This "classic" article (1972) in the field of deaf studies includes some interpretive notes for current readers. The article examines the effect of deafness on basic developmental tasks at each of the eight developmental stages of Erik Erikson's theory of psychosocial development and explains the more successful passage through these…

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…

Elusive developmental processes are most often examined in the context of the philosophic problem of scientific determinism. The Markov process model, enhancing a probabilistic viewpoint for the explanation of developmental data, should be restricted. Attention should be focused on the immediate context and situational setting of a subject. The…