How does income affect childhood brain development? | Kimberly Noble

譯者: Lilian Chiu 審譯者: Thomas Tam

What I'm about to share with you are findings from a study

我打算跟各位分享一項研究的發現，

of the brains of more than 1,000 children and adolescents.

該研究探索了超過一千名 孩童與青少年的大腦。

Now, these were children who were recruited

這些孩子是從美國各地

from diverse homes around the United States,

不同家庭招募而來的，

and this picture is an average of all of their brains.

這張圖是根據所有大腦資料 得到的平均圖像。

The front of this average brain is on your left

這個平均大腦的正面 是在你的左邊，

and the back of this average brain is on your right.

大腦的後部是在你的右邊。

Now, one of the things we were very interested in

我們非常感興趣的一個主題，

was the surface area of the cerebral cortex,

是大腦皮質的表面面積，

or the thin, wrinkly layer on the outer surface of the brain

就是位於大腦表面又薄又皺的那層，

that does most of the cognitive heavy lifting.

負責處理大部分繁重的認知工作。

And that's because past work by other scientists has suggested

那是因為過去 其他科學家的研究顯示，

that in many cases,

在許多案例中，

a larger cortical surface area

皮質表面面積越大，

is often associated with higher intelligence.

通常和較高的智力有關。

Now, in this study, we found one factor

在我們的研究中，發現了一個因素，

that was associated with the cortical surface area

幾乎和整個大腦的皮質表層有關。

across nearly the entire surface of the brain.

That factor was family income.

那個因素，就是家庭的收入。

Now, here, every point you see in color is a point where higher family income

在這裡的每一個顏色點， 都表示較高家庭收入的兒童

was associated with a larger cortical surface area in that spot.

皮質層面積增大的地方。

And there were some regions, shown here in yellow,

這裡有些區域是黃色，

where that association was particularly pronounced.

表示相關程度特別顯著。

And those are regions that we know support a certain set of cognitive skills:

那些區域是支援某些認知技能：

language skills like vocabulary and reading

語言能力，比如詞彙和閱讀、

as well as the ability to avoid distraction

避免分心

and exert self-control.

及自我控制的能力。

And that's important,

這一點很重要，

because those are the very skills

因為就是這些技能，

that children living in poverty are most likely to struggle with.

是生活在貧困的孩子最掙扎的地方。

In fact, a child living with poverty

事實上，生活在貧困的孩子，

is likely to perform worse on tests of language and impulse control

甚至在兩歲前，就可能在語言 和自我控制能力的測試中表現較差。

before they even turn two.

Now, there are a few points I'd like to highlight about this study.

關於這項研究，我有幾點想要強調。

Number one:

第一：

this link between family income and children's brain structure

孩子的大腦結構 和家庭收入之間的關聯，

was strongest at the lowest income levels.

在收入最低的族群中表現最明顯。

So that means that dollar for dollar,

這意味著，一分錢一分貨，

relatively small differences in family income

即使家庭收入的差異只有一點點，

were associated with proportionately greater differences in brain structure

對處境最不利的家庭， 此差異對大腦結構的影響更大。

among the most disadvantaged families.

And intuitively, that makes sense, right?

直覺上是很合理，對吧？

An extra 20,000 dollars for a family earning, say, 150,000 dollars a year

舉例來說，多賺兩萬美金，

對一個年收入十五萬美金的家庭

would certainly be nice, but probably not game-changing,

當然很棒，但不至於帶來重大改變，

whereas an extra 20,000 dollars

相對的，這額外的兩萬美金 對於一年只賺兩萬美金的家庭來說，

for a family only earning 20,000 dollars a year

would likely make a remarkable difference in their day-to-day lives.

就可以為他們的日常生活 帶來顯著的差異。

Now, the second point I'd like to highlight

我想要強調的第二點是，

is that this link between family income and children's brain structure

家庭收入和孩童 大腦結構之間的關係，

didn't depend on the children's age,

並不取決於孩童的年齡、

it didn't depend on their sex

性別、

and it didn't depend on their race or ethnicity.

和種族或人種。

And the final point --

這最後一點——

and this one's key --

是關鍵——

there was tremendous variability from one child to the next,

孩子與孩子之間都有很大的差異，

by which I mean there were plenty of children from higher-income homes

我的意思是，有不少 來自較高收入家庭的孩子

with smaller brain surfaces

有較少的大腦表面，

and plenty of children from lower-income homes

也有不少來自較低收入家庭的孩子

with larger brain surfaces.

