Cognitive psychologists suggest that it is important for learners to be exposed early to molecular structure and dynamics (Jones, Stillings, & Jordan, 2005). This study investigated the impact of exposing students to molecular-level diagrams on understanding of chemistry concepts. Three types of adjunct questions were used to enhance and assess student learning of molecular-level chemistry concepts. Subjects were 98 volunteers in a college–level general chemistry course. The subjects were divided into three groups, each of which completed the same multimedia computer lessons, but with different types of adjunct questions: (a) text-based macroscopic/symbolic questions, (b) text-based questions that emphasize the particulate nature of matter, and (c) pictorial questions that emphasize the particulate nature of matter. A conceptual test was administered that consisted of similar items of the same three types of questions. No significant differences were found among the three groups on any part of the test. However, there was a significant positive relationship between logical thinking ability and each of the three parts of the test. There was also a significant positive relationship between mental capacity and Parts (a) and (c) of the test.

Jones, L. L., Stillings, N. A., and Jordan, K. D. (2005). "Molecular visualization in chemistry education: The role of multidisciplinary collaboration," Chemical Education Research and Practice, 6(3), 136-149.