Development of Conditional Reasoning: A Longitudinal Study

This study examines the development of conditional reasoning within a longitudinal design. Two age cohorts were assessed each year for 3 years. One cohort began the investigation as 6th-grade students (M = 11 years, 6 months of age); the other cohort began as 8th-grade students (M =13 years, 8 months of age). At each measurement point, each participant completed 5 reasoning problems consisting of modified versions of the Wason Selection Task (Overton, 1990). Results demonstrated a significant improvement in reasoning performance for each cohort. Furthermore, participants performed better when "if-then" propositions were formulated with the antecedent phrase specifying an action and the consequent specifying a condition, than they did when the antecedent specified a condition and the consequent an action. The results are consistent with the position that the development of logical thinking moves toward the integration of inferential schemes into a systematic network, and that this network is not consistently available before adolescence.