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]