Affective Acting: An Appraisal-based Architecture for Agents as Actors

Emotion plays a central role in engaging drama. The conflicts between the characters in a play and the emotions involved in resolving them are the constituents of a dramatic structure, a plot. This premise leads to the assumption that a cast of characters driven by a simulation of the process described by the appraisal theory of emotion might realize dramatic structures by simply interacting in an environment that is prone to conflict. This should even be possible without any directing entity that controls the characters. Using an appraisal-based architecture is thus seen as a key to construct emotionally and dramatically believable characters for interactive drama. This thesis presents the ActAffAct project, an effort to test these ideas with an implementation of such characters in order to gain experiences about the feasibility and the involved complexity. A belief-desire-intention architecture for software agents is extended by an appraisal component following a psychological model of the appraisal process. Key features of different theories of drama are considered during the construction of the environment and the internal setup of the synthetic actors. Goals, standards and preferences as well as emotional expressions and coping activities are not only central aspects of theories of emotion but can also provide a dramatic structure with the causal relationships needed to set it apart from amere sequence of actions. ActAffAct succeeds to create such structures, if only for a rather limited meaning of drama. It nevertheless shows a promising direction for further work. ActAffAct Stefan Rank