Probing student reasoning in physics through the lens of dual-process theories

In the past several decades, systematic research has identified significant conceptual difficulties in a number of topics in physics. In many cases, these findings have led to the development of effective instructional interventions. Nevertheless, there are problems that still prove very difficult for most students, even those who demonstrate sound conceptual understanding elsewhere. In a series of investigations informed by dual-process theories of reasoning and decision-making, we are attempting to identify those cases in which the tendency to reply on quick, intuitive judgments is a deciding factor in student success. Moreover, we are attempting to use such findings to enhance the effectiveness of instructional interventions. In this talk, an example in the context of buoyancy will be used to illustrate the process. In introductory physics courses we conducted a series of experiments in order to gain greater insight into the factors impacting student performance on the “five-blocks problem,” which has been used in the literature to probe student thinking about buoyancy. In particular, we examined both the impact of problem design and the impact of targeted instruction focused on density-based arguments for sinking and floating, and on neutral buoyancy. We found that instructional modifications designed to diminish the intuitive appeal of the first-available response led to significantly improved performance, without improving student conceptual understanding of the requisite buoyancy concepts. These findings represent an important first step in identifying systematic strategies for using theories from cognitive science to guide the development and refinement of research-based instructional materials.