Natural Break Points

What factors determine when people interleave tasks when multitasking? Here the authors look at the role of priorities and cognitive and motor cues. A study was conducted in which participants steered a simulated vehicle while also dialing two phone numbers that contained sets of repeating digits. Participants tended to interleave tasks after typing in a complete set of repeating digits and sometimes also at the cognitive chunk boundary. The exact pattern of how participants interleaved these tasks depended on their priority objective. A modeling analysis that explored performance for a series of alternative strategies for task interleaving, given the cognitive and task constraints, suggested why participants avoided interleaving at other points: Such strategies tend to move performance away from a trade-off curve that strikes an optimal balance between dialing and driving performance. The study highlights the role that cognitive and motor cues can play in dual-task performance and the importance of being aware, and acting on, priorities. Further implications and limitations are discussed.

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

[2]  D Gopher,et al.  Different difficulty manipulations interact differently with task emphasis: evidence for multiple resources. , 1982, Journal of experimental psychology. Human perception and performance.

[3]  Dario D. Salvucci.  Predicting the effects of in-car interface use on driver performance: an integrated model approach , 2001, Int. J. Hum. Comput. Stud..

[4]  William J. Horrey,et al.  Driver-initiated distractions: examining strategic adaptation for in-vehicle task initiation. , 2009, Accident; analysis and prevention.

[5]  D. Norman,et al.  Psychological Issues in Support of Multiple Activities , 1986 .

[6]  John D. Lee,et al.  Preface to the Special Section on Driver Distraction , 2004, Hum. Factors.

[7]  K A Brookhuis,et al.  The effects of mobile telephoning on driving performance. , 1991, Accident; analysis and prevention.

[8]  D. Strayer,et al.  Supertaskers: Profiles in extraordinary multitasking ability , 2010, Psychonomic bulletin & review.

[9]  Duncan P. Brumby,et al.  Strategic Adaptation to Performance Objectives in a Dual-Task Setting , 2010, Cogn. Sci..

[10]  Wayne D. Gray,et al.  The soft constraints hypothesis: a rational analysis approach to resource allocation for interactive behavior. , 2006, Psychological review.

[11]  Dario D. Salvucci,et al.  Multitasking and monotasking: the effects of mental workload on deferred task interruptions , 2010, CHI.

[12]  Harold Pashler,et al.  Task prioritisation in multitasking during driving: opportunity to abort a concurrent task does not insulate braking responses from dual‐task slowing , 2008 .

[13]  Daniel Gopher,et al.  On the Economy of the Human Processing System: A Model of Multiple Capacity. , 1977 .

[14]  Barry Kirwan,et al.  A Guide To Task Analysis: The Task Analysis Working Group , 1992 .

[15]  Dario D. Salvucci,et al.  Threaded cognition: an integrated theory of concurrent multitasking. , 2008, Psychological review.

[16]  P. Fitts.  The information capacity of the human motor system in controlling the amplitude of movement. , 1954, Journal of experimental psychology.

[17]  Robert W Proctor,et al.  Acquisition and Transfer of Attention Allocation Strategies in a Multiple-Task Work Environment , 2007, Hum. Factors.

[18]  A. Shepherd,et al.  Guide to Task Analysis , 2003 .

[19]  Anthony J. Hornof.  Task-Constrained Interleaving of Perceptual and Motor Processes in a Time-Critical Dual Task as Revealed Through Eye Tracking , 2010 .

[20]  W J Horrey,et al.  Dissociation between driving performance and drivers' subjective estimates of performance and workload in dual-task conditions. , 2009, Journal of safety research.

[21]  Allen Newell,et al.  The psychology of human-computer interaction , 1983 .

[22]  A J McKnight,et al.  The effect of cellular phone use upon driver attention. , 1993, Accident; analysis and prevention.

[23]  H Alm,et al.  The effects of a mobile telephone task on driver behaviour in a car following situation. , 1995, Accident; analysis and prevention.

