Eyes may help measure stress, mental workload

Our eyes could serve as a window to how stressed we are, say scientists who found that pupil dilation can be used to indicate the mental workload of a person when they multitask.

The demands of work productivity in today's society seem to have increased tenfold. Workers have to multitask to cope with the insistence that tasks be completed almost immediately.

Previous studies on workload and productivity include physical aspects, such as how much a person walks or carries, but they do not take into account a person's state of mind.

"If your vitals are bad, then something is wrong with your body and doctors will work to figure out what's wrong with you," said Jung Hyup Kim, an assistant professor at University of Missouri-Columbia in the US.

"Many people multitask, but currently there is no measurement for someone's mental well-being. However, we found that the size of a pupil could be the key to measuring someone's mental state while they multitask," Kim said.

Everyone experiences stress differently.

Researchers wanted to find a data-driven way for different industries to universally measure the levels of stress in their employees while they are multitasking, or performing work-related duties with simultaneous low and high complexity tasks.

To do this, they compared data from a workload metric developed by NASA for its astronauts with their observations of pupillary response from participants in a lab study.

Using a simulated oil and gas refinery plant control room, researchers watched as the participants reacted to unexpected changes, such as alarms, while simultaneously watching the performance of gauges on two monitors.

During the scenario's simple tasks, the participants' eye searching behaviours were more predictable.

Yet, as the tasks became more complex and unexpected changes occurred, their eye behaviours became more erratic.

Researchers discovered that pupil dilation could be used to indicate the mental workload of a person in a multitasking environment.

The findings can give a better insight into how systems should be designed to avoid mentally overloading workers and build a safer working environment, they said.