Study Reveals Brain Biology Behind Self-Control

A new neuroscience twist on a classic psychology study offers some clues to what makes one student able to buckle down for hours of homework before a test while his classmates party.

The study, published in this month’s edition of Proceedings of the National Academy of Science, suggests environmental cues may “hijack” the brain’s mechanisms of self-control in some people and some circumstances.

The findings add to a growing body of research suggesting that a student’s ability to delay gratification can be as important to academic success as his or her intelligence—and that educators may soon know how to teach it.

More than 40 years ago, Stanford University researchers led by Walter Mischel conducted anow-famous study in self-control: They asked 4-year-olds at Stanford’s Bing Nursery School to hold off eating one sweet in exchange for the promise of two sweets 15 minutes later. Fewer than one in three children passed the so-called “marshmallow test.”

In the years that followed, numerous follow-up and variation studies have found that the preschoolers who managed to delay gratification were also more likely later on to do well in school, avoid substance abuse, maintain a healthy weight, and even perform better on the sat than peers who couldn’t resist temptation.

The studies by Mr. Mischel, who is now a psychology professor at Columbia University, and a cadre of other researchers have helped change the way scholars and educators think about why students succeed academically. In a separate self-control study, Angela L. Duckworth, an assistant psychology professor at the University of Pennsylvania, even found that self-control was a better predictor of a student’s academic performance than an IQ test.

Yet the brain has remained a missing piece of the puzzle, according to B.J. Casey, the director of the Sackler Institute for Developmental Psychobiology at the Weill Cornell Medical College in New York City. The new study is the first to compare brain differences among those original Stanford preschoolers.

“What we wanted to do is try to understand how the brain is related to this behavior,” said Ms. Casey, who led the new study. Brain imaging, she said, “is helping us to disentangle the impulse control from sensitivity to rewards and social cues.”