The Subgoal Heuristic and its effect on Internal Representations

Abstract

Abstract Two studies examined the changes made in humans' internal representations of problem-solving tasks that result from using a subgoal heuristic. In Study 1, undergraduates were instructed to “think out loud” while solving an unfamiliar logical deduction problem. A protocol analysis indicated that several categories of subjects' comments did not occur with equal frequency in each half of the subjects' protocols. The preponderance of comments made in the first half of the protocols suggests that the subjects were working toward the attainment of a spontaneously chosen subgoal. In Study 2, several forms of the logical deduction task were used, including semicompleted fragments corresponding to the results of the protocol analysis. Subjects approached these fragments in much the same way that they solved the full task, making particular types of deductions when given certain types of fragments, even though all fragments present other types of information that are equally deducible. These findings suggest that, when using the subgoal heuristic, a person engages an internal calculus that computes the individual's locale among the states of knowledge comprising the entire problem. The outcome of this calculus apparently constrains the solver's perception of the states of knowledge that are currently accessible, meaning that the internal representation in use by the problem solver is apparently influenced by the heuristic chosen. The implications for Newell and Simon's (1972) theory are discussed.