|
Are you capable of multiplying 147,631,789 by
23,674 in your head,
instantly?
Physicist Allan Snyder says you probably can,
based on his new theory
about the origin of the extraordinary skills of
autistic savants
[By Douglas S. Fox in Discover Vol. 23 No. 2
(February 2002). Thanks
to Bonnie Sayers on the FEATBack list.]
http://www.discover.com/feb_02/gthere.html?article=featsavant.html
Nadia appeared healthy at birth, but by the
time she was 2, her
parents knew something was amiss. She avoided
eye contact and didn't
respond when her mother smiled or cooed. She didn't
even seem to recognize her
mother. At 6 months she still had not spoken a
word. She was unusually
clumsy and spent hours in repetitive play, such
as tearing paper into
strips.
But at 31/2, she picked up a pen and began to
draw-not scribble,
draw.
Without any training, she created from memory
sketches of galloping horses
that only a trained adult could equal. Unlike
the way most people might
draw a horse, beginning with its outline, Nadia
began with random details.
First a hoof, then the horse's mane, then its
harness. Only later did she lay
down firm lines connecting these floating features.
And when she did connect
them, they were always in the correct position
relative to one another. ¦
Nadia is an autistic savant, a rare condition
marked by severe mental and
social deficits but also by a mysterious talent
that appears spontaneously-usually before age
6.
Sometimes the ability of a savant is so striking,
it eventually makes news. The most famous savant
was a man called Joseph, the individual Dustin
Hoffman drew upon for his character in the 1988
movie Rain Man. Joseph could immediately answer
this question: "What number times what number
gives 1,234,567,890?" His answer was "Nine
times 137,174,210."
Another savant could double 8,388,628 up to 24
times within several seconds, yielding the sum
140,737,488,355,328. A 6-year-old savant named
Trevor listened to his older brother play the
piano one day, then climbed onto the piano stool
himself and played it better. A savant named Eric
could find what he
called the "sweet spot" in a room full
of speakers playing music, the spot where
sound waves from the different sources hit his
ears at exactly the same
time.
Most researchers have offered a simple explanation
for these
extraordinary gifts: compulsive learning. But
Allan Snyder, a vision
researcher and award-winning physicist who is
director of the Center for
the Mind at the University of Sydney and the Australian
National University,
has advanced a new explanation of such talents.
"Each of us has the innate
capacity for savantlike skills," says Snyder,
"but that mental machinery
is unconscious in most people."
Savants, he believes, can tap into the human mind's
remarkable
processing abilities. Even something as simple
as seeing, he explains,
requires phenomenally complex information processing.
When a person looks
at an object, for example, the brain immediately
estimates an object's
distance by calculating the subtle differences
between the two images on each
retina (computers programmed to do this require
extreme memory and speed).
During the process of face recognition, the brain
analyzes countless details,
such as the texture of skin and the shape of the
eyes, jawbone, and lips. Most
people are not aware of these calculations. In
savants, says Snyder, the
top layer of mental processing-conceptual thinking,
making conclusions-is
somehow stripped away. Without it, savants can
access a startling capacity
for recalling endless detail or for performing
lightning-quick calculations.
Snyder's theory has a radical conclusion of its
own: He believes it may be
possible someday to create technologies that will
allow any nonautistic
person to exploit these abilities.
The origins of autism are thought to lie in early
brain development. During the first three years
of life, the brain grows at a tremendous rate.
In autistic children, neurons seem to connect
haphazardly, causing
widespread abnormalities, especially in the cerebellum,
which integrates
thinking and movement, and the limbic region,
which integrates experience
with specific emotions. Abnormalities in these
regions seem to stunt
interest in the environment and in social interaction.
Autistic children
have narrowed fields of attention and a poor ability
to recognize faces.
They are more likely to view a face, for example,
as individual components
rather than as a whole. Imaging studies have shown
that when autistic
children see a familiar face, their pattern of
brain activation is different from that of normal
children.
