The authors used a person-centered, longitudinal approach to identify and evaluate naturally occurring combinations of intrinsic and extrinsic motivations among 490 third-through fifth-grade students. Cluster analysis revealed 3 groups, characterized by high levels of both motivations (high quantity): high intrinsic motivation but low extrinsic motivation (primarily intrinsic) and low intrinsic motivation but high extrinsic motivation (primarily extrinsic). Analyses of stability and change in

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... uster membership indicated that the primarily intrinsic cluster was most stable (76% stability) and the high-quantity cluster most precarious (45% stability) over the course of an academic year. Students in the primarily intrinsic cluster outperformed their peers in the other 2 clusters and showed the greatest increase in achievement over time.