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Coordinative structure models

The ``Coordinative model'' [339,106,163,164,307] (Scott Kelso 1983,Salzman 1986, 1991,Keller 1990) is based on the metaphor of generalized physics models. Other names referring to the same group of theories are ``Synergetics'' or ``Systems Dynamics'' (as applied to motor control). This theoretical direction developedin contrast to cybernetic and algorithmical models. It is based on coordinative structures, that is functional groups of muscles behaving like coordinated units according to rules learnt by training. The articulatory trajectories are the result of the interactive work of coordinative structures aimed at reaching a ``qualitative'' target in a flexible and adaptive way (Saltzman 1991). Using tools from non-linear systems dynamics, oscillatory behaviors like walking and juggling with balls can be nicely described. However, the parsimony of the approach breaks down in complex patterning tasks. As an example we can take cursive handwriting. In this motor task, discrete action pattern units are concatenated. Even if we would succeed in describing an oscillator configuration for a single letter, or even two letters, how then are the basic action units concatenated? Is this done by an associative process, or by "buffering"? The same argument holds for speech and manipulation tasks. In order to solve this problem, cognitive representational concepts will be needed in a theory of motor control, eventually.

Thu May 18 16:00:17 MET DST 1995