Citing a study by Norwegian researchers Petter Kristensen and Tor Bjerkedal which has been premiered in the latest issue of Science magazine (sciencemag.org), The New York Times reports that growing up as the senior child in the home translates into higher IQ scores.
The findings came at the end of a study, by the two scientists, of a sample base of 241,310 Norwegian men.
Among these, the scientists found, the IQ of first-born children averaged out at around 103.2; that of second-born children at 101.2; and third-born children averaged 100.0.
While the difference in IQ is a matter of a mere three points between the eldest child and his closest sibling, researchers say the finding is significant from a nurture point of view.
Even from a more practical point of view, The New York Times points out, three points could make the difference between a high B and a low A which, in turn, can mean the difference between admission to an elite college and a less exclusive one.
The New York Times points out that among other tangential indices, firstborns have won more Nobel Prizes in science than younger siblings.
Intriguingly, the study suggests that it is not just a matter of in what order you were born, but of what the two scientists call 'social rank'.
For instance, children who were born second, but whose elder sibling(s) died and hence they were elevated to the status of the family's eldest child, showed an improvement in their IQ scores.
Thus, though second-born children studied by the scientists averaged 101.2 on the IQ test, those whose older sibling had died in infancy averaged 102.9. Similarly, though the base average for third-borns was 100.0, such children whose elder siblings had died showed an average score of 102.6.
Experts say the true value of the study is that it traces a co-relation between IQ, and how a child is raised. Frank J Sulloway, of the Institute for Personality and Social Research at the University of California, Berkeley, is quoted as saying that the 'elegantly designed' study indicated that the elder child pulls ahead, perhaps as a result of additional learning gained while tutoring younger brothers and sisters.
Tangentially, the study also appears to indicate that a child who in the family structure is given a position of responsibility -- in this case, of being treated as the eldest child -- tends to grow mentally, as opposed to children treated as `subordinate' units of the family.
The research, The New York Times suggests, could now lead to more intensive study into the family dynamics behind such differences. Though the study was done in men, the scientists said the results would almost certainly apply to women as well, especially since sex has little effect on IQ scores.
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