Comprehending Diagrams

The article I read was titled "Psychologists Study the Effects of Diagram Orientation on Comprehension." In this article, it investigated phylogenetic trees and whether the orientation of the phylogenetic tree (how it is drawn) affects how well it is understood by those reading it. A phylogenetic tree is a branching diagram or tree showing the inferred evolutionary relationships.

When I first began reading this article, I wondered why out of any type of diagram they could've used, they chose to use a phylogenetic tree in their experiment. As I read on I soon found the answer. The reason is for an important process they call "tree thinking". The fact that there is a distinctive relationship between taxa
allows you to infer certain biological, physiological, and pharmaceutical commonalities that might be relevant by looking at the tree.The way that tree is perceived by the one reading it affects the overall perception of the data.

During the experiment that was carried out, students were told to examine one of two phylogenetic trees displaying the same information in different orientations and to write down the evolutionary relationships shown by those diagrams. The result was that students who examined the tree with the upward diagonal trunk were less accurate than those who studied the downward diagonal tree.  

A possible problem with this experiment is that some of the students used may have had a better understanding of phylogenetic trees beforehand, thus allowing them to perceive the diagram easier regardless of the tree's orientation. I believe that if both diagrams accurately showed the same information, and the students used in the experiment had the same understanding of phylogenetic trees going into it, then the results should have came out equal.

If it is true that the orientation of a phylogenetic tree has a great effect on how it is perceived, then I think that this information could be used to improve diagrams in textbooks and worksheets, and also improve lessons given to students on how to build a phylogenetic tree. It could also create a standard for how these diagrams must be built to ensure the utmost accuracy.