User Goals and Attention Costs Attuning Notification Design to

about multiple sources of information while engaged in other tasks. Notification systems are interfaces specifically designed to support user access to additional digital information from sources secondary to current activities. Many such interfaces, especially examples such as Web page advertisements and animated software agents, seem to be ineffective and distracting, and are abandoned or ignored after brief use. We believe dissatisfaction results from incorrect estimates of the user's task prioritization during design time. Consequently , information is introduced at inappropriate times and with unsuitable presentation choices. Factors such as the nature of ongoing activities, perceived urgency, 67 and attentional focus require changes in the way information should be delivered. By tracking priorities of user attention and inferring workload characteristics through eye gaze, physical or bio-medical sensors, and input devices, attentive user interfaces (AUI) [8] and more specifically, attention -centric systems [1], can adapt information delivery to avoid overloading the user. This interface adaptivity suggests a key paradigm with enormous potential for notification systems. To best leverage the AUI paradigm for notification design, we explore how we might understand the associated costs and benefits of user notification in terms of its impact on user attention. We introduce a framework that allows these costs and benefits to be described and design options to be compared. Based on this, we show how user goal representations can be integrated with information design guidelines from usability studies. This demonstrates vast potential for AUIs in notifying users—compelling attentive notification systems. We also suggest some challenges for this emerging research community. The paramount challenge of notification is preventing unwanted distraction to the primary task, while still delivering information in an accurate and timely manner. In many cases, very little distraction can be tolerated. For example, a typical in-vehicle information system may notify the user about navigation instructions, incoming communications , and other information secondary from the main task of the user—driving the car. Such systems should be designed to ensure notification is provided without diverting attention from driving-related tasks. In other cases, a user is willing to accept some distraction in exchange for valued information. Desktop computer users may perform daily word-processing tasks while casually alert Why is the attentive user interface paradigm important for human-computer interaction? The human attention system is so sensitive to various methods of notification that traditional design involves too much compromise and guesswork.