There is a longstanding myth that children who are born first are more intelligent than their siblings, more outgoing, more likely to be leaders, and more likely to achieve in life. Middle children are supposedly squished in the middle, vying for attention. They are apparently more likely to go with the flow, play the peacemaker role, and be creative. And youngest children… well they’re the spoiled ones.
But as fun as it is to work out how true the stereotypes are of each of us, there is not a shred of credible evidence to support the birth order myth. (I wrote a number of reasons why this is the case right here.) Some of the more plausible reasons the birth order theories are far-fetched include the lack of consideration of gender, or the failure for the theories to effectively account for the length of the gap between each child? The theories ignore the education and socio-economic status of the parents when each child is raised? What about peers?
What about when twins are born? Or when there are only two children? Or four or more? (Some birth-order myth promoters say that the fourth child becomes like the eldest, the fifth, like the second-born, and the sixth like the third-born.) What happens when a child dies? Or when families mesh following breakups? The number of social, environmental, and even genetic variables that such a theory ignores is significant, yet people continue to buy the idea that birth order matters. The science says one thing increasingly clearly: birth order doesn’t mean much at all.
In July 2015 another significant, large study adds further weight to the argument against birth order theories.
Older Children Really Are Smarter?
The study is the biggest birth order study in history, and involved 377 000 children throughout the USA. The researchers actually found that eldest children’s IQ was higher than their siblings – by 1 IQ point. While that may be enough for bragging rights, the difference is so minuscule as to be essentially meaningless.
If you were to sit two people side by side and ask them to talk with you, sit a test, or live their lives, you would not notice an IQ difference of 1 point. Previous large-scale studies have found similar outcomes. This is not new. But it certainly adds substantial weight to the argument against birth order myths.
There are Personality Differences
The study also looked at the personalities of children in families and found that it is true that older children are more extroverted, more conscientious, and more agreeable than their younger siblings. They also found it was true that younger siblings were a little more anxious than their older siblings. But once again the magnitude of those differences were so small as to be meaningless.
As an example, a correlation of 0 means there is no relationship. These measured around 0.02, which means that while a test shows the tiniest fractional difference, no observer would be able to point to a child and deduce, based on their personality, where they came in birth order within their family.
Why do we believe the myth?
Some people find life easier when they can find meaning and patterns in certain aspects of life. It can be nice to say, “He’s like that because of x.” Yet the message of this study (and others like it) is that last born children are just as likely to be leaders, capable of changing the world as first born children. Middle children are just as likely to be extroverted – or shy – as are their older and younger siblings, and that it does not make a skerrick of difference where your child is born. Their intelligence, personality, and lifestyle choices are about the energy and effort we (as parents) put into raising them, and the decisions that they make as they get older.
Who we become, and who our children become, is not about birth order. To argue in favour of birth order teaches people to be victims of something beyond their own control. The evidence tells a different story.