Interactive visualizations: Understanding perceptual tradeoffs for effective presentation of information

Modern computing technology now allows us to visualize data in ways that were not possible before. However, understanding the nature of the task is critical for visualizing data in a manner that aids comprehension. To gain insight into this problem, a visual information processing model for interactive visualizations was constructed. The model not only illustrates that presentation types drive visual information processing in a bottom-up manner, but task types drive processing in a top-down manner. Task performance is also affected by the limitations of attention and working memory. Hence, the nature of the task and its impact on attention and working memory can affect the usability of presentation techniques. To examine this relationship further, two commonly used presentation types, fisheye views and multiple views, and their impact on either attention-demanding or working-memory-demanding tasks were studied. In Study 1, fisheye views were investigated. Results suggest that fisheye views were not beneficial for an attention-demanding task, where browsing for objects of interest was the chief concern; however, they may be useful if legibility is an issue. Furthermore, fisheye views had detrimental effects on working memory when subjects were asked to revisit objects of interest. In Study 2, multiple views were investigated. When subjects were asked to perform an attention-demanding task, such as a real-time monitoring task, divided attention was an issue for both sequential and simultaneous views, but design issues apparent with the simultaneous view were not issues with the sequential view. Meanwhile, when subjects were asked to perform a working-memory-demanding task, such as comparing different object sets, the simultaneous view was more useful than the sequential view. This dissertation highlights the importance of understanding the nature of the task within the context of interactive visualizations. Since task performance is influenced by limitations in visual attention and working memory, the usability of a visualization technique can be significantly affected by the type of task being performed. Based on the outcomes of the studies, design guidelines are provided for effective presentation of information