The science of siblings

There are a lot of ways to study a painting, and one of the best is to
get to know the painter. The splash or splatter of color makes a lot
more sense when you understand the rage or whimsy or heart behind it.
The songwriter, similarly, can lay bare the song, the poet the poem,
the builder the building.

So
what explains the complex bit of artistry that is the human
personality? We may not be born as tabulae rasae. Any parent can tell
you that each child comes from the womb with an individual temperament
that seems preloaded at the factory. But from the moment of birth, a
lot of things set to work on that temperament–moderating it,
challenging it, annealing it, wounding it. What we’re left with after
10 or 20 or 50 years is quite different from what we started out with.

For
a long time, researchers have tried to nail down just what shapes
us–or what, at least, shapes us most. And over the years, they’ve had
a lot of eureka moments. First it was our parents, particularly our
mothers. Then it was our genes. Next it was our peers, who show up last
but hold great sway. And all those ideas were good ones–but only as
far as they went.

The fact is once investigators had strip-mined
all the data from those theories, they still came away with as many
questions as answers. Somewhere, there was a sort of temperamental dark
matter exerting an invisible gravitational pull of its own. More and
more, scientists are concluding that this unexplained force is our
siblings.

From the time they are born, our brothers and sisters
are our collaborators and co-conspirators, our role models and
cautionary tales. They are our scolds, protectors, goads, tormentors,
playmates, counselors, sources of envy, objects of pride. They teach us
how to resolve conflicts and how not to; how to conduct friendships and
when to walk away from them. Sisters teach brothers about the mysteries
of girls; brothers teach sisters about the puzzle of boys. Our spouses
arrive comparatively late in our lives; our parents eventually leave
us. Our siblings may be the only people we’ll ever know who truly
qualify as partners for life. "Siblings," says family sociologist
Katherine Conger of the University of California, Davis, "are with us
for the whole journey."

Within the scientific community,
siblings have not been wholly ignored, but research has been limited
mostly to discussions of birth order. Older sibs were said to be
strivers; younger ones rebels; middle kids the lost souls. The
stereotypes were broad, if not entirely untrue, and there the
discussion mostly ended.

But all that’s changing. At research
centers in the U.S., Canada, Europe and elsewhere, investigators are
launching a wealth of new studies into the sibling dynamic, looking at
ways brothers and sisters steer one another into–or away from–risky
behavior; how they form a protective buffer against family upheaval;
how they educate one another about the opposite sex; how all siblings
compete for family recognition and come to terms–or blows–over such
impossibly charged issues as parental favoritism.

From
that research, scientists are gaining intriguing insights into the
people we become as adults. Does the manager who runs a congenial
office call on the peacemaking skills learned in the family playroom?
Does the student struggling with a professor who plays favorites summon
up the coping skills acquired from dealing with a sister who was
Daddy’s girl? Do husbands and wives benefit from the intergender
negotiations they waged when their most important partners were their
sisters and brothers? All that is under investigation. "Siblings have
just been off the radar screen until now," says Conger. But today
serious work is revealing exactly how our brothers and sisters
influence us.

•Why childhood fights between siblings can be good

THE
FIRST THING THAT STRIKES contemporary researchers when they study
siblings is the sheer quantity of time the kids spend in one another’s
presence and the power this has to teach them social skills. By the
time children are 11, they devote about 33% of their free time to their
siblings–more time than they spend with friends, parents, teachers or
even by themselves–according to a well-regarded Penn State University
study published in 1996. Later research, published last year, found
that even adolescents, who have usually begun going their own way,
devote at least 10 hours a week to activities with their siblings–a
lot when you consider that with school, sports, dates and sleep, there
aren’t a whole lot of free hours left. In Mexican-American homes, where
broods are generally bigger, the figure tops 17 hours.

"In
general," says psychologist Daniel Shaw of the University of
Pittsburgh, "parents serve the same big-picture role as doctors on
grand rounds. Siblings are like the nurses on the ward. They’re there
every day." All that proximity breeds an awful lot of intimacy–and an
awful lot of friction.

Laurie Kramer, professor of applied
family studies at the University of Illinois at Urbana-Champaign, has
found that, on average, sibs between 3 and 7 years old engage in some
kind of conflict 3.5 times an hour. Kids in the 2-to-4 age group top
out at 6.3–or more than one clash every 10 minutes, according to a
Canadian study. "Getting along with a sister or brother," Kramer says
dryly, "can be a frustrating experience."