有較大的大腦表面。

Here's an analogy.

打個比喻：

We all know that in childhood,

我們都知道，

童年期間男孩通常會比女孩高，

boys tend to be taller than girls,

but go into any elementary school classroom,

但在任何小學教室中，

and you'll find some girls who are taller than some boys.

你都會發現有些女孩比男孩高。

So while growing up in poverty is certainly a risk factor

所以，在貧困家庭長大 的確是一個風險因子，

for a smaller brain surface,

會有較小的大腦表面，

in no way can I know an individual child's family income

但我絕不能就著 任何一位孩子的家庭收入，

and know with any accuracy

精確知道某個孩子的大腦 會是怎樣的。

what that particular child's brain would look like.

I want you to imagine, for a moment, two children.

請各位想像一下，有兩個孩子。

One is a young child born into poverty in America;

都出生在美國，一個在貧窮家庭，

the other is also an American child,

另一位幸運地，

but one who was born into more fortunate circumstances.

在較富裕家庭。

Now, at birth, we find absolutely no differences

在出生時，我們完全找不到

他們的大腦運作上有什麼差別。

in how their brains work.

But by the time those two kids are ready to start kindergarten,

但當兩個孩子進入幼稚園時，

we know that the child living in poverty

我們知道來自貧窮家庭的孩子，

is likely to have cognitive scores that are, on average, 60 percent lower

在認知測驗的平均分數上，

有可能比富裕家庭的 孩子要低 60%。

than those of the other child.

Later on, that child living in poverty

後來，貧窮家庭的孩子

will be five times more likely to drop out of high school,

在高中休學的機會， 很可能是五倍之高，

and if she does graduate high school,

如果她真的從高中畢業了，

she'll be less likely to earn a college degree.

也不太可能拿到大學學位。

By the time those two kids are 35 years old,

當兩個孩子三十五歲時，

if the first child spent her entire childhood living in poverty,

如果第一個孩子的整個童年 都是在貧窮中渡過，

she is up to 75 times more likely to be poor herself.

長大後過著貧窮生活的機會， 就有七十五倍之高。

But it doesn't have to be that way.

但這是可以改變的。

As a neuroscientist, one of things I find most exciting about the human brain

我作為神經科學家， 最讓我感到興奮的一點，

is that our experiences change our brains.

就是我們的經驗會改變我們的大腦。

Now, this concept, known as neuroplasticity,

這個概念就是神經可塑性，

means that these differences in children's brain structure

意謂孩子大腦結構的差異，

don't doom a child to a life of low achievement.

並不限制孩子將來的成就。

The brain is not destiny.

嬰兒的腦並非宿命。

And if a child's brain can be changed,

如果孩子的大腦可以被重塑，

then anything is possible.

那麼任何事都有可能發生。

As a society, we spend billions of dollars each year, educating our children.

我們社會為教育孩子每年 要花數十億美元。

So what can we tell schools, teachers and parents

那麼我們又如何讓老師和父母，

who want to help support kids from disadvantaged backgrounds

能支援弱勢背景的孩童，

to do their best in school and in life?

在學校與人生發揮最大的潛力呢？

Well, emerging science suggests

新興科學指出，

that growing up in poverty is associated with a host of different experiences

在貧困家庭中長大的孩子， 伴隨著許多不同的經歷，

and that these experiences in turn may work together

這些綜合的經驗，

to help shape brain development and ultimately help kids learn.

促進大腦的發育， 並最終幫助孩子們學習。

And so if this is right,

若這些是事實，就會帶出一個問題：

it begs the question:

Where along this pathway can we step in and provide help?

在孩童學習路途上， 從何處可介入提供協助呢？

So let's consider first intervening at the level of learning itself --

我們先來思考一下，從學習 本身的層級來進行干預——

most commonly through school-based initiatives.

最常見是透過學校為基礎來進行。

Now, should we be encouraging teachers to focus on the kinds of skills

我們應該鼓勵老師要把焦點放在

that disadvantaged kids are most likely to struggle with?

弱勢兒童最可能掙扎的技能嗎？

Of course.

當然是這樣。

The importance of high-quality education based in scientific evidence

科學證據顯示，高品質教育的重要性

的確非常大。

really can't be overstated.

