We’ve all had it ingrained: oldest siblings are ambitious, responsible over-achievers, youngest siblings are creative rebels, and kids in the middle are easy-going Jan Bradys.
There’s just one complicating detail: According to a recent study out of the University of Illinois, none of that seems to be true.
The link between birth order and personality — including propensity for leadership? Virtually non-existent.
The study, which researchers say is “the biggest in history looking at birth order and personality,” looked at a sample of 377,000 high school students, taking into account their family structures, birth orders, IQs, and displays of various personality traits (confidence, leadership, impulsiveness, and “tidiness,” among others).
And while they did find differences between firstborns and their younger siblings — true to stereotype, firstborns do have slightly higher IQs and do tend to be slightly more conscientious, extroverted, and agreeable — they also found those differences are so minuscule as to be practically meaningless.
The average correlation between personality traits and birth order: 0.02. “[I]n terms of personality traits and how you rate them, a 0.02 correlation doesn’t get you anything of note,” explains psychology professor Brent Roberts, one of the study’s coauthors, in a statement.
“You’re not going to be able to sit two people down next to each other and see the differences between them. It’s not noticeable by anybody.”
There’s a catch, though: while the link between birth order and personality is “negligible,” researcher Rodica Damian, now a professor at the University of Houston and coauthor of the study, tells Business Insider, “that does not necessarily mean that firstborns are not more likely to succeed or be in leadership positions.”
The stats about more CEOs, astronauts, Nobel-winners, and presidents being eldest children? This research isn’t arguing with that. “The idea that firstborns end up more successful and in more leadership positions might still hold,” Damian says, “but this study suggests that it would not be due to real differences in personality or intelligence.”
In other words, being the oldest doesn’t “predestine” you for success by magically endowing you with leader-like qualities — but it likely does confer other leadership advantages. “There might be other factors at work there, such as social roles and expectations,” Damian says, noting that while the study looked at things that could factor into success (intelligence, personality), it did not investigate success itself.
If you’re a firstborn, there’s good news and bad news here. The bad news: based on personality and intelligence, at least, you may not be inherently more cut out for the corner office than your younger siblings. The good news (for you, at least): there may be plenty of possible reasons you’re more likely to get there anyway.
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