Leipzig University in Germany, which is one of the oldest universities in the world has released findings from a study it carried out that suggest first-born children are more intelligent than their siblings.
The study shows that the difference is minimal with just a 1.5 IQ points drop between each child. The researchers are exactly sure what causes the eldest child to be more intelligent, but it may well be due to having their parents undivided attention, until No.2 comes along. Another factor may be the fact that the eldest child sometimes acts as teacher to their younger sibling, passing along their wisdom and knowledge.
The study was initially commissioned to look at personality and sibling position in more than 20,000 adults from Germany, the UK and US and the findings are more relevant to a family with 3 children, rather than 2.
The data they used were IQ and personality test results and families with 4 or more children were excluded from the study because there were too few of them to have a meaningful input.
Professor Stefan Schmuklesay said: “This effect on the intelligence can be found reliably in large samples, but is not very meaningful at the individual level. When comparing two siblings, the later-born have higher IQ in about 40 percent of cases.”
Another researcher, Julia Rohrer, said such a question has fascinated scientists and the general public for a long time.
Dr Rohrer went on to say “‘One theory is that subsequent children ‘dilute’ the resources of their parents. While the firstborn gets full parental attention, at least for some months or years, the subsequent children 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”