The Sibling With The Best Personality, According To Research

Last updated on Sep 01, 2026

Sibling has the best personality. Chayene Rafaela | Unsplash
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A surprising study — or unsurprising, depending on where you place in birth order — suggests that the middle child takes the cake when it comes to certain personality traits. 

There's no denying that birth order impacts personality, and it's long been believed that those middle kids kind of get lost in the shuffle between the eldest and the babies of the bunch. A recent study published in Psychological and Cognitive Sciences found that the middle child is much more "honest, humble, and agreeable" compared to their siblings. 

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A study shows that middle children have the best personalities among siblings

three siblings smiling together Luis Quintero / Pexels

The study used the HEXACO Personality Inventory to assess six personality traits based on sibling birth order: honesty-humility, emotionality, extraversion, agreeableness, conscientiousness, and openness to experience.

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Middle children are more honest, humble, and agreeable

According to the HEXACO Personality Inventory, agreeableness, as a personality trait, is reflected in people who "forgive the wrongs that they suffered, are lenient in judging others, are willing to compromise and cooperate with others, and can easily control their temper." Whereas anyone with a high score on the Honesty-Humility scale "avoids manipulating others for personal gain, feels little temptation to break rules, is uninterested in lavish wealth and luxuries, and feels no special entitlement to elevated social status."

Basically, middle kids are kind, forgiving, level-headed, humble, and empathetic. They are literally the best of all the siblings.

RELATED: What Your Birth Order Can Predict About Your Love Life

How does birth order impact personality?

Michael Ashton and Kibeom Lee, the authors of the study, suggest that middle children who score higher on these traits might be the result of their position in the family. They aren't the firstborn who often gets more attention, and they receive the same leniency as the youngest, who enjoys having more privileges. The middle child is forced to compromise and cooperate. By nature, they are required to be more agreeable, diplomatic, and flexible.

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On the other hand, the study also found that only children tend to score lower in these traits. This may be due to only children not having the same opportunities to practice collaboration as children in larger families do. This leads them to have personality traits that align more with individualism than with cooperation. 

RELATED: Your Biggest Relationship Issue, Based On Birth Order

Every family and child is different, so birth order is not a playbook for anyone's personality

While the findings are intriguing and may seem unbelievable to some, it's important to note that the debate between birth order and personality will not be settled anytime soon. Other studies have also questioned the notion that birth order directly shapes who we are. 

Research conducted in 2019 examining birth order and personality traits found so few differences between siblings that they concluded birth order did not play a role. These conflicting results show that birth order may not be the deciding factor in determining personality. Other factors may play a larger role, such as culture, life experiences, and parenting styles. Even the age gap between siblings can affect the results, making it hard to establish a baseline for study.

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While the idea that middle children have the best personalities might hold some merit based on this study, it's certainly not definitive. Regardless of whether you have siblings or navigate through life as an only child, the uniqueness of your personality goes beyond the birth order. The most important thing to remember is that every child is unique and amazing in their own right, and even those babies who tend to be spoiled rotten have their redeeming qualities, too.

RELATED: The Sibling Who Usually Becomes The Parent's Favorite, According To Research

Erika Ryan is a writer working on her bachelor's degree in Journalism. She is based in Florida and covers relationships, psychology, self-help, and human interest topics.

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