Constructing internal diagrammatic proofs from external logic diagrams

Internal syntactic operations on diagrams play a key role in accounting for efficacy of diagram use in reasoning. However, it is often held that in the case of complex deductive reasoning, diagrams can serve merely as an auxiliary source of information in interpreting sentences or constructing models. Based on experiments comparing subjects’ performances in syllogism solving where logic diagrams of several different forms are used, we argue that internal manipulations of diagrams, or what we call internal constructions of diagrammatic proofs, actually exist, and that such constructions are naturally triggered even for users without explicit prior knowledge of their inference rules or strategies.