If your older brother always insisted he was smarter than you — well, he may have been right.
Boys at the top of the pecking order — either by birth or because their older siblings died — score higher on IQ tests than their younger brothers, according to a Norwegian study published in Friday’s issue of the journal Science.
The researchers say it isn’t a matter of being born first, but growing up the senior child, that seems to result in the higher IQ scores.
The study looked at the IQ test results of 241,310 Norwegian men drafted into the armed forces between 1967 and 1976. All were aged 18 or 19 at the time.
The average IQ of first-born men was 103.2, researchers found. Second-born men averaged 101.2, but second-born men whose older sibling died in infancy scored 102.9. For third-borns, the average was 100.0, but if both older siblings died young, the third-born score rose to 102.6.
