The four‐card problem resolved? Formal operational reasoning and reasoning to a contradiction

To test the hypothesis that adolescents classified as formal operational, based upon use of proportional reasoning on the “Pouring Water Task” (Lawson, Karplus, & Adi, 1978) have acquired the mental structures necessary to comprehend hypothetico‐deductive arguments of a pattern referred to as “reasoning to a contradiction,” while adolescents classified as concrete operational, based upon use of additive reasoning on the same task have not, a sample of 100 high school students were administered the task and three versions of a problem requiring use of reasoning to a contradiction before, immediately after, and one month after brief verbal instruction in use of that reasoning pattern. Results were generally supportive of the hypothesis as most of the concrete students failed the immediate and delayed posttest problems (62 and 80%, respectively) while most of the formal students succeeded (80 and 71%, respectively). Group differences were significant ( p < .001) in both cases. These results suggest that, contrary to those who have argued that content plays a substantial role in logical performance, a general hypothetico‐deductive reasoning competence exists in some adolescents and is applicable across a wide variety of task domains. Science instruction which aims to teach this competence is recommended.