Measuring the workload for individuals doing individual tasks is becoming fairly simple. Researchers measure the time each task takes and how much time it takes up during a worker’s given day.
But what about the workload of people who multitask, with their focus changing from instant to instant? People such as air traffic controllers, 911 operators, plant safety technicians and more.
Using variances in pupil dilation, Mizzou Engineering Assistant Professor Jung Hyup Kim has found a way to do just that.
Kim and Industrial and Manufacturing Systems Engineering doctoral candidate Xiaonan Yang recently published “Measuring Workload in a Multitasking Environment Using Fractal Dimension of Pupil Dilation” in The International Journal of Human-Computer Interaction.
Fractal analysis is defined by the National Institutes of Health as “a contemporary method of applying nontraditional mathematics to patterns that defy understanding with traditional Euclidean concepts.” Kim and Yang used it here to set a baseline to eliminate environmental factors when measuring pupil dilation.
What they found using this method in a controlled environment was that the higher the level of workload and stress the participants felt, their pupil dilation data showed less self-similar patterns, and vise versa. Their discovery provides a new method of determining workload physiologically.
“If we can find a relationship between the fractal dimension of pupil dilation and the human workload in a multitasking environment, we might be able to use this data as an indicator of measuring workload,” Kim explained.
Participants were required to complete process monitoring and Multi-Attribute Task Battery tasks together. Essentially, they worked as control room operators in an oil and gas refinery plant — monitoring gauges, responding to alerts, tracking information on computer screens and more.
Pupillary response was recorded, and for a subjective measurement, participants filled out the NASA-TLX, one of the most widely used forms for users to measure their own workload.
This research is part of a larger series of projects Kim has worked on studying workload and how best to get the most out of workers without overtaxing them to the point where mistakes become more likely. The eventual goal of this research is to create a real-time workload measurement tool.
“The outcome of this study will give us a deeper insight into how multitasking systems should be designed to avoid work overload and build a safer working environment,” Kim said.