Multiple Notifications in Desktop Computing

This paper describes current research on the attentional effects and usability of multiple notifications. An experiment is described in which 25 participants encountered one, two, or four simultaneous onscreen notifications during cognitively effortful or simple computer tasks. The time participants attended to the notifications vs. the primary computer task served as a measure of the distraction caused by the notifications. Multiple notifications were found to be significantly more distracting than single notifications. While there was a large difference in distraction time between one and two notifications, there was minimal difference in the distraction caused by two vs. four notifications. There was also a significant difference in distraction time for cognitively effortful vs. cognitively simple tasks, but there were no significant interactions. It is concluded that in order to mitigate user disruption, software designers should restrict the number of notifications that are presented on a computer display simultaneously.