Viewing trees: an investigation into how students visually interact with phylogenetic trees

Tree-reading is the ability to understand, use, and communicate hypotheses represented within phylogenetic trees accurately. Unfortunately, students often face difficulties with tree-reading. We investigated eye movement patterns of introductory biology students to determine how they visually assessed trees during tree-interpretation tasks. We used an eye-tracking approach to capture participants' visual processing while solving tree-reading problems. We documented specific areas of interest that students may visually assess when solving tree-reading questions. By analyzing participant eye movements, we identified significant differences in dwell time and fixation event counts between participants who answered tasks accurately versus inaccurately. Participants who provided incorrect responses showed longer dwell times on the task prompt and less visual attention to the phylogenetic tree than participants who provided correct responses. They also spent more time visually processing less informative phylogenetic tree features than more accurately performing students on each task. While tree-reading instruction has been expanded in introductory biology courses, more explicit tree-thinking instruction is needed to enhance students' comprehension of phylogenetic trees. By identifying visual elements of these models that are likely causing longer dwell time or are being ignored by learners, educators can begin focusing on how to better adapt instruction in ways that enhance informative areas of interest and promote more accurate tree-thinking.