That narrowed focus may explain the autistic child's
ability to concentrate endlessly on a single repetitive
activity, such as rocking in a chair or watching
clothes tumble in a dryer. Only one out of 10
autistic children show special skills.
In a 1999 paper, Snyder and his colleague John
Mitchell challenged
the compulsive-practice explanation for savant
abilities, arguing that the
same skills are biologically latent in all of
us. "Everyone in the world was
skeptical," says Vilayanur Ramachandran,
director of the Center for Brain
and Cognition at the University of California
at San Diego. "Snyder
deserves credit for making it clear that savant
abilities might be extremely
important for understanding aspects of human nature
and creativity."
Snyder's office at the University of Sydney is
in a Gothic building,
complete with pointed towers and notched battlements.
Inside, Nadia's
drawings of horses adorn the walls; artwork by
other savants hangs in
nearby rooms.
Snyder's interest in autism evolved from his studies
of light and
vision. Trained as a physicist, he spent several
years studying fiber
optics and how light beams can guide their own
path. At one time he was
interested
in studying the natural fiber optics in insects'
eyes. The question that
carried him from vision research to autism had
to do with what happens
after light hits the human retina: How are the
incoming signals transformed into
data that is ultimately processed as images in
the brain?
Snyder was fascinated by the processing power
required to accomplish such a feat. During a sabbatical
to Cambridge in 1987, Snyder devoured
Ramachandran's careful studies of perception and
optical illusions. One
showed how the brain derives an object's three-dimensional
shape: Falling
light creates a shadow pattern on the object,
and by interpreting the
shading, the brain grasps the object's shape.
"You're not aware how your
mind comes to those conclusions," says Snyder.
"When you look at a ball,
you don't know why you see it as a ball and not
a circle. The reason is your
brain is extracting the shape from the subtle
shading around the ball's
surface." Every brain possesses that innate
ability, yet only artists can
do it backward, using shading to portray volume.
"Then," says Snyder, speaking slowly
for emphasis, "I asked the
question that put me on a 10-year quest"-how
can we bypass the mind's
conceptual thinking and gain conscious access
to the raw, uninterpreted
information of our basic perceptions? Can we shed
the assumptions built
into our visual processing system?
A few years later, he read about Nadia and other
savant artists in
Oliver Sacks's The Man Who Mistook His Wife for
a Hat and Other Clinical
Tales. As he sat in his Sydney apartment one afternoon
with the book in
hand, an idea surfaced. Perhaps someone like Nadia
who lacked the ability
to organize sensory input into concepts might
provide a window into the
fundamental features of perception.
Snyder's theory began with art, but he came to
believe that all savant skills, whether in music,
calculation, math, or spatial relationships, derive
from a lightning-fast processor in the brain that
divides things-time, space, or an object-into
equal parts. Dividing time might allow a savant
child to know the exact time when he's awakened,
and it might help Eric find the sweet spot by
allowing him to sense millisecond differences
in the sounds hitting his right and left ears.
Dividing space might allow Nadia to place a disembodied
hoof and mane on a page precisely where they belong.
It might also allow two savant twins to instantaneously
count matches
spilled on the floor (one said "111";
the other said "37, 37, 37").
Meanwhile, splitting numbers might allow math
savants to factor 10-digit
numbers or easily identify large prime numbers-which
are impossible to
split.
Compulsive practice might enhance these skills
over time, but Snyder
contends that practice alone cannot explain the
phenomenon. As evidence,
he cites rare cases of sudden-onset savantism.
Orlando Serrell, for example,
was hit on the head by a baseball at the age of
10. A few months later, he
began recalling an endless barrage of license-plate
numbers, song lyrics,
and weather reports.
If someone can become an instant savant, Snyder
thought, doesn't
that suggest we all have the potential locked
away in our brains? "Snyder's
ideas sound very New Age. This is why people are
skeptical," says Ramachandran.
"But I have a more open mind than many of
my colleagues simply because
I've seen [sudden-onset cases] happen."
