In the long-running debate over whether birth order shapes personality, a powerful new study has weighed in on the side of “yes.” Canadian researchers analyzed data from over 700,000 people, making it one of the largest investigations into sibling dynamics ever conducted. Their intriguing findings suggest that middle children and those from bigger families tend to be more cooperative than their brothers and sisters.
While the effects were modest, they challenge the notion that birth order has no meaningful impact on personality development. Psychology professors Michael Ashton of Brock University and Kibeom Lee of the University of Calgary believe their results show clear differences based on both birth order and total number of siblings.
Cooperation Boosts for Middle Kids
The researchers discovered that on average, middle children scored higher than their siblings on personality traits linked to cooperation, like agreeableness and honesty-humility. Firstborns and youngest siblings lagged slightly behind on these measures.
Scores for cooperative traits also climbed higher in bigger families, hinting that children may develop more agreeable personalities when raised as part of a larger group. In essence, having more siblings around seems to foster skills in getting along and working together.
Understanding the “Overlooked” Middle Child
The findings shed new light on the psychology of middle children, who have long been tagged as “forgotten” or “overlooked” in the family pecking order. Rather than getting lost in the shuffle, their unique position may actually nurture valuable social abilities. As one researcher explained:
Being a middle child calls for maintaining good relationships with both older and younger siblings. The cooperativeness we observed in middles may stem from occupying this central role in the family.
– Michael Ashton, Psychology Professor
So while middle children have often been viewed through a lens of disadvantage, this research paints their situation in a more positive light. Needing to navigate between bossy older siblings and needy younger ones might provide perfect training ground for honing people skills.
Firstborns Still Have an Edge
Although they ranked lower on cooperation, firstborn children upheld their reputation for other traits. In line with previous studies, the eldest siblings scored a bit higher on intelligence measures compared to later-born kids.
This supports the longstanding theory that parental attention gives a special boost to the intellectual development of firstborns. With undivided focus before siblings arrive, they may benefit from more mental stimulation in those critical early years.
Predicting Personality No Simple Task
However, the researchers caution not to read too much into these generalizations. While the averages reveal valid differences, it’s impossible to reliably predict any one person’s personality from their birth order or family size alone.
Many factors shape our traits besides sibling dynamics. You can’t tell that much about an individual knowing only their birth position. But across large groups, we do see these intriguing patterns emerge.
– Kibeom Lee, Psychology Professor
In other words, these findings speak to statistical trends, not ironclad rules. Countless exceptions no doubt exist to the cooperative middle child or the intellectual eldest archetypes. Like all things in psychology, variation from person to person remains the norm.
Sibling Science Marches On
Despite the caveats, this study marks a major step forward in sibling research. By gathering such an enormous dataset, the Canadian team has brought more statistical firepower to a field long plagued by inconsistent results from small samples.
- Over 700,000 participants, dwarfing past study sizes
- Detailed personality measures for traits like agreeableness and honesty
- Separate analysis of birth order and total siblings
Armed with this more robust evidence, the case is strengthening that our sibling relationships, both in terms of birth order and sheer family size, leave real imprints on personality. While always a lively topic at family gatherings, sibling dynamics increasingly appear to be a legitimate force in psychological development.
So the next time you find yourself cooperating effortlessly on a work project or smoothly brokering a family dispute, you may have your middle child origins to thank. And if you’re a parent, consider that adding a few more little ones to the mix might just raise a more agreeable brood.
Of course, as any parent of multiple children knows, getting siblings to actually cooperate is far easier said than done, no matter the birth order. But perhaps we can all learn a thing or two from the hidden gifts of the middle child—and the unexpected benefits of not always being number one.
