When they adjusted their statistics to take away the influence of motivation upon the results, the researchers found that the IQ tests did a poorer job of predicting what would happen to the boys later in life.
It's possible that some of the things that make someone motivated -- compliance, a natural interest in solving problems, competitiveness -- are high in those who do well on the tests and may help them do better in life, Duckworth said.
However, the findings "don't say these IQ scores are all about motivation," Duckworth said. "It's not saying anyone can get 140 if they try hard enough."
Robert Sternberg, a psychology professor and provost at Oklahoma State University, praised the study but added that the findings aren't exactly shocking. "To almost anyone except some subset of those psychologists who study IQ testing, it will come as little surprise that motivation is an extremely powerful determinant of performance in school and in life," he said.
The study is published in this week's Proceedings of the National Academy of Sciences.
For more about IQ, visit the U.S. National Library of Medicine.
SOURCES: Angela Lee Duckworth, Ph.D., assistant professor, department of psychology, University of Pennsylvania, Philadelphia; Robert Sternberg, Ph.D., professor, psychology, and provost, Oklahoma State University, Stillwater; April 25-29, 2011, Proceedings of the National Academy of Sciences
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