Birth order isn’t destiny.
You may have grown up hearing from your parents that your older sister is bossy because she’s the eldest. Or that because you’re the youngest, you’re the most agreeable, trying to get along with everyone—or more spoiled and selfish.
The truth is that birth order doesn’t seem to matter—unless it affects your self-image.
Our ideas about how birth order affects personality largely come from the theories of Alfred Adler, published in 1928. However, recent large studies find that there’s no link between birth order and personality at all. Psychologists see personality in different ways, but one of the most common research paradigms is the Big 5 traits: extraversion, emotional stability, agreeableness, conscientiousness and imagination. In 2015, a landmark study of more than 20,000 individuals, in the United States, Germany and Great Britain, concluded that birth order didn’t affect your scores on those measures. A 2019 study backed that up.
For twins, birth order can influence dominance, says Nancy Segal, professor of psychology and director of the Twin Studies Center at Cal State Fullerton. Continue reading in Psychology Today.