The fascinating 7 Up series of documentaries, which follows a diverse group of Brits from childhood into late middle age, is a real-life test of the aphorism "Give me the child until he is 7, and I will show you the man."

Newly published research suggests that cliché is actually a bit conservative. It finds a sensitive evaluation of a child's behavior at age 5 has remarkable predictive power.

The study traced 753 young Americans from kindergarten into adulthood. It found that young children who have the ability to get along with others were significantly more likely to mature into responsible, successful adults.

This association was "independent of child, family, and contextual factors that typically predict adult outcomes," a research team led by Damon Jones of Pennsylvania State University writes in the American Journal of Public Health.

The study's participants were recruited from schools in Durham, North Carolina; Nashville, Tennessee; Seattle, Washington; and a rural district in central Pennsylvania. Roughly half were considered "at high risk for long-term behavioral problems and conduct disorders," while the others belonged to a control group.

Their kindergarten teacher rated each child using nine measurements of emotional intelligence and how well she interacted with others. On a one-to-five scale, the teacher noted how well the child "cooperates with peers without prompting," "is helpful to others," "very good at understanding feelings," and "resolves problems on own."

"Final follow-up data were collected 19 years later, when participants were aged approximately 25," the researchers write. The results showed a strong correlation between those early social-competence abilities and a positive life trajectory.

Specifically, "Kindergarten pro-social skills were significantly and uniquely predictive of whether participants graduated from high school on time, completed a college degree, obtained stable employment in young adulthood, and were employed full-time in young adulthood," the researchers report.

One striking result: For every one-point increase in a child's social competence score in kindergarten, he or she was twice as likely to have earned a college degree two decades later.

On the other side of the equation, kids with strong skills were less likely to be living in public housing or on public assistance. And they were less likely to have had any involvement with the police as juveniles.

Jones and his colleagues, Mark Greenberg and Max Crowley, concede their study does not prove causality. But at the least, they write, early social skills serve "as a marker for important long-term outcomes." And one can make a strong argument that they are "instrumental in influencing other developmental factors that collectively affect the life course."

That's certainly the lesson drawn from the results by the Robert Wood Johnson Foundation, which funded the research. "This study shows that helping children develop social and emotional skills is one of the most important things we can do to prepare them for a healthy future," said Kristin Schubert, the foundation's program director, in a press release.

Indeed, the policy implications of this study seem clear. While teaching teens skills to manage their emotions is incredibly useful, these results suggest there is no point in waiting. Programs that model and reward cooperative, sharing behavior — or teach parents how to instill such attitudes in the home — could set kids on a positive path from a very early age.

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