Individual differences in use of diagrams as external memory in mechanical reasoning

Abstract Participants in two experiments solved mechanical reasoning problems that involved inferring the motion of components of mechanical systems from static diagrams of the systems. Some participants were allowed to make notes on the diagrams while solving these problems and others were not. Previous research shows that low-spatial individuals have difficulty solving these problems, possibly because they have limited spatial working memory capacity. We predicted that participants would make notes on the diagram indicating the inferred motion of each component and that making notes in this way would improve performance, particularly for low-spatial participants. Consistent with previous research (Hegarty & Sims 1994), low-spatial participants made more errors than high-spatial participants. Participants made more notes on problems that placed high demands on working memory. Making notes on diagrams was associated with more accurate performance of low-spatial participants, but was not related to performance of high-spatial participants. The results are discussed in terms of working memory limitations and compensating metacognitive skills.