16:47
TEDGlobal 2011

Annie Murphy Paul: What we learn before we're born

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Pop quiz: When does learning begin? Answer: Before we are born. Science writer Annie Murphy Paul talks through new research that shows how much we learn in the womb -- from the lilt of our native language to our soon-to-be-favorite foods.

- Science author
Annie Murphy Paul investigates how life in the womb shapes who we become. Full bio

My subject today is learning.
00:15
And in that spirit, I want to spring on you all a pop quiz.
00:18
Ready?
00:21
When does learning begin?
00:23
Now as you ponder that question,
00:26
maybe you're thinking about the first day of preschool
00:28
or kindergarten,
00:30
the first time that kids are in a classroom with a teacher.
00:32
Or maybe you've called to mind the toddler phase
00:35
when children are learning how to walk and talk
00:38
and use a fork.
00:41
Maybe you've encountered the Zero-to-Three movement,
00:43
which asserts that the most important years for learning
00:46
are the earliest ones.
00:49
And so your answer to my question would be:
00:51
Learning begins at birth.
00:54
Well today I want to present to you
00:56
an idea that may be surprising
00:58
and may even seem implausible,
01:01
but which is supported by the latest evidence
01:04
from psychology and biology.
01:06
And that is that some of the most important learning we ever do
01:09
happens before we're born,
01:12
while we're still in the womb.
01:14
Now I'm a science reporter.
01:17
I write books and magazine articles.
01:19
And I'm also a mother.
01:21
And those two roles came together for me
01:23
in a book that I wrote called "Origins."
01:26
"Origins" is a report from the front lines
01:29
of an exciting new field
01:32
called fetal origins.
01:34
Fetal origins is a scientific discipline
01:36
that emerged just about two decades ago,
01:39
and it's based on the theory
01:42
that our health and well-being throughout our lives
01:45
is crucially affected
01:48
by the nine months we spend in the womb.
01:50
Now this theory was of more than just intellectual interest to me.
01:53
I was myself pregnant
01:57
while I was doing the research for the book.
01:59
And one of the most fascinating insights
02:02
I took from this work
02:04
is that we're all learning about the world
02:06
even before we enter it.
02:09
When we hold our babies for the first time,
02:12
we might imagine that they're clean slates,
02:14
unmarked by life,
02:17
when in fact, they've already been shaped by us
02:19
and by the particular world we live in.
02:22
Today I want to share with you some of the amazing things
02:26
that scientists are discovering
02:28
about what fetuses learn
02:30
while they're still in their mothers' bellies.
02:32
First of all,
02:36
they learn the sound of their mothers' voices.
02:38
Because sounds from the outside world
02:41
have to travel through the mother's abdominal tissue
02:44
and through the amniotic fluid that surrounds the fetus,
02:47
the voices fetuses hear,
02:51
starting around the fourth month of gestation,
02:53
are muted and muffled.
02:56
One researcher says
02:58
that they probably sound a lot like the the voice of Charlie Brown's teacher
03:00
in the old "Peanuts" cartoon.
03:03
But the pregnant woman's own voice
03:06
reverberates through her body,
03:09
reaching the fetus much more readily.
03:11
And because the fetus is with her all the time,
03:14
it hears her voice a lot.
03:17
Once the baby's born, it recognizes her voice
03:20
and it prefers listening to her voice
03:23
over anyone else's.
03:25
How can we know this?
03:27
Newborn babies can't do much,
03:29
but one thing they're really good at is sucking.
03:31
Researchers take advantage of this fact
03:34
by rigging up two rubber nipples,
03:37
so that if a baby sucks on one,
03:40
it hears a recording of its mother's voice
03:42
on a pair of headphones,
03:44
and if it sucks on the other nipple,
03:46
it hears a recording of a female stranger's voice.
03:48
Babies quickly show their preference
03:52
by choosing the first one.
03:55
Scientists also take advantage of the fact
03:58
that babies will slow down their sucking
04:01
when something interests them
04:03
and resume their fast sucking
04:05
when they get bored.
04:07
This is how researchers discovered
04:10
that, after women repeatedly read aloud
04:12
a section of Dr. Seuss' "The Cat in the Hat" while they were pregnant,
04:15
