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Understanding changes in mental workload during execution of goal-directed tasks and its application for interruption management

Published:19 January 2008Publication History
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Abstract

Notifications can have reduced interruption cost if delivered at moments of lower mental workload during task execution. Cognitive theorists have speculated that these moments occur at subtask boundaries. In this article, we empirically test this speculation by examining how workload changes during execution of goal-directed tasks, focusing on regions between adjacent chunks within the tasks, that is, the subtask boundaries. In a controlled experiment, users performed several interactive tasks while their pupil dilation, a reliable measure of workload, was continuously measured using an eye tracking system. The workload data was extracted from the pupil data, precisely aligned to the corresponding task models, and analyzed. Our principal findings include (i) workload changes throughout the execution of goal-directed tasks; (ii) workload exhibits transient decreases at subtask boundaries relative to the preceding subtasks; (iii) the amount of decrease tends to be greater at boundaries corresponding to the completion of larger chunks of the task; and (iv) different types of subtasks induce different amounts of workload. We situate these findings within resource theories of attention and discuss important implications for interruption management systems.

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          cover image ACM Transactions on Computer-Human Interaction
          ACM Transactions on Computer-Human Interaction  Volume 14, Issue 4
          January 2008
          204 pages
          ISSN:1073-0516
          EISSN:1557-7325
          DOI:10.1145/1314683
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          Publication History

          • Published: 19 January 2008
          • Accepted: 1 May 2007
          • Revised: 1 October 2006
          • Received: 1 August 2005
          Published in tochi Volume 14, Issue 4

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