There’s always a lot of banter between siblings. The oldest one always thinks they’ve got the rough end of the stick and that the younger one can do no wrong in their parents’ eyes. Memes across the internet often suggest that one sibling is smarter than the other, but the science is finally in – the older sibling is statistically more likely to score higher on cognitive tests than the younger one. And, you can probably blame your parents for it.
Older Sibling’s Mental Edge
Research from the University of Edinburgh suggests that the thinking skills of first-born children outperform their siblings. This is because they receive more mental stimulation from their parents in their early years. While the study goes on to confirm that they receive the same level of emotional support, first-born children receive more support with tasks that develop thinking skills. This is likely to do with the one on one attention they can receive from their parents, as well as the anxiety of new parents working tirelessly to do everything possible to give their child the very best start in life. This isn’t to say they don’t do the same for subsequent children, it’s just that now their attention is divided and they only have 24 hours in a day. (1)
Birth Order Effect
The 2016 study was undertaken to further explore something known as the ‘birth order effect’. This is when children born earlier in a family enjoy better wages and more education in later life. Researchers found that parents often changed their behavior as subsequent children were born. They offered less mental stimulation to younger siblings. They also took part in fewer activities such as reading with the child, arts and crafts, and playing musical instruments with them. Now, this can most likely be explained by a lack of time or energy. But it’s not ideal from the perspective of child number two or three. ( 2)
The Sibling Study
Economists at the University of Edinburgh, Analysis Group and the University of Sydney examined data collected by the US Bureau of Labor Statistics. They found that older siblings scored higher than their younger brothers and sisters in IQ tests as early as age one. The Journal of Human Resources study observed nearly 5,000 children from pre-birth to age 14. It assessed the children every two years through tests including reading recognition, such as matching letters, identifying names, reading single words aloud, and picture vocabulary assessments. (1, 2)
Dr Ana Nuevo-Chiquero, one of the researchers, concluded the study by saying, ‘Our results suggest that broad shifts in parental behavior are a plausible explanation for the observed birth order differences in education and labor market outcomes’. (1)
By virtue of being the first child, the first-born will be a product of trial and error for the new parents. They’ll likely be subjected to a lot more worry and attention than their subsequent siblings who will, in turn, likely have more freedom. By the time second and third children come along, the parents will have gotten the hang of this parenting thing and won’t be as panicked every time the child bumps its head or develops a bit of a temperature.
Luckily, this isn’t set in stone. As long as you try to give as much stimulation as possible to all of your children, you could end up with a brood of equally intelligent geniuses and no risk of being accused of favoritism. But for now, I’m off to share this study with my younger brother.