The Challenges of "Bottleneck Graphs" in the Earth Sciences: Evidence from Expert and Novice Eye-Tracks

Thursday 11:30am-1:30pm UMC Aspen Rooms
Poster Presentation Part of Digital Geology and Visualization


Karl Wirth, Macalester College
James Lindgren, Macalester College
Professionals and students in the earth sciences use an array of graphs to study the earth. Earth scientists make use of a number of unique types of graphical formats that facilitate the representation and interpretation of data. For example, when describing the relationship between temperatures with depth in the earth, the traditional binary plot is rotated upside-down so that pressure (on the y-axis) increases downward, parallel to its orientation in the earth. Similar graph orientations are also used for plotting stratigraphic sections, depth-to-water tables, and metamorphic facies. These graphs present significant challenges to students learning but—once mastered—can foster new learning. In this companion poster presentation (see Lindgren and Wirth, this volume), we compare the eye-tracks of experts and novices when observing "bottleneck" graphs.

We observe ordinal differences in eye-fixations between individuals in novice (undergraduate student) and expert (faculty and staff) groups. When asked to examine a graph without a prompt, the expert behavior is consistently systematic and deliberate, while the novice behavior is not. When novices and experts observe traditional binary line or scatter graphs under prompted conditions, the eye-tracks of individuals from both groups look more similar. Interestingly, the eye-track patterns of the individuals in the novice and expert groups diverge in response to non-traditional graph types (e.g., inverted binary plots, normalized plots, ternary plots). The comprehension accuracy of "bottleneck graphs" distinguishes those experts with heightened graphical capacity (regular disciplinary graph use) from those experts with "adaptive expertise" (those who do not regularly use graphs in their discipline). One explanation is that experts, with better-developed metacognitive or critical thinking skills, might be able to compensate for lack of familiarity in reading and comprehending new kinds of graphical information.

We seek input from the community on other "bottleneck graphs" and interventions for improving student graph reading and comprehension.

Presentation Media

Wirth & Lindgren (2015) Poster (Acrobat (PDF) 32.2MB Jul25 15)