The linguistic genius of babies Patricia Kuhl

[Music]

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

gonna 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 coral

which is a newly discovered language and

she’s talking to her baby what this

mother and the eight hundred people who

speak coral in the world understand that

it 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

we’ve done that and you’ll see on the

vertical your skill at acquiring a

second language the 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 A to E if they do so that the

appropriate time the black box lights up

and a panda bear pounds a drum a six

month or adores the task what have we

learned well babies all over the world

are what I like 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 in the United

States here in Seattle as they listen to

raw 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 the 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

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 ah I love your big blue eyes so

pretty and nice you know me so good all

right coming 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 ours and

ELLs 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 are 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 stabilized

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 had never heard a second

language to Mandarin for the first time

during the critical period we knew that

when monolinguals were tested in Taipei

in Seattle on the Mandarin sounds they

showed the same pattern

6-8 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 in the laboratory so what have

we done to their little brains we we had

to run a control group to make sure that

just coming into the laboratory it

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 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 were get 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

Magneto and Cefalu grafite to do this it

looks like a hairdryer 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

three hundred and six 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 Emmy Jima scene while they are

learning so this is little Emma she’s a

six month er 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 bay as the baby here is 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 gonna 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]