their newborn babies recognized that passage
04:19
when they hear it outside the womb.
04:22
My favorite experiment of this kind
04:25
is the one that showed that the babies
04:28
of women who watched a certain soap opera
04:30
every day during pregnancy
04:32
recognized the theme song of that show
04:35
once they were born.
04:38
So fetuses are even learning
04:41
about the particular language that's spoken
04:43
in the world that they'll be born into.
04:46
A study published last year
04:48
found that from birth, from the moment of birth,
04:51
babies cry in the accent
04:54
of their mother's native language.
04:56
French babies cry on a rising note
04:59
while German babies end on a falling note,
05:02
imitating the melodic contours
05:05
of those languages.
05:07
Now why would this kind of fetal learning
05:09
be useful?
05:11
It may have evolved to aid the baby's survival.
05:13
From the moment of birth,
05:16
the baby responds most to the voice
05:18
of the person who is most likely to care for it --
05:20
its mother.
05:22
It even makes its cries
05:24
sound like the mother's language,
05:26
which may further endear the baby to the mother,
05:28
and which may give the baby a head start
05:31
in the critical task
05:33
of learning how to understand and speak
05:35
its native language.
05:38
But it's not just sounds
05:40
that fetuses are learning about in utero.
05:42
It's also tastes and smells.
05:44
By seven months of gestation,
05:47
the fetus' taste buds are fully developed,
05:49
and its olfactory receptors, which allow it to smell,
05:51
are functioning.
05:54
The flavors of the food a pregnant woman eats
05:56
find their way into the amniotic fluid,
05:59
which is continuously swallowed
06:01
by the fetus.
06:03
Babies seem to remember and prefer these tastes
06:05
once they're out in the world.
06:08
In one experiment, a group of pregnant women
06:11
was asked to drink a lot of carrot juice
06:14
during their third trimester of pregnancy,
06:16
while another group of pregnant women
06:19
drank only water.
06:21
Six months later, the women's infants
06:23
were offered cereal mixed with carrot juice,
06:26
and their facial expressions were observed while they ate it.
06:29
The offspring of the carrot juice drinking women
06:33
ate more carrot-flavored cereal,
06:35
and from the looks of it,
06:37
they seemed to enjoy it more.
06:39
A sort of French version of this experiment
06:41
was carried out in Dijon, France
06:44
where researchers found
06:46
that mothers who consumed food and drink
06:48
flavored with licorice-flavored anise during pregnancy
06:51
showed a preference for anise
06:56
on their first day of life,
06:58
and again, when they were tested later,
07:00
on their fourth day of life.
07:02
Babies whose mothers did not eat anise during pregnancy
07:04
showed a reaction that translated roughly as "yuck."
07:08
What this means
07:12
is that fetuses are effectively being taught by their mothers
07:14
about what is safe and good to eat.
07:16
Fetuses are also being taught
07:19
about the particular culture that they'll be joining
07:21
through one of culture's most powerful expressions,
07:24
which is food.
07:27
They're being introduced to the characteristic flavors and spices
07:29
of their culture's cuisine
07:32
even before birth.
07:34
Now it turns out that fetuses are learning even bigger lessons.
07:37
But before I get to that,
07:40
I want to address something that you may be wondering about.
07:42
The notion of fetal learning
07:46
may conjure up for you attempts to enrich the fetus --
07:48
like playing Mozart through headphones
07:51
placed on a pregnant belly.
07:53
But actually, the nine-month-long process
07:55
of molding and shaping that goes on in the womb
07:58
is a lot more visceral and consequential than that.
08:01
Much of what a pregnant woman encounters in her daily life --
08:05
the air she breathes,
08:09
the food and drink she consumes,
08:11
the chemicals she's exposed to,
08:13
even the emotions she feels --
08:15
are shared in some fashion with her fetus.
08:17
They make up a mix of influences
08:20
as individual and idiosyncratic
08:23
as the woman herself.
08:25
The fetus incorporates these offerings
08:27
into its own body,
08:29
makes them part of its flesh and blood.
08:31
And often it does something more.
08:34
It treats these maternal contributions
08:36
as information,
08:39
as what I like to call biological postcards
08:41
from the world outside.
08:43
