Human gaze-parameters as an indicator of mental workload

Abstract

In this study we have investigated which eye-parameters that most reliably can indicate increased mental workload. Being able to detect high mental workload in individuals, allows for early detection of potentially dangerous situations, and possibly adjustment of the information flow that creates the high workload. N-back memory tasks with four difficulty levels were designed to induce mental workload for a sample of 21 university students. 17 eye parameters were measured using an Eye Tracker at a sampling rate of 250 Hz. Data indicate that peak fixation duration is the most suitable eye parameter to estimate mental workload. It has a negative relationship with mental workload, where higher peak fixation duration can be observed at lower mental workload and lower peak fixation duration at higher mental workload. Moreover, blink frequency, blink count, peak blink duration, and pupil diameter show a significant positive relationship to mental workload. Most of the saccade parameters failed to show a significant relationship, while fixation frequency, fixation duration, fixation count, blink duration, saccade velocity, and peak saccade amplitude showed a partial relationship with mental workload.