Multitasking and monotasking: the effects of mental workload on deferred task interruptions

Recent research has found that forced interruptions at points of higher mental workload are more disruptive than at points of lower workload. This paper investigates a complementary idea: when users experience deferrable interruptions at points of higher workload, they may tend to defer processing of the interruption until times of lower workload. In an experiment, users performed a mail-browser primary task while being occasionally interrupted by a secondary chat task, evenly distributed between points of higher and lower workload. Analysis showed that 94% of the time, users switched to the interrupting task during periods of lower workload, versus only 6% during periods of higher workload. The results suggest that when interruptions can be deferred, users have a strong tendency to ''monotask'' until primary-task mental workload has been minimized.

[1]  Víctor M. González,et al.  No task left behind?: examining the nature of fragmented work , 2005, CHI.

[2]  J. Gregory Trafton,et al.  Preparing to resume an interrupted task: effects of prospective goal encoding and retrospective rehearsal , 2003, Int. J. Hum. Comput. Stud..

[3]  Eric Horvitz,et al.  Disruption and recovery of computing tasks: field study, analysis, and directions , 2007, CHI.

[4]  Christopher G. Atkeson,et al.  Predicting human interruptibility with sensors: a Wizard of Oz feasibility study , 2003, CHI '03.

[5]  Brian P. Bailey,et al.  If not now, when?: the effects of interruption at different moments within task execution , 2004, CHI.

[6]  K. Dismukes,et al.  Prospective Memory, Concurrent Task Management, and Pilot Error , 2007 .

[7]  Víctor M. González,et al.  "Constant, constant, multi-tasking craziness": managing multiple working spheres , 2004, CHI.

[8]  Niels Taatgen,et al.  The Multitasking Mind , 2010, Oxford series on cognitive models and architectures.

[9]  James Fogarty,et al.  Examining the robustness of sensor-based statistical models of human interruptibility , 2004, CHI.

[10]  Eric Horvitz,et al.  Models of attention in computing and communication , 2003, Commun. ACM.

[11]  Laura A. Dabbish,et al.  Self-interruption on the computer: a typology of discretionary task interleaving , 2009, CHI.

[12]  Brian P. Bailey,et al.  Understanding changes in mental workload during execution of goal-directed tasks and its application for interruption management , 2008, TCHI.

[13]  Mikael Wiberg,et al.  Managing availability: Supporting lightweight negotiations to handle interruptions , 2005, TCHI.

[14]  J. Trafton,et al.  The effect of interruption duration and demand on resuming suspended goals. , 2008, Journal of experimental psychology. Applied.

[15]  John R. Anderson.  How Can the Human Mind Occur in the Physical Universe , 2007 .

[16]  Niels Taatgen,et al.  Toward a unified theory of the multitasking continuum: from concurrent performance to task switching, interruption, and resumption , 2009, CHI.

[17]  Daniel C. McFarlane,et al.  Comparison of Four Primary Methods for Coordinating the Interruption of People in Human-Computer Interaction , 2002, Hum. Comput. Interact..

[18]  Mary Czerwinski,et al.  Instant Messaging: Effects of Relevance and Timing , 2000 .

[19]  Mary Czerwinski,et al.  Effects of instant messaging interruptions on computing tasks , 2000, CHI Extended Abstracts.

[20]  Jelmer P. Borst,et al.  The Costs of Multitasking in Threaded Cognition , 2007 .

[21]  Brian P. Bailey,et al.  Investigating the effectiveness of mental workload as a predictor of opportune moments for interruption , 2005, CHI Extended Abstracts.