Investigating student ability to follow reasoning chains: The role of conceptual understanding

In this paper, we seek to evaluate the extent to which students can follow a deductive reasoning chain when it is presented to them. A great deal of instruction in introductory physics courses is centered on presenting students with a logical argument that starts from first principles and systematically leads to a particular conclusion. This approach to instruction may conflict with current models of how students reason, including dual-process theories of reasoning and decision making. We investigated student ability to follow reasoning chains at several different institutions, across multiple topics that span introductory mechanics and electricity and magnetism. (For the purposes of this study, we operationally define "following"a reasoning chain - either a correct chain or an incorrect chain - as selecting the appropriate conclusion to a given chain.) To accomplish this, we asked students to answer a physics question and provide an explanation for their answer. We then presented them with a reasoning chain generated by a fictitious student and asked them to select the appropriate concluding statement for that chain. Some of these fictitious chains were fully correct, while others contained a conceptual or logical error. We intentionally used tasks for which students would be unlikely to generate correct reasoning chains on their own. We found that for most tasks, students were generally successful at following chains based on common incorrect reasoning. Students who themselves generated the correct reasoning, however, were much more successful at following correct reasoning chains. Connections between this work and dual-process theories, as well as implications for instruction, are discussed.