A new study by Leipzig University revealed that the first-born children’s IQ is higher than their sibling’s one. The higher IQ is caused by two important factors – first, they get undivided attention from their parents and second, they teach their younger siblings to do things. And we all know that teaching is the best way to learn something yourself as well.
The differences in IQ levels are affected by upbringing and nurture, not so much by biology. The study estimates a 1,5 drop in IQ points per sibling. But this is not accurate in a two-child family, where the older one has 60% chance of a higher IQ. This means that the younger one has still a strong change to beat the other one’s IQ.
Three national studies from UK, which researched the IQs and personalities and looked at more than 20 000 participants, reported that first children also display an increased perception of their brain power.
According to Dr. Julia Rohrer, the first child gets undivided attention and more energy from parents, others are left with diluted resources of their parents.
Another reason lies in the tutoring theory – being older means that they have to teach their younger ones and by showing and explaining thing to them, they themselves learn and develop much more and much faster as they would without the tutoring. Teaching means having patients, structure and explaining things in a logical way, which can boost the firstborn’s intelligence.
As mentioned above, the most important part of the child’s development is the upbringing. This means that parents play a huge role and therefore are responsible for their child’s IQ and intelligence.
“One theory is that following children “dilute” the resources of their parents.”, Dr. Julia said. “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.”, she added.
