Comparison of Physiological Cues for Cognitive Load Measures in VR

Cognitive load (CL) is an important measure for detecting whether a user is struggling with a task. Many researchers have investigated physiological cues for measuring CL, such as pupil dilation, galvanic skin response (GSR), heart rate, and electroencephalography (EEG). However, physical activity can often affect the measured signals, so it is unclear how suitable these measures are for use in Virtual Reality (VR). In this paper we present a VR game, PlayMeBack, for measuring users' CL using different physiological cues. In the game, the user is shown different patterns of tiles lighting up and is asked to replay the patterns by pressing tiles in the same sequence. Task difficulty increases with the length of the lighting pattern. We found that for this type of VR environment, EEG and GSR are the most reliable physiological cues for measuring the user's cognitive load, whereas pupil dilation and heart rate did not vary significantly with increasing task difficulty.