But as much as all the
fighting can set parents’ hair on end, there’s a lot of learning going
on too, specifically about how conflicts, once begun, can be settled.
Shaw and his colleagues conducted a years-long study in which they
visited the homes of 90 2-year-old children who had at least one
sibling, observing the target kids’ innate temperaments and their
parents’ discipline styles. The researchers returned when the children
were 5 and observed them again, this time in a structured play session
with one close-in-age sib. The pairs were shown three toys but given
only one to play with. They were told they could move onto the next one
only when both agreed it was time to switch and further agreed which
toy they wanted next.

That, as any parent knows,
is a scenario trip-wired for fights–and that’s what happened. The
experimenters ranked the conflicts on a five-point scale, with one
being a single cross word and five being a full-blown brawl. The next
year, they went to the same children’s schools to observe them at play
and interview their teachers. Almost universally, the kids who
practiced the best conflict-resolution skills at home carried those
abilities into the classroom.

Certainly, there are other things
that could account for what makes some kids battlers in school and
others not. But the most powerful variables–parents and
personality–were identified and their influence isolated during the
course of the two-year-long observations. Socioeconomic status, an X
factor that bedevils studies like this one, was controlled by selecting
all the families from the same economic stratum. Distill those
influences away and what is left is the interaction of the sibs.
"Siblings have a socializing effect on one another," Shaw says. "When
you tease out all the other variables, it’s the play styles that make
the difference. Unlike a relationship with friends, you’re stuck with
your sibs. You learn to negotiate things day to day."

It’s that
permanence, researchers believe, that makes siblings so valuable a
rehearsal tool for later life. Adulthood, after all, is practically
defined by peer relationships–the workplace, a marriage, the church
building committee. As siblings, we may sulk and fume but by nighttime
we still return to the same twin beds in the same shared room. Peace is
made when one sib offers a toy or shares a thought or throws a pillow
in a mock provocation that releases the lingering tension in a burst of
roughhousing. Somewhere in there is the early training for the e-mail
joke that breaks an office silence or the husband who signals that a
fight is over by asking his wife what she thinks they should do about
that fast-approaching vacation anyway. "Sibling relationships are where
you learn all this," says developmental psychologist Susan McHale of
Penn State University. "They are relationships between equals."

• How not being Mom’s favorite can have its advantages

MULTICHILD
HOUSEHOLDS CAN BE NOTHING short of palace courts, with alliances,
feuds, grudges and loyalties, all changing day to day. Perhaps the
touchiest problem in most such families is favoritism.

Parents
feel a lot of guilt over the often evident if rarely admitted
preference they harbor for one child over another–the sensitive mom
who goes gooey over her son the poet, the hard-knocks dad who adores
his tough-as-nails daughter. If favorites exist, however, it may be not
the parents’ fault, but evolution’s.

The family
began as–and remains–a survival unit, with parents agreeing to care
for the kids, the kids agreeing to carry on the genes and all of them
doing what they can to make sure no one gets eaten by wolves. But the
resources that make this possible are limited. "Economic means, types
of jobs, even love and affection are in finite supply," says
psychologist Mark Feinberg of Penn State. Parents, despite themselves,
are programmed to notice the child who seems most worthy of the
investment. While millenniums of socialization have helped us resist
and even reverse this impulse, and we often pour much of a family’s
wealth and energy into the care of the disabled or difficult child, our
primal programming still draws us to the pretty, gifted ones.

Conger
devised a study to test how widespread favoritism is. She assembled a
group of 384 adolescent sibling pairs and their parents, visiting them
three times over three years and questioning them all about their
relationships, their sense of well-being and more. To see how they
interacted as a group, she videotaped them as they worked through
sample conflicts. Overall, she concluded that 65% of mothers and 70% of
fathers exhibited a preference for one child–in most cases, the older
one. What’s more, the kids know what’s going on. "They all say, ‘Well,
it makes sense that they would treat us differently, because he’s older
or we’re a boy and a girl,’" Conger reports.

