Toward Distinguishing Cybersickness, Visual fatigue, Cognitive load and Acute Stress in Virtual Reality: Two Randomized and Controlled Studies

Virtual Reality (VR) is increasingly used to study Cognitive load and Acute Stress. But VR comes with side effects such as Cybersickness and Visual fatigue. It remains unclear if we can dissociate psychophysiological responses due to confounding effects. Hence, we conducted two experiments to study and distinguish them. Participants fulfilled a Baseline, Stroop task under four different experimental conditions, Relaxation and Endline. We recorded Stroop performances, Eye tracking (ET), Electrocardiography (ECG), Electrodermal activity (EDA), self-reported Cognitive load, Stress, Cybersickness, Visual fatigue, and Disorientation. Pupil diameter, Blink frequency, Fixations, HR, HRV, and Skin Conductance Response derived between the different conditions. Most of the extracted features from ET, ECG, and EDA showed no differences between states. Despite relaxation steps, Saccade ratio, Blink frequency, Blink duration and Pupil size for ET, Heart rate for ECG, Rise time of the mean skin conductance level, the Arc length of the skin conductance level for EDA were still not back equivalent to baseline. Cognitive load differs from Acute stress based on the Heart rate feature from the ECG sensor. Cognitive load provoked more response with EDA features than Visual fatigue / Cybersickness with the ALSC feature. However, most of those differences have small effect sizes. We underline a 60 minutes immersion “limit.” ET was more sensitive to Visual fatigue / Cybersickness compared to Cognitive load and Acute Stress and ECG to Cognitive load compared to Acute Stress. We documented physiological features varying depending on the state and which one allowed their differentiation. However, side effects can confound other state measures; especially the longer participants are immersed. More experimental inputs are necessary to tackle this research question.