Comparison of Four Primary Methods for Coordinating the Interruption of People in Human-Computer Interaction

Abstract Interruptions can cause people to make mistakes or errors during human-computer interaction (HCI). Interruptions occur as an unavoidable side-effect of some important kinds of human computer-based activities, for example, (a) constantly monitor for unscheduled changes in information environments, (b) supervise background autonomous services, and (c) intermittently collaborate and communicate with other people. Fortunately, people have powerful innate cognitive abilities that they can potentially leverage to manage multiple concurrent activities if they have specific kinds of control and interaction support. There is great opportunity, therefore, for user-interface design to increase people's ability to successfully handle interruptions, and prevent expensive errors. The literature contains very little concrete design wisdom about how to solve the interruption problems in user interfaces (UIs). Coordination support, however, is identified as a most important design topic. This article presents the results of an empirical investigation to compare basic design solutions for coordinating human interruption in computer-based multitasks. A theory-based taxonomy of human interruption is used to identify the four primary methods for coordinating human interruption. An experiment with 36 participants compares these four different design solutions within an abstracted common user multitasking context. The results show important design tradeoffs for coordinating the interruption of people in HCI and support some UI design guidelines. Negotiation support is the best overall solution except where small differences in the timeliness of handling interruptions is critical and then immediate is best.