When we look at the classical conception of development, it
treats thinking and learning as a progression through a series of stages
that form steps in a developmental ladder, In a dynamic skills
framework, development is much more variable and flexible and shows
complex, dynamic patterns of change with many of the properties
described by mathematical theories of complexity, chaos, and
catastrophe (van der Maas & Molenaar, 1992; van Geert, in press).