Learning How To Use the Brain
by Ronald Kotulak
Why are IQ levels rising throughout the developed world? In the U.S.,
for instance, the average IQ has climbed 24 points since 1918. Similar
increases were registered in other countries.
We like to think of ourselves as the top of the line, the epitome of a
long lineage of human beings. But we still have a lot to learn about our
brains and our bodies.
Not too long ago breaking the four minute mile was thought to be
impossible. But once that barrier was breached by Roger Bannister in 1954,
it set the stage for the rise of the superathlete. Today runners routinely
run a mile in less than four minutes and every Olympics sees old records
smashed.
A similar phenomenon is happening to the brain. Not too long ago the
brain was considered to be hard-wired. For the most part, people were not
concerned about the development of a child's brain until he or she went
off to school.
Scientists are finding that this notion is as much of a myth as the
unbreakable four-minute mile. There is a growing recognition today that
the kind of experiences the brain is exposed to in the first three years
dramatically influence how it operates-for the rest of its life.
Some revolutions are obvious because they are fought with weapons.
Others, especially those that require new ways of thinking, tend to sneak
up on us. The revolution in brain research is only now revealing itself.
For the past 5 to 10 years scientists have been busy figuring out how the
brain gets built, how it gets damaged and how it can be repaired.
At the core of this new knowledge is the plasticity factor, a term that
scientists use to describe the brains amazing ability to constantly change
its structure and function in response to experiences coming in from the
outside. They recently discovered chemical lifesavers inside the brain
called neurotrophic factors, which are critical for the development and
maintenance of brain cells. Scientists are searching for ways to replenish
these vital chemicals when they decline with age.
With the growing understanding of how the brain works comes the
opportunity to increase brain power. Who wouldn't want to improve their
memory, stop forgetfulness and prevent Alzheimer's disease and other
neurodegenerative disorders. For me this is the best time to be a science
writer because the powerful new tools of molecular biology and genetic
engineering are revolutionizing most fields.
Look what's happened to cancer. Ten or so years ago cancer was thought
to be more than 100 different diseases and scientists didn't' t think they
would ever understand it. But, using molecular biology's new tools, they
have solved cancer's mystery. Cancer is a derangement of normal genes. In
a sense, we all carry the seeds of our own cancers in our genetic codes.
How does that happen? Genes that promote cell division can cause cancer
when they forget to turn off. They are like accelerators stuck to the
floor. But cancers can also result when the brakes fail, as when genes
that are supposed to regulate cell division fall asleep on the job.
Turning those same tools loose in neuroscience is producing a similar
revolution. Scientists have learned more about the brain in the past 5
years than in the last 100. The explosion of new knowledge has led
scientists to a greater understanding of the brain's biology and to
finding potential causes of violence. What we thought we knew about the
relationship between a deprived or bad upbringing and the increased risk
of criminal behavior is now being traced to the brain's chemistry. It is
the biological smoking gun of violence. We are now finding the molecular
answers to the things that happen to the brain that we could only grope
for with older techniques - such as psychology, psychiatry, and sociology.
Now we can see thoughts with new imaging devices that can spy on the
living, working brain, and we can eavesdrop on individual brain cells to
listen to their chatter. With this new technology we can begin to
understand through genes, chemistry and experience the sayings, which were
based only on observation, "the child is father to the man" and
"as the twig is bent, so grows the tree." It also is evident now
why a child can easily learn a new language in a foreign country, if he or
she does so at the age when the brain cells that process language are
being wired.
And this new knowledge puts to rest the old, contrived argument of
which is more important, nature or nurture, genes or environment. Do we
come into the world fully programmed to act the way we do or are we blank
slates waiting to be written upon? The answer is that genes and
environment are probably equally important. The environment affects how
genes work and genes determine how the environment is interpreted.
Most people are delighted with all the new information about the organ
that is most curious to us. But some don't believe it and others are
afraid of it, convinced that such research is a plot to discriminate
against some groups, or gain mind control over others.
I suppose it is somewhat disconcerting to realize that our thoughts are
created by molecules and that the molecules are manipulated by our
experiences. But, instead of being limiting, or threatening, I believe the
new knowledge about the brain is enlightening and liberating.
