Pragmatic factors in conditional reasoning

Abstract

We investigated the importance of pragmatic factors in conditional reasoning. The performance of 54 subjects was examined, with the four basic inferences of Modus Ponens (MP), Denial of the Antecedent (DA), Affirmation of the consequent (AC) and Modus Tollens (MT), on the usual three-answer format. The empirical relation in the real world between antecedent and consequent of the premises on conditional arguments (probabilistic, deterministic and without relation) and scenario availability (available versus non-available), were manipulated. The results showed that: a) the scenario availability is not sufficient in itself to explain differences in performance, but affects the subjects' degree of confidence in their conclusions; b) there is an interaction between availability and logical structure of rules on correct performance. The results support the semantic theories of conditional reasoning and are not consistent with theories based on formal rules of inference