Abstract
Skilled perceptual-motor performance should be approached from a point of view of the processing operations performed by S in a skilled task. This perspective is emphasized in recent attempts to develop analytic or computer-simulation models of tracking tasks. These models are illustrated, and it is argued that a model that has a discrete correction compensatory path and a continuously programmed pursuit path may form one starting point for a more general representation. This representation needs to incorporate as yet undefined processing and storage units to handle coherence prediction, memorized movement patterns, and compensation for external system dynamics.