Integrating the User in the Social Group Dynamics of Agents * Matthias Rehm, Birgit Endrass, and Michael Wissner Multimedia Concepts and Applications Institute of Computer Science, University of Augsburg 86159 Augsburg, Germany {rehm|endrass|wissner}@informatik.uni-augsburg.de Abstract This paper introduces the Virtual Beergarden as a virtual meeting place for agents and users. The agents behavior is controlled by a behavior control component, which allows testing different theories of social group dynamics. Agents interact via natural language that is generated by a statistical language component and takes into account the social interaction categories and the social relationships between agents. The user can freely navigate and interact with the other agents relying on the above mentioned components. An evaluation shows if the user can really be integrated in the agents’ social group dynamics. Keywords: multiagent system, social group behavior, natural language generation, user in- teraction 1 Introduction Synthetic agents have been employed in many games and entertainment applications with the aim to engage users and enhance their experience. However, to achieve this goal it does not suffice to provide only for sophisticated animation and rendering techniques. Rather, other qualities have to come into focus as well, including the provision of conversational skills as well as the simulation of social competence that manifests itself in a number of different abilities. Important progress has been made in the area of embodied conversational agents focusing on dyadic interactions between a single user and a single agent (see e.g. Cassell et al., 2000; Prendinger and Ishizuka, 2004). Scaling up to multiple users and/or multiple agents poses some new challenges. For multiple agents, their individual behavior has to be accompanied by coherent group behav- ior, which will not simply emerge by itself if some agents are put together because a group is more than just a bunch of single characters that happen to be at the same location. Instead, a group is constituted of relations between the different group members that influence how they will behave and communicate among each other. Thus, endowing agents with social group dynamics will allow them to build relationships among each other ideally following theories from social psychology. This is important because of two reasons. On the one hand, Reeves and Nass (1996) have shown that people tend to socialize with technical artefacts and agents are an ideal vehicle for project- ing assumptions about human-human interaction to the interaction with agents. Interacting with multiple agents results in the need for consistent and believable group behaviors for the agents. On the other hand, commercial games such as “The Sims” exemplify that the simulation of social skills can render interactions between virtual characters more believable and engaging. Different approaches have been presented that try to handle social (group) behaviors. For instance, Prendinger and Ishizuka (2001) investigate the relationship between an agent’s social role and the associated constraints on emotion expression. They allow a human script writer to specify the social distance and social power relationships among the characters involved in an * Partly funded by DFG under research grant RE 2619/2-1 (CUBE-G) and by EU under research grant IST-34800 (CALLAS).