REASONING WITH 3 TYPES OF CONDITIONAL - BIASES AND MENTAL MODELS

Two experiments are reported which compare conditional reasoning with three types of rule. These consist of two types of rule that have been widely studied previously, if p then q and p only if q, together with a third type, q if p. In both experiments, the p only if q type of ru le yields a different pattern of performance from the two other types of rule. Experiment 1 is an abstract rule-evaluation task and demonstr ates differential effects of temporal order and of suppositional bias. Experiment 2 investigates rule generation, rephrasing, and comparison , and demonstrates differential effects of temporal order and of thema tic content. An analysis of the results is offered in terms of biases and mental models. Effects of rule form and context can be explained a s reflecting the different sequences in which mental models are create d for each rule form. However, it is necessary to consider the interna l structure of individual mental models to account for effects arising from temporal ordering of rules.