Bruce Miller, a neurologist at the University
of California at San Francisco, has seen similar
transformations in patients with frontotemporal
dementia, a degenerative brain disease that strikes
people in their fifties and sixties. Some of these
patients, he says, spontaneously develop both
interest and skill in art and music. Brain-imaging
studies have shown that most patients with frontotemporal
dementia who develop skills have abnormally low
blood flow or low metabolic activity in their
left temporal lobe. Because language abilities
are concentrated in the left side of the
brain, these people gradually lose the ability
to speak, read, and write.
They also lose face recognition. Meanwhile, the
right side of the brain,
which supports visual and spatial processing,
is better preserved.
"They really do lose the linguistic meaning
of things," says Miller, who believes Snyder's
ideas about latent abilities complement his own
observations about frontotemporal dementia.
"There's a loss of higher-order processing
that goes on in the anterior temporal lobe."
In particular, frontotemporal dementia damages
the ventral stream, a brain region that is associated
with naming objects. Patients with damage in this
area can't name what they're looking at, but they
can often paint it beautifully. Miller
has also seen physiological similarities in the
brains of autistic savants and
patients with frontotemporal dementia. When he
performed brain-imaging
studies on an autistic savant artist who started
drawing horses at 18
months, he saw abnormalities similar to those
of artists with frontotemporal dementia: decreased
blood flow and slowed neuronal firing in the left
temporal lobe.
One blustery, rainy morning I drove to Mansfield,
a small farm town
180 miles northeast of Melbourne. I was heading
to a day clinic for
autistic adults, where I hoped to meet a savant.
The three-hour drive pitched and
rolled through hills, occasionally cutting through
dense eucalyptus
forests punctuated with yellow koala-crossing
signs. From time to time, I saw
large, white-crested parrots; in one spot, a flock
of a thousand or more in
flight wheeled about like a galaxy.
I finally spotted my destination: Acorn Outdoor
Ornaments. Within
this one-story house, autistic adults learn how
to live independently. They
also create inexpensive lawn decorations, like
the cement dwarf I see on the
roof.
Joan Curtis, a physician who runs Acorn and a
related follow-up
program, explained that while true savants are
rare, many people with
autism have significant talents. Nurturing their
gifts, she said, helps draw them
into social interaction. Guy was one of the participants
I met at Acorn.
Although he was uncomfortable shaking my hand,
all things electronic
fascinated him, and he questioned me intently
about my tape recorder.
Every horizontal surface in Guy's room was covered
with his
creations. One was an electric fan with a metal
alligator mouth on the front that
opened and closed as it rotated from side to side.
On another fan a metal
fisherman raised and lowered his pole with each
revolution. And then I saw
the sheep. Viewed from the left, it was covered
in wool. Viewed from the
right, it was a skeleton, which I learned Guy
had assembled without any
help. Guy didn't say much about himself. He cannot
read nor do arithmetic,
but he has built an electric dog that barks, pants,
wags its tail, and
urinates.
During my visit, another Acorn participant, Tim,
blew into the room
like a surprise guest on The Tonight Show. He
was in a hurry to leave
again, but asked me my birthday-July 15, 1970.
"Born on a Wednesday, eh?" he responded
nonchalantly-and correctly.
"How did you do that?" I asked.
"I did it well," he replied.
"But how?" I asked.
"Very well," he replied, with obvious
pleasure. Then he was out the
door and gone.
How do calendar savants do it? Several years ago
Timothy Rickard, a
cognitive psychologist at the University of California
at San Diego,
evaluated a 40-year-old man with a mental age
of 5 who could assign a day
of the week to a date with 70 percent accuracy.
Because the man was blind from
birth, he couldn't study calendars or even imagine
calendars. He couldn't
do simple arithmetic either, so he couldn't use
a mathematical algorithm. But
he could only do dates falling within his lifetime,
which suggests that he
used memory.
He could, however, do some arithmetic, such as
answer this question:
If today is Wednesday, what day is two days from
now? Rickard suspects
that memorizing 2,000 dates and using such arithmetic
would allow 70 percent
accuracy. "That doesn't reduce it to a trivial
skill, but it's not
inconceivable that someone could acquire this
performance with a lot of
effort," he says. It's especially plausible
given the single-minded drive
with which autistics pursue interests.
