DOES DETAIL MATTER? A STUDY OF DIAGRAM AFFORDANCE AND HYDROLOGY UNDERSTANDING

A picture is worth a thousand words, so how can we ensure that the images we use will convey the meaning we intend? Geoscience instruction involves many spatial and visual concepts, and diagrams and figures are relied upon to convey those concepts. Despite the common use of such imagery, it can be difficult to assess just how effective those images are at aiding instruction. The affordances of an image need to assist in conveying the intended information without extraneous and distracting details. Additionally, how a student interprets an image is dependent on their prior exposure to similar imagery, and in the absence of anything familiar they will attempt to assign meaning using existing knowledge. These issues present instructors with a wide variety of variables to consider when choosing diagrams and figures.

To investigate, this study sought to answer the question “do diagram details affect student responses?”. We used a set of diagrams with varying levels of detail to assess undergraduate students’ (N = 201) knowledge of hydrologic features. Seventeen multiple-choice and click-on-diagram questions were asked, repeating questions using diagrams with different levels of detail. Three base diagrams were used, and each had three variations with different levels of detail: simple, intermediate, and complex. Students were randomly sorted into one of three groups that determined the diagram order they received. The assessment was administered using Qualtrics electronic survey program and participants were recruited from six introductory Earth Science courses at two different universities.

Results show that adding visual detail to river diagrams increased the number of correct responses regarding erosion, but not for deposition. Additionally, detail changes made to groundwater diagrams did not influence the number of correct responses. We tested significance using a chi-square test of independence and used an analysis of variance test to determine whether question order influenced responses. The results of this study provide researchers, instructors, and instructional designers with evidence for the level of detail that will enhance student understanding of ground and surface water diagrams.