A team of researchers from UCSB, Vanderbilt University and West Carolina University presented their work, a study on the effects of diagram orientation on interpretation abilities, in the most recent issue of Bioscience.

Andrew Stull, a researcher in UCSB’s psychology department, utilized phylogenetic trees, which are diagrams used to show relations among organisms, to illustrate that although two trees may contain the same information, their interpretation is not always paralleled. Because Western culture is accustomed to reading from left to right, the trees are often depicted as extending from the bottom left in an upward direction. Although it seems more natural to represent phylogenetic trees with the trunks angling up and to the right, it has been shown that comprehension is more accurate when the trees are angled down to the right. Stull explained that cognitive processes should be considered in addition to aesthetics when designing visual information.

To test their work, eye-tracking technology was used to record students’ responses to researchers’ questions regarding a pair of phylogenetic trees. After the test subjects were shown one tree and then another, they were asked to determine if they were similar. The eye-tracking recordings showed that when the subjects studied the tree in the upward-diagonal trunk — left to right — they were less accurate than when they studied the other downward-diagonal tree.

A part of being scientifically literate is to be able to access and make informed decisions based on these trees, coined as being able to “tree think.” Catley, the head of the secondary science education program at WCU, is collaborating with Stull and Vanderbilt’s Laura R. Novick to help high school and university students better understand the process and principles of evolutionary biology.

Learning to read hierarchic diagrams is useful in other science, math and even in nonrelated fields. The “language tree,” for example, suggests that the Indo-European family of languages originated in modern-day Turkey. “Tree thinking” is translatable to other subjects, and there are written and tested instructional materials that show essentially that anyone can improve their tree reading and reasoning skills, Catley said.