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  • I want you to take a look at this baby.

  • What you're drawn to are her eyes

  • and the skin you love to touch.

  • But today I'm going to talk to you about something you can't see --

  • what's going on up in that little brain of hers.

  • The modern tools of neuroscience

  • are demonstrating to us that what's going on up there

  • is nothing short of rocket science.

  • And what we're learning

  • is going to shed some light

  • on what the romantic writers and poets

  • described as the "celestial openness"

  • of the child's mind.

  • What we see here

  • is a mother in India,

  • and she's speaking Koro,

  • which is a newly discovered language.

  • And she's talking to her baby.

  • What this mother --

  • and the 800 people who speak Koro in the world --

  • understands [is] that, to preserve this language,

  • they need to speak it to the babies.

  • And therein lies a critical puzzle.

  • Why is it that you can't preserve a language

  • by speaking to you and I, to the adults?

  • Well, it's got to do with your brain.

  • What we see here

  • is that language has a critical period for learning.

  • The way to read this slide is to look at your age on the horizontal axis.

  • (Laughter)

  • And you'll see on the vertical

  • your skill at acquiring a second language.

  • Babies and children are geniuses

  • until they turn seven,

  • and then there's a systematic decline.

  • After puberty, we fall off the map.

  • No scientists dispute this curve,

  • but laboratories all over the world

  • are trying to figure out why it works this way.

  • Work in my lab is focused

  • on the first critical period in development --

  • and that is the period in which

  • babies try to master which sounds are used in their language.

  • We think, by studying how the sounds are learned,

  • we'll have a model for the rest of language,

  • and perhaps for critical periods that may exist in childhood

  • for social, emotional

  • and cognitive development.

  • So we've been studying the babies

  • using a technique that we're using all over the world

  • and the sounds of all languages.

  • The baby sits on a parent's lap,

  • and we train them to turn their heads when a sound changes --

  • like from "ah" to "ee."

  • If they do so at the appropriate time,

  • the black box lights up

  • and a panda bear pounds a drum.

  • A six-monther adores the task.

  • What have we learned?

  • Well, babies all over the world

  • are what I like to describe

  • as "citizens of the world."

  • They can discriminate all the sounds of all languages,

  • no matter what country we're testing and what language we're using,

  • and that's remarkable because you and I can't do that.

  • We're culture-bound listeners.

  • We can discriminate the sounds of our own language,

  • but not those of foreign languages.

  • So the question arises:

  • when do those citizens of the world

  • turn into the language-bound listeners that we are?

  • And the answer: before their first birthdays.

  • What you see here is performance on that head-turn task

  • for babies tested in Tokyo and the United States,

  • here in Seattle,

  • as they listened to "ra" and "la" --

  • sounds important to English, but not to Japanese.

  • So at six to eight months the babies are totally equivalent.

  • Two months later something incredible occurs.

  • The babies in the United States are getting a lot better,

  • babies in Japan are getting a lot worse,

  • but both of those groups of babies

  • are preparing for exactly the language that they are going to learn.

  • So the question is: what's happening

  • during this critical two-month period?

  • This is the critical period for sound development,

  • but what's going on up there?

  • So there are two things going on.

  • The first is that the babies are listening intently to us,

  • and they're taking statistics as they listen to us talk --

  • they're taking statistics.

  • So listen to two mothers speaking motherese --

  • the universal language we use when we talk to kids --

  • first in English and then in Japanese.

  • (Video) English Mother: Ah, I love your big blue eyes --

  • so pretty and nice.

  • Japanese Mother: [Japanese]

  • Patricia Kuhl: During the production of speech,

  • when babies listen,

  • what they're doing is taking statistics

  • on the language that they hear.

  • And those distributions grow.

  • And what we've learned

  • is that babies are sensitive to the statistics,

  • and the statistics of Japanese and English are very, very different.

  • English has a lot of Rs and Ls.

  • The distribution shows.

  • And the distribution of Japanese is totally different,

  • where we see a group of intermediate sounds,

  • which is known as the Japanese "R."

  • So babies absorb

  • the statistics of the language

  • and it changes their brains;

  • it changes them from the citizens of the world

  • to the culture-bound listeners that we are.

  • But we as adults

  • are no longer absorbing those statistics.

  • We're governed by the representations in memory

  • that were formed early in development.

  • So what we're seeing here

  • is changing our models of what the critical period is about.

