The introductory organic chemistry course is considered a "gatekeeper" for many professions, particularly for underrepresented minorities. Reaction mechanisms and electron pushing formalism are central to organic chemistry, but students often struggle throughout their educational careers with understanding the meanings underlying these tools. One central reason for students’ difficulties with reaction mechanisms lies in the (missing) link between the representation of a chemical reaction (i.e., symbols, Lewis structures) and the chemical concepts (i.e., knowledge about bond polarity) that must be inferred from the representation. Hence, success in terms of understanding and using reaction mechanisms requires aligning three aspects: 1) understanding the representation, 2) cueing upon the contextually adequate conceptual knowledge, and 3) using this conceptual knowledge to infer an explanation or to make a prediction about the reactivity or the next step of the mechanism.
We design and test instructional settings with the aim of helping students to make inferences about the chemical concepts implicit in representations of organic reaction mechanisms. These settings include so-called eye movement modeling examples. These are visual displays of an expert’s eye gaze, recorded with an eye-tracker, showing the expert’s step-by-step processing of the representation and the expert’s verbal explanation to convey the chemical meaning. Empirical evidence in other fields (e.g., classification of botanical and zoological species; medical diagnosis) indicates that eye movement modeling examples can improve students’ learning in visually complex domains.
