2 Overview of A GENT S CAPE

Virtual environments have a variety of uses, ranging from entertainment to simulation of hard-to-create environments for training and testing purposes. A common feature of virtual environments, especially those aimed at entertainment, is the presence of virtual entities we call agents, characters or objects in the virtual world possessing human characteristics and able to interact pro-actively with the user, that is interacting not simply in reaction to events, but interaction as a result of internal motivation and goals. Although a modicum of intelligence seems to be a requirement for agency, for entertainment purposes believability is often much more of a concern. An agent is believable if a person interacting with the agent can temporarily “forget” that she is faced with an artifical artefact. In [2], it is argued that achieving believability requires broad agents, that is agents with a large number of shallow capabilities (breadth instead of depth), as well as a personality that imbues every action performed by the agent. An integral aspect of personality is the handling of emotion and the effect of such on the actions of the agent.