

11:43

Thank you.

謝謝。

11:44

(Applause)

（鼓掌）