ABSTRACT
Cognitive developmental psychology is faced with new developments in the mathematical theory of nonlinear dynamic systems and in psychometrics. The incorporation of these developments in current theorizing in cognitive developmental psychology is a complex matter, but one whose importance has been emphasized repeatedly (Butterworth, 1993; Molenaar, 1986; Rindskopf, 1987). The new mathematical understanding of nonlinear dynamic systems and the application of resulting ideas and techniques in an amazing number of disciplines might be called a revolution in study of change (Gleick, 1987). New fundamental relationships have emerged between chaos and unpredictability, nonlinearity and self-organization, strange attractors and fractals, disequilibrium and sudden qualitative changes, and between limit cycles and oscillatory behavior.
