Study Finds Middle Children Are the Most Cooperative Among Siblings

Research on over 700,000 individuals reveals that personality traits like agreeableness and honesty-humility are higher in middle children and those with more siblings.

A large-scale study involving over 700,000 participants examined the relationship between birth order, family size, and personality traits.
Middle children scored the highest on traits linked to cooperation, such as agreeableness and honesty-humility, followed by youngest, firstborn, and only children.
The findings suggest that growing up with more siblings fosters slightly higher levels of cooperative personality traits on average.
Researchers found that while the number of siblings was the primary factor, birth order also had a modest impact on personality traits.
The study controlled for variables like socioeconomic status and upbringing, showing that the trends remained consistent across diverse groups.