Personality traits are not determined by the order in which siblings are born, a study of 20,000 adults has found.
The long-held superstitions that first-borns are more responsible, or last-borns are rebellious has been overturned by a study which found that central personality traits are not affected by the order in which children are born.
The study only found small changes in self-reported aspects of personality, for example first-borns were more likely to report a greater vocabulary and less difficulty understanding abstract ideas.
The study also confirmed a small decline in objectively measured intelligence from first to last in the order of birth, a trend which has already been established.
Professor Stefan Schmukle said:
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.