Behaviour of Pupil Diameter during Authoritative Control Interventions in Driving Automation

This work seeks to ascertain the validity of pupil diameter as a physiological measure of arousal in a driving simulation study in the context of a highly automated system (SAE Level 4). N = 18 participants were repeatedly exposed to four different driving scenarios in which an authoritative control intervention occurred — either the automation completely blocked driver control authority (Type 1 intervention) or took control authority away from the driver (Type 2 intervention). No significant change in pupil diameter was observed following the interventions, and neither scenario criticality (p = 0.874) nor the intervention type (p = 0.932) impacted pupil diameter. Multilevel modelling results show (1) marginal significance linking pupil diameter change to participants’ prior experience with automated systems and age (2) significant levels of inter-individual variation. To better understand driver arousal during authoritative control interventions, future research should additionally consider factors that cause inter-individual variation, such as other genetic and psychological information.