Does a Behavioral Experiment on Reasoning Support the Neurological Findings?

To better understand the development and cognitive architecture of human reasoning, a divide between deductive and probabilistic reasoning has often been proposed. Neurological studies carried out on clinical and typical populations have overwhelmingly found that the two proposed types of reasoning are underpinned by relatively independent neural substrates. This article seeks to determine through behavioral experiment whether the two alleged reasoning types have similar or different developmental trajectories with the notion that similar trajectories would question these findings while different trajectories would support the idea of separate systems. An experiment was carried out on children from age 4 to 14 requiring them to choose whether a given conclusion was certain or merely likely to be true or untrue. Results showed significantly different development trajectories between deductive and probabilistic reasoning, thereby supporting the neurological studies’ findings of separate systems. Further results allow hypotheses on the nature of interplay between these systems.