Integration of multiple external representations in chemistry: a requirements-gathering study

Abstract

Multiple external representations (MERs) are crucial in the learning and practice of chemistry. Representational competence (RC), the ability to simultaneously process, integrate and transform between MERs, marks expertise in chemistry. A major strand of chemistry education research attributes students' difficulties in learning to difficulty in understanding MERs, particularly the ability to imagine the various inter-connections between them. A dominant model of RC is Johnstone's model of three thinking levels, which describes three different levels of representations in chemistry (symbolic equations, molecular models and reaction phenomena), and treats cognitive load as the core problem underlying student difficulties with MERs. This model is used to design a number of computer interventions in chemistry, mostly focusing on lowering cognitive/working memory load, by simultaneously displaying on a screen, molecular animations, graphs and equations. In contrast to this classical information processing framework, our theoretical approach seeks to understand the internal cognitive mechanisms that support the processing of MERs, using recent cognitive theories such as distributed and embodied cognition. At the intervention level, we focus on achieving integration of MERs, through enactive/embodied interaction design approaches (such as fully interconnected and manipulable interfaces). Before developing the actual form factor of the interventions, we wanted to characterize student difficulties, and how students navigated through existing MERs. For this, we presented a categorization task to students, where 3D molecular animations (depicting only molecular level reaction dynamics, without symbols, text and other representations), graphs, chemical equations and videos of some chemical reactions were given to 6 chemistry undergrad students. Eye-tracking was used to obtain fine-grained data about participants' gaze and eye movement patterns while they viewed these representations. Addition of molecules, molecular aggregation, heat source and increase in velocity of the molecules were frequently attended-to features. Only one student made chemically meaningful groups with animations. Her eye-movement analysis reveals systematic mapping of animation features to chemical equations and other representations.