Focuses on the question of whether developmental improvement in performance on cognitive tasks is abrupt or continuous. Explains three model-based approaches to this question, and stresses that research conducted in these approaches has indicated that developmental improvements consist of jumps through discrete states. Concludes that these results…

Two experiments used a formal model of developmental discontinuity derived from catastrophe theory to test whether the transition from Rule I to Rule II on the balance scale task proceeds discontinuously from ages 6 to 10, focusing on five catastrophe flags. Found that bimodality, inaccessible region, hysteresis, and sudden jump were clearly…

Argues that what matters is not the difference between learning and development, but the dynamic relationships that form the key to understanding. Examined two models of these relationships: (1) a semantic approach, distinguishing five dimensions along which learning and development can be compared; and (2) a mathematical nonlinear growth model…