PREDICTING INTERMEDIATE AND MULTIPLE CONCLUSIONS IN PROPOSITIONAL LOGIC INFERENCE PROBLEMS - FURTHER EVIDENCE FOR A MENTAL LOGIC

This article examines whether a particular mental logic introduced by M.D.S. Braine, B.J. Reiser, and B. Rumain (1984) is a reasonably accur ate model of people's logical routines for propositional reasoning. Pa rticipants are presented with reasoning problems; to make their reason ing steps explicit, they write down, in order, everything they infer. The inferences predicted by the model are compared with participants' output. Three quarters of participants' responses were predicted, and 85%-90% of the time the output of the model's core inference rules was written down. To predict equally well, L. J. Rips's (1994) mental log ic model would need to adopt some of our model's features. The data in dicate several problems in the mental models theory and cannot be expl ained by pragmatic reasoning schemas. Arguments against a mental logic are questioned.