So what a fetus is learning about in utero
08:46
is not Mozart's "Magic Flute"
08:49
but answers to questions much more critical to its survival.
08:51
Will it be born into a world of abundance
08:55
or scarcity?
08:57
Will it be safe and protected,
08:59
or will it face constant dangers and threats?
09:02
Will it live a long, fruitful life
09:05
or a short, harried one?
09:07
The pregnant woman's diet and stress level in particular
09:10
provide important clues to prevailing conditions
09:13
like a finger lifted to the wind.
09:16
The resulting tuning and tweaking
09:19
of a fetus' brain and other organs
09:21
are part of what give us humans
09:24
our enormous flexibility,
09:26
our ability to thrive
09:28
in a huge variety of environments,
09:30
from the country to the city,
09:32
from the tundra to the desert.
09:34
To conclude, I want to tell you two stories
09:37
about how mothers teach their children about the world
09:39
even before they're born.
09:42
In the autumn of 1944,
09:46
the darkest days of World War II,
09:48
German troops blockaded Western Holland,
09:51
turning away all shipments of food.
09:54
The opening of the Nazi's siege
09:57
was followed by one of the harshest winters in decades --
09:59
so cold the water in the canals froze solid.
10:02
Soon food became scarce,
10:06
with many Dutch surviving on just 500 calories a day --
10:08
a quarter of what they consumed before the war.
10:12
As weeks of deprivation stretched into months,
10:15
some resorted to eating tulip bulbs.
10:18
By the beginning of May,
10:21
the nation's carefully rationed food reserve
10:23
was completely exhausted.
10:25
The specter of mass starvation loomed.
10:27
And then on May 5th, 1945,
10:30
the siege came to a sudden end
10:33
when Holland was liberated
10:35
by the Allies.
10:37
The "Hunger Winter," as it came to be known,
10:39
killed some 10,000 people
10:42
and weakened thousands more.
10:44
But there was another population that was affected --
10:46
the 40,000 fetuses
10:49
in utero during the siege.
10:51
Some of the effects of malnutrition during pregnancy
10:54
were immediately apparent
10:56
in higher rates of stillbirths,
10:58
birth defects, low birth weights
11:00
and infant mortality.
11:02
But others wouldn't be discovered for many years.
11:04
Decades after the "Hunger Winter,"
11:07
researchers documented
11:09
that people whose mothers were pregnant during the siege
11:11
have more obesity, more diabetes
11:15
and more heart disease in later life
11:17
than individuals who were gestated under normal conditions.
11:20
These individuals' prenatal experience of starvation
11:23
seems to have changed their bodies
11:27
in myriad ways.
11:29
They have higher blood pressure,
11:31
poorer cholesterol profiles
11:33
and reduced glucose tolerance --
11:35
a precursor of diabetes.
11:37
Why would undernutrition in the womb
11:40
result in disease later?
11:42
One explanation
11:44
is that fetuses are making the best of a bad situation.
11:46
When food is scarce,
11:49
they divert nutrients towards the really critical organ, the brain,
11:51
and away from other organs
11:54
like the heart and liver.
11:56
This keeps the fetus alive in the short-term,
11:58
but the bill comes due later on in life
12:01
when those other organs, deprived early on,
12:04
become more susceptible to disease.
12:06
But that may not be all that's going on.
12:09
It seems that fetuses are taking cues
12:12
from the intrauterine environment
12:14
and tailoring their physiology accordingly.
12:17
They're preparing themselves
12:19
for the kind of world they will encounter
12:21
on the other side of the womb.
12:23
The fetus adjusts its metabolism
12:25
and other physiological processes
12:27
in anticipation of the environment that awaits it.
12:30
And the basis of the fetus' prediction
12:33
is what its mother eats.
12:36
The meals a pregnant woman consumes
12:38
constitute a kind of story,
12:40
a fairy tale of abundance
12:42
or a grim chronicle of deprivation.
12:44
This story imparts information
12:47
that the fetus uses
12:50
to organize its body and its systems --
12:52
an adaptation to prevailing circumstances
12:54
that facilitates its future survival.
12:57
Faced with severely limited resources,
13:00
a smaller-sized child with reduced energy requirements
13:03
will, in fact, have a better chance
13:06
of living to adulthood.
13:08
The real trouble comes
13:10
when pregnant women are, in a sense, unreliable narrators,
