Researchers from the University of Mainz and Leipzig in Germany have discovered that the birth order has a strong influence on a child’s intelligence quotient.
Researcher Stefan Schmukle said “The first born gets the most intellectual stimulation and the later ones get less.
“This effect on intelligence replicates very well in large samples, but it is barely meaningful on the individual level, because it is extremely small. And even though mean scores on intelligence decline, in four out of ten cases the later-born is still smarter than his or her older sibling.
“The real news of our study is that we found no substantial effects of birth order on any of the personality dimensions we examined. This does not only contradict prominent psychological theories, but also goes against the intuition of many people.”
The researchers analysed data from more than 20,000 adults from Germany, the United States, and Great Britain.
The study was published in the journal Proceedings of the National Academy of Sciences of the United States of America.