Measuring the After-Effects of Disruption on Task Performance

In many settings, multi-tasking and interruption are commonplace. Multi-tasking has been a popular subject of recent research, but a multitasking paradigm normally allows the subject some control over the timing of the task switch. In this paper we focus on interruptions-situations in which the subject has no control over the timing of task switches. We consider three types of task: verbal (reading comprehension), visual search, and monitoring/situation awareness. Using interruptions from 30 s to 2 min in duration, we found a significant effect in each case, but with different effect sizes. For the situation awareness task, we experimented with interruptions of varying duration and found a non-linear relation between the duration of the interruption and its after-effect on performance, which may correspond to a task-dependent interruption threshold, which is lower for more dynamic tasks.