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Multitasking and Task Switching

In today's information-rich society, people frequently attempt to perform many tasks at once. This often requires them to juggle their limited resources in order to accomplish each of these tasks successfully. This juggling is not always easy, and in many cases can lead to greater inefficiency in performing each individual task. For example, using a cellular telephone while driving can lead to both poor communication and poor driving. In the brain, juggling multiple tasks ("Multitasking") is performed by mental executive processes that manage the individual tasks and determine how, when, and with what priorities they get performed. These executive processes act like a choreographer who orchestrates many individual dancers so that they can perform as a single unit, or an air-traffic controller who schedules many airplanes that take off and land on the same runway. If the individual dancers or airplanes are not scheduled appropriately, the results can be catastrophic.

Multitasking can be difficult when a person must perform two tasks simultaneously, but problems can also occur when a person switches from performing one task to performing another. Performing two or more tasks in rapid succession requires an individual to reorient to each new task, which itself takes time and other attentional resources. In our research, we have studied this aspect of multitasking using a task-switching paradigm. In our task-switching experiments, participants either perform a single task throughout a trial block, or alternate between two tasks during the trial block. By comparing completion times of single-task and dual-task blocks, we can measure the cost (in time) for the task-switching processes. By conducting these experiments, we have been able to understand how aspects of the individual tasks (such as task difficulty and task familiarity) can affect these task-switching costs.

For More Information:

  • Rubinstein, J. S., Meyer, D. E., & Evans, J. E. (2001). Executive Control of Cognitive Processes in Task Switching. Journal of Experimental Psychology: Human Perception and Performance, 27(4), 763-797.

  • Kieras, D. E., Meyer, D. E., Ballas, J. A., & Lauber, E. J. (2000). Modern Computational Perspectives on Executive Mental Processes and Cognitive Control: Where to from Here?. In S. Monsell & J. Driver (eds.) Control of Cognitive Processes: Attention and Performance XVIII, (pp. 681-712). Cambridge, MA: M.I.T. Press, 2000.

  • Meyer, D. E., Evans, J. E., Lauber, E. J., Gmeindl, L., Rubinstein, J., Junck, L., & Koeppe, R. A. (1998). The role of dorsolateral prefrontal cortex for executive cognitive processes in task switching. Poster presented at the meeting of the Cognitive Neuroscience Society, San Francisco, CA, April, 1998. Abstract published in Journal of Cognitive Neuroscience, 1998, Vol. 10.

  • Meyer, D. E., Evans, J. E., Lauber, E. J., Rubinstein, J., Gmeindl, L., Junck, L., & Koeppe, R. A. (1997). Activation of brain mechanisms for executive mental processes in cognitive task switching. Poster presented at the meeting of the Cognitive Neuroscience Society, Boston, MA, March, 1997. Abstract published in Journal of Cognitive Neuroscience, 1997, Vol. 9.

  • Rubinstein, J., Evans, J., & Meyer, D. E. (1994). Task switching in patients with prefrontal cortex damage. Poster presented at the meeting of the Cognitive Neuroscience Society, San Francisco, CA, March, 1994. Abstract published in Journal of Cognitive Neuroscience, 1994, Vol. 6.

    Our research on multi-tasking has appeared in a number of non-academic publications:

    Life Inter-rupted: Plugged into it all, we're stressed to distraction
    A Seattle Times article about cognitive overload and stresses of multitasking (Nov. 28, 2004).

    Pressured to multitask, workers juggle a fragmented existence
    A Boston Globe article about stresses of multitasking (Sept. 26, 2004).

    We're all multitasking, but what's the cost?
    A Los Angeles Times article about multitasking and health (July 19th, 2004).

    Driving? Maybe you shouldn't be reading this
    A New York Times article about the dangers of multitasking (July 13th, 2004).

    Is multitasking more efficient? Shifting mental gears costs time, especially when shifting to less familiar tasks: Studying The "Inner CEO" Can Improve Interface Design, Personnel Training And Diagnosis Of Brain Damage.
    An APA press release regarding Rubinstein, Meyer, and Evans (2001) (August 5, 2001).

    CNN TONIGHT: Multitasking Has Problems, Study Finds
    A CNN T.V. Interview of David Meyer about Multitasking (August 5, 2001).

    Study: Multitasking is counterproductive (Your boss may not like this one)
    A CNN.com article on multi-tasking (August 7, 2001).

    Problems associated with multitasking [RealAudio version]
    A National Public Radio Interview of David Meyer about Multitasking (August 6, 2001).

    The Thief of Time: Multitasking is Inefficient, Studies Show
    An NPR.org report on multi-tasking (August 6, 2001).

    Wasted Time: Study Says 'Multitasking' Inefficient
    An ABCNews.com article on multi-tasking (August 7, 2001).

    Multitasking Creates Health Problems
    A UPI article about multi-tasking (August 5, 2001).

    Stop all that multitasking, study suggests
    A Toronto Star article about multi-tasking. (August 7, 2001)

    Please turn off your radio before reading this
    A Globe and Mail article about multi-tasking (August 6, 2001).

    Some news stories related to our work on multi-tasking:

    Study: All cell phones distract drivers
    A CNN.com article about car phones, related to our multitasking work.

    Chuck Hurley: Hands-free car phones not risk free
    Another CNN.com article about car phones, related to our multitasking work.

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