Reasoning with Realistic Disjunctives

The research reported here investigated how people interpret and reason with disjunctive statements. Experiment 1 demonstrated a general preference for exclusive over inclusive interpretations, although this varied as a function of the context in which the statement occurred, and there were some contexts in which other, quite different, interpretations were possible. Experiments 2 and 3 showed that the logical inferences subjects would draw from disjunctive statements also varied with context. It is concluded that or permits a number of different interpretations, which are determined by contextual cues. Previous research may have underestimated disjunctive reasoning performance by using contexts that lead to non-logical responses; certainly in the present experiments reasoning was generally accurate given the interpretation adopted.