Proceedings of the Annual Meeting of the Cognitive Science Society

It has been found that expert physicians use forward reasoning in diagnostic explanations of clinical cases. This paper shows that the Kintsch-Greeno model for solving arithmetic word problems, which assumes a forward chaining process, can be extended to explain this phenomena. The basic approach is to modify the lexicon and the schema structure of the existing simulation program while retaining the basic control structure. The principle modifications are in the structure of the schemata which make use of three slots: indicator,abnormality and consequence. As with the Kintsch-Greeno theory,the model proceeds by using these schemata to build super-schemata from the propositional representation of the problem text.