Self-discipline may be more important than high IQ when it comes to getting good grades and graduating from high school.

Those are the findings of a study by Angela Duckworth, doctoral candidate at the Positive Psychology Center, and Martin E.P. Seligman, the Fox Leadership Professor of Psychology that set out to measure self-discipline in eighth grade students.

It’s hardly a surprise to parents and educators that the more highly disciplined students outperform their peers in report card grades, standardized achievement test scores, admission to a competitive high school and attendance. More surprising perhaps is the fact that the self-discipline tests administered by Duckworth and Seligman, and published in the journal Psychological Science, predicted which students would achieve and improve their grades better than a simple IQ test alone.

Duckworth is quick to defend IQ as a measurement of intelligence and potential. “We didn’t find that IQ doesn’t matter at all,” she says. “IQ’s been around as a concept for a century or so. …We know how to measure IQ relatively well. It’s harder to measure a personality trait.”

Valid ways to measure self-discipline do exist, though tests have often focused on adults or young children. To test self-discipline in two groups of eighth graders, Duckworth and Seligman had the first group of students fill out two questionnaires—one that asked questions about doing or saying things impulsively and another asking if they would prefer an immediate smaller reward or a delayed larger one. Researchers also included reports from parents and homeroom teachers and measured their grades from the fall through the rest of the school year.

In the second group of students, Duckworth and Seligman added an IQ test, questions about study and lifestyle habits and a behavioral measure to the monetary questionnaire, asking students to choose between getting $1 now or $2 a week later. Twenty percent of the students chose to take the dollar immediately, while 80 percent opted to wait to collect $2.
Duckworth defines self discipline as “doing what you have to do when you don’t want to do it.” That could mean foregoing television in favor of starting homework early or studying for a test. Or, in the example used in the questionnaire, giving up immediate gratification for a superior reward in the future.

Duckworth and Seligman found that the self-disciplined students watched less television and spent more time on their homework than their impulsive peers. This time paid off in the classroom and on report cards, as those students got higher grades and standardized achievement test scores and easily gained admission to competitive high schools. They also were more likely to have better attendance records and show up to school on time.

The researchers also found that the girls were more self-disciplined than the boys, which again translated into higher grades and GPAs. Girls, they discovered, start their homework earlier in the day and, according to a companion study, to be published in the Journal of Educational Psychology, spend almost twice as much time completing it.

What remains to be seen is whether self-discipline can be taught in schools. “To some extent, every parent and teacher tries to do this,” says Duckworth. “Maybe we can improve it.”
Duckworth, a former teacher, says she saw a much higher level of self-discipline in schools with high-achieving, college-bound students. At another school, which was filled with bright but low-achieving students, Duckworth says the “self-discipline and other non-cognitive factors played a role.”