This project aims to serve the national interest by exploring how students develop and use mechanistic reasoning in their study of physiology. One of the most fundamental core competencies in science is mechanistic reasoning, a powerful form of thinking that addresses how and why the underlying components of a system give rise to phenomena. The project plans specifically to explore how mechanistic reasoning evolves in the study of physiology, a course taken by most undergraduate students hoping to pursue careers in healthcare. Mechanistic reasoning is a form of scientific reasoning that enables learners to generate powerful predictions and robust explanations for complex phenomena. By interviewing individuals with differing levels of physiology experience, for example, undergraduate students, medical students, and physiology or nursing faculty, the project hopes to uncover how mechanistic reasoning is used at these various levels of expertise, with the broad goal of enhancing undergraduate physiology instruction to effectively address mechanistic reasoning. By focusing instruction on mechanistic reasoning, students may rely less on memorization and develop the ability to simplify complex problems, helping them to succeed in their coursework.<br/><br/>Previous work on mechanistic reasoning has focused primarily on simple systems, but the phenomena in physiology are complex and interrelated. Such phenomena involve entities at multiple scalar levels and draw on concepts from multiple disciplines. The proposed project will investigate mechanistic reasoning by conducting semi-structured interviews with individuals with a range of physiology expertise. Individuals will be asked to both think aloud through complex phenomena and explain their general approaches to making sense of the unknown. These data will be used to identify patterns in the ways undergraduate physiology students use mechanistic reasoning and to compare undergraduate students’ reasoning to those more expert, leading to an enhanced understanding of how mechanistic reasoning develops and how to effectively address the core idea of mechanistic reason in undergraduate physiology education. <br/><br/>This project is funded by the STEM Education Postdoctoral Research Fellowship (STEM Ed PRF) program that aims to enhance the research knowledge, skills, and practices of recent doctorates in STEM, STEM education, education, and related disciplines to advance their preparation to engage in fundamental and applied research that advances knowledge within the field.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.