  • We're arguing from a mathematical standpoint

  • that the learning of language material may slow down

  • when our distributions stabilize.

  • It's raising lots of questions about bilingual people.

  • Bilinguals must keep two sets of statistics in mind at once

  • and flip between them, one after the other,

  • depending on who they're speaking to.

  • So we asked ourselves,

  • can the babies take statistics on a brand new language?

  • And we tested this by exposing American babies

  • who'd never heard a second language

  • to Mandarin for the first time during the critical period.

  • We knew that, when monolinguals were tested

  • in Taipei and Seattle on the Mandarin sounds,

  • they showed the same pattern.

  • Six to eight months, they're totally equivalent.

  • Two months later, something incredible happens.

  • But the Taiwanese babies are getting better, not the American babies.

  • What we did was expose American babies during this period

  • to Mandarin.

  • It was like having Mandarin relatives come and visit for a month

  • and move into your house

  • and talk to the babies for 12 sessions.

  • Here's what it looked like in the laboratory.

  • (Video) Mandarin Speaker: [Mandarin]

  • PK: So what have we done to their little brains?

  • (Laughter)

  • We had to run a control group

  • to make sure that just coming into the laboratory

  • didn't improve your Mandarin skills.

  • So a group of babies came in and listened to English.

  • And we can see from the graph

  • that exposure to English didn't improve their Mandarin.

  • But look at what happened to the babies

  • exposed to Mandarin for 12 sessions.

  • They were as good as the babies in Taiwan

  • who'd been listening for 10-and-a-half months.

  • What it demonstrated

  • is that babies take statistics on a new language.

  • Whatever you put in front of them, they'll take statistics on.

  • But we wondered what role

  • the human being played

  • in this learning exercise.

  • So we ran another group of babies

  • in which the kids got the same dosage, the same 12 sessions,

  • but over a television set

  • and another group of babies who had just audio exposure

  • and looked at a teddy bear on the screen.

  • What did we do to their brains?

  • What you see here is the audio result --

  • no learning whatsoever --

  • and the video result --

  • no learning whatsoever.

  • It takes a human being

  • for babies to take their statistics.

  • The social brain is controlling

  • when the babies are taking their statistics.

  • We want to get inside the brain

  • and see this thing happening

  • as babies are in front of televisions,

  • as opposed to in front of human beings.

  • Thankfully, we have a new machine,

  • magnetoencephalography,

  • that allows us to do this.

  • It looks like a hair dryer from Mars.

  • But it's completely safe,

  • completely non-invasive and silent.

  • We're looking at millimeter accuracy

  • with regard to spatial

  • and millisecond accuracy

  • using 306 SQUIDs --

  • these are Superconducting

  • QUantum Interference Devices --

  • to pick up the magnetic fields

  • that change as we do our thinking.

  • We're the first in the world

  • to record babies

  • in an MEG machine

  • while they are learning.

  • So this is little Emma.

  • She's a six-monther.

  • And she's listening to various languages

  • in the earphones that are in her ears.

  • You can see, she can move around.

  • We're tracking her head

  • with little pellets in a cap,

  • so she's free to move completely unconstrained.

  • It's a technical tour de force.

  • What are we seeing?

  • We're seeing the baby brain.

  • As the baby hears a word in her language

  • the auditory areas light up,

  • and then subsequently areas surrounding it

  • that we think are related to coherence,

  • getting the brain coordinated with its different areas,

  • and causality,

  • one brain area causing another to activate.

  • We are embarking

  • on a grand and golden age

  • of knowledge about child's brain development.

  • We're going to be able to see a child's brain

  • as they experience an emotion,

  • as they learn to speak and read,

  • as they solve a math problem,

  • as they have an idea.

  • And we're going to be able to invent brain-based interventions

  • for children who have difficulty learning.

  • Just as the poets and writers described,

  • we're going to be able to see, I think,

  • that wondrous openness,

  • utter and complete openness,

  • of the mind of a child.

  • In investigating the child's brain,

  • we're going to uncover deep truths

  • about what it means to be human,

  • and in the process,

  • we may be able to help keep our own minds open to learning

  • for our entire lives.

  • Thank you.

  • (Applause)

I want you to take a look at this baby.

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B1 TED language mandarin brain critical period

【TED】Patricia Kuhl: The linguistic genius of babies (The linguistic genius of babies | Patricia Kuhl)

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    VoiceTube posted on 2013/05/11
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