ABSTRACT

Making inferences to integrate information coming from different sources or from different events is a basic part of human cognition. A complete inventory of the sorts of inferences people make obviously would include those that involve conditionals, conjunctions, disjunctions, and negations-information often conveyed by the English words if, and, or, and not, respectively. Just as obviously, people do not make all of the inferences sanctioned in standard systems of propositional logic (nor could they, because the number is infinite). The present proposal comes from a research program that seeks to describe the logical inferences that are made regularly and routinely in a variety of tasks, including reasoning, conversational discourse, and text processing (e.g., Braine, 1978, 1990; Braine, Reiser, & Rumain, 1984; Lea, O’Brien, Fisch, Noveck, & Braine, 1990; O’Brien, 1987, 1993; O’Brien & Braine, 1990). Our approach proposes that these inferences depend on a mental logic that defines a set of highly accessible inference forms.