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Are eldest children more intelligent with 'better' personalities? Massive study settles this sibling rivalryEldest siblings are more intelligent, a new study of 377,000 high school students finds.
However, the difference is equal to, on average, just one IQ point.
This difference is so small as to be almost meaningless.
There were also consistent differences in personality.
Eldest siblings tended to be more outgoing, conscientious and agreeable, while being less anxious.
But, again, these differences were very small.
Professor Brent Roberts, who led the study, explained how small the differences were:
"In some cases, if a drug saves 10 out of 10,000 lives, for example, small effects can be profound.
But in terms of personality traits and how you rate them, a 0.02 correlation doesn't get you anything of note.
You are not going to be able to see it with the naked eye.
You're not going to be able to sit two people down next to each other and see the differences between them.
It's not noticeable by anybody."
The study controlled for factors like economic status and the number of children.
Professor Rodica Damian, who co-authored the study, said:
"The message of this study is that birth order probably should not influence your parenting, because it's not meaningfully related to your kid's personality or IQ,"
The research was published in the
Journal of Research in Personality (
Damian & Roberts, 2015).
Comment: Interesting that the study came up with the following statement:
The message of this study is that birth order probably should not influence your parenting. Another aspect of sibling rivalry that parents should be aware of is shared in the following article:
Bully in the next bedroom - are we in denial about sibling aggression?
Sibling relationships can be difficult, and never more so than in childhood. But society often regards the scrapping and squabbling, the play fighting and not-so-playful fighting as a normal part of growing up.
"The public brushes off aggression between siblings as just rivalry," says Corinna Tucker of the University of New Hampshire.
Tucker is the lead author of a new study on the issue for the journal Pediatrics. Almost a third of the 3,600 children questioned said they had been the victim of some sort of sibling aggression in the past 12 months. The included a range of acts from theft and psychological abuse to physical assault, either mild or severe. In comparison, research suggests that up to a quarter of children are victims of schoolyard aggression every year.
Corinna Tucker uses the term "sibling aggression" in her study, but psychologists are increasingly reaching for a familiar label for the bad stuff that goes on between brothers and sisters - bullying. This is defined by experts as intentional acts of aggression, repeated over a period of time, where an individual or group is in a position of power over someone.
So sibling relationships would seem the perfect breeding ground for bullying, since children live together for a long period of time and there is usually an intellectual and physical power imbalance. Although there might not be an outright malevolence, there is often reason for jealousy.
Comment: Interesting that the study came up with the following statement: The message of this study is that birth order probably should not influence your parenting. Another aspect of sibling rivalry that parents should be aware of is shared in the following article: Bully in the next bedroom - are we in denial about sibling aggression?