Proceedings of the Annual Meeting of the Cognitive Science Society

Perseverative subgoaling, the repeated successful solution of subgoals, is a common feature of much problem solving, and its pervasive nature suggests that it is an emergent property of a problem solving architecture. This paper presents a set of minimal requirements on a production system architecture for problem solving which will allow perseverative subgoaling whilst guaranteeing the possibility of recovery from such situations. The fundamental claim is that perseverative subgoaling arises during problem solving when the results of subgoals are forgotten before they can be used. This prompts further attempts at the offending subgoals. In order for such attempts to be effective, however, the production system must satisfy three requirements concerning working memory structure, production structure, and memory decay. The minimal requirements are embodied in a model (developed within the COGENT modelling software) which is explored with respect to the task of multicolumn addition. The inter-relationship between memory decay and task difficulty within this task (measured in terms of the number of columns) is discussed.