Toward a unified theory of human reasoning

This article presents a unified theory of human reasoning. The goal of the theory is to specify what constitutes reasoning, as opposed to other psychological processes, and to characterize the psychological distinction between inductive and deductive reasoning. The theory views reasoning as the controlled and mediated application of three processes— selective encoding, selective comparison, and selective combination—to inferential rules. The first two of these processes are essentially inductive in nature; the third is essentially deductive. The theory describes these three processes, specifies the kinds of inferential rules and their use in several reasoning tasks, and specifies the mediators that affect how well the processes can be applied to the rules. The theory is shown to apply to a variety of reasoning tasks and is compared to other theories as well.