Reasoning about benefits, costs, and risks of chemical substances: Mapping different levels of sophistication

The ability to evaluate options and make informed decisions about problems in relevant contexts is a core competency in science education that requires the use of both domain-general and discipline-specific knowledge and reasoning strategies. In this study we investigated the implicit assumptions and modes of reasoning applied by individuals with different levels of training in chemistry when engaged in a task that demanded the evaluation of the benefits, costs, and risks (BCR) of using different chemical substances. We were interested in identifying and characterizing different levels of sophistication in the use of chemistry concepts and ideas in BCR reasoning. Our qualitative study elicited reasoning patterns that ranged from intuitive to mixed to normative, with students mostly in mid-undergraduate years demonstrating reasoning that was a mixture of intuitive and chemical ways of thinking. Intuitive reasoning was governed primarily by affective impressions about the substances under evaluation. Consideration of compositional, structural, and energetic features of substances was observed with increased training in chemistry, with a tendency to mix particle-level explanations with intuitive assumptions. Normative thinking shifted toward proactive use of appropriate disciplinary knowledge, recognition of a need for more data about bulk properties particularly on large scales, and consideration of pros, cons, and trade-offs. Implications are discussed for ways to improve the undergraduate chemistry curriculum so that students gain proficiency in making productive judgments and informed decisions.