Accession Number : ADA186645

Title :   Flexible Execution of Cognitive Procedures.

Descriptive Note : Final rept. 1 Jun 85-31 May 86,

Corporate Author : CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF PSYCHOLOGY

Personal Author(s) : VanLehn, Kurt ; Ball, William

PDF Url : ADA186645

Report Date : 30 Jun 1987

Pagination or Media Count : 67

Abstract : Several current theories of procedural knowledge hypothesize that procedures are organized as hierarchies of goals, wherein accomplishing a goal requires accomplishing all or some of its subgoals. This form of knowledge is most naturally executed with the aid of a temporary last-in-first-out stack of goals. This article presents evidence that a stack regime is not flexible enough to account for the procedural problem solving exhibited by a sample of 26 third-graders solving subtraction problems. Two alternative control regimes are investigated. One stores goals on an agenda (an unordered set) and the other stores goals in tree. Both the agenda regime and the tree regime employ a rule-based scheduler that picks the next goal for execution. Both regimes succeed at modelling our subjects' problem solving strategies. The tree regime is able to account for data from another study as well. However, a closer examination of the fit between models and data shows that some students change their execution strategies in the midst of problem solving. This finding challenges fundamental assumptions underlying research on cognitive architectures.

Descriptors :   *COGNITION, *PROBLEM SOLVING, ARCHITECTURE, CONTROL, HIERARCHIES, STACKING, STRATEGY, STUDENTS, THEORY, METHODOLOGY, CHILDREN

Subject Categories : Psychology

Distribution Statement : APPROVED FOR PUBLIC RELEASE