IQ and birth order

If you are a sibling or a parent to a sibling then you will know that siblings need no encouragement to disagree. You might at first think that this study we are about to report will do nothing but pour oil on the internecine fire as it points out the differences between siblings according to where they are born in the family structure, but the good news is that the differences aren’t so great after all.

The new study involved 377,000 high school students who declared where they fell in the birth order of their family (first born, second born, third born etc.) and then undertook personality and IQ tests.

The results showed that first-borns on average showed a one point higher IQ than later borns. Before you first borns start enjoying your advantage however, the researchers make the point that this one IQ point might be statistically significant but in terms of how you live your life and what you are capable of, it is meaningless.

In terms of personality it emerged that first borns tend to be more extroverted, agreeable and conscientious as well as having less anxiety than later-borns. Again however, the researchers say that the tendency is “infinitesimally small” amounting to a correlation of 0.02 which means you would not detect any difference between a first-born and third-born if you sat down and quizzed them.

Nevertheless the minor differences were there and they remained there when the researchers examined a subset of the subjects who had two siblings.

In the end though, it would seem that siblings really have nothing to rival over…not that it will stop them of course.