Seeing Resonance: On Students’ Perception-Based Reasoning in Organic Chemistry

Abstract

Representations are central to conceptual understanding and problem-solving in Organic Chemistry. Resonance, in particular, is a concept that is closely linked to the construction and interpretation of resonance structures. However, understanding these structures as dynamic electron distribution imposes a high cognitive load on learners. While research has emphasized manifold conceptual barriers learners encounter with this concept, little is known about how students perceive resonance structures and use these representations in problem-solving. To address this gap, a quantitative study with Organic Chemistry (OC) I students investigated how the variation of structural features influences students’ consideration of resonance stabilization across different molecular structures. A k-means cluster analysis revealed different profiles regarding students’ proficiency in recognizing resonance stabilization. It became evident that students’ decision-making on resonance was markedly influenced by the visual affordances of the structural features. Students’ consideration of resonance was often guided by the visual similarity of features to familiar structural patterns. Yet, students’ flexibility in perceiving resonance increased with higher prior conceptual knowledge. Quantitative analysis further revealed that students’ recognition of resonance significantly depends on the display of electron lone pairs, as students showed an affirmation bias towards resonance stabilization when electron lone pairs were present. Extending these findings, a qualitative interview study investigated students’ perceptual processes when drawing (un-)productive resonance structures in context. Using eye-tracking, students’ connection of visual information and attention distribution to structural features were examined. Analyzing students’ verbal drawing rationales further served to triangulate eye-tracking data. While the productivity of resulting resonance structures did not depend on the total amount of integrated and connected visual information, productive drawings were characterized by a more straightforward drawing process transitioning from previous to target drawing. Moreover, the results showcased that flexibility in perceiving interrelated structural features is crucial for constructing valid resonance structures. The interview study also served to investigate students’ use of resonance across different task contexts in OC I. Coordination Class Theory was used as an analytical lens to analyze students’ problem-solving. Results showed that students’ concept use was diverse and shaped by the complex interplay of task affordances and individual factors. However, a more detailed comparison of students’ concept use revealed that a more reflective and flexible use of their structural drawings enhanced productive concept use, both in terms of students’ task approaches and the activation of task-relevant resources. Thus, this thesis demonstrates that flexibility in perceiving and engaging with representations is crucial for the successful use of resonance in Organic Chemistry. By highlighting the close link between conceptual and perceptual processes in students’ reasoning about resonance, it yields new, process-oriented insights into how students perceive, construct, and use resonance structures in problem-solving.