If there’s ever been banter about who is the most intelligent among your siblings at a family gathering, science has tipped the balance towards the eldest child.
A study that evaluated available data from three national panels across the United States, Great Britain, and Germany found that firstborns “score higher on objectively measured intelligence.”
It revealed that in a family of only two children, the older sibling had a higher IQ than his or her younger sibling in 6 of 10 cases.
Although they also concluded that they were able to measure the same effect on “self-reported intellect” for the first borns, they couldn’t establish that these set of children were more emotionally stable, imaginative, or extroverted than their siblings.
This implies that a person’s personality doesn’t have anything to do with their position in the order of birth, even if they are a first born.
And so while first borns can be generally smarter than their siblings, they are not necessarily the child with the strongest personality type, contrary to previous theories that may have suggested such.
The study cites Frank Sulloway’s Family Niche Theory of birth-order effects which postulates that firstborns perform better on psychometric intelligence tests and correspondingly score higher on intellect, a self-reported trait correlated with objectively measured intelligence.
It notes that Sulloway predicted firstborns are more anxious and quicker to anger while later-borns are more depressed, vulnerable, self-conscious, and impulsive.
But also recommends a comparison of the independent assessments of each sibling’s personality for a more accurate understanding of how much impact birth order has on personality development.
