A theory of the representation, organization and timing of action with implications for sequencing disorders

This paper develops a theory for explaining how the components of everyday actions are sequenced and timed (e.g., typing, hammering a naill. Under the theory, a hierarchy of content nodes represents the form of a pre planned action, while an independently stored set of (sequence) nodes codes the serial order rules for the action and determines sequence in the final output. Another independently stored set of (timing) nodes determines when and how rapidly these action compo nents become activated. The theory also postulates a superordinate organization of content, sequence and timing nodes into systems. Each system has unique characteristics and rules of its own and is independently controllable, enabling thought of particular kinds without the occurence of action. Four systems are discussed i