Intelligence is not enough: Non -IQ predictors of achievement

Angela Lee Duckworth, University of Pennsylvania


The importance of intelligence to achievement in all professional domains is well-established, but less is known about other individual differences that predict success. The current investigation documents the contribution of two non-IQ traits, self-discipline and grit, to achievement. Chapter 1 summarizes two longitudinal studies in which self-discipline, measured using a multimethod, multisource approach, predicted the academic performance of adolescents several months later. In the second of these studies, self-discipline explained more than twice the variance in academic performance as did IQ, to which self-discipline was not strongly related. Chapter 2 explores gender differences in self-discipline and the relative contribution of this advantage to various measures of academic performance. In two longitudinal studies involving the same cohorts studied in Chapter 1, girls were more self-disciplined than boys. The female advantage in self-discipline contributed to higher grades in all courses including mathematics, despite only marginally superior achievement test scores and lower IQ scores. In Chapter 3, I introduce a related but different trait: grit. Defined as perseverance and passion for long-term goals, grit was hypothesized to predict success over and beyond self-discipline and IQ in especially challenging settings. Five studies are presented in support of this hypothesis. Specifically, grit predicted educational attainment among a larger sample of adults aged 25 or older, GPA among high-achieving adolescents and undergraduates, retention and GPA at the United States Military Academy (West Point), and final ranking in the National Spelling Bee. In the latter four studies, grit provided incremental predictive validity over and beyond that of IQ. Grit was a better predictor than self-discipline of retention at West Point and performance in the Spelling Bee, but in three studies, self-discipline was a better predictor of GPA. I speculate that grit is more important to the accomplishment of especially challenging goals in which the temptation to give up altogether is great, whereas self-discipline is more important to the accomplishment of more moderate, highly structured tasks. (Abstract shortened by UMI.)

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Recommended Citation

Duckworth, Angela Lee, "Intelligence is not enough: Non -IQ predictors of achievement" (2006). Dissertations available from ProQuest. AAI3211063.