Immersive versus Non-Immersive Virtual Reality Environments: Comparing Different Visualization Modalities in a Cognitive-Motor Dual-Task

In fields like cognitive and physical rehabilitation, adopting immersive visualization devices can be unfeasible. In these cases, the main challenge is to develop Virtual Reality (VR) scenarios that still provide a strong sense of presence, usability, and user agency, even without full immersion. This paper explores a cognitive motor dual-task in VR, consisting in counting and reaching, comparing three non-immersive visualization methods on a 2D screen (tracked perspective camera, fixed perspective camera, fixed orthographic camera) with the immersive experience provided by a head-mounted display. The comparison focused on factors like sense of presence, usability, cognitive load, and task accuracy. Results show, as expected, that immersive VR provides a higher sense of presence and better usability with respect to the non-immersive visualization methods. Unexpectedly, the implemented 2D visualization based on a tracked perspective camera seems not to be the best approximation of immersive VR. Finally, the two fixed camera conditions showed no significant differences in performance based on the type of projection.