Tom Popomaronis

CNBC

For parents, one of life’s biggest challenges is raising smart, well-rounded children. But let’s be honest, we also want them to grow up to be successful adults with high-paying jobs.

Luckily, observing how your children interacts with others can reveal a lot about who they’ll be and what they’ll do as adults.

That’s according to a 30-year study, published in the Journal of American Medical Association Psychiatry last month, which found that inattentive children are more likely to earn lower salaries in their early to mid-30s.

Researchers analyzed teacher questionnaires for 2,850 kindergartners in Quebec, Canada in 1980 and 1981 – and then cross-referenced the behavioral ratings for each child with their government tax returns from 2013 to 2015.

How I ditched massive student loan debt:‘I just pretended I didn’t have money’

Early behavioral traits as a predictor of future income

After adjusting for IQ and family adversity, the results showed that five- and six-year-old boys and girls who were inattentive in kindergarten had lower annual earnings between the ages of 33 and 35.

Specific behaviors associated with inattention included opposition (e.g., disobeying, blaming others), hyperactive (e.g., fidgety, constantly moving), anxiety (e.g. crying easily, constantly worried) and physical aggression (e.g., fighting, bullying).

In the follow-up, high scores of inattention were associated with a decrease in annual earnings of $1271.49 for male participants, and $924.25 for females.

“Over the course of a 25-year career, the differences between the two groups can reach $77,000,” Sylvana Côté, a health professor and lead author of the study, said in a media release.

Children who displayed less signs of inattention – or none at all – would “theoretically” lead to an increase of $3,077 in annual earnings for males and $1,915 for females, the researchers noted.

Not quite as cheap as it used to be:Has a Netflix subscription finally gotten too expensive?

The pros of prosocial behavior

Meanwhile, boys who showed prosocial behaviors (e.g., showing sympathy, sharing with others, stopping disputes, resolving peer problems on their own) positively correlated with higher-than-average future incomes. Girls didn’t follow the same trend.

While inattention was the only behavioral predictor of income among girls, other studies have suggested that both boys and girls who are prosocial have increased chances of future success in school, work and life.

One 2015 study from Penn State University, for example, found that kindergartners who showed signs of prosocial behaviors were twice as likely to graduate from college and 46% more likely to have a full-time job by age 25.

Can you afford to retire?:Most Americans fear they can't

Limitations of the study

“Researchers have examined what childhood behavior can tell us about how individuals will do economically later in life. But the methods they used to reach an answer were limited, which tempered the studies’ findings,” Côté told MEAWW.

The researchers also acknowledged that the study didn’t account for earnings through the informal economy or accumulation of debt.

The big takeaway

Certainly, there are other factors, such as parenting styles, health status, social interactions and daily environment that can affect a child’s future.

While the findings don’t prove causality, the real importance of the study, the authors noted, is that it specifies the association between childhood behaviors and adult earnings, thus informing “the development of screening tools and preventive interventions.”

Also, parents who identify traits associated with inattention in their children at an early age should make an effort to modify their behaviors – sooner rather than later.

After all, it goes without saying that children with better social skills (e.g., good at managing emotions, gets along with others, expresses sympathy and compassion) are more likely to be successful – and, hopefully, wealthier – in the future.

Chick-fil-A dominates chicken sandwiches:McDonald's franchisees want to compete

Tom Popomaronis is a commerce expert and proud Baltimore native. Currently, he is the Senior Director of Product Innovation at the Hawkins Group. His work has been featured in Forbes, Fast Company and The Washington Post. In 2014, he was named one of the “40 Under 40” by the Baltimore Business Journal.

©CNBC is a USA TODAY content partner offering financial news and commentary. Its content is produced independently of USA TODAY.