My foray into this revolution began in 1992 when then editor of The Chicago
Tribune, Jack Fuller, was getting ready to launch a year-long project
called "Killing Our Children." He asked if there was anything
going on in brain research that might be helpful. For me that was like
being given the keys to the candy store.
As I began to dig in, what initially turned me on was the work of the
University of Chicago's Peter Huttenlocher. He was, for the first time,
counting synapses, the telephone lines that enable brain cells to
communicate with each other. These connections are so small and so
numerous that they had previously defied a scientific census.
From autopsies of the brains of fetuses and people ranging in age from
a few months to their nineties, he took samples about the size of the head
of a pin, each containing about 70,000 brain cells. In a sample from a
28-week-old fetus he found 124 million connections between the cells. The
same size sample in a newborn had 253 million synaptic connections and in
an 8 month old the number exploded to 572 million.
At the fastest rate, connections were being built at the incredible
speed of 3 billion a second, eventually reaching a total of about 1,000
trillion connections in the whole brain. After that point, the connections
begin a gradual decline. By about age 10 or so, half the connections have
died off, leaving about 500 trillion, a number that remains fairly
constant through most of life.
Obviously something pretty terrific was going on. I then became curious
about what was happening to the brain cells themselves. I learned that
scientists had found a similar explosion there, but it occurred during
fetal development. From conception to about halfway through fetal life,
brain cells grow from one to about 200 billion. Then brain cells begin to
die off, leveling off at about 100 billion at birth, the number that
remain through adulthood.
Again, something amazing was happening. Both phenomena were examples of
genetic frugality. Humans do not contain anywhere near enough genes to
make a fully operational brain at birth. So they are given an
overabundance of the same or similar cells and connections between them
and the brain then has to learn how to make itself work.
A surplus of brain cells makes sure that there are enough available for
the awakening body to plug into to make the heart beat, muscles twitch,
lungs breathe and eyes move. Brain cells compete for the jobs. It's as if
they all come out of the same mold but have to learn different jobs,
depending on where they find themselves. Those cells that don't connect
die off. There is some thought that the extra cells also give the brain
the ability to evolve new capacities, such as language and abstract
thinking.
A similar thing happens to the synaptic connections after birth. Twice
as many are made to guarantee that a newborn will be able to receive input
from any environment it is born into, whether it's Chicago or Calcutta,
and to adapt to the food, language and culture.
The outside world shapes the brain's architecture. The connections that
do not become part of this structure perish. The outside world comes in
through the senses -- vision, hearing, smell, touch, taste -- teaching the
brain what to become.
As I continued my research, other pieces of the puzzle began to fall
into place. One was a fairly old piece. In the 70s Torsten Wiesel and
David Hubel sewed shut one eye of newborn kittens. Two weeks later the
eyes were opened. Although anatomically perfect, the eyes that had been
closed could not see.
It was the most vivid evidence that there are critical stages of
development in which the brain needs the right kind of outside stimulation
to teach brain cells how to do their jobs. In this case it was vision. But
it is also true for speech and other functions.
During critical developmental periods, brain cells that normally
process vision do not learn how to do so if no visual stimuli come in to
activate them. They either go off to perform another job, such as helping
to process information coming in through the uncovered eye, or they
shrivel and die.
This discovery had an immediate impact on children who are born with
cataracts. Doctors used to wait until the children were older and stronger
before removing-the cataracts. They found, to their dismay, that while the
children's eyes were perfect, they couldn't see. The same thing that had
happened to Wiesel's and Hubel's cats was happening to these children.
Learning that early visual stimulation was essential for the cells in
the visual cortex to be able to see, surgeons began removing cataracts as
soon after birth as possible. Today thousands of children born with
cataracts have sight who otherwise wouldn't. That's something to remember
when you think about the need for animal research.
Another piece of the puzzle was provided by Bill Greenough of the
University of Illinois. He exposed one group of rats to a stimulating
environment - toys, colors, playmates, exercise devices, challenges. A
comparison group of rats was housed in routine laboratory cages with
little stimulation.
When Greenough looked at the brains of the animals in the two groups he
found the key to building brain power. The animals living in the
stimulating environment had 25 percent more connections between their
brain cells than the control rats, and they were a lot smarter.
For a human being, that translates into trillions of extra connections
- and remember, connections mean brain power - and possibly a boost in IQ
of 20 points or more.
