Are Older Siblings Smarter?

Apparently so, according to a new large-scale study that found older brothers, statistically speaking, actually have higher IQs than their younger siblings:

The study, detailed in the June 22 issue of the journal Science, analyzed the IQs of nearly 250,000 Norwegian 18- and 19-year-old draftees and found that older siblings had higher scores than younger siblings.
Another study, by the same authors of the new Science study but published recently in the journal Intelligence, looked at more than 100,000 Norwegian brothers and found that first-borns on average had an IQ 2.3 points higher than their younger brothers (the IQs were all taken when the brothers were 18 or 19, so they compare the older brother’s score at that age to the younger brother’s score when he reached that same age).

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