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Bad News: You Can’t Blame Your Sisters for All Your Defects

Area siblings Khloé, Kourtney, and Kim.
Area siblings Khloé, Kourtney, and Kim. Photo: Parisa/Corbis

We hold these truths to be self-evident: that all firstborn siblings are know-it-alls, middle children are attention-seekers, and the youngest are spoiled brats. But new research is challenging the notion that birth order can affect personality, and has created cracks in our very foundations.

For a study published in the journal Proceedings of the National Academy of Sciences, researchers at the University of Leipzig in Germany reviewed personality and birth-order data from more than 20,000 adults in Germany, the United States, and Great Britain. Specifically, they used surveys conducted in each country that ranked people on the “big five” personality traits — extroversion, emotional stability, agreeableness, conscientiousness, and openness to experience. To their surprise, they found no significant connection between these traits and where a person fell in the family. “This does not only contradict prominent psychological theories, but also goes against the intuition of many people,” co-author Stefan Schmukle, Ph.D., said in a release.

Time points out that previous studies on the topic used different measures to test the effect of birth order on personality and this single paper doesn’t refute what’s come before. But there’s an empowering takeaway nonetheless: Don’t let your sibling position hold you back from being the monster you know you are in your heart.

You Can’t Blame Your Sisters for Your Defects