Complex systems approaches to the development of action

Currently there is much interest in applying physical theories of complex systems to the study of motor development. In the past such applications never really progressed beyond proposing analogies between physical and biological systems. Contemporary approaches based on principles of self-organization offer the very real promise of transcending the shortcomings of previous applications. We trace the historical roots of such approaches which can be distinguished in terms of their allegiances to deterministic or stochastic principles. More recent approaches, such as synergetics, attempt to account for both principles and as such are particularly relevant for tackling the neglected, but central issue of qualitative transitions in motor development. Accordingly we conclude that ontogentic change results from an interplay of deterministic and stochastic processes and that the mathematical tools for modelling such change can be found in contemporary approaches to complex behaviour.