On the Nature of Verbal Rules and Their Role in Problem Solving *

This paper develops the idea of a verbal rule as a concise, linguistic description of a plan for problem solving. The first section discusses the properties of verbal rules, including what they are, why they are useful, what kind of plan is described, the additional knowledge needed to convert them into performable procedures, and how they might be used in problem solving. The second section reports the results of an empirical study of the role of signed‐arithmetic verbal rules when they were instructed as a problem‐solving method. Analysis of problem‐solving protocols yields three kinds of results. Mental procedures constructed from verbal rules can be structurally different from the instructed verbal rules. Difficulties arise in selecting and executing procedures because of inadequate parsing procedures. Verbal rules tend to be used optionally and drop out of performance when a person becomes skilled, but they can be recalled and used explicitly when appropriate mental procedures are unavailable. Drawing on the results of the empirical study, the third section discusses the role of verbal rules in learning and problem solving, the process of converting verbal rules into mental procedures, and two hypotheses about the origins of systematic performance errors.