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

Brian P. Bailey, Shamsi T. Iqbal

Research output: Contribution to journalArticle

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.

Original languageEnglish (US)
Article number21
JournalACM Transactions on Computer-Human Interaction
Volume14
Issue number4
DOIs
StatePublished - Jan 1 2008

Keywords

  • Attention
  • Interruption
  • Pupil size
  • Task models
  • User studies
  • Workload

ASJC Scopus subject areas

  • Human-Computer Interaction

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