Two people, one graph: the effect of rotated viewpoints on accessibility of data visualizations.

In co-located, multi-user settings such as multi-touch tables, user interfaces need to be accessible from multiple viewpoints. In this project, we investigated how this goal can be achieved for depictions of data in bar graphs. We designed a laboratory task in which participants answered simple questions based on information depicted in bar graphs presented from differently rotated points of view. As the dependent variable, we measured differences in response onsets relative to the standard viewpoint (i.e., upright graphs). In Experiment 1, we manipulated graph and label orientation independently of each other. We observed that rotations of the labels rather than rotations of the graph itself pose a challenge for accessing depicted information from rotated viewpoints. In Experiment 2, we studied whether replacing word labels with pictographs could overcome the detrimental effects of rotated labels. Rotated pictographs were less detrimental than rotated word labels, but performance was still worse than in the unrotated baseline condition. In Experiment 3, we studied whether color coding could overcome the detrimental effects of rotated labels. Indeed, for multicolored labels, the detrimental effect of label rotation was in the negligible range. We discuss the implications of our findings for the underlying psychological theory as well as for the design of depicted statistical information in multi-user settings.