My cousin, an eldest sibling, alerted me to this news finding: The eldest children in families tend to develop higher I.Q.’s than their siblings, researchers are reporting, in a large study that could settle more than a half-century of scientific debate about the relationship between I.Q. and birth order.

Salient Points

• The study was carried out only on men. Researchers say sex doesn’t matter, and that findings would apply equally to females.
• The researchers looked at IQ scores in 250,000 men entering mandatory military service. They found a significant difference in IQ scores in 60,000 pairs of siblings.
• Men who were first in social or birth order had, on average an IQ about 2.3 points higher than those who were second in social or birth order. This pattern continued in the sense that second born men had higher IQs than the third born, and so on.
• The causes are social, not biological.

My Observations

• Interestingly, about a year ago, Medical News had reported findings about a similar study, conducted in the US, with exactly opposite results.
• Though the study doesn’t cover single children, the social factors that are cited as responsible for higher IQ in elder siblings would work wonders when there’s only a single child. So does this mean countries like China, with a one-child-per-family program will produce a nation of geniuses?

For Parents

• Parents should not be unduly concerned about these results. Having high IQ and knowing how to use it are different attributes.
• A child might score a few points lower in their IQ but have other assets such as curiosity, imagination and what is increasingly being called “emotional intelligence” that helps them use their IQ more effectively.
• If you have several children, then spending some one-to-one time with each one is probably a good thing to do but if you can’t manage it, don’t lose sleep over it.
• 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.
• 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.

For Elder Siblings

• Chill out!

For Younger Siblings

Don’t despair:

• You can kill your elder siblings (as suggested by another youngest-in-family cousin)
• If the above sounds anathema to you (even if you have low IQ), you can encourage your parents to have more children (so you’ll have higher IQ than them)
• You already have impressive friends and are in distinguished company
• Evidence suggests that younger siblings are more likely than older ones to take risks based on their knowledge and instincts.
• The study did not look at the effect of age gaps on IQ. But previous research has suggested that a younger sibling with a large enough age gap might be able to recoup the IQ points.
• The study was conducted in Norway. If you’re Norwegian, as per Asterix, you’ve nothing to fear. Even if you’re not, you’ve nothing to fear. The study doesn’t talk about cultural differences in upbringing.
• It doesn’t mean younger siblings aren’t more intelligent in other ways, like emotional intelligence.

Further, the New York Times quotes experts:

To distinguish themselves, younger siblings often develop other skills, like social charm, a good curveball, mastery of the electric bass, acting skills. They are developing diverse interests and expertise that the I.Q. tests do not measure.

This kind of experimentation might explain evidence that younger siblings often live more adventurous lives than their older brother or sister. They are more likely to participate in dangerous sports than eldest children, and more likely to travel to exotic places. They tend to be less conventional than firstborns, and some of the most provocative and influential figures in science spent their childhoods in the shadow of an older brother or sister.

Firstborns have won more Nobel Prizes in science than younger siblings, but often by advancing current understanding, rather than overturning it.

It’s the difference between every-year or every-decade creativity and every-century creativity,” Dr. Sulloway said, “between innovation and radical innovation”.