The Effects of Feedback on Targeting Performance in Visually Stressed Conditions

In most graphical user interfaces, a substantial part of the user's interaction involves targeting screen objects with the mouse cursor. Targeting tasks with small targets are visually demanding, and can cause users difficulty in some circumstances. These circumstances can arise either if the user has a visual disability or if factors such as fatigue or glare diminish visual acuity. One way of reducing the sensory demands of targeting is to add redundant feedback to the interface that indicates when the user has successfully acquired a target. Under optimal viewing conditions, such feedback has not significantly improved targeting performance. However, we hypothesized that targeting feedback would be more beneficial in a visually stressed situation. We carried out an experiment in which normally sighted participants in a reduced-acuity environment carried out targeting tasks with a mouse. We found that people were able to select targets significantly faster when they were given targeting feedback, and that they made significantly fewer errors. People also greatly preferred interfaces with feedback to those with none. The results suggest that redundant targeting feedback can improve the usability of graphical interfaces, both for low-vision users and also for normally sighted users in visually stressed environments. 1