Exploring the Influence of Light and Cognitive Load on Pupil Diameter in Driving Simulator Studies

Pupil diameter can be used as a physiological measure of cognitive load in driving simulator studies. However, pupil size depends on both cognitive load and lighting conditions. In order to accurately estimate cognitive load these two effects must be separated. In this study the authors introduce illumination only, cognitive only and combined tasks. Based on these they decouple the two effects on pupil diameter and they design a predictor of the pupil’s reaction to light which can be used to estimate changes in pupil diameter that are due to cognitive load.