In the 1960s, researchers began a study of 123 African-American children born into poverty. When the children were 3 years old, they were randomly assigned to either a treatment group, and given a high-quality preschool education, or to a control group, which received no preschool education at all.
The subjects were then tracked over the ensuing decades, with the most recent analysis comparing the groups at the age of 40. The differences, even decades after the intervention, were stark: adults assigned to the preschool program were 20 percent more likely to have graduated from high school and 19 percent less likely to have been arrested more than five times.
The Perry Preschool study is a powerful demonstration that early childhood education has lasting benefits. But what skills did the preschool experience actually improve? The initial evidence suggested that the children benefited from dramatic boosts in their IQ scores, but the effect faded with time, and by age 10 it had vanished. James J. Heckman, an economist at the University of Chicago, has recently demonstrated that, rather than boost intelligence, the Perry Preschool led to permanent improvements in various personality traits, such as self-control and grit. He argues that it's time policy makers stop fixating on academic test scores and instead devote resources to improving these attributes.
"Our educational approach in America is rather misguided," Heckman says. "We've been focused on cognitive this, cognitive that, but we've mostly ignored the traits and skills that actually predict success in life."
