Quiet: The Power of Introverts in a World That Can\'t Stop Talking pdfdrive com

parties full of kids she doesn’t know? But what we’re really observing is
a child’s sensitivity to novelty in general, not just to people.
High-and low-reactivity are probably not the only biological routes to
introversion and extroversion. There are plenty of introverts who do not
have the sensitivity of a classic high-reactive, and a small percentage of
high-reactives grow up to be extroverts. Still, Kagan’s decades-long series
of discoveries mark a dramatic breakthrough in our understanding of
these personality styles—including the value judgments we make.
Extroverts are sometimes credited with being “pro-social”—meaning
caring about others—and introverts disparaged as people who don’t like
people. But the reactions of the infants in Kagan’s tests had nothing to
do with people. These babies were shouting (or not shouting) over Q-
tips. They were pumping their limbs (or staying calm) in response to
popping balloons. The high-reactive babies were not misanthropes in the
making; they were simply sensitive to their environments.
Indeed, the sensitivity of these children’s nervous systems seems to be
linked not only to noticing scary things, but to noticing in general. High-
reactive children pay what one psychologist calls “alert attention” to
people and things. They literally use more eye movements than others to

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compare choices before making a decision. It’s as if they process more
deeply—sometimes consciously, sometimes not—the information they
take in about the world. In one early series of studies, Kagan asked a
group of first-graders to play a visual matching game. Each child was
shown a picture of a teddy bear sitting on a chair, alongside six other
similar pictures, only one of which was an exact match. The high-
reactive children spent more time than others considering all the
alternatives, and were more likely to make the right choice. When Kagan
asked these same kids to play word games, he found that they also read
more accurately than impulsive children did.
High-reactive kids also tend to think and feel deeply about what
they’ve noticed, and to bring an extra degree of nuance to everyday
experiences. This can be expressed in many different ways. If the child is
socially oriented, she may spend a lot of time pondering her
observations of others—why Jason didn’t want to share his toys today,
why Mary got so mad at Nicholas when he bumped into her
accidentally. If he has a particular interest—in solving puzzles, making
art, building sand castles—he’ll often concentrate with unusual intensity.
If a high-reactive toddler breaks another child’s toy by mistake, studies
show, she often experiences a more intense mix of guilt and sorrow than
a lower-reactive child would. All kids notice their environments and feel
emotions, of course, but high-reactive kids seem to see and feel things
more. If you ask a high-reactive seven-year-old how a group of kids
should share a coveted toy, writes the science journalist Winifred
Gallagher, he’ll tend to come up with sophisticated strategies like
“Alphabetize their last names, and let the person closest to A go first.”
“Putting theory into practice is hard for them,” writes Gallagher,
“because their sensitive natures and elaborate schemes are unsuited to
the heterogeneous rigors of the schoolyard.” Yet as we’ll see in the
chapters to come, these traits—alertness, sensitivity to nuance, complex
emotionality—turn out to be highly underrated powers.
Kagan has given us painstakingly documented evidence that high
reactivity is one biological basis of introversion (we’ll explore another

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likely route in 
chapter 7
), but his findings are powerful in part because
they confirm what we’ve sensed all along. Some of Kagan’s studies even
venture into the realm of cultural myth. For example, he believes, based
on his data, that high reactivity is associated with physical traits such as
blue eyes, allergies, and hay fever, and that high-reactive men are more
likely than others to have a thin body and narrow face. Such conclusions
are speculative and call to mind the nineteenth-century practice of
divining a man’s soul from the shape of his skull. But whether or not
they turn out to be accurate, it’s interesting that these are just the
physical characteristics we give fictional characters when we want to
suggest that they’re quiet, introverted, cerebral. It’s as if these
physiological tendencies are buried deep in our cultural unconscious.
Take Disney movies, for example: Kagan and his colleagues speculate
that Disney animators unconsciously understood high reactivity when
they drew sensitive figures like Cinderella, Pinocchio, and Dopey with
blue eyes, and brasher characters like Cinderella’s stepsisters, Grumpy,
and Peter Pan with darker eyes. In many books, Hollywood films, and
TV shows, too, the stock character of a reedy, nose-blowing young man
is shorthand for the hapless but thoughtful kid who gets good grades, is
a bit overwhelmed by the social whirl, and is talented at introspective
activities like poetry or astrophysics. (Think Ethan Hawke in 
Dead Poets
Society
.) Kagan even speculates that some men prefer women with fair
skin and blue eyes because they unconsciously code them as sensitive.
Other studies of personality also support the premise that extroversion
and introversion are physiologically, even genetically, based. One of the
most common ways of untangling nature from nurture is to compare the
personality traits of identical and fraternal twins. Identical twins develop
from a single fertilized egg and therefore have exactly the same genes,
while fraternal twins come from separate eggs and share only 50 percent
of their genes on average. So if you measure introversion or extroversion
levels in pairs of twins and find more correlation in identical twins than
in fraternal pairs—which scientists do, in study after study, even of twins
raised in separate households—you can reasonably conclude that the
trait has some genetic basis.
None of these studies is perfect, but the results have consistently
suggested that introversion and extroversion, like other major
personality traits such as agreeableness and conscientiousness, are about

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40 to 50 percent heritable.
But are biological explanations for introversion wholly satisfying?
When I first read Kagan’s book 
Galen’s Prophecy
, I was so excited that I
couldn’t sleep. Here, inside these pages, were my friends, my family,
myself—all of humanity, in fact!—neatly sorted through the prism of a
quiescent nervous system versus a reactive one. It was as if centuries of
philosophical inquiry into the mystery of human personality had led to
this shining moment of scientific clarity. There was an easy answer to
the nature-nurture question after all—we are born with prepackaged
temperaments that powerfully shape our adult personalities.
But it couldn’t be that simple—could it? Can we really reduce an
introverted or extroverted personality to the nervous system its owner
was born with? I would guess that I inherited a high-reactive nervous
system, but my mother insists I was an easy baby, not the kind to kick
and wail over a popped balloon. I’m prone to wild flights of self-doubt,
but I also have a deep well of courage in my own convictions. I feel
horribly uncomfortable on my first day in a foreign city, but I love to
travel. I was shy as a child, but have outgrown the worst of it.
Furthermore, I don’t think these contradictions are so unusual; many
people have dissonant aspects to their personalities. And people change
profoundly over time, don’t they? What about free will—do we have no
control over who we are, and whom we become?
I decided to track down Professor Kagan to ask him these questions in
person. I felt drawn to him not only because his research findings were
so compelling, but also because of what he represents in the great
nature-nurture debate. He’d launched his career in 1954 staunchly on
the side of nurture, a view in step with the scientific establishment of the
day. Back then, the idea of inborn temperament was political dynamite,
evoking the specter of Nazi eugenics and white supremacism. By
contrast, the notion of children as blank slates for whom anything was
possible appealed to a nation built on democracy.
But Kagan had changed his mind along the way. “I have been dragged,
kicking and screaming, by my data,” he says now, “to acknowledge that
temperament is more powerful than I thought and wish to believe.” The
publication of his early findings on high-reactive children in 
Science
magazine in 1988 helped to legitimize the idea of inborn temperament,