Effects of Constant and Time-Varying Display Lag on DVP and Cybersickness When Making Head-Movements in Virtual Reality

When HMD users move their heads in virtual reality (VR), display lag creates differences between their virtual and physical head pose (DVP). This study examined whether objective estimates of DVP could predict experiences of cybersickness during simulations with three different types of added lag: (1) Constant lag (where the display was always delayed by 250 ms); (2) Predictable time-varying lag (where delays alternated between 0 and 250 ms every 5 s); and (3) Random time-varying lag (where delays alternated between 0 and a randomly determined value, up to 250 ms, every 1-5 s). Constant, Predictable, and Random added lag were found to generate similar levels of cybersickness-with all three conditions producing more severe sickness than the Baseline lag control. Consistent with our DVP hypothesis, the spatial magnitude and temporal dynamics of our participants' DVP were both found to be reliable predictors of their cybersickness in all display lag conditions tested.