13:12
when fetuses are led
13:15
to expect a world of scarcity
13:17
and are born instead into a world of plenty.
13:19
This is what happened to the children of the Dutch "Hunger Winter."
13:22
And their higher rates of obesity,
13:25
diabetes and heart disease
13:27
are the result.
13:29
Bodies that were built to hang onto every calorie
13:31
found themselves swimming in the superfluous calories
13:34
of the post-war Western diet.
13:36
The world they had learned about while in utero
13:39
was not the same
13:42
as the world into which they were born.
13:44
Here's another story.
13:47
At 8:46 a.m. on September 11th, 2001,
13:49
there were tens of thousands of people
13:53
in the vicinity of the World Trade Center
13:55
in New York --
13:57
commuters spilling off trains,
13:59
waitresses setting tables for the morning rush,
14:01
brokers already working the phones on Wall Street.
14:04
1,700 of these people were pregnant women.
14:08
When the planes struck and the towers collapsed,
14:11
many of these women experienced the same horrors
14:14
inflicted on other survivors of the disaster --
14:17
the overwhelming chaos and confusion,
14:20
the rolling clouds
14:22
of potentially toxic dust and debris,
14:24
the heart-pounding fear for their lives.
14:28
About a year after 9/11,
14:30
researchers examined a group of women
14:32
who were pregnant
14:35
when they were exposed to the World Trade Center attack.
14:37
In the babies of those women
14:39
who developed post-traumatic stress syndrome, or PTSD,
14:41
following their ordeal,
14:44
researchers discovered a biological marker
14:46
of susceptibility to PTSD --
14:49
an effect that was most pronounced
14:51
in infants whose mothers experienced the catastrophe
14:54
in their third trimester.
14:57
In other words,
14:59
the mothers with post-traumatic stress syndrome
15:01
had passed on a vulnerability to the condition
15:04
to their children while they were still in utero.
15:07
Now consider this:
15:10
post-traumatic stress syndrome
15:12
appears to be a reaction to stress gone very wrong,
15:14
causing its victims tremendous unnecessary suffering.
15:17
But there's another way of thinking about PTSD.
15:21
What looks like pathology to us
15:24
may actually be a useful adaptation
15:27
in some circumstances.
15:29
In a particularly dangerous environment,
15:31
the characteristic manifestations of PTSD --
15:34
a hyper-awareness of one's surroundings,
15:37
a quick-trigger response to danger --
15:40
could save someone's life.
15:43
The notion that the prenatal transmission of PTSD risk is adaptive
15:46
is still speculative,
15:50
but I find it rather poignant.
15:52
It would mean that, even before birth,
15:55
mothers are warning their children
15:57
that it's a wild world out there,
15:59
telling them, "Be careful."
16:01
Let me be clear.
16:04
Fetal origins research is not about blaming women
16:06
for what happens during pregnancy.
16:09
It's about discovering how best to promote
16:11
the health and well-being of the next generation.
16:14
That important effort must include a focus
16:17
on what fetuses learn
16:19
during the nine months they spend in the womb.
16:21
Learning is one of life's most essential activities,
16:24
and it begins much earlier
16:27
than we ever imagined.
16:29
Thank you.
16:31
(Applause)
16:33

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About the Speaker:

Annie Murphy Paul - Science author
Annie Murphy Paul investigates how life in the womb shapes who we become.

Why you should listen

To what extent the conditions we encounter before birth influence our individual characteristics? It‘s the question at the center of fetal origins, a relatively new field of research that measures how the effects of influences outside the womb during pregnancy can shape the physical, mental and even emotional well-being of the developing baby for the rest of its life.

Science writer Annie Murphy Paul calls it a gray zone between nature and nurture in her book Origins, a history and study of this emerging field structured around a personal narrative -- Paul was pregnant with her second child at the time. What she finds suggests a far more dynamic nature between mother and fetus than typically acknowledged, and opens up the possibility that the time before birth is as crucial to human development as early childhood.

Read Annie Murphy Paul's essay on CNN.com>>

More profile about the speaker
Annie Murphy Paul | Speaker | TED.com