And there are a number of examples of excellent interventions

有一些關於優秀的介入的例子，

targeting things like literacy or self-regulation

是針對讀寫能力或自律等目標，

that do in fact improve kids' cognitive development and their test scores.

實際上可以改善孩童的 認知能力和測驗分數。

But as any intervention scientist doing this work would tell you,

就如許多進行這類 介入做法的科學家所言，

this work is challenging.

這類工作充滿挑戰性。

It's hard to implement high-quality, evidence-based education.

很難實現高品質的循證教育。

And it can be labor-intensive,

因為它可能是勞動密集型的， 有時成本也很高。

it's sometimes costly.

And in many cases, these disparities in child development emerge early --

而且在很多情況下，這些差距 在兒童發育早期出現——

well before the start of formal schooling --

在正規教育開始之先——

sometimes when kids are just toddlers.

有時甚至還在學步時期就開始了。

And so I would argue:

所以，我認為：

school is very important,

學校很重要，

but if we're focusing all of our policy efforts

但如果我們只集中資源於

常規教育政策之上，

on formal schooling,

we're probably starting too late.

我們很可能起步得太晚了。

So what about taking a step back

因此，是否該退一步想想，

and focusing on trying to change children's experiences?

應該專注於嘗試改變孩子的經歷？

What particular experiences are associated with growing up in poverty

在貧困中成長有哪些特殊的經歷，

and might be able to be targeted to promote brain development

可能成為促進大腦發育

and learning outcomes for kids?

和學習成果的目標？

Of course, there are many, right?

當然，有許多經驗都符合，對吧？

Nutrition, access to health care,

營養、獲得醫療保健、

exposure to second-hand smoke or lead,

接觸二手煙或鉛、

experience of stress or discrimination,

遭受壓力或歧視，

to name a few.

都只是少部分例子。

In my laboratory,

在我的實驗室裡， 我們特別關注幾種類型的體驗，

we're particularly focused on a few types of experiences

that we believe may be able to be targeted

是我們認為可以成為目標

to promote children's brain development

促進兒童的大腦發育，

and ultimately improve their learning outcomes.

並最終改善他們的學習成果。

As one example,

用我所謂的家庭語言環境為例，

take something I'll call the home language environment,

by which I mean, we know that the number of words kids hear

意思是，我們知道孩子 聽到的單詞數量，

and the number of conversations they're engaged in every day

以及他們每天參與的談話次數，

can vary tremendously.

可以變化很大。

By some estimates,

據估計，

kids from more advantaged backgrounds

來自有優勢背景的孩子們

hear an average of 30 million more spoken words

在生命的最初幾年，平均多聽 3,000 萬個口語單詞，

in the first few years of life

compared to kids from less advantaged backgrounds.

與來自弱勢的孩子相比。

Now, in our work, we're finding

我們的研究發現，

that kids who experience more back-and-forth,

那些經歷過更多 來回應答會話的孩子，

responsive conversational turns

tend to have a larger brain surface in parts of the brain

會在我們所知負責語言和閱讀技能的 大腦部位產生較大的表面積。

that we know are responsible for language and reading skills.

And in fact, the number of conversations they hear

事實上，他們所聽到的談話次數

seems to matter a little bit more than the sheer number of words they hear.

似乎比他們所聽到的 單詞數量更重要一些。

So one tantalizing possibility

有一個誘引人的選擇是，

is that we should be teaching parents not just to talk a lot,

我們應該教父母不僅僅是說話，

but to actually have more conversations with their children.

實際上要和孩子們進行更多的對話。

In this way, it's possible that we'll promote brain development

這樣，可能會促進孩子的大腦發育，

and perhaps their kids' language and reading skills.

並幫助他們的語言和閱讀技巧。

And in fact, a number of scientists are testing

事實上，許多科學家正在測試

that exciting possibility right now.

那令人興奮的可能性。

But of course, we all know

當然我們都知道，

that growing up in poverty is associated with lots of different experiences

孩子在貧困中成長， 還會有許多不同的經歷，

beyond just how many conversations kids are having.

不僅是與父母有多少次談話。

So how do we choose what else to focus on?

那麼又如何選擇聚焦於那些呢？

The list can be overwhelming.

這份清單可能長得驚人。

There are a number of high-quality interventions

有許多高品質的介入方式

that do try to change children's experience,

試圖改變孩子的經歷，

many of which are quite effective.

當中有許多都很有效。

But again, just like school-based initiatives,

但同樣，就像校本倡議一樣

this is hard work.

