Just after Christmas last year,

132 kids in California got the measles

by either visiting Disneyland

or being exposed to someone
who'd been there.

The virus then hopped the Canadian border,

infecting more than
a hundred children in Quebec.

One of the tragic things
about this outbreak

is that measles, which can be fatal
to a child with a weakened immune system,

is one of the most easily
preventable diseases in the world.

An effective vaccine against it

has been available for more
than half a century,

but many of the kids involved
in the Disneyland outbreak

had not been vaccinated

because their parents were afraid

of something allegedly even worse:

autism.

But wait: wasn't the paper
that sparked the controversy

about autism and vaccines

debunked, retracted,

and branded a deliberate fraud

by the British Medical Journal?

Don't most science-savvy people

know that the theory
that vaccines cause autism is B.S.?

I think most of you do,

but millions of parents worldwide

continue to fear that vaccines
put their kids at risk for autism.

Why?

Here's why.

This is a graph of autism
prevalence estimates rising over time.

For most of the 20th century,

autism was considered
an incredibly rare condition.

The few psychologists and pediatricians
who'd even heard of it

figured they would get through
their entire careers

without seeing a single case.

For decades, the prevalence estimates
remained stable

at just three or four children
in ten thousand.

But then, in the 1990s,

the numbers started to skyrocket.

Fundraising organizations
like Autism Speaks

routinely refer to autism as an epidemic,

as if you could catch it
from another kid at Disneyland.

So what's going on?

If it isn't vaccines, what is it?

If you ask the folks down at
the Centers for Disease Control in Atlanta

what's going on,

they tend to rely on phrases like
"broadened diagnostic criteria"

and "better case finding"

to explain these rising numbers.

But that kind of language

doesn't do much to allay
the fears of a young mother

who is searching her
two-year old's face for eye contact.

If the diagnostic criteria
had to be broadened,

why were they so narrow
in the first place?

Why were cases of autism
so hard to find

before the 1990s?

Five years ago, I decided to try
to uncover the answers to these questions.

I learned that what happened

has less to do with the slow and cautious
progress of science

than it does with the seductive
power of storytelling.

For most of the 20th century,

clinicians told one story

about what autism is
and how it was discovered,

but that story turned out to be wrong,

and the consequences of it

are having a devastating impact
on global public health.

There was a second,
more accurate story of autism

which had been lost and forgotten

in obscure corners
of the clinical literature.

This second story tells us everything
about how we got here

and where we need to go next.

The first story starts with a child
psychiatrist at Johns Hopkins Hospital

named Leo Kanner.

In 1943, Kanner published a paper

describing 11 young patients
who seemed to inhabit private worlds,

ignoring the people around them,

even their own parents.

They could amuse themselves for hours

by flapping their hands
in front of their faces,

but they were panicked by little things

like their favorite toy
being moved from its usual place

without their knowledge.

Based on the patients
who were brought to his clinic,

Kanner speculated
that autism is very rare.

By the 1950s, as the world's
leading authority on the subject,

he declared that he had seen
less than 150 true cases of his syndrome

while fielding referrals from
as far away as South Africa.

That's actually not surprising,

because Kanner's criteria
for diagnosing autism

were incredibly selective.

For example, he discouraged giving
the diagnosis to children who had seizures

but now we know that epilepsy
is very common in autism.

He once bragged that he had turned
nine out of 10 kids

referred to his office as autistic
by other clinicians

without giving them an autism diagnosis.

Kanner was a smart guy,

but a number of his theories
didn't pan out.

He classified autism as a form
of infantile psychosis

caused by cold and unaffectionate parents.

These children, he said,

had been kept neatly
in a refrigerator that didn't defrost.

At the same time, however,

Kanner noticed that some
of his young patients

had special abilities
that clustered in certain areas

like music, math, and memory.

One boy in his clinic

could distinguish between 18 symphonies
before he turned two.

When his mother put on
one of his favorite records,

he would correctly declare,
"Beethoven!"

But Kanner took a dim view
of these abilities,

claiming that the kids
were just regurgitating things

they'd heard their pompous parents say,

desperate to earn their approval.

As a result, autism became
a source of shame and stigma for families,

and two generations of autistic children

were shipped off to institutions
for their own good,

becoming invisible to the world at large.

Amazingly, it wasn't until the 1970s

that researchers began to test
Kanner's theory that autism was rare.

Lorna Wing was a cognitive
psychologist in London

who thought that Kanner's theory
of refrigerator parenting

were "bloody stupid," as she told me.

She and her husband John were warm
and affectionate people,

and they had a profoundly
autistic daughter named Susie.

Lorna and John knew how hard it was
to raise a child like Susie

without support services,

special education,

and the other resources that are
out of reach without a diagnosis.

To make the case
to the National Health Service

that more resources were needed
for autistic children and their families,

Lorna and her colleague Judith Gould

decided to do something that should
have been done 30 years earlier.

