Eye-tracking reveals where students look wrong when reading phylogenetic trees

Students who struggle to interpret phylogenetic trees may be looking in the wrong places, according to a new eye-tracking study of introductory biology students. The research, published in Developmental Biology Advances, documented how learners visually process evolutionary trees, the branching diagrams scientists use to represent hypotheses about relationships among species.

The study team, led by Mallika Saha with Daniel Ferguson, Tina Marcroft and Kristy L. Daniel, asked introductory biology students to complete tree-reading tasks while an eye tracker recorded their gaze patterns. The researchers defined tree-reading as the ability to understand, use and accurately communicate the hypotheses represented within phylogenetic trees, a skill students are known to find difficult.

By analyzing where participants looked and for how long, the researchers identified specific areas of interest that students visually assess when solving tree-reading questions. They compared the eye movements of students who answered the tasks accurately with those who answered incorrectly.

The comparison revealed significant differences in both dwell time and fixation event counts between the two groups. Participants who gave incorrect responses spent longer dwell times on the task prompt itself and directed less visual attention to the phylogenetic tree than participants who answered correctly.

Inaccurate performers also spent more time visually processing less informative features of the trees than their more accurate peers on each task. In other words, struggling students were not simply looking away from the problem; they were allocating their attention to elements of the diagram that carried less information relevant to the question.

The authors argue that 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. They suggest that identifying which visual elements of these models cause longer dwell times, or which are being ignored by learners, can help educators adapt instruction to emphasize the most informative areas of interest and promote more accurate tree-thinking.

Because the study examined introductory biology students during interpretation tasks using an eye-tracking approach, its findings describe visual processing patterns in that setting rather than establishing which teaching interventions would improve performance. The authors note the work is intended as a starting point for educators seeking to understand how students visually engage with evolutionary diagrams before designing better instruction.

Subject of Research: Eye-tracking study of how introductory biology students visually process phylogenetic trees during interpretation tasks

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

Article References: Saha, M., Ferguson, D., Marcroft, T., & Daniel, K. L. (2026). Viewing trees: an investigation into how students visually interact with phylogenetic trees. Developmental Biology Advances. https://doi.org/10.1186/s13227-026-00276-8

Image Credits: AI Generated

DOI: 10.1186/s13227-026-00276-8

Keywords: phylogenetic trees, eye tracking, tree-reading, biology education, introductory biology, dwell time, fixations, tree-thinking, student misconceptions, visual attention, Viewing, trees