[24]  J. Gregory Trafton,et al.  Memory for goals: an activation-based model , 2002, Cogn. Sci..

[25]  Andrew Howes,et al.  Focus on driving: how cognitive constraints shape the adaptation of strategy when dialing while driving , 2009, CHI.

[26]  William J Horrey,et al.  Modeling drivers' visual attention allocation while interacting with in-vehicle technologies. , 2006, Journal of experimental psychology. Applied.

[27]  Hansjörg Neth,et al.  Discretionary task interleaving: heuristics for time allocation in cognitive foraging. , 2007, Journal of experimental psychology. General.

[28]  C. Lebiere,et al.  An integrated theory of list memory. , 1998 .

[29]  Duncan P. Brumby,et al.  Natural Break Points: Utilizing Motor Cues when Multitasking , 2010 .

[30]  Christopher D. Wickens,et al.  Multiple Resources and Mental Workload , 2008, Hum. Factors.

[31]  Eric Horvitz,et al.  Cars, calls, and cognition: investigating driving and divided attention , 2010, CHI.

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

[33]  D. Gopher.  The skill of attention control: acquisition and execution of attention strategies , 1993 .

[34]  Duncan P. Brumby,et al.  Dialing while driving? A bounded rational analysis of concurrent multi-task behavior , 2007 .

[35]  Daniel G Bobrow,et al.  On data-limited and resource-limited processes , 1975, Cognitive Psychology.

[36]  N. Taatgen,et al.  The problem state: a cognitive bottleneck in multitasking. , 2010, Journal of experimental psychology. Learning, memory, and cognition.

[37]  Dario D. Salvucci,et al.  Effects of Memory Rehearsal on Driver Performance: Experiment and Theoretical Account , 2008, Hum. Factors.

[38]  Richard L. Lewis,et al.  Rational adaptation under task and processing constraints: implications for testing theories of cognition and action. , 2009, Psychological review.

[39]  Christopher D. Wickens,et al.  Examining the Impact of Cell Phone Conversations on Driving Using Meta-Analytic Techniques , 2006, Hum. Factors.

[40]  Nick Reed,et al.  Drivers' attitudes to distraction and other motorists' behaviour: a focus group and observational study , 2009 .

[41]  Dario D. Salvucci,et al.  Inferring Multitasking Breakpoints from Single-Task Data , 2010 .

[42]  Nick Chater,et al.  Identifying Optimum Performance Trade-Offs Using a Cognitively Bounded Rational Analysis Model of Discretionary Task Interleaving , 2011, Top. Cogn. Sci..

[43]  David L. Strayer,et al.  Driven to Distraction: Dual-Task Studies of Simulated Driving and Conversing on a Cellular Telephone , 2001, Psychological science.

[44]  Donald A. Norman,et al.  User Centered System Design: New Perspectives on Human-Computer Interaction , 1988 .

[45]  David E. Kieras,et al.  Model-based evaluation , 2002 .

[46]  Matthew P. Reed,et al.  Comparison of driving performance on-road and in a low-cost simulator using a concurrent telephone dialling task , 1999 .

[47]  Andrew Sears and Julie A. Jacko.  The human-computer interaction handbook , 2013 .

[48]  Richard M. Young,et al.  The Role of Cognitive Architecture in Modeling the User: Soar's Learning Mechanism , 1997, Hum. Comput. Interact..

[49]  Kristen L. Macuga,et al.  Predicting the effects of cellular-phone dialing on driver performance , 2002, Cognitive Systems Research.

[50]  Fokie Cnossen,et al.  Adaptive strategy changes as a function of task demands: a study of car drivers , 2004, Ergonomics.

[51]  Duncan P. Brumby,et al.  Fast or safe?: how performance objectives determine modality output choices while interacting on the move , 2011, CHI.

[52]  Dario D. Salvucci.  A Multitasking General Executive for Compound Continuous Tasks , 2005, Cogn. Sci..