A curved-walking illusion: Effects of locomotion on presence and cybersickness

Treadmill Virtual Reality (VR) has a potential application in rehabilitation, but its adoption is hampered by commonly experienced cybersickness symptoms, and an incomplete understanding of the factors that influence relevant (learning) outcomes. Previous studies have suggested that with active locomotion (self-motion) cybersickness symptoms may be limited. Restriction of the field-of-view – e.g., via the use of video vignettes – may also reduce symptoms. Whether a VR intervention is effective may also depend on the subjective presence within the virtual environment as experienced by the user. It remains unclear, however, what the optimal conditions to prevent cybersickness and to induce high levels of presence are. In the current study we investigated the effect of self-motion (walking vs. standing) and field of view as manipulated by vignetting (on vs. off) on cybersickness, presence and memory. Thirty-two healthy adults walked two predetermined routes in two different virtual environments: During one trial participants walked on the treadmill, determining direction with a handlebar (walking condition; using a Virtuwalk-treadmill), and during the other trial (order counterbalanced between participants), participants used the handlebar while standing still to move around the virtual environment (standing condition). In a between-subjects design, half the participants experienced the virtual environments with a vignette that restricted the field-of-view, while vignetting was not applied for the other half of the participants. In contrast to expectations, cybersickness was not influenced by walking or vignetting. However, results showed a positive effect of self-motion on presence, with higher presence in the walking than no-walking condition. In addition, presence and motivation were positively correlated. Vignetting did not affect presence, but it reduced landmark memory, potentially by partially obstructing the field-of-view. The current study’s findings thus suggest that self-motion is positively associated with presence, and in turn higher presence is associated with higher motivation. Vignetting did not reduce cybersickness and may not be recommended when memory of the environment is of relevance.