Caught up in the throes of sibling rivalry? You may have some new ammunition for your next Thanksgiving Day blowout. Birth order stereotypes would have you believe that firstborns are conscientious leaders who glow with ambition. The middle child is often thought to be caught in a kind of limbo between the firstborn and the youngest. At the same time, they can become withdrawn or even resentful. They’re also depicted as natural mediators. The youngest is the wild child, babied, accustomed to roaming free, and often creative.
A new study out of the University of Edinburgh reports that as early as age 1, firstborns outshine their brothers and sisters on IQ tests. This could be due to the uninterrupted support they may have received from their parents when asked to perform tasks requiring cognitive skills. This could also explain why children born earlier tend to go further in their educations and out-earn their younger siblings later in life.
The earliest proponent of this idea was 19th-century scientist Francis Galton, who noticed that several of his colleagues were firstborn sons. He cited the same reasons as the Edinburgh researchers: a greater focus on and investment in firstborn children and, in those days no doubt, sons.
From Galton to Alfred Adler in the 1920s to Frank Sulloway, who has published research on birth order including its connection to political activism as recently as 2002, the debate continues. Going by the findings of Galton and the University of Edinburgh researchers, it would seem that the explanation is more nurture than nature. In the words of Crosby, Stills, Nash & Young, “teach your children well”—all of your children, while managing to avoid favoritism or just succumbing to fatigue.