ABSTRACT
The purpose of this study is to investigate the usefulness of the fractal dimension of pupil dilation as a measure of workload in a multitasking environment. Researchers have found that pupil dilation can reveal the underlying mechanism of the cognitive workload in a dynamic task environment. However, the workload metrics by using pupillary responses in a multitasking environment are not well studied in the literature. In this study, the participants’ pupil dilation was collected and analyzed by using a fractal analysis technique to assess the participants’ workload during the experiment. During the experiment, each participant performed a process monitoring task and Multi-Attribute Task Battery (MATB) task together. The process monitoring task simulated the responsibilities of process operators in the control room of oil and gas refinery plants. The MATB task consisted of system monitoring, target tracking, and dynamic resource management. To validate the outcome of this new metric, NASA-TLX questionnaires were used to measure the subjective workload, and the result of NASA-TLX was compared to the fractal dimension result. The findings from this study showed that the fractal dimension of pupil dilation could be used as a new physiological index to measure the workload in a multitasking environment.
Acknowledgments
This research was supported by the University of Missouri Research Board Grant.
Additional information
Notes on contributors
Xiaonan Yang
Xiaonan Yang is a PhD candidate in Industrial Engineering at the University of Missouri-Columbia. Her research interests include human–computer interaction, eye tracking, and behavior modeling.
Jung Hyup Kim
Jung Hyup Kim is an Assistant Professor in the Department of Industrial and Manufacturing Systems Engineering at the University of Missouri. He holds a Ph.D. in Industrial Engineering from the Pennsylvania State University, University Park. His research interests include human–computer interaction, human-in-the-loop simulation, workload, and human performance.