They undertook a study of autism
prevalence in the general population.

They pounded the pavement
in a London suburb called Camberwell

to try to find autistic children
in the community.

What they saw made clear
that Kanner's model was way too narrow,

while the reality of autism
was much more colorful and diverse.

Some kids couldn't talk at all,

while others waxed on at length
about their fascination with astrophysics,

dinosaurs, or the genealogy of royalty.

In other words, these children
didn't fit into nice, neat boxes,

as Judith put it,

and they saw lots of them,

way more than Kanner's monolithic model
would have predicted.

At first, they were at loss
to make sense of their data.

How had no one noticed
these children before?

But then Lorna came upon a reference
to a paper that had been published

in German in 1944,

the year after Kanner's paper,

and then forgotten,

buried with the ashes of a terrible time

that no one wanted to remember
or think about.

Kanner knew about this competing paper,

but scrupulously avoided
mentioning it in his own work.

It had never even
been translated into English,

but luckily, Lorna's husband spoke German,

and he translated it for her.

The paper offered
an alternate story of autism.

Its author was a man named Hans Asperger,

who ran a combination clinic
and residential school

in Vienna in the 1930s.

Asperger's ideas about teaching children
with learning differences

were progressive even
by contemporary standards.

Mornings at his clinic began
with exercise classes set to music,

and the children put on plays
on Sunday afternoons.

Instead of blaming parents
for causing autism,

Asperger framed it as a lifelong,
polygenetic disability

that requires compassionate forms
of support and accommodations

over the course of one's whole life.

Rather than treating the kids
in his clinic like patients,

Asperger called him his little professors,

and enlisted their help in developing
methods of education

that were particularly suited to them.

Crucially, Asperger viewed autism
as a diverse continuum

that spans an astonishing range
of giftedness and disability.

He believed that autism
and autistic traits are common

and always have been,

seeing aspects of this continuum
in familiar archetypes from pop culture

like the socially awkward scientist

and the absent-minded professor.

He went so far as to say,

it seems that for success
in science and art,

a dash of autism is essential.

Lorna and Judith realized that Kanner
had been as wrong about autism being rare

as he had been about parents causing it.

Over the next several years,

they quietly worked with
the American Psychiatric Association

to broaden the criteria for diagnosis

to reflect the diversity of what
they called "the autism spectrum."

In the late '80s and early 1990s,

their changes went into effect,

swapping out Kanner's narrow model

for Asperger's broad and inclusive one.

These changes weren't
happening in a vacuum.

By coincidence, as Lorna and Judith
worked behind the scenes

to reform the criteria,

people all over the world were seeing
an autistic adult for the first time.

Before "Rain Man" came out in 1988,

only a tiny, ingrown circle of experts
knew what autism looked like,

but after Dustin Hoffman's unforgettable
performance as Raymond Babbitt

earned "Rain Man" four Academy Awards,

pediatricians, psychologists,

teachers, and parents all over the world
knew what autism looked like.

Coincidentally, at the same time,

the first easy-to-use clinical tests
for diagnosing autism were introduced.

You no longer had to have a connection
to that tiny circle of experts

to get your child evaluated.

The combination of "Rain Man,"

the changes to the criteria,
and the introduction of these tests

created a network effect,

a perfect storm of autism awareness.

The number of diagnoses started to soar,

just as Lorna and Judith predicted,
indeed hoped, that it would,

enabling autistic people
and their families

to finally get the support
and services they deserved.

Then Andrew Wakefield came along

to blame the spike
in diagnoses on vaccines,

a simple, powerful,

and seductively believable story

that was as wrong as Kanner's theory

that autism was rare.

If the CDC's current estimate,

that one in 68 kids in America
are on the spectrum, is correct,

autistics are one of the largest
minority groups in the world.

In recent years, autistic people
have come together on the Internet

to reject the notion that they
are puzzles to be solved

by the next medical breakthrough,

coining the term "neurodiversity"

to celebrate the varieties
of human cognition.

One way to understand neurodiversity

is to think in terms
of human operating systems.

Just because a PC is not running Windows
doesn't mean that it's broken.

By autistic standards,
the normal human brain

is easily distractable,

obsessively social,

and suffers from a deficit
of attention to detail.

To be sure, autistic people
have a hard time

living in a world not built for them.

Eighty years later, we're still
catching up to Asperger,

who believed that the "cure"
for the most disabling aspects of autism

is to be found in understanding teachers,

accommodating employers,

supportive communities,

and parents who have faith
in their children's potential.

An autistic woman
named Xoxia Zax once said,

"We need all hands on deck
to right the ship of humanity."

As we sail into an uncertain future,

we need every form
of human intelligence on the planet

working together to tackle
the challenges that we face as a society.

We can't afford to waste a brain.

Thank you.

(Applause)