Characteristics of Pre-Service Chemistry Teachers' Mechanistic Reasoning In Organic Chemistry Tasks: An Eye-Tracking Study

Organic chemistry is challenging for novices as it involves a large quantity of organic reactions. Effective learning requires not only profound theoretical knowledge but also the ability to reason about causal mechanisms. This study investigated pre-service chemistry teachers' mechanistic reasoning and the implicit cognitive process. Participants (N = 33) were asked to complete three tasks, which required them to explain chemical phenomena or analyze chemical reactions. This work analyzed the components involved in participants' explanations based on the discourse analysis framework and evaluated the mechanistic reasoning by identifying the causal relationship between different components. An eye-tracking method was employed to recognize the mental activity underlying participants' performance. Four parameters, percentage of dwell time, percentage of fixation count, heat maps, and average pupil size, were used to conduct quantitative analyses on the data collected from the eye-tracker. Each parameter on predefined areas of interest was compared to identify the information that participants paid more attention to and bore more cognitive load while reasoning. The results revealed that pre-service chemistry teachers demonstrate four different types of reasoning in organic chemistry tasks: descriptive, relational, simple causal, and mechanistic reasoning. Pre-service chemistry teachers were more concerned with key information and symbolic representations. It was symbolic representations that increased cognitive load.