Firstborn Children Are More Intelligent Than Their Younger Siblings, Study Suggests
The stereotype about oldest children being overachievers now has some science to back it up.
A recently resurfaced November 2016 study, published in The Journal of Human Resources, suggests that firstborn kids could, in fact, be more intelligent than their younger siblings — and it’s possible it’s all about how they’re parented from the get-go.
“As early as age 1, latter-born children score lower on cognitive assessments than their siblings, and the birth order gap in cognitive assessment increases until the time of school entry and remains statistically significant thereafter,” reads the study, authored by Jee-Yeon K. Lehmann, Ana Nuevo-Chiquero and Marian Vidal-Fernandez.
The reason, they suggest, could be because “mothers take more risks during pregnancy and are less likely to breastfeed and to provide cognitive stimulation for latter-born children.”
“Variations in parental behavior can explain most of the differences in cognitive abilities before school entry,” they continue. “Our findings suggest that broad shifts in parental behavior from first to latter-born children is a plausible explanation for the observed birth order differences in education and labor market outcomes.”
Want all the latest pregnancy and birth announcements, plus celebrity mom blogs? Click here to get those and more in the PEOPLE Parents newsletter.
Researchers came to their conclusions after studying thousands of young Americans ages 14 to 21, via the Children of the National Longitudinal Survey of the Youth, over the past 40 years or so.
Speaking with Today about the study in February 2017, Lehmann — an assistant professor in the University of Houston’s economics department — said that “First-time parents tend to want to do everything right and generally have a greater awareness of their interactions with and investments in the firstborn.”
“With each subsequent child, parents tend to relax to a greater extent what they might deem as non-essential needs for their kids,” she added.
RELATED VIDEO: Former Bachelorette Ashley Hebert Rosenbaum Opens Up About Her Sibling-Rivalry Fears
According to Today, Lehmann and her fellow authors concluded that while parents did not sacrifice care and affection with their children born second and later, the big ingredient missing was mental stimulation that they had given their oldest children (e.g., reading to them, teaching them the alphabet, providing them with educational toys).
Today shared that the study found that moms limited alcohol less with second pregnancies and beyond, waited longer to begin embracing prenatal care and more.
“The lesson here for parents is that the types of investments that you make in your kids matter a lot, especially those that you make in the children’s first few years of life,” Lehmann told Today. “All those learning activities that you did with your first child as excited, nervous and over-zealous parents actually seem to have some positive, long-lasting impact on their development.”