Spontaneous avatar behavior for human territoriality

The challenge of making a virtual world believable includes a requirement for AI entities which autonomously react to a dynamic environment. After the breakthroughs in believability introduced by modern lightning and physics techniques, the focus is shifting to better AI behavior sophistication. Avatars and agents in a realistic virtual environment must exhibit a certain degree of presence and awareness of the surroundings, reacting consistently to unexpected contingencies and social situations. Unconscious reactions serve as evidence of life, and can also signal social availability and spatial awareness to others. These behaviors get lost when avatar motion requires explicit user control. This paper presents a new approach for generating believable social behavior in avatars. The focus is on human territorial behaviors during social interactions, such as during conversations and gatherings. Driven by theories on human territoriality, we define a reactive framework which allows avatars group dynamics during social interaction. This approach gives us enough flexibility to model the territorial dynamics of social interactions as a set of social norms which constrain the avatar's reactivity by running a set of behaviors which blend together. The resulting social group behavior appears relatively robust, but perhaps more importantly, it starts to bring a new sense of relevance and continuity to virtual bodies that often get separated from the simulated social situation.