Once, parents were given all the credit -- and all the blame -- for how
their children turned out. Then researchers told us that heredity
determines who we are. The latest take: parents can work with their
children's innate tendencies to rear happy, healthy kids. It's a message
many parents will find reassuring -- but it may make others very
nervous.
David Reiss, M.D., didn't want to believe it. The George Washington
University psychiatrist had worked for more than 12 years on a study of
adolescent development -- just completed -- and its conclusions were a
surprise, to say the least. "I'm talking to you seven or eight years
after the initial results came out, so I can sound very calm and
collected now," says Reiss. "But I was shocked." This, even though other
scientists had previously reached similar conclusions in many smaller
scale studies. "We knew about those results, but we didn't believe it,"
says Reiss, speaking of himself and one of his collaborators, E. Mavis
Heatherington, Ph.D. "Now we've done the research ourselves, so... " He
sighs. "We're not ever going to believe it, but we're going to have to
act as if we do."
What Reiss and his colleagues discovered, in one of the longest and
most thorough studies of child development ever attempted, was that
parents appear to have relatively little effect on how children turn out,
once genetic influences are accounted for. "The original objective was to
look for environmental differences," says Reiss. "We didn't find many."
Instead, it seems that genetic influences are largely responsible for how
"adjusted" kids are: how well they do in school, how they get along with
their peers, whether they engage in dangerous or delinquent behavior. "If
you follow the study's implications through to the end, it's a radical
revision of contemporary theories of child development," says Reiss. "I
can't even describe what a paradigm shift it is."
The only member of the research team who wasn't surprised by the
results, Reiss recalls, was Robert Plomin, Ph.D., a researcher at the
Institute of Psychiatry in London. Plomin is a behavioral geneticist, and
he and others in his field have been saying for years what Reiss has just
begun to accept: genes have a much greater influence on our personalities
than previously thought, and parenting much less. The work of behavioral
geneticists has been the focus of considerable controversy among
psychologists, but it has been mostly ignored by parents, despite ample
attention from the media. That may be because such coverage has rarely
described just how genes are thought to wield their purported influence.
Behavioral geneticists don't claim that genes are blueprints that direct
every detail of our personality and behavior; rather, they propose that
heredity reveals itself through complex interactions with the
environment. Their theories are far more subtle, and more persuasive,
than the simple idea of heredity as destiny. It is by participating in
these very interactions, some scientists now say, that parents exert
their own considerable influence -- and they can learn to exert even
more.
NATURE MEETS NURTURE
As behavioral geneticists understand it, the way heredity shapes
who we are is less like one-way dictation and more like spirited rounds
of call and response, with each phrase spoken by heredity summoning an
answer from the environment. Scientists' unwieldy name for this exchange
is "evocative gene-environment correlations," so called because people's
genetic makeup is thought to bring forth particular reactions from
others, which in turn influence their personalities. A baby with a sunny
disposition will receive more affection than one who is difficult; an
attractive child will be smiled at more often than a homely one. And the
qualities that prompt such responses from parents are likely to elicit
more of the same from others, so that over time a self-image is created
and confirmed in others' eyes.
Even as genes are calling forth particular reactions, they're also
reaching out for particular kinds of experience. That's because each
person's DNA codes for a certain type of nervous system: one that feels
alarm at new situations, one that craves strong sensations, or one that
is sluggish and slow to react. Given an array of opportunities, some
researchers say, children will pick the ones that are most suited to
their "genotype," or genetic endowment. As they grow older, they have
more chances to choose -- friends, interests, jobs, spouses -- decisions that
both reflect and define personality.
