Why do first-born children do better in school than their siblings?

Beach boys
© Katherine Martinko

First-born children perform better in school than their younger siblings. A recent study, conducted by economists V. Joseph Hotz and Juan Pantano, attributes this to parents, who demand higher academic standards of older kids in order to set an example for the younger ones, who then get an easier time of it. While some parents might disagree, the fact is that many international surveys on birth order and behavior support the economists’ conclusion. First-borns have higher IQs and get better grades, and mothers are more likely to consider their first-born to be a high achiever than any of their other children.

In some ways, this theory doesn’t make sense. Doesn’t practice make perfect? Shouldn’t parents screw up the first kid and improve their parenting techniques as they move on down the line? But that’s not the case. Parenting relaxes with time and experience, even if access to child-raising resources increases, which means that later-born kids don’t get the attention that is showered on the first one.

“We provide robust empirical evidence that school performance of children … declines with birth order as does the stringency of their parents' disciplinary restrictions. And, when asked how they will respond if a child brought home bad grades, parents state that they would be less likely to punish their later-born children.” (Hotz and Pantano, “Strategic Parenting, Birth Order, and School Performance")

This study is interesting to me, a first-born who’s married to another first-born. Our exuberant first child has a personality that we can both relate to, but our passive second child is a mystery whose personality resembles that of both our younger siblings. When I watch my kids interact – the oldest leading and the youngest following – I wonder where this dynamic comes from. While I don’t like all of Hotz and Pantano’s theories for why this is the case, they’re certainly thought provoking:

1) The Divided-Attention Theory: First-borns get more attention from parents than later siblings do.

2) The Bad Genes Theory: Many first-borns have higher IQs, which leads some people to think that younger kids are somehow getting “diminished” genes.

3) The “I’ve-had-it-with-kids!” Theory: Some parents keep having kids until one is so challenging that they can’t handle another -- a form of selection bias.

4) The “No-one-to-teach” Theory: Oldest kids benefit from teaching younger siblings, but little ones have no one to instruct.

5) The Divorce Theory: Family crises usually happen after the first baby has arrived and been established, so the negative impact is more disruptive for younger kids.

6) The Lazy Parent Theory: Parents’ standards relax over time and they’re no longer scared of screwing up.

I’d add that first-borns are the rule-breakers. We (and I speak from experience!) forge the paths that our younger siblings can follow without the same parental confrontations. First-borns are surrounded by adults, so they assume adult-like behavior. They also act as surrogate parents, or enforcers for the parents, trying to discipline and/or direct younger children.

It’s hard being the oldest… and it’s probably just as hard being the youngest. For those of us with multiple children, this study is a good reminder to maintain the attention that every child needs, regardless of where they fall in terms of birth order.

Why do first-born children do better in school than their siblings?
Parenting styles evolve, and so do the results.

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