Our personality is not primarily affected by being the first-born or last-born, suggests a new study published in Proceedings of the National Academy of Sciences (PNAS). It seems that we are who we are, regardless of our birth position among our siblings.
Psychologists from the universities of Mainz and Leipzig, Germany, wanted to determine whether birth order has an established effect on one’s personality. So many myths exist as to the effects one’s position among one’s siblings has on personality traits; for instance, last-borns are often stereotyped to be rebellious while first-borns are said to have much higher IQs. Are these really true?
The team of researchers evaluated data involving over 20,000 adults from Germany, the US and the UK. Their findings show that birth order does not impact on central personality traits like extraversion, emotional stability, agreeableness, and conscientiousness.
Any effect reported only concerned self-reported intellect, and that too was small. For example, first-borns had a greater likelihood of claiming to have a rich vocabulary and were more able to understand abstract concepts. This effect is actually mentioned in allegedly objective studies that note the trend of a small decline in intelligence from first- to last-born.
“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,” says Professor Stefan Schmukle, one of the authors.
“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.”