DIAGRAM AFFORDANCES AND THEIR IMPACT ON STUDENTS’ ANSWERS ABOUT RIVERS AND GROUNDWATER

Diagrams are important tools for conveying information in geoscience education. But choosing what imagery to use and assessing its effectiveness is not straightforward. A diagram needs sufficient affordances (i.e., details, dimension) for the viewers to comprehend the intended message, but the viewer’s knowledge and experience impact how the affordances are interpreted. Understanding the interaction between knowledge, context, and diagram affordance is critical for education and assessment.

To investigate how changes in affordances affect student interpretation of images, we surveyed undergraduate students (N = 201) in introductory geology courses. The survey included multiple-choice and click-on-diagram questions about surface water and groundwater features portrayed in diagrams accompanying the questions. All participants received all versions of the diagrams (e.g., simple, intermediate, complex) but order was counterbalanced such that participants were randomly assigned to one of three groups receiving the versions in different orders. The number of correct responses a question received was used to gauge the efficacy of each accompanying diagram’s affordances. Differences between the number of correct responses between related diagrams was measured using a Pearson chi square test of independence. The ordering effects were assessed using a Kruskal-Wallis one way analysis of variance test.

Results showed that affordances added to the intermediate and complex river increased correct responses to questions about erosion, but not deposition. None of the affordance changes in groundwater diagrams led to significant changes in the number of correct answers to the accompanying questions. Results of this study provide researchers, instructors, and instructional designers with evidence on how affordance and detail choices in diagrams may affect student responses. Understanding what diagram affordances are present in a diagram, the context in which they are presented, and how those affordances might be perceived by students are all factors to take into consideration when choosing or designing diagrams for instruction.