People often believe that first born kids are supposedly perfectionists, for example, while middle children develop a talent for diplomacy and last borns are expected to be rebellious. The question of whether a person's position among siblings has a lasting impact on one's personality has occupied researchers for more than 100 years. However, a new study has revealed that whether you become a perfectionist or rebellious has very little to do with your birth position in the family.
One of the researchers Stefan Schmukle from Leipzig University in Germany said, "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."
To find out whether the personality differences due to birth positions actually exist, the researchers analyzed the data of more than 20,000 grown-ups from Germany, Britain and the US. The team found that central personality traits such as extroversion, emotional stability, agreeableness and conscientiousness are not affected by birth-order position.
However, small effects of birth positions were found regarding self-reported intellect. First born kids were more likely to report a rich vocabulary and less difficulty understanding abstract ideas. Schnukle explained, "This effect on intelligence replicates very well in large samples, but it is barely meaningful on the individual level, because it is extremely small."
The study was published in Proceedings of the National Academy of Sciences.