At first, kids
appear to adapt well to the disparity and often learn to game the
system, flipping blatant favoritism back to their shared advantage.
"They’ll say to one another, ‘Why don’t you ask Mom if we can go to the
mall because she never says no to you,’" says Conger. But at a deeper
level, second-tier children may pay a price. "They tend to be sadder
and have more self-esteem questions," Conger says. "They feel like
they’re not as worthy, and they’re trying to figure out why."

Think
you’re not still living the same reality show? Think again. It’s no
accident that employees in the workplace instinctively know which
person to send into the lion’s den of the corner office with a risky
proposal or a bit of bad news. And it’s no coincidence that the sense
of hurt feelings and adolescent envy you get when that same colleague
emerges with the proposal approved and the boss’s applause seems so
familiar. But what you summon up with the feelings you first had long
ago is the knowledge you gained then too–that the smartest strategy is
not to compete for approval but to strike a partnership with the
favorite and spin the situation to benefit yourself as well. This idea
did not occur to you de novo. You may know it now, but you learned it
then.

•Why your sibling is–or isn’t–your best role model

IT’S
NO SECRET THAT BROTHERS AND SISTERS emulate one another or that the
learning flows both up and down the age ladder. Younger siblings mimic
the skills and strengths of older ones. Older sibs are prodded to
attempt something new because they don’t want to be shown up by a
younger one who has already tried it. More complex–and in many ways
more important–are those situations in which siblings don’t mirror one
another but differentiate themselves–a phenomenon psychologists call
de-identification.

Alejandra and Sofia Romero,
5-year-old fraternal twins growing up in New York City, entered the
world at almost the same instant but have gone their own ways ever
since–at least in terms of temperament. Alejandra has more of a
tolerance–even a taste–for rules and regimens. Sofia observed this
(and her parents observed her observing it) and then distinguished
herself as the looser, less disciplined of the two. Sofia is also the
more garrulous, and Alejandra eventually became the more taciturn.
"Sofie served as their mouthpiece," says Lisa Dreyer, 39, the girls’
mother, "and Alejandra was perfectly happy to let her do it."

De-identification
helps kids stake out personality turf inside the home, but it has
another, far more important function: pushing some sibs away from risky
behavior. On the whole, siblings pass on dangerous habits to one
another in a depressingly predictable way. A girl with an older,
pregnant teenage sister is four to six times as likely to become a teen
mom herself, says Patricia East, a developmental psychologist at the
University of California, San Diego. The same pattern holds for
substance abuse. According to a paper published in the Journal of Drug
Issues earlier this year, younger siblings whose older sibs drink are
twice as likely to pick up the habit too. When it comes to smoking, the
risk increases fourfold.

But some kids break the mold–and for
surprising reasons. East conducted a five-year study of 227 families
and found that those girls who don’t follow their older sisters into
pregnancy may be drawn not so much to the wisdom of the choice as to
the mere fact that it’s a different one. One teen mom in a family is a
drama; two teen moms has a been-there-done-that quality to it. "She
purposely goes the other way," says East. "She decides her sister’s
role is teen mom and hers will be high achiever."

Younger sibs
may avoid tobacco for much the same reason. Three years ago, Joseph
Rodgers, a psychologist at the University of Oklahoma, published a
study of more than 9,500 young smokers. He found that while older
brothers and sisters often do introduce younger ones to the habit, the
closer they are in age, the more likely the younger one is to resist.
Apparently, their proximity in years has already made them too similar.
One conspicuous way for a baby brother to set himself apart is to look
at the older sibling’s smoking habits and then do the opposite.

• How a sibling of the opposite sex can affect whom you marry

FAR
SUBTLER–AND OFTEN FAR SWEETER–than the risk-taking modeling that
occurs among all sibs is the gender modeling that plays out between
opposite-sex ones. Brothers and sisters can be fierce de-identifiers.
In a study of adolescent boys and girls in central Pennsylvania, the
boys unsurprisingly scored higher in such traits as independence and
competitiveness while girls did better in empathic characteristics like
sensitivity and helpfulness. What was less expected is that when kids
grow up with an opposite-sex sibling, such exposure doesn’t temper
gender-linked traits but accentuates them. Both boys and girls hew
closer still to gender stereotype and even seek friends who conform to
those norms. "It’s known as niche picking," says Kimberly Updegraff, a
professor of family and human development at Arizona State University
and the person who conducted the study. "By having a sibling who is one
way, you strive to be different."

