Employing causality when teaching physiology: Deriving the Wiggers diagram from scratch to build better student understanding of cardiac function

We recently published two papers that collectively highlight the essential nature of causality in the development of higher order cognitive skills (analysis and evaluation) during the teaching of physiology. Prediction, an ability derived from these skills, is the pinnacle of learning outcomes and depends upon comprehension of the biological, chemical, or physical causal links between events in physiological cascades. The challenge in creating essential cognitive frameworks is to effectively present complex topics as a series of linked causal events. Presented individually and as a logical unit, each event stays within working memory capacity, while the causal links connecting them provide the very framework students need to reason with the content rather than merely recall it. We've found that the difficulty in proposing such an approach is not in conveying the value of it but rather in expressing what that instruction looks like in practice. To complete our trilogy of papers, we will here describe how we would develop such a logic-driven explanation using the classical Wiggers diagram, a complex summary of all cardiac electrical and mechanical activity during a single heartbeat. We will derive every element of the graph, each from its prior stimulus, using cause-and-effect core principles such that students can cognitively follow a clear progression of falling biological "dominoes". In this way, students will more fully understand the multifaceted Wiggers plot and realize that even the most challenging topics in physiology can be mastered via sound cause-and-effect reasoning.