Monica G.M. Ferguson-Hessler

Cognitive Structures of Good and Poor Novice Problem Solvers in Physics.

The way knowledge is organized in memory is generally expected to relate to the degree of success in problem solving. In the present study, we investigated whether good novice problem solvers have their knowledge arranged around problem types to a greater extent than poor problem solvers have. In the subject of physics (electricity and magnetism), 12 problem types were distinguished according to their underlying physics principles. For each problem type, a set of elements of knowledge containing characteristics of the problem situation, declarative knowledge, and procedural knowledge was constructed. All of the resulting 65 elements were printed on cards, and first-year university students in physics ( N = 47) were asked to sort these cards into coherent piles shortly after they had taken an examination on electricity and magnetism. Essentially, good novice problem solvers sorted the cards according to problem types; the sorting by the poor problem solvers seemed to be determined to a greater extent by the surface characteristics of the elements. We concluded than an organization of knowledge around problem types might be highly conducive to good performance in problem solving by novice problem solvers.

On the quality of knowledge in the field of electricity and magnetism

Problem solving in physics requires a certain quantity of knowledge of the subject matter: principles, procedures, etc. In addition, the problem solver must be able to access these principles and procedures in a given situation. Investigations have shown that failure in problem solving is often caused by lack of availability of knowledge, and also that availability is closely related to the organization of knowledge in memory. Opinions differ, however, on whether the optimal form of this organization should be centered around problem types or arranged in a hierarchical way. In this study two concrete examples of knowledge structures in the field of electricity and magnetism are compared. An experiment is also described, in which the actual knowledge structure of beginning students was studied. The outcome indicates that students with good results in problem solving organize their knowledge more in accordance with problem types than do students with poor results. The results of the experiment are discussed in the light of the two knowledge structures described. The possible role of these structures in physics teaching is treated in the final paragraph

Knowledge of problem situations in physics: A comparison of good and poor novice problem solvers

In this study we examined models of problem situations in the memory of good and poor novice students. Subjects were shown very briefly descriptions of physics problems, and after each exposure they were asked to reconstruct the given problem. The short exposure time forces students to rely on models of problem situations in memory for giving reconstructions. Presentation of situations, and reconstructions asked for, varied in modality (words, figures, or combinations). For a number of situations subjects were asked, after they had given a reconstruction, to write down information they thought necessary for solving the problems. Results showed that all students reconstructed important information better than less important information, so both good and poor students seem to have models of problem situations at their disposal. There were, however, also differences between the two groups. First, good students gave a better reconstruction of the question than weak students did. Second, when subjects were requested to change modality in reconstruction (from figure to words or vice versa), good students tended to reconstruct important information better than the weak students. Finally, good students outperformed the weak group in generating information concerning the solution of the problem