A new study carried out by Leipzig University suggests that the IQ of first-borns increases because they have to teach their younger siblings how things work. The fact that first-borns have their parents’ attention all to themselves also boosts their IQ.
It is said that the variations in intelligence are a result of how a child is raised and nurtured, not of biology.
The study evaluates a 1.5 IQ drop per sibling. In families with two children, however, the first-born isn’t necessarily the most intelligent since they only have a 60% chance of having a higher IQ. In this equation, there is still a good chance that the younger sibling will surpass them later on life.
Apart from boosted intelligence, first-born children also show a heightened perception of their brain capabilities. The data for this study was accumulated from personality and IQ tests from three different national studies, one of which was carried out in the UK and involved more than 20,000 participants.
“One theory is that following children “dilute” the resources of their parents.”, Dr. Julia Rohrer told the Daily Mail.
“While the firstborn gets full parental attention, at least for some months or years, late-borns will have to share from the beginning.”
“Another possible factor is described by the tutoring hypothesis: A firstborn can “tutor” their younger siblings, explaining to them how the world works and so on.”
“Teaching other people has high cognitive demands – the children need to recall their own knowledge, structure it and think of a good way to explain it to younger siblings, which could provide a boost to intelligence for some firstborns.”