Cognitive Load Measurement with Physiological Sensors in Virtual Reality during Physical Activity

Abstract

Many Virtual Reality (VR) experiences, such as learning tools, would benefit from utilising mental states such as cognitive load. Increases in cognitive load (CL) are often reflected in the alteration of physiological responses, such as pupil dilation (PD), electrodermal cctivity (EDA), heart rate (HR), and electroencephalography (EEG). However, the relationship between these physiological responses and cognitive load are usually measured while participants sit in front of a computer screen, whereas VR environments often require a high degree of physical movement. This physical activity can affect the measured signals, making it unclear how suitable these measures are for use in interactive Virtual Reality (VR). We investigate the suitability of four physiological measures as correlates of cognitive load in interactive VR. Suitable measures must be robust enough to allow the learner to move within VR and be temporally responsive enough to be a useful metric for adaptation. We recorded PD, EDA, HR, and EEG data from nineteen participants during a sequence memory task at varying levels of cognitive load using VR, while in the standing position and using their dominant arm to play a game. We observed significant linear relationships between cognitive load and PD, EDA, and EEG frequency band power, but not HR. PD showed the most reliable relationship but has a slower response rate than EEG. Our results suggest the potential for use of PD, EDA, and EEG in this type of interactive VR environment, but additional studies will be needed to assess feasibility under conditions of greater movement.