T HESPIAN : An Architecture for Interactive Pedagogical Drama Mei Si, Stacy C. Marsella and David V. Pynadath Center for Advanced Research in Technology for Education USC Information Sciences Institute 4676 Admiralty Way, Marina del Rey, CA, 90292 USA {mei,marsella,pynadath}@isi.edu Abstract. Interactive drama is increasingly being used as a pedagogical tool in a wide variety of computer-based learning environments. However, the effort re- quired to build interactive dramas is quite significant. We built Thespian, an archi- tecture that supports faster development of IPDs, open-ended interaction, encoding of pedagogical goals and quantitative metrics for evaluating those goals. Thespian uses autonomous agents to control each character and assumes that the starting point for the design process is a set of standard scripts. A “fitting” algorithm facil- itates the design process by automatically adjusting the goals of the agents so that the agents perform their roles according to the scripts. This also ensures the agents will behave true to their character’s motivations even when the interactive drama deviates from the scripts. In this paper, we discuss this basic approach in detail and illustrate its application to the Tactical Language Training System. Keywords. pedagogical agents, authoring & assessments tools, language learning 1. Introduction Interactive drama is increasingