We performed an empirical study to investigate whether the context of interruptions makes a difference. We found that context does not make a difference but surprisingly, people completed interrupted tasks in less time with no difference in quality. Our data suggests that people compensate for interruptions by working faster, but this comes at a price: experiencing more stress, higher frustration, time pressure and effort. Individual differences exist in the management of interruptions: personality measures of openness to experience and need for personal structure predict disruption costs of interruptions.
The Cost of Interrupted Work: More Speed and Stress
by Gloria Mark, Daniela Gudith and Ulrich Klocke
http://www.ics.uci.edu/~gmark/chi08-mark.pdf
Surprisingly our results show that interrupted work is performed faster. We offer an interpretation. When people are constantly interrupted, they develop a mode of working faster (and writing less) to compensate for the time they know they will lose by being interrupted. Yet working faster with interruptions has its cost: people in the interrupted conditions experienced a higher workload, more stress, higher frustration, more time pressure, and effort. So interrupted work may be done faster, but at a price.
Our results suggest that interruptions lead people to change not only work rhythms but also strategies and mental states. Another possibility is that interruptions do in fact lengthen the time to perform a task but that this extra time only occurs directly after the interruption when reorienting back to the task, and it can be compensated for by a faster and more stressful working style. More sophisticated measurements of working speed directly after an interruption must be done to test this. We found that the more open one is to experiences, the quicker one handled interrupted work and surprisingly, we found the same relation for those who score high on needing personal structure. Perhaps those who need personal structure are better able to manage their time when interrupted.
While laboratory studies are always subject to criticism of ecological validity, our task design was based on real fieldwork. We simulated office conditions using an email task, which is different from many laboratory studies of attention switching that use abstract tasks. The lab environment enabled us to isolate variables of interest.
Our results have implications for system design. A certain amount of interruptions may be tolerable because people can compensate with a higher working speed. However, technology could be used to keep track of and control interruptions over a long period of time so as not to overload people (as our mental workload measures suggest). After only 20 minutes of interrupted performance people reported significantly higher stress, frustration, workload, effort, and pressure. We cannot say whether people would cope over time or if these measures would only increase. Our results confirm experimentally the anecdotal reports of informants in field studies who describe high stress when interrupted in real work situations. Our data also contributed to finding individual differences in interruptions. Our personality measures suggest the need for customization for systems to fit people’s preferred interruption tolerance. We hope that our study will spark continued interest in this area.