Physiology Core Concepts Guide Successful Mechanistic Reasoning
Authors: Doherty Jennifer , Todd Kylie , VanDerSlik Aeryn , Cole Elijah 
Published: May 2024

Mechanistic reasoning is a powerful strategy used to organize one’s thinking by leveraging the properties and behaviors of underlying entities to explain how and why phenomena occur. Modell identified seven “general models” (i.e., principles) in physiology that could serve as a cognitive framework for students to use to reason mechanistically about a variety of seemingly-distinct processes. Many of these principles are also Physiological Core Concepts. Though there are frameworks to analyze students’ use of mechanistic reasoning, there is currently no framework to analyze how physiology students use principles or Core Concepts to support their use of mechanistic reasoning to solve complex problems. In this study we ask two research questions about students use of the principle of Flux (i.e., the Core Concept of Flow Down Gradients) 1) How do students use the Flux Relationship to guide their mechanistic reasoning? 2) Are students who use the Flux Relationship to guide their mechanistic reasoning more successful when solving complex organismal biological problems? We recorded and transcribed in-class discussions of 14 introductory biology students in 4 small groups as they worked across a term to solve complex problems related to the principle of Flux (rate of movement ∝ gradient/resistance). To address RQ1, we combined emergent codes with established frameworks for mechanistic reasoning and Flux reasoning. We iteratively applied our codes to a subset of transcripts, compared interpretations and coding, revised the framework and re-coded. In this way we developed a framework to characterize how students use the Flux Relationship to guide their mechanistic reasoning. To address RQ2, we scored each discussion for accuracy and whether or not the students used the Flux relationship to guide their mechanistic reasoning. We then used a chi-square test to determine if more students who used Flux to guide their reasoning were accurate. RQ1 results: Our principle-based mechanistic reasoning framework for Flux includes two established mechanistic reasoning categories: identification (introduction of components of a system) and chaining (using the relationships between components to reason mechanistically). The framework then identifies how students use flux, or don’t, while discussing a complex physiological problem. For example, students may 1) identify or chain without using Flux, 2) identify an aspect of the Flux Relationship without using it to chain, 3) use the Flux relationship to chain. RQ2 results: We found that students who used the Flux Relationship to chain were significantly more likely to be accurate in their discussion. Our study adds to the current literature by providing researchers and instructors with a more meaningful analysis of how students use physiological principles/Core Concepts when mechanistically reasoning to solve complex problems. Additionally, our results support the claim that supporting students' use of principles/Core concepts can lead to higher accuracy in their reasoning. Finally, our framework can be used to measure the impact of instructional interventions designed to increase the use of students' principle-based mechanistic reasoning. Work funded by NSF. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.