What Huttenlocher was seeing in his autopsy studies, and Greenough,
Wiesel and Hubel were seeing in animal studies, researcher Harry Chugani
was seeing in people.
Using PET scans, which can follow the chemistry of thoughts in living
brains, Chugani found that the brain is superactive from the ages of 4 to
about 10, the years in which brain cells are vigorously learning which
connections to keep and which to discard. These are the wonder years of
learning, when a child can easily pick up a foreign language without an
accent and learn a musical instrument with ease. You can learn a foreign
language in adulthood, but it is much harder and you will have an accent.
Responding to these new findings about the role that the environment plays
in physically shaping the brain, especially during the critical periods of
development, the National Institute of Mental Health has refocused its
mission. Its goal now is to promote earlier and earlier intervention
strategies to prevent some of the bad things that are associated with
stressful environments during childhood.
In its recent report, Starting Points, the influential Carnegie
Corporation of New York said the first three years of a child's life are
vitally important to brain development. Unfortunately, for a growing
number of children the period from birth to age three has become a mental
wasteland. Society, said the Carnegie report, needs to invest adequate
resources in helping these children at this critical period in their lives
if we are to stem the growing epidemic of violence.
There is increasing concern that the lack of proper stimulation, may be
damaging brains. The same may be true of too much exposure to the wrong
kind of stimulation, such as violence. Indeed, in the last 25 years there
has been a doubling, of the rates of crimes of violence, depression,
suicide, and drug and alcohol abuse.
The culprit, many scientists now fear, may well be brain cells that do
not learn what they are supposed to do because they have been deprived of
normal stimulation on the one hand and overexposed to violence and
stressful events on the other.
For millions of American children the world they encounter is
relentlessly menacing and hostile. So, with astounding speed and
efficiency, their brains adapt in an effort to protect them by preparing
for battle. Cells rewire trillions of connections that create the chemical
pathways of aggression.
But the brain does not have to be victimized. It can be prevented from
going down the wayward path.
Craig Ramey of the University of Alabama showed that what Greenough did
with animal brains by providing stimulating experiences, he could do with
children. Starting as early as 6 weeks of age, his intervention program
showed that impoverished children exposed to nurturing and mentally
stimulating experiences could be prevented from having low IQ's and mental
retardation.
After 3 years children in the intervention group had IQs in the normal
range, around 100, whereas children living in similar poor neighborhoods,
but who were not in the intervention program, averaged IQs that were 20
points lower.
By age 12, 50 percent of the children in the control group, those who
continued to live unstimulating lives, had failed one or more grades. But
only 13 percent of the children in the intervention group had a similar
failure record.
Early intervention also seems to work on middle class children. Using
Ramey's stimulating learning experiences, Jeanne Brooks-Gunn of Columbia
University's Teachers College wanted to find out if she could raise the
IQs and reduce behavioral problems of premature infants, who come into the
world at a biological disadvantage.
In a study of nearly 1,000 premature infants at 10 centers, those in
the intervention group had modest, but significantly higher IQs than
infants in the control group after three years.
Importantly, her study included middle class families as well as poor
ones, a spectrum that other intervention studies had not looked at. It
also included middle class blacks and poor whites. These across-the-board
intellectual and behavioral improvements among all socioeconomic levels
indicate that early intervention has universal powers.
Did the intellectual benefits last? The gains remained solid after five
years and appear to be holding now, some eight years later.
Just as Wiesel and Hubel showed that brain cells that normally process
vision won't work if they are not stimulated, Saul Schanberg of Duke and
Tiffany Field of the University of Miami showed that touch is also
critical to the brain.
Newborn mice separated from their mothers stop growing. The researchers
found that the mothers' licking was the cue that told the pups that all
was well and that they could continue their development. Without the
licking the brains of the pups went into a survival mode. The absence of
licking meant that the mother was not present, so there was no food. Their
brains shut down the feeding response to conserve what energy the animals
had. After a prolonged absence of licking, the pups failed to thrive. But
the pups' feeding response could be restored when the mother resumed
licking them, or when researchers stroked them with a wet artist's brush.
Knowing that premature infants who were kept in incubators bearing
"Do Not Touch" signs did not thrive, Schanberg and Field got an
idea. Human babies are not licked, but they are held and their backs are
rubbed.
The researchers found that touching preemies in this way affected their
brains, just as it did the infant mice. Stress hormones declined, and the
preemies doubled their growth rate. Thanks to this discovery, preemies are
routinely held and rubbed and they develop at a more normal rate.
