Modeling How User-Avatar Movement Inconsistency Affects the Sense of Body Ownership in Virtual Reality

An avatar mirroring the user’s movement is commonly adopted in Virtual Reality. Maintaining the user-avatar movement consistency provides the user a sense of body ownership and thus an immersive experience. However, breaking this consistency can enable new interaction functionalities, such as pseudo haptic feedback or input augmentation at the expense of immersion. We thus propose to quantify how the enlargement of movement inconsistency affects the body ownership.

 

We applied angular offsets to the avatar's shoulder and elbow joints and modeled their effects on the probability of the user noticing the inconsistency through a series of three user studies. Results show that the lost of body ownership increases roughly quadratically with stronger offsets and the probability distributions at two joints negatively affect each other. Leveraging the model, we implemented a technique that amplifies the user's arm movements with unnoticeable offsets and then evaluated implementations with diff parameters(offset strength, offset distribution). Results show that the technique with medium-level and balanced-distributed offsets achieves the best overall performance. Then we demonstrated our model's extendability with three VR applications including stroke rehabilitation, action game and widget arrangement.