  In immersive Virtual Reality (VR), your brain can trick you into believing
that your virtual hands are your real hands. Manipulating the representation of
the body, namely the avatar, is a potentially powerful tool for the design of
innovative interactive systems in VR. In this study, we investigated
interactive behavior in VR by using the methods of experimental psychology.
Objects with handles are known to potentiate the afforded action. Participants
tend to respond faster when the handle is on the same side as the responding
hand in bi-manual speed response tasks. In the first experiment, we
successfully replicated this affordance effect in a Virtual Reality (VR)
setting. In the second experiment, we showed that the affordance effect was
influenced by the avatar, which was manipulated by two different hand types: 1)
hand models with full finger tracking that are able to grasp objects, and 2)
capsule-shaped -- fingerless -- hand models that are not able to grasp objects.
We found that less than 5 minutes of adaptation to an avatar, significantly
altered the affordance perception. Counter intuitively, action planning was
significantly shorter with the hand model that is not able to grasp. Possibly,
fewer action possibilities provided an advantage in processing time. The
presence of a handle speeded up the initiation of the hand movement but slowed
down the action completion because of ongoing action planning. The results were
examined from a multidisciplinary perspective and the design implications for
VR applications were discussed.
