The effects of task interruption on user performance in a multitasking environment: implications for computerized reminders

Abstract

Large and complex operations environments such as the one being designed for the Space Station Freedom will undoubtedly place many requirements on crewmembers to simultaneously perform multiple tasks; i.e., “multitasking.” Moreover, it is unlikely crewmembers will finish a task without being interrupted several times. Depending on the nature of these interruptions, crewmembers may be forced to suspend their activities. One danger in suspending activities is forgetting (e.g., forgetting what the activities were, or one's position within the activities, or certain procedures, etc.). Forgetting to complete even a single activity in space may have serious consequences. As a countermeasure to forgetting, the present study introduced the use of computer- based “reminders.” The purpose of this study was to: (1) establish a baseline measure of multitasking, (2) examine the effects of interruptions on task performance, and (3) explore the use of computer-based "reminders."

The results revealed subjects could perform three and five simultaneous tasks with a response accuracy of 98 percent. A large portion of that performance was attributed to practice and response pacing. In addition, the interruption task chosen for this study did not affect reaction time or response error performance on the main tasks. The use of a computer-based checkmark reminder proved to be beneficial in reducing menu search time regardless of the number of items to be located. Search time decreased considerably when the reminder was available to subjects as opposed to when it was absent. This study concludes that with practice and pacing, people can perform at least five simple tasks simultaneously. Furthermore, the benefits of incorporating computer-based reminders should not be limited only to multitasking environments.