Even short-term babies can benefit from massage. Field studied
normal-weight babies born to depressed adolescent mothers. These infants
have two strikes against them---their stress hormones are churning and
they receive little stimulation from their mothers. Field compared 15
minutes of massage twice a week to a similar period of rocking to
determine which technique was more effective at calming these babies.
She found that massaging significantly lowered stress hormone levels in
the babies, and that they cried less, gained more weight and showed
greater improvement in measures of emotionality, sociability and
soothability temperament. Rocking did not do much for the babies.
Once the door into the brain was opened, it was only a matter of time
before scientists realized they could study the biology of violence.
Researchers are finding that genes can be altered by environmental
stimulation to work harder or to work less, sometimes increasing a
person's risk of aggression or violence. They are also finding gene
mutations that are more easily affected by environmental factors, such as
alcohol and stress, making some people who have these mutations even more
prone to violence.
As a society we seem to be inadvertently contributing to the increased
rate of violence by what we do and what we fail to do. Among the factors
that are now implicated as potential contributors to the
genetic-environmental link to violence are the great increase in births to
unmarried teenagers, babies born into overcrowded and impoverished
environments, brain injuries, alcohol, cocaine, steroids, and lead
poisoning.
As we learn how to use the brain, we are also learning how easily it
can be damaged by the lack of the right kind of stimulation or too much of
the wrong kind, violence.
The wonderful world of molecular biology is also revealing the brain's
self-healing powers - hormones and other chemicals that nurture and
sustain brain cells. When these chemicals begin to dry up, as they
sometimes do with age and with some mental disorders, brain cells wither
and die.
Memory loss, Alzheimer's disease, Parkinson's, Huntington's, and other
degenerative diseases of the brain are now believed to be the biological
desert created when these rejuvenating chemicals vanish. If we can measure
when our brain-nurturing chemicals start to decline and restore them to
youthful levels, we may be able to cure or prevent many of the things that
go wrong with the brain.
Among the exciting new findings:
Hormones -- estrogen, progesterone, testosterone and growth hormone --
play key roles in maintaining many types of brain cells. Some of these
hormones, which may become the first effective drugs to prevent
Alzheimer's disease and memory loss, have already produced promising
preliminary results.
Estrogen, once thought to be solely a female sex hormone involved in
reproduction, is turning out to be an important rejuvenator of female and
male brains. A number of studies now show that women who are on estrogen
replacement therapy after menopause have a dramatically lower risk of
developing Alzheimer's, in addition to their greatly reduced risk of heart
disease and osteoporosis.
Drugs are improving learning and memory in animals and some of them are
being tested in humans. In one study at Northwestern University Medical
School, researchers are testing a drug that boosts memory in normal older
adults by 50 percent as measured on a test.
Brain chemicals called neurotrophic factors keep cells healthy and
communicating with each other. When these factors diminish or disappear,
the brain cells they nourish shrivel up. Prodded by the National
Institutes of Health, scientists are gearing up to test one of them, nerve
growth factor, to determine if it can stop the destruction caused by
Alzheimer' s disease. Other neurotrophic factors may make it possible to
grow new brain cells to replace missing ones.
Is there a bottom line to this new research? Most certainly. The
amazing discovery of the brain's plasticity - its ability to physically
rewire itself to become smarter - makes mental stimulation, in the long
run, more essential to the body than food. That the brain thrives with
good nourishment is a concept that has profound significance for
individual achievement and for the way parents raise their children.
The brain's food is education. Just as the food we eat gives our immune
systems the strength to fight off life-threatening infectious germs,
education protects us against bad choices. In effect, education acts like
a vaccine that boosts our mental powers, making us more resistant to
illness and premature aging.
Education provides such strong immunity, in fact, that people who
acquire more of it are living longer than ever before while those who
don't have it are falling farther behind. It is the secret to a healthier,
longer life.
For people who don't grab at the opportunity for education, the news is
grim. They are on the wrong end of a widening gap between people who build
more brain power and those who ignore it, and they are more likely to die
younger.
Despite an overall decline in death rates in the U.S. since 1960,
poorly educated low income white males die at rates that are three to
seven times higher than white men with better education or higher income,
Dr. Gregory Pappas of the National Center for Health Statistics found in a
1993 study.
