Not only may firstborn children be smarter than their siblings, but they may be more well-mannered, too.
According to a report from Joseph Doyle, an MIT economist, second-born children are more likely to misbehave and suffer more severe consequences than their older siblings. Doyle and his colleagues say that the "curse of the second-born child" is true, concluding that older siblings (usually boys) are typically more rebellious than their younger counterparts.
The team collected data from thousands of sets of brothers in both the U.S. and Europe and found that second-born children are 25 to 40 percent more likely to get in serious trouble at school or with the law.
A possible explanation for this finding is the fact that parenting styles can change with each child, notes NPR. For instance, first-born kids have the privilege of receiving their parents' undivided attention, while second-born children often have to compete for affection. And as a family expands, dynamics can be further altered.
"The firstborn has role models, who are adults. And the second, later-born children have role models who are slightly irrational 2-year-olds, you know, their older siblings," Doyle told NPR. "Both the parental investments are different, and the sibling influences probably contribute to these differences we see in the labor market and what we find in delinquency. It's just very difficult to separate those two things because they happen at the same time."
Of course, second-born children aren't necessarily doomed to be naughty. But it is important to note that birth order can play a huge part in changing the way parents interact with each new addition to the family—And if you really think about, couldn't it be the reason why you always wanted to get that ear piercing, just because mom said no?
h/t Woman's Day