Development: Sequences, structure, and chaos

In van Geert’s article, a number of themes are discussed. To us, the pivotal theme concerns the construction of (mathematical) models to understand development. We have a great deal of sympathy with this position and have argued that progress in developmental theory is contingent on modeling (Howe & Brainerd, 1989; Howe & Rabinowitz, 1989, 1990; Rabinowitz, Grant, & Dingley, 1987). In this article, we discuss the merits of stage-based, knowledge-based, sequence-based, and chaotic conceptions in modeling development.