Thursday, 4:30 PM
Older siblings really are know-it-alls, study finds
By Colin Nickerson, Globe Staff
Is big sister always telling you what's best? Does big brother seem to know it all?
Instead of stewing in resentment, maybe you should start listening when they dispense smart-alecky advice.
Turns out, they really are brighter than you, by and large.
A massive study by Norwegian scientists appearing in today's edition of the journal Science concludes that a child raised as the eldest has a higher intelligence quotient, on average, than younger siblings.
YOUR VIEW: The difference is just a couple IQ points -- not exactly the gap between Albert Einstein and Homer Simpson.
But the extra smarts conferred by birth order are significant enough in the broad sense. Spread over tens of thousands of individuals, the tiny difference may translate into a higher likelihood of acceptance into better colleges, improved chances of landing a good job or even better luck at winning a brainy spouse, according to some child specialists.
Researchers Petter Kristensen and Tor Bjerkedal make no such bold assertions in their study of 241,310 Norwegian 18- and 19-year-olds. The findings of the Norwegian medical scientists -- Kristensen is an epidemiologist with Norway's Institute of National Health; Bjerkedal is a physician-researcher with the Norwegian Armed Forces Medical Service -- are sure to roil the world of child psychology and family studies.
Slightly better brains appear to be a result of the way the senior child is raised and adapts to the family, not to any special genetic traits that go with being born first, the researchers say.
The study is long on numbers and notably short on interpretation. But the bottom line is blunt: the child who holds position as the oldest will possess, on average, an IQ 2.3 points higher than younger siblings. With a sample size of nearly a quarter-million test subjects, that's compelling scientific evidence, according to one specialist.
"This is one of the most important findings in this field to come along in the past 70 years or so," said Frank J. Sulloway, a science historian, visiting professor of psychology at the University of California at Berkeley and an advocate of the view that birth order influences personality.
Sulloway spoke in an interview, but also wrote an accompanying commentary in Science on the Norwegian study
"This is a beautiful study that should put an end to an unnecessarily heated debate over intelligence and birth order," he said. "If you were raised as the first born, you will most likely have a higher IQ -- end of story. Now we should focus effort on finding what this means."
Other specialists weren't so sure, however.
The Norwegian study yields "interesting and valuable data, but nevertheless leaves important methodological questions unanswered that raise the same kind of doubts" that scientists have debated in the past, said Joseph L. Rodgers, professor of psychology at the University of Oklahoma. Rodgers has been critical of the view that birth order affects intelligence.
