Abstract
In Experiment 1, preadolescents, middle adolescents, and late adolescents were presented 3 deductive reasoning tasks. With some important exceptions, conditional reasoning improved with age on problems containing permission conditional relations, and reasoning fallacies increased with age on problems containing causal conditional relations. The results of Experiments 2a and 2b indicated that problem type (i.e., permission or causal) does not mediate the activation of conditional reasoning skills. Rather, valid conditional inferences are more common on problems for which plausible alternative antecedents can be generated than on problems for which alternative antecedent generation is difficult. Conditional rules for which alternative antecedent generation is difficult may be misrepresented as biconditionals, resulting in biconditional rather than conditional reasoning.