是項艱苦工作。

It can be challenging,

工作可能具有挑戰性， 或是勞動密集型，

it can be labor-intensive,

sometimes costly ...

有時代價也很高……

and on occasion,

且，偶爾，

it can be somewhat patronizing for scientists to swoop in

科學家們有點屈尊要蜂擁到訪，

and tell a family what they need to change in order for their child to succeed.

告訴家人需要改變那些 才能讓孩子成功。

So I want to share an idea with you.

所以我想跟大家分享一個想法。

What if we tried to help young children in poverty

要試圖幫助貧困幼兒要怎麼辦呢？

by simply giving their families more money?

僅僅是給他家人更多的錢？

I'm privileged to be working with a team of economists,

我很幸運和一群經濟學家、

social policy experts and neuroscientists

社會政策專家和神經科學家合作，

in leading Baby's First Years,

在「嬰兒的最初幾年」，

the first-ever randomized study

第一次隨機研究

to test whether poverty reduction causes changes in children's brain development.

測試改善貧窮是否會導致 兒童大腦發育的改變。

Now, the ambition of the study is large,

這項研究的野心很大，

but the premise is actually quite simple.

但前提條件其實很簡單。

In May of 2018,

在 2018 年五月， 我們開始招募 1000 名

we began recruiting 1,000 mothers living below the federal poverty line

生活在美國貧困線以下

shortly after they gave birth in a number of American hospitals.

在醫院分娩後不久的母親。

Upon enrolling in our study,

她們參加研究後，

all mothers receive an unconditional monthly cash gift

所有母親都會收到 無條件的每月現金禮物，

for the first 40 months of their children's lives,

在孩子生命的最初 40 個月裡

and they're free to use this money however they like.

隨意使用。

But importantly, mothers are being randomized,

但重要的是，母親們會被隨機分配，

so some mothers are randomized to receive a nominal monthly cash gift

有獲得象徵性的每月現金禮物，

and others are randomized to receive several hundred dollars each month,

也有獲得每月數百美元，

an amount that we believe is large enough

是足夠大的金額 會讓他們的日常生活產生變化，

to make a difference in their day-to-day lives,

in most cases increasing their monthly income by 20 to 25 percent.

在多數情況下，能讓她們月入 增加 20% ~ 25%。

So in this way,

這樣，

we're hoping to finally move past questions

我們希望最終能夠解決

of how poverty is correlated with child development

貧困與兒童的發展關係問題，

and actually be able to test whether reducing poverty causes changes

並且能夠測試減輕貧困是否會導致

in children's cognitive, emotional and brain development

兒童認知、情感和大腦發育的改變，

in the first three years of life --

在生命的最初三年 ——

the very time when we believe

這三年是我們認為

the developing brain may be most malleable to experience.

發展中的大腦最具可塑性的時期。

Now, we won't have definitive results from this study for several years,

這項研究要幾年後才有確切的成果，

and if nothing else,

如果不如預期，

1,000 newborns and their moms will have a bit more cash each month

至少每月有 1,000 名新生兒 及其媽媽獲得分派

that they tell us they very much need.

一些她們非常需要的額外現金。

But what if it turns out that a cost-effective way

如果結果顯示， 若要協助貧窮的幼兒，

to help young children in poverty

最有成本效益的方式就是

is to simply give their moms more money?

單純拿錢給他們的母親， 那該怎麼辦？

If our hypotheses are borne out,

如果我們的假設成立，

it's our hope that results from this work will inform debates about social services

希望能透過這項研究的成果， 將為社會服務辯論提供

that have the potential to effect millions of families with young children.

有可能影響數百萬幼兒家庭的助證。

Because while income may not be the only or even the most important factor

儘管收入未必是唯一， 甚至是最重要的因素，

in determining children's brain development,

影響幼兒的大腦發育，

it may be one that,

但可能是一個

from a policy perspective,

從政策角度很容易解決的問題。

can be easily addressed.

Put simply,

簡言之，

if we can show that reducing poverty changes how children's brains develop

如果我們能夠證明改善貧窮

就能夠改變孩子的大腦發展，

and that leads to meaningful policy changes,

因此導致有意義的政策改變，

then a young child born into poverty today

那麼，現今在貧窮家庭中出生的孩子

may have a much better shot at a brighter future.

就可能會擁有更光明的未來。

Thank you.

謝謝。

(Applause)

（掌聲）