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Braintwisters
The Myth of the First Three Years: A New Understanding
of Early Brain Development and Lifelong Learning
by John T. Bruer
Free Press. 244 pp. $25.00
Reviewed by
Christopher F. Chabris
In April 1997, Bill and Hillary Clinton co-hosted something called the
"White House Conference on Early Childhood Development and Learning: What New
Research on the Brain Tells Us About Our Youngest Children." This event, widely
reported in the media, was designed in part to send an important message to
America's parents: a child's experiences and environment during his first three
years play a crucial role in determining the course of his later life, directly
affecting how his brain will develop and thus his intelligence, his ability to
learn, and his lifelong mental health.
At the White House conference, the idea that "the first years last forever"
where the brain is concerned was not a point of debate but a point of
departure--and one, moreover, that was said to be well established by
cutting-edge research. Yet as John T. Bruer shows, this view of infant
development, which has become an ever more deeply entrenched piece of
conventional wisdom, is a myth. Bruer is the president of the James S.
McDonnell Foundation in St. Louis, which supports research in psychology and
neuroscience. He happened to attend the White House conference--where, despite
the ritual genuflections to brain research, only one neuroscientist was
included among the speakers and the relationship between neuroscience and most
of what was discussed was merely rhetorical. He was disturbed enough by what he
observed, and by the larger phenomenon it illustrated, to produce this
significant book.
THE BELIEF that early experience is important for the developing child is not
false; indeed, in some obvious (and therefore trivial) ways it must be true. A
child raised alone in a dark closet for 36 months will not emerge looking and
acting like a normal, healthy three-year-old, and the effects of the isolation
will never be fully reversed. But, as Bruer persuasively argues, aside from
offering a superfluous injunction against such extreme cases of neglect,
research in neuroscience, in and of itself, tells us little about effective
child-rearing.
Not that this area of research is without promise; quite the contrary. What
exercises Bruer is, rather, the misappropriation of its findings to serve banal
public-policy purposes. Examples of such misappropriation abound, and he has
collected a good number of them here. They include the call that went out from
the White House conference, in the name of science, for initiating or
expanding a variety of government programs aimed at helping disadvantaged
children, and the lament by the Boston Globe columnist Thomas Oliphant
that "the undeniable fact that the human brain is almost entirely formed in the
first three years is mocked by the fact that hardly any social resources are
aimed at this critical period." All such pronouncements tend to be built on
overgeneralization from and misinterpretation of three basic findings that have
emerged from brain science over the past few decades.
First, synapses--the connections among brain cells that enable them to
communicate with one another--are formed at a very fast rate as the brain
develops during the early years of life. Second, there are "critical periods"
for brain development, during which the child must receive appropriate
stimulation if catastrophic interruption is to be avoided. Third, the
environment in which an animal is raised can affect the development of its
brain.
Contrary to those who have made a myth of the first three years, however, none
of this indicates the existence of some grand critical period for the entire
brain, or that "enriching" a child's environment while new synapses are forming
will create more connections and "build a better brain." Nor does it mean that
if the alleged critical period is allowed to expire without the benefits of
enrichment, the number of synapses will be fixed and the child's experiences
will no longer affect how his brain works or how he functions in the world.
For one thing, there is no known link between the number of synapses in the
brain and the intellectual capacity of a child (or, for that matter, an adult).
To the contrary, massive "pruning" or removal of synapses occurs during the
later stages of childhood when new mental abilities are developing at a rapid
clip. Moreover, although Bruer does not raise this point, increasing ability in
performing a mental task leads to less use of brain resources for that
task. For still another thing, critical periods in development apply neither to
the entire brain nor to the entire interval when new skills are being acquired
but only to a limited range of basic brain functions, as when the visual system
begins to integrate the slightly different images registered by our two eyes.
Finally, extrapolating from studies performed on animals to draw conclusions
about human behavior--let alone about social policy--is an enterprise fraught
with risk. Experiments on the brain development of rats, though widely cited as
proving the claims of the mythmakers, have not compared "normal" and "enriched"
environments but what are best described as "deprived" and "less-deprived"
environments. Whatever limited implications these experiments might have for
human beings, the benefits of an environment that is indisputably richer in
stimulation--exposing an infant, say, to fifteen minutes of music per day as
opposed to placing him in complete silence for the same interval--cannot be
proved by studying rats, whose brains have evolved to face a very different set
of environmental challenges and developmental events from our own.
BRUER EXPLORES all these points at length, delving deep into the history of the
early-years' myth, analyzing its historical antecedents and founding documents
(which consist primarily of thinly reasoned magazine articles, popular-science
books, and foundation reports), and tracing the way it has established itself
in the popular mind and marketplace.
His presentation drags at times, but that may be because there is no breezy or
entertaining way to refute an appealing myth by means of sober facts of history
and science, which is what Bruer has done. Much more regrettable is that he has
needlessly chosen to denigrate Richard J. Herrnstein and Charles Murray's
The Bell Curve rather than to discuss the growing evidence of genetic
influence on intelligence, personality, and behavior--evidence that would only
strengthen his own case. Still, Bruer has performed a valuable public service,
for the myth he demolishes and the public mindset in which it has thrived have
costs that extend beyond dollars and cents and the misallocation of government
resources.
The more we depend on science to shape our choices, the more we lose sight of
other perfectly valid reasons to act as we should. If parents come to play with
their children, read to them, and talk with them on purely instrumental grounds
alone--because doing so "builds better brains"--what will they do if those
grounds should be disproved, as Bruer has disproved the myth of the first three
years? Will that then give parents a reason for neglect?
The question may seem frivolous, but it points to where the real danger lies:
in the ever-greater reliance of ordinary people on alleged scientific facts to
guide decisions and behavior that should rather be directed by their common
reason. In the face of the flood of new claims and counterclaims about health,
education, and public policy, what we need is not an unreflective dependence on
what "new studies show" but the application of skeptical logic and an
appreciation that many scientific facts are still subjects of debate, not
eternal truths. To those ends, The Myth of the First Three Years makes a
signal contribution.
CHRISTOPHER F. CHABRIS is a cognitive neuroscientist at Massachusetts
General Hospital and Harvard Medical School.
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