A model of conditional reasoning predicted that children under 12 would respond correctly to questions of uncertain logical form if premises and context enabled them to access counterexamples from memory, and that children's performance with uncertain logical forms would decrease when empirically true premises are presented in a fantasy context.…

Proposes a variant of mental model theory which suggests that the development of conditional reasoning (if--then) can be explained by such factors as the capacity of working memory, range of knowledge available to a reasoner, and his/her ability to access this knowledge "on-line." Finds much empirical data explained by this model.…

Tested with adolescents and adults two predictions from Markovits and Barrouillet's developmental model of conditional reasoning related to the effects of the association between antecedent and consequent terms and the formulation of the minor premise on uncertainty responses. Found results consistent with hypotheses and indicating importance of…