As grown-ups everywhere have long suspected, poorly behaved 6-year-olds will come to no good. Or, at least not as much good as their more attentive, kinder and less aggressive peers.
New research used tax return data to determine the income, at age 33 to 35, of 2,850 children tracked by the Quebec Longitudinal Study of Kindergarten Children, an academic research project following kids from kindergarten through adulthood. The analysis, led by first author Francis Vergunst at the Université de Montréal, found that children who were bad at paying attention as 6-year-olds earned less than their peers as adults. The study also found that boys, but not girls, who were aggressive or who scored low on measures of “prosocial” behavior in kindergarten also earned less than their peers as adults. These findings held even when economic status and IQ were taken into account. The study was published online in the journal JAMA Psychiatry in June 2019.
There is substantial existing research on the power of self-control demonstrated at an early age to predict later success, said Daniel Nagin, a co-author and professor of public policy and statistics at Carnegie Mellon University in Pittsburgh. But little has been done to pull apart the specific traits that are usually measured to determine a child’s level of self-control, he said. He also thinks this study is the first to connect behavior data to tax return data, rather than relying on self-reported income.
In this case, researchers were able to tell exactly how much more or less an adult might earn as predicted by a given kindergarten behavior pattern. For example, the boys who were rated one point more inattentive than their peers on a scale used by researchers made $1,271 less in annual earnings as adults. More aggressive boys earned $700 less per year as adults and more social ones earned $477 more. (Though the research was done in Canada, all figures listed are in U.S. dollars.)
Family income and IQ have long been known to affect later earning power, Nagin said. But since those factors are hard to change, he and his co-authors were interested in studying something that teachers might actually be able to address: behavior. Finding a connection between behavior and adult income could strengthen the case for early behavioral interventions, he said.
Teachers try many ways to improve attentiveness in young children. Some techniques, like increasing the amount of physical activity kids get, have held up to rigorous research. Others, like practicing meditation and mindfulness, have not.
Aggression, in particular, has often proved a long-term problem. An aggressive preschooler is likely to grow into an aggressive high schooler. But a 2012 report on the subject from the University of Alabama suggests some solutions. Research shows that teachers and parents can be trained to teach kids better behavior, the report states. Teaching kids explicitly about how to solve problems can also help.
Nagin would like to understand why aggression and unfriendliness in kindergarten predict lower earnings for adult men but not for women. His initial hypothesis is that a subset of boys who are highly aggressive and very bad at connecting with other people are driving the association with lower earnings. Fewer girls, he pointed out, are extremely aggressive or extremely bad at making friends. This could mean that middling levels of aggression don’t have much effect on earnings. So far, there’s no evidence to back up his idea but Nagin said the more he thinks about it, the more he’s inspired to launch a new research project to find out if he’s right.
This story about kindergarten behavior was produced by The Hechinger Report, a nonprofit, independent news organization focused on inequality and innovation in education. Sign up for the Hechinger newsletter.