User interfaces can improve task performance by exploiting the powerful human capabilities for spatial cognition. This opportunity has been demonstrated by many prior experiments. It is tempting to believe that providing greater spatial flexibility--by moving from flat 2D to 3D user interfaces--will further enhance user performance. This paper describes an experiment that investigates the effectiveness of spatial memory in real-world physical models and in equivalent computer-based virtual systems. The different models vary the user's freedom to use depth and perspective in spatial arrangements of images representing web pages. Results show that the subjects' performance deteriorated in both the physical and virtual systems as their freedom to locate items in the third dimension increased. Subjective measures reinforce the performance measures, indicating that users found interfaces with higher dimensions more `cluttered' and less efficient. Keywords Spatial memory, 3D ...
Andy Cockburn, Bruce J. McKenzie