The New York Times (pg A17)  [Printer-friendly version]
June 25, 2007

FINDINGS ON BIRTH ORDER AND I.Q. PROMPT DEBATE

By Benedict Carey

The new evidence that eldest children develop higher I.Q.'s than their
siblings has intensified the debate over two of the most stubborn
questions in social science: What are the family dynamics that enhance
intelligence? And can they -- and should they -- be changed?

The new findings, from a landmark study published Friday, showed that
eldest children had a slight but significant edge in I.Q. -- an
average of three points over the closest sibling. And it found that
the difference was not because of biological factors but the
psychological interplay of parents and children.

Predictably, the study set off a swarm of Internet commentary from
parents, social scientists and others, speculating about what in
families could enrich one child's intellectual environment more than
others'.

"Anyone with siblings wonders about this," said Sue Monaco, 51, of
Delaware, who has two sons and five siblings. She was one of about 150
readers who posted questions on Friday to a New York Times Web forum
about the study.

Researchers acknowledge that few of the family variables affecting
intelligence are well understood, and some argue that peer influences
are eventually more significant. But studies suggest that two elements
are important during childhood: the perceived role a child has in the
family; and the apparent benefit a child receives when he or she
tutors someone else, like a younger sibling.

Well before entering the high school hothouse of geeks and jocks,
children who grow up with siblings get tagged with labels: The screw-
up of the family. The airhead, the klutz, the whiner. And then there
is the serious one, little Mr. or Ms. Responsible, who most often is
the eldest, psychologists have found.

"In our family we had the straight one, the oldest, followed by the
one who snuck out," said Elisabeth Ferris, 55, a former teacher who
lives near Baltimore. "I was the one who snuck out, who had a lot
more fun in high school, and who went to art school."

Studies suggest that other family members tend to consider the eldest
the most conscientious of the siblings, more likely to achieve
academically. At least for some firstborns, that role may be self-
fulfilling.

"I don't know about our I.Q.'s but, yes, she was the more studious
one," Ms. Ferris said of her older sister.

Psychologists say that filling the role of the responsible firstborn,
while important to academic achievement, still does not account for
eldest children's higher average scores on intelligence tests. Robert
Zajonc, a psychologist at Stanford University, has argued that in fact
having a younger sibling or two diminishes the overall intellectual
environment for eldest children -- who otherwise would be benefiting
from the rich vocabulary and undivided attention of parents.

This helps explain why, under the age of 12, younger siblings actually
outshine older ones on I.Q. tests.

Something else is at work, Dr. Zajonc said, and he has found evidence
that tutoring -- a natural role for older siblings -- benefits the
teacher more than it does the student. "Explaining something to a
younger sibling solidifies your knowledge and allows you to grow more
extensively," he said. "The younger one is asking questions, and
challenging meanings and explanations, and that will contribute to the
intellectual maturity of the older one." (Only children receive the
benefit of more parental attention but miss the opportunity to tutor a
younger brother or sister.)

Ms. Monaco, who has two sons in their 20s, said her oldest was
expected to help his brother from an early age. "He was a teacher to
his brother, and he has grown up to be a more intense thinker; he's
studying business management," she said. "His brother is more
easygoing, independent; he's studying leisure and recreation and has
an internship at a golf course." The two are very close friends, she
said.

Parents who recognize the different niches that their children fill
can enhance the family's intellectual environment by exploiting each
child's expertise, researchers say. "Given the evidence we have on
this, I would as a parent encourage late-born siblings to take on
teaching roles, with other siblings or other children," said Paul
Trapnell, a psychologist at the University of Winnipeg.

Dr. Trapnell compared this process to the so-called jigsaw approach
used in classrooms, in which complex projects are divided up and each
child becomes an expert in a particular task and instructs the others.

Younger siblings often have something more to pass on than the tricks
of their favorite hobby, or the philosophy behind their social charm.
Evidence suggests that younger siblings are more likely than older
ones to take risks based on their knowledge and instincts.

It is important to keep in mind, too, that the new study found average
difference in I.Q.; the scores varied widely from family to family. In
many families, younger brothers and sisters eventually took the lead
in I.Q., no matter if they were the screw-up or the whiner.

Moreover, experts have long noted that while even slight differences
in I.Q. score can be important for some, the test measures a narrow
set of skills. Excessive attention to it can blind parents to the
diverse and equally rich expertise that later-born children usually
develop.

The best way to react to the news, some psychologists said, is to
relax.

"When parents ask me what to do about this, I always say the same
thing: nothing," said Frank J. Sulloway, a psychologist at the
Institute of Personality and Social Research at the University of
California, Berkeley, and the author of an editorial in the journal
Science that accompanied one of the reports. Another report on the
study was published in the journal Intelligence.

"Younger siblings are more likely to take chances," Dr. Sulloway
added, and to challenge the status quo in creative ways.

Jackie Orsi, 53, of Morrow, Ohio, grew up the youngest of four, five
years behind her nearest sibling, and said she discovered in high
school that she scored the highest on I.Q. tests. She remembers the
sister closest to her bringing home books from elementary school to
read to her.

"The older three held me, cherished me, ragged on me, taught me, and
gave me an acute view of life," she wrote in an e-mail message. She
added, "I spent my high school years absorbing their books. What a
gift. I got my dad's genius genes, and I got a boost from being last-
born. Amen."