Beyond Bertin: Seeing the Forest despite the Trees
Visualization needs a new theory. Bertin's ideas about marks and retinal variables have provided a great starting point, but we are now seeing their limitations. We need to turn a new page and move beyond those cosy, familiar ideas, into new territory. A recent paper by Caroline Ziemkiewicz and myself makes an argument why, and provides some possible directions.
Our criticism of the status quo is based on Caroline's Ph.D. work on structure in visualization. She found that the physical layout has a lot more influence on our understanding of a visualization than we were previously aware of.
In an experiment that pitched treemaps against node-link diagrams, we showed that compatible linguistic and graphical metaphors lead to faster responses than incompatible ones. We also found that seemingly meaningless design variations can have a drastic impact on the interpretation of even simple charts. What's more, there seems to be a lot of physical interpretation of static, abstract scenes. Finally, in work to be presented at InfoVis 2010, Caroline will discuss the effects of gravity and attraction between objects in visualizations.
What does all this mean? We don't really know that yet, but we know that the existing theoretical tools we have cannot explain all of that. What we need to figure out is not just how to ask more fundamental questions to discover these things, but also how to turn them into practical design guidelines and knowledge that can make visualizations more effective and avoid deception.
In the paper, we are calling for a structural theory of visualization, to complement the current marks-based one. Our results on structure and dynamics in visualization should certainly be part of that, but there's also other work like that of Barbara Tversky on the effect of lines, and some other interesting results from both visualization and psychology.
These are exciting times. We are on the cusp of a major shift towards more theory work in visualization, which will enable us to take bigger steps and to explore new directions in the future. We might even end up turning this field into a science.
Caroline Ziemkiewicz, Robert Kosara, Beyond Bertin: Seeing the Forest despite the Trees, Computer Graphics and Applications (CG&A), Visualization Viewpoints, vol. 30, no. 5, pp. 7–11, 2010.
See also: Workshop The Role of Theory in Information Visualization at VisWeek 2010