Models and Moves

Extensive research on students’ understanding of science has documented persistent shortfalls at all ages. One way to account for students’ difficulties is to consider the particular challenges posed by individual science concepts. This article offers an alternative view. We argue that students’ difficulties in large part reflect unfamiliarity with a small number of causal modeling styles characteristic of received scientific models. These include, for instance, explaining surface phenomena with an underlying mechanism, relying on constraint-system explanations as in Ohm’s law, including probabilistic elements as in chaos theory, and acknowledging causal webs and self-organizing systems as in ecologies--in sum, aspects of “complex causality.” A further barrier to understanding is students’ unfamiliarity with epistemic moves that might challenge their initial explanations, such as looking for missing links in a causal story or putting a model at risk. The article offers a framework for classifying aspects of complex causality in modeling and for supporting epistemic moves. Empirical research both from the literature and our own work is presented in support of the framework, including evidence that instruction based on causal models and epistemic moves enhances students’ understanding of science concepts.