Supporting Interruption Handling

Due to the high cost of certain interruptions, several approaches and methods have been proposed to improve the handling of interruptions and reduce their cost. These approaches range from simple manual strategies that knowledge workers use in their every-day life to more advanced and automatic systems developed by various researchers.

Several researchers studied how knowledge workers cope with interruptions. For instance, González and Mark observed knowledge workers and investigated strategies they apply to manage different activities in order to remind themselves of relevant information and goals, as they usually experience a high level of discontinuity in the execution of their activities [González and Mark, 2004]. They found that knowledge workers use post-it notes, print-outs of email messages and planners to manage their variety of tasks and cope with the fragmented nature of their work. Another common strategy to deal with unwanted interruptions is the usage of earphones or ear buds, to either signal that one does not want to be disturbed or to tune out distractions [Sykes, 2011]. Rather than looking at the prevention of interruptions, Parnin and Rugaber investigated strategies to better deal with interruptions, in particular, resumption after an interruption during a programming task [Parnin and Rugaber, 2011]. They found that programmers went back to the last edit, navigated through code or looked at other task specific information in the bug tracking tool or the revision history to rebuild their context and resume the current task.

In addition to the strategies that knowledge workers came up with, researchers have also developed approaches to support interruption handling. The most prominent techniques in this domain are strategies to defer interruptions to breakpoints and to provide awareness on the interruptibility of a knowledge worker automatically and continuously to co-workers.

Postponing Interruptions to Breakpoints. Several researchers developed tools to mediate interruptions by postponing them to more opportune moments. Most of these approaches implement the defer-to-boundary policy that aims at finding natural breakpoints during work and delaying interruptions to these breakpoints

1.7 Background and Related Work 33 instead of displaying them immediately [Iqbal et al., 2004a]. This idea is based on studies that found that the cognitive load drops at task boundaries, and that interruptions at lower cognitive load are less harmful [Bailey and Iqbal, 2008,Borst et al., 2015]. Researchers predominantly applied the defer-to-boundary strategy to computer-based interruptions, such as notifications from incoming emails or instant messages. For instance, a decision-rule-based software developed by Arroyo and Selker delivers unrelated instant messages only at times of context switches that were determined based on mouse movement and window switching. In their study they achieved a five times higher answer rate to messages compared to non-mediated message delivery [Arroyo and Selker, 2011]. Iqbal and Bailey developed a system that implements the defer-to-breakpoint policy to reschedule notifications to more opportune moments [Iqbal and Bailey, 2008]. In a study, they found that notifications delivered at breakpoints caused less frustration and a shorter reaction time compared to notifications which were delivered immediately.

Indicating Interruptibility. Another strategy to better handle interruptions is to indicate a knowledge worker’s interruptibility continuously to potential inter- rupters. While knowledge workers already use simple and manual indicators such as headphones [Sykes, 2011] or manual busy lights [Embrava, 2016], researchers have also developed applications to indicate interruptibility based on automatic interruptibility measurements.

Most prior work that designed availability indicators, created contact-list style tools installed on the computer along with information on a person’s inter- ruptibility. Examples are Connexus, Lilsys, and MyVine. Connexus integrates awareness information, instant messaging and other communication channels and indicates availability to potential interrupters [Tang et al., 2001]. Lilsys and MyVine extend this approach mainly by adding further data sources to improve the accuracy of the interruptibility measurement [Begole et al., 2004, Fogarty et al., 2004]. Evaluations of these tools indicate that these contact-list style tools did not reduce in-person interruptions, but could show a qualitative improvement in interruption awareness.

As in-person interruptions are the most common and expensive interruption in the workplace, in particular due to their immediate nature and disruptive- ness [Sykes, 2011], researchers have also tried to address in-person interruptions by indicating interruptibility to co-workers, but more research is needed to assess the effects of such approaches.

The research most similar to the FlowLight presented in this thesis is by Milan et al. In their work, they developed an automatic interruptibility indicator based on the cost of interruptions during certain automatically detected activities (e.g. email or being in a meeting) using audio, video and computer interaction data [Bjelica et al., 2011]. To evaluate their approach, they conducted a small user study with one participant in an office environment and over the course of a single workday per indication modality. In their study, they investigated the effects of two modalities of the interruptibility indicator: a busy flag (small light placed on desk), and ambient lighting effects. Both modalities for indicating the status decreased the number of interruptions, yet the ambient lighting effect had a bigger effect.

In our work, we combine an automatic interruptibility measure based on computer interaction with a physical indicator in the form of a traffic-light like LED placed on a knowledge worker’s desk. We conducted a large-scale and long-term user study to investigate the effects of such an automatic indicator in office workplaces and the interaction behavior of knowledge workers.