Yet Tim, the savant at Acorn, can calculate dates
as far back as
1900, as well as into the future. And there are
reports of twins who could
calculate dates 40,000 years in the past or future.
Still, practice may be
part of it. Robyn Young, an autism researcher
at Flinders University in
Adelaide, Australia, says some calendar savants
study perpetual calendars
several days a week (there are only 14 different
calendar configurations;
perpetual calendars cross-reference them to years).
But even if savants practice, they may still tap
into that universal
ability Snyder has proposed. Here it helps to
consider art savants. That
Nadia began drawings with minor features rather
than overall outlines
suggests that she tended to perceive individual
details more prominently
than she did the whole-or the concept-of what
she was drawing. Other
savant artists draw the same way.
Autistic children differ from nonautistic children
in another way.
Normal kids find it frustrating to copy a picture
containing a visual
illusion, such as M. C. Escher's drawing in which
water flows uphill.
Autistic children don't. That fits with Snyder's
idea that they're
recording what they see without interpretation
and reproducing it with ease in their own drawings.
Even accomplished artists sometimes employ strategies
to shake up
their preconceptions about what they're seeing.
Guy Diehl is not a savant,
but he is known for his series of crystal-clear
still lifes of stacked
books, drafting implements, and fruit. When Diehl
finds that he's hit a
sticking point on a painting, for example, he
may actually view it in a
mirror or upside down. "It reveals things
you otherwise wouldn't see,
because you're seeing it differently," he
says. "You're almost seeing it
for the first time again."
Diehl showed me how art students use this technique
to learn to
draw. He put a pair of scissors on a table and
told me to draw the negative
space around the scissors, not the scissors themselves.
The result: I felt I was
drawing individual lines, not an object, and my
drawing wasn't half bad,
either.
Drawing exercises are one way of coaxing conceptual
machinery to
take five, but Snyder is pursuing a more direct
method. He has suggested that a
technique called transcranial magnetic stimulation,
which uses magnetic
fields to disrupt neuronal firing, could knock
out a normal person's
conceptual brain machinery, temporarily rendering
him savantlike.
Young and her colleague Michael Ridding of the
University of
Adelaide tried it. Using transcranial magnetic
stimulation on 17 volunteers, they
inhibited neural activity in the frontotemporal
area. This language and
concept-supporting brain region is affected in
patients with
frontotemporal dementia and in the art savant
whom Miller studied. In this altered state, the
volunteers performed savantlike tasks-horse drawing,
calendar
calculating, and multiplying.
Five of the 17 volunteers improved-not to savant
levels, but no one
expected that, because savants practice. Furthermore,
transcranial
magnetic stimulation isn't a precise tool for
targeting brain regions. But the five
volunteers who improved were those in whom separate
neurological
assessments indicated that the frontotemporal
area was successfully targeted.
"Obviously I don't think the idea is so outlandish
anymore," says Young. "I think it
is a plausible hypothesis. It always was, but
I didn't expect we'd actually
find the things we did."
Snyder himself is experimenting with grander ideas.
"We want to
enhance conceptual abilities," he says, "and
on the other hand remove them
and enhance objectivity." He imagines a combination
of training and
hardware that might, for example, help an engineer
get past a sticking point on a
design project by offering a fresh angle on the
problem. One method would
involve learning to monitor one's own brain waves.
By watching one's own
brain waves during drawing exercises, Snyder imagines
it may be possible
to learn to control them in a way that shuts down
their concept-making
machinery-even the left temporal lobe itself.
Even if further research never fully reveals why
savants have
extraordinary skills, we may at least learn from
their potential. Snyder
is optimistic. "I envisage the day,"
he says, "when the way to get out of a
[mental rut] is you pick up this thing-those of
us with jobs that demand a
certain type of creativity-and you stimulate your
brain. I'm very serious
about this."
http://www.feat.org
|