The Residual Costs of Multitasking: Causing Trouble down the Road

• Published in: Proceedings of the Human Factors and Ergonomics Society Annual Meeting 2016-09, Vol.60 (1), p.1967-1970
• Main Authors: Turrill, Jonna, Coleman, James R., Hopman, Rachel J., Cooper, Joel M., Strayer, David L.
• Format: Article
• Language: English
• ISSN: 2169-5067; 1071-1813; 2169-5067
• DOI: 10.1177/1541931213601448

Objective: The cognitive workload of three Smartphone Digital Assistants (SDA) was manipulated in an on-off manner while participants drove an instrumented vehicle in order to measure the costs associated with intermittent dual tasking. Background: Previous research has shown costs in productivity when switching between two discrete tasks; however, similar costs have not yet been examined using intermittent, continuous dual tasks. Methods: Participating drivers completed 5 conditions: baseline driving, 3 SDA conditions, and a cognitively demanding math-memory operation span (OSPAN) task, each while responding to Detection Response Task (DRT) stimuli. Within the SDA conditions, on- and off-task DRT performance was compared to baseline driving and to the OSPAN task performance. Results: The on-task periods of the SDA conditions resulted in similar RTs as the OSPAN condition, while the off-task periods did not immediately return to baseline driving performance. Post hoc analyses of the on-off transitions within the SDA conditions revealed a gradual return to baseline driving performance over the course of 18 seconds. Conclusions: The delays in returning to baseline driving performance after completing a secondary task raise concerns about the usage of in-vehicle devices while driving as the effects of the delays last beyond the cessation of the SDA interaction.