Dual-process theories of reasoning suggest that humans reason using two processes often referred to as process 1 (heuristic) and process 2 (analytic). When presented with a situation requiring any sort of reasoning or decision making, process 1 automatically engages and generates an initial mental model to address the situation. Process 2 may or may not be engaged to assess the initial model as a plausible solution. In a study by Kryjevskaia et al., a "screening" question regarding a pulse on a spring aimed to identify students with relevant content knowledge who nevertheless seemed to rely on process 1 when answering a subsequent "target" question. The study was offered as evidence that dual-process theories can explain some discrepancies in student responses to related questions. The study described here assesses the same pair of questions for their ability to distinguish between incorrect answers that stem from inadequate conceptual understanding and those that stem from reasoning approaches. We use Frederick's cognitive reflection test as part of this analysis. Our results largely support a dual-process-theories perspective of student reasoning.