Evaluating Control Schemes for the Third Arm of an Avatar

Recent research on immersive virtual environments has shown that users can not only inhabit and identify with novel avatars with novel body extensions, but also learn to control novel appendages in ways beneficial to the task at hand. But how different control schemas might affect task performance and body ownership with novel avatar appendages has yet to be explored. In this article, we discuss the design of control schemas based on the theory and practice of 3D interactions applied to novel avatar bodies. Using a within-subjects design, we compare the effects of controlling a third arm with three different control schemas (bimanual, unimanual, and head-control) on task performance, simulator sickness, presence, and user preference. Both the unimanual and the head-control were significantly faster, elicited significantly higher body ownership, and were preferred over the bimanual control schema. Participants felt that the bimanual control was significantly more difficult than the unimanual control, and elicited less appendage agency than the head-control. There were no differences in reported simulator sickness. We discuss the implications of these results for interface