Popular press is replete with articles and books touting the relationship between birth order and personality. However, due to data limitations, there is very little convincing evidence documenting these relationships. Using unique registry data from Sweden on a large sample of men, we are able to estimate the relationship between birth order and measures of non-cognitive ability and occupational characteristics, all of which serve as reasonable proxies for individual personalities.
Consistent with the existing literature on earnings and IQ, we find evidence that non- cognitive abilities are declining with birth order. This is true across a variety of measures of abilities, including the Big Five dimensions of personality. These results are somewhat at odds with the psychology literature, where later borns are expected to be more emotionally stable, open to experience and social. We also find systematic differences in occupational sorting by birth order—first-born children are more likely to be managers, while later-born children are more likely to be self-employed. This occupational sorting is consistent with predictions from evolutionary psychology where first borns are suggested to dominate younger siblings, whereas later borns are assumed to use more unorthodox strategies to attract attention.
The patterns vary by the sex composition of the children—later born boys are particularly affected when their older siblings are brothers. For non-cognitive ability, the effects of birth order are more than twice as large if one is later born with older brothers. However, when we consider creative occupations, later-born boys are less likely to enter these occupations if they have older sisters while later-born boys are more likely to enter these occupations if they have older brothers.
When we examine possible mechanisms underlying the observed birth order patterns, we find support for post-birth environmental factors driving the negative birth order effects, while biological factors go in the other direction. Additionally, we find that study behaviors vary by birth order; teenagers are more likely to read books, spend more time on homework, and less time watching TV if they are first-born. We also find that some parental investments decline by birth order, which could partly explain the negative effects of birth order on non-cognitive abilities. However, this does not rule out that other factors—including parental resources or sibling competition—can help to explain these patterns.
Chosen excerpts by Job Market Monitor. Read the whole story at Born to Lead? The Effect of Birth Order on Non-Cognitive Abilities