Thanks to Walter Mischel's "marshmallow test," now there's scientific proof that patience is a virtue.

The University of Louisville in Kentucky has awarded Mischel, a professor of psychology at Columbia University, with this year's $100,000 Grawemeyer Award for Psychology for his groundbreaking research on delayed gratification, which he expanded using fMRI to pinpoint brain regions linked to willpower.

Mischel's foray into willpower began in the 1960s at Stanford University when he gave 500 4-year-old children two options: Once he left the room, they could eat one marshmallow right away, or they could wait until he returned 15 minutes later and have two marshmallows.

At the time, Mischel was only trying to determine how some are able to wait and control themselves in this situation, such as by distracting themselves from the treat. Ten years later, he inquired how some of the children from his sample were faring in school and took a second look at his original data.

"It was only as an afterthought that I looked at differences between these kids as time passed," Mischel recalls. "But the more I looked, the more I saw how dramatic some of these differences turned out to be."

He found that the children's ability to resist temptation helped them over the long term. The children who were able to distract themselves from the marshmallow as 4-year-olds (the high-delay group) earned higher SAT scores and had better social-cognitive and emotional coping skills as teenagers than the children who gobbled their single marshmallow (low-delay group). Mischel has since followed his original participants into adulthood — his sample is now in their forties. He has found that the high-delay group also had higher levels of academic achievement, lower body mass index and lower rates of drug abuse, divorce and separation than their more impatient peers.

And, in research published in August in the Proceedings of the National Academy of Sciences, Mischel and colleagues found differences in the brain activity of his high and low-delay groups during a variation of the marshmallow task. Brain scans revealed that those in the low-delay group showed more activity in the ventral striatum, an area of the brain linked to addiction and pleasure-seeking, than those in the high-delay group.

Economists have used his findings to guide financial decision-making models, and education researchers have used them to design interventions aimed at improving children's self-control. "It's become almost a growth industry," says Mischel.

He is still studying his Stanford sample, most recently working with economists to compare the financial management and decision-making abilities of his low and high-delay groups. He and researchers at Cornell Weill Medical Center in New York are also working with a new sample of children to study the connection between emotion regulation and gratification delay.

Following a group of children for 40 years has been fascinating, says Mischel, 81.

"It's also a longevity study," he adds. "You have to live a long time to do it."

The University of Louisville presents annual Grawemeyer Awards in five categories: music composition, ideas improving world order, psychology, education and religion.

—J. Chamberlin