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  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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?

  • 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.

  • 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.

  • 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.

  • 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.

  • 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?

  • 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.

  • 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.

  • 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?

  • 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.

  • 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.

  • Thank you.

  • (Applause)

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

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TED】キンバリー・ノーブル:収入が幼少期の脳の発達に与える影響とは?(収入は子供の脳の発達にどのように影響を与えるのか|キンバリー・ノーブル) (【TED】Kimberly Noble: How does income affect childhood brain development? (How does income affect childhood brain development? | Kimberly Noble))

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    林宜悉 に公開 2021 年 01 月 14 日
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