Establishing aesthetics based on human graph reading behavior: two eye tracking studies

A great deal of real-world data have graph structures, and such structures are often visualized into node-link diagrams for a better understanding of the data. Aesthetic criteria have been used as quality measures to evaluate the effectiveness of graph visualizations in conveying the embedded information to end users. However, commonly applied aesthetics are originally proposed based on common senses and personal intuitions; thus, their relevance to effectiveness is not guaranteed. It has been agreed that aesthetics should be established based on empirical evidence and derived from theories of how people read graphs. As the first step to this end, we have conducted two eye tracking studies in an attempt to understand the underlying mechanism of edge crossings, the most discussed aesthetic, affecting human graph reading performance. These studies lead to the findings of an important aesthetic of crossing angles and a graph reading behavior of geodesic path tendency. We demonstrate that eye tracking is an effective method for gaining insights into how people read graphs and that how aesthetics can be established based on human graph reading behavior.