The earlier education is acquired, the more impact it has against
sickness and early death. Education throughout life acts like a continuing
series of booster shots.
Education works in two fundamental ways:
Biologically, by laying down significantly more connections between
brain cells that accompany learning. Memory, as a result, is increased and
the additional connections also provide a buffer against the destructive
forces of Alzheimer's disease.
Behaviorally, by promoting positive values and attitudes about health,
higher self-esteem, effective coping skills, access to preventive health
services and association with people who have similar views. At the same
time, education reduces risky behaviors such as smoking.
Just as some people fail to get vaccinated against common childhood
infections, others fail to take advantage of the immunizing effects of
education. Half of all high school students in Chicago and some other
large cities, for instance, fail to graduate.
The toll this takes on the brain is staggering. Children born to
mothers who have less than 12 years of education have a fourfold increased
risk of mental retardation, said Dr. Marshalyn Yeargin-Allsop, a medical
epidemiologist at the CDC's Division of Birth Defects and Developmental
Disabilities. "This regardless of race," she said. "White
children had the same fourfold risk as black children if their mothers
didn't complete high school."
A CDC study of more than 1,000 children showed that mild retardation,
defined as having an IQ between 5O and 70, occurs at the rate of nearly
one in 100 children. The biggest risk factor for mild retardation is the
mother's low educational level, which far exceeds the risk posed by
poverty. About 22 percent of all births in this country are to mothers
with less than a high school education, Yeargin-Allsop said. These women
often do not know how to provide stimulation - such as talk, toys, and
physical activity - to their infants, which can lead to stunting of the
brain during the crucial first three years of life, she explained.
Mild mental retardation is generally believed to be caused by a failure
to provide the brain with the kinds of experiences from its surrounding
world that it needs to develop to its maximum capacity. Early educational
intervention programs for children at-risk have shown that they can
increase IQ levels by 15 points or more.
"At least half of the cases of mild mental retardation are
preventable," Yeargin-Allsop said. "We can leapfrog over the
risks if young people stay in school and get as much education as they
can."
If early education is like a vaccine against risk factors, then giving
it to poor, deprived children should help protect them as they grow older.
That's what David Weikart, president of the groundbreaking High-Scope
Perry Preschool Study in Ypsilanti, Michigan, set out to prove in the late
60s.
Weikart randomly divided 127 African American children ages 3 and 4
into two groups. The children were born into poverty and had a high risk
of failing in school. One group received intensive preschool education 2.5
hours a day for 3.0 weeks. The other group served as controls.
"The educational program focused on getting kids to make choices
between things that might either be good or bad for them and to invent
solutions to the problems they were working on," he said.
Now, 27 years later, the children who were in the intervention program
are doing significantly better as adults than the controls. Seventy-one
percent of them finished high school compared to 54 percent of the
controls.
And they have less risky lifestyles. The children who were in the
education program have less than one-third the risk of being arrested for
drugs as the controls, and girls in the program are one-third less likely
to have babies out-of-wedlock than their peers in the control group. Those
in the program are less likely to have been on welfare and more likely to
own their own homes, have good jobs and be in a stable marriage.
Society benefits too. For every dollar initially spent on educating the
children in the intervention group, the public is receiving $7.16 in
savings from reduced crime, reduced welfare, reduced cost of education and
more tax payment on earnings.
The evidence continues to grow that low IQ levels are preventable in
many children if they are given the right help early in their lives.
But, getting back to the question at the beginning of my talk, why are
overall IQ levels rising? Researchers looking at this phenomenon have come
up with three possible explanations. The boom in technology since the
Industrial Revolution has improved mental skills. The average American has
more education than ever before, and better educated parents tend to have
children with higher IQ' s. Today' s better education enables brain cells
to work efficiently. All of these add up to the fact that we are using our
brains more. The questions now are how much higher can IQ scores rise? How
much smarter can we become? Is there a limit?
~~~~~~~~~~
© 1997, New Horizons for Learning. All rights
reserved.
Source - Paper presented by Ronald Kotulak
(Science Writer, Chicago Tribune), at the "Brain Development
in Young Children: New Frontiers for Research, Policy and
Practice" Conference in Chicago, on June 13, 1996. It is
posted on NLD on the Web! with the permission of New
Horizons for Learning.
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