Influence of Task-evoked Mental Workloads on Oculo-motor indices and their connections

The frequency of microsaccades is often used as a measurement of eye movement in order to estimate the level of effort required, because some indices of oculo-motors suggest the level of mental activity. In an experiment involving several task-manipulation levels, ocular information including microsaccades, saccades and pupil diameters were measured and compared in order to estimate workload levels during problem solving. While some oculo-motor metrics correlate with the estimated scores of the mental workload, these metrics mutually correlate with each other. A causal relationship model was created using all metrics, including subjective measurements. Metrics of microsaccades perform the function of intermediating behaviour between participant’s subjective assessments and conventional ocular measurements, such as saccades and pupil responses.