Visual sensitivities of dynamic graphical displays
Advanced display design, such as Ecological Interface Design (EID), makes extensive use of complex graphical objects. Research has shown that by following EID methodologies, supervisory operators have better performance with the EID displays than with non-EID displays. However, the effect of particular dynamic graphical objects seen in EID displays has never been studied. In this study, we examined how different visual features of graphical objects affect the performance of the objects. We used a modified dynamic just noticeable difference task to investigate the graphical objects that show changes most sensitively. We also investigated the sensitivities of graphical objects in determining target levels, directional changes, and proportions. A commercial EID design company generated the graphical objects examined. We had subjects perform four tasks with graphical objects that varied in their visual features but were still representative of objects currently being used in ecological design. It was found that for simple dynamic objects such as bars and polygon objects, a line changing in angle was the most noticeable emergent feature to show a departure from normal state. For complex graphical objects, those target-indicator displays that mimic a bull's eye when at the target value should be used for displays that show observers when a target value has been reached. Abrupt changes in shape should be used in trend meters to show when variables or processes have changed direction. Finally, solid objects that make use of vertical lines and shading should be used for comparison meters that compare two values and keep them in a particular ratio. The findings provide guidance for designers of dynamic advanced graphical displays by encouraging the consideration of visual aspects of graphical objects, as well as prescribing graphical objects that should be used in the types of tasks investigated.
graphical displays ecological interface design