This article reports on a controlled study to investigate the efficacy of incorporating explicit discussions about the duality of human reasoning and its implications for learning in physics instruction. The central goal is to probe to what extent, if at all, such discussions improve student performance on tasks that tend to elicit intuitively appealing but incorrect responses. We hypothesized that explicitly discussing the reasoning pathways and hazards associated with the interactions between automatic process 1 and deliberate process 2 could boost students' performance on a variety of topics in physics. In addition, we explored the relationships between student performance in physics, as measured by the Force and Motion Conceptual Evaluation (FMCE), and student tendency toward cognitive reflection, as measured by the cognitive reflection test (CRT). The results revealed a strong link between postinstruction performance on FMCE and the CRT score. However, no measurable effect of explicit discussions on the duality of reasoning on FMCE performance was observed. Possible explanations for the null result and future directions for research are explored.