But as kids get older, that
distance from the other gender must, of necessity, close. Here kids
with opposite-sex siblings have a marked advantage. Last year William
Ickes, a psychologist at the University of Texas at Arlington,
published a study in which he paired up male and female students–all
of whom had grown up with an opposite-sex sibling–and set them to
chatting with one another. Then he questioned the subjects about how
the conversation went. In general, boys with older sisters or girls
with older brothers were less fumbling at getting things going and kept
the exchange flowing much more naturally.

"The guys who had
older sisters had more involving interactions and were liked
significantly more by their new female acquaintances," says Ickes.
"Women with older brothers were more likely to strike up a conversation
with the male stranger and to smile at him more than he smiled at her."

If
siblings can indeed be as powerful an influence on one another as all
the research suggests, are all siblings created at least potentially
equal? What about half-sibs and stepsibs? Do they reap–and confer–the
same benefits? Research findings are a bit scattered on this, if only
because shared or reconstituted families can be so complicated. A
dysfunctional home in which parents and siblings hunker behind
barricades alongside the ones they’re biologically closest to does not
lend itself to good sibling ties. Well-blended families, on the other
hand, may produce step- or half-siblings who are extraordinarily close.
One of the best studies on this topic is being conducted in Britain
with a large group of many different kinds of nontraditional families.
In general, the researchers have found that the intensity of the
relationships closely follows the degree of physical relatedness. No
hard rules have emerged, but the more genes you share, the more deeply
invested you tend to grow. "Biological siblings just get into it more,"
says Thomas O’Connor, an associate professor of psychiatry at the
University of Rochester Medical Center. "They are warmer and also more
conflicted."

• How those early bonds can grow stronger with age

ONE
OF THE GREATEST GIFTS OF THE SIBLING tie is that while warmth grows
over time, the conflicts often fade. After the shooting stops, even the
fiercest sibling wars leave little lasting damage. Indeed, siblings who
battled a lot as kids may become closer as adults–and more emotionally
skilled too, often clearly recalling what their long-ago fights were
about and the lessons they took from them. "I’m very sensitized to the
fact that it’s important to listen to others," a respondent wrote in a
recent study conducted in Britain. "People get over their anger, and
people who disagree are not terrible," wrote another. Even those with
troubled or self-destructive siblings came away with something
valuable: they learned patience, acceptance and cautionary lessons.
"[You] cannot change others," wrote one. "[But] I wasn’t going to be
like that."

Full-blown childhood crises may forge even stronger
lifelong links. The death of a parent blows some families to bits. But
when older sibs step in to help raise younger ones, the dual role of
contemporary and caretaker can lay the foundation for an indestructible
closeness later on. Wayne Duvall, 48, a television and film actor in
New York City and the youngest of three brothers, was just 13 when his
father died. His older brothers, who had let him get away with all
manner of mischief when both parents were in residence, intuitively
knew that the family no longer had that luxury. "I vividly remember
them leaning down to me and saying, ‘The party’s over,’" Duvall
recalls. "My brothers are my best friends now, though they still
consider me the little brother in every imaginable way."

Such
powerful connections become even more important as the inevitable
illnesses or widowhood of late life lead us to lean on the people we’ve
known the longest. Even siblings who drift apart in their middle years
tend to drift back together as they age. "The relationship is
especially strong between sisters," who are more likely to be
predeceased by their spouses than brothers are, says Judy Dunn, a
developmental psychologist at London’s Kings College. "When asked what
contributes to the importance of the relationship now, they say it’s
the shared early childhood experiences, which cast a long shadow for
all of us."

Of course, that shadow–like all shadows–is a thing
created by light. Siblings, by any measure, are one of nature’s better
brainstorms, and all the new studies on how they make us who we are is
one of science’s. But the rest of us, outside the lab, see it in a more
primal way. In a world that’s too big, too scary and too often too
lonely, we come to realize that there’s nothing like having a band of
brothers–and sisters–to venture out with you.

See what famous siblings have said about one another at time.com/siblings

—With reporting by  With reporting by Jessica Carsen/London, Wendy Cole/Chicago, Sonja Steptoe/Los