KEY POINTS:
The eternal question of whether children who are at the top of the pecking order are smarter than their younger siblings may well have been answered.
A study by Norwegian researchers now claims that boys who grow up as the senior child are more likely to score high IQ scores than their younger siblings.
Petter Kristensen and Tor Bjerkedal report their findings in the current issue of the journal Science.
And it's all about social ranking in the family, according to the pair.
During their study, the highest scores were recorded by the senior child - the first born, or if the first born was deceased, the next oldest.
Kristensen, employed by Norway's National Institute of Occupational Health, and Bjerkedal, of the Norwegian Armed Forces Medical Services, analysed the IQ results of more than 241,310 Norwegians drafted into the armed forces between 1967 and 1976.
The average IQ of first-born men was 103.2, they found.
Second-born men averaged 101.2, but second-born men whose older sibling died in infancy scored 102.9. And as for the third-borns, the average was 100.0.
But if both older siblings died young, the third-borns' average scores rose to 102.6.
According to the researchers, the findings "provide evidence that the relation between birth order and IQ score is dependent on the social rank in the family and not birth order as such".
The issue of whether higher intelligence scores for first-borns is science fact, as opposed to science fiction, has been debated for many years.
Sir Francis Galton first noted in 1874 that men in prominent positions tend to be first-borns more often than statistics would normally indicate.
- NZ HERALD STAFF
