Peripheral Notifications: Effects of Feature Combination and Task Interference

Visual notifications are integral to interactive computing systems. The design of visual notifications entails two main considerations: first, visual notifications should be noticeable, as they usually aim to attract a user`s attention to a location away from their main task; second, their noticeability has to be moderated to prevent user distraction and annoyance. Although notifications have been around for a long time on standard desktop environments, new computing environments such as large screens add new factors that have to be taken into account when designing notifications. With large displays, much of the content is in the user's visual periphery, where human capacity to notice visual effects is diminished. One design strategy for enhancing noticeability is to combine visual features, such as motion and colour. Yet little is known about how feature combinations affect noticeability across the visual field, or about how peripheral noticeability changes when a user is working on an attention-demanding task. We addressed these questions by conducting two studies. We conducted a laboratory study that tested people's ability to detect popout targets that used combinations of three visual variables. After determining that the noticeability of feature combinations were approximately equal to the better of the individual features, we designed an experiment to investigate peripheral noticeability and distraction when a user is focusing on a primary task. Our results suggest that there can be interference between the demands of primary tasks and the visual features in the notifications. Furthermore, primary task performance is adversely affected by motion effects in the peripheral notifications. Our studies contribute to a better understanding of how visual features operate when used as peripheral notifications. We provide new insights, both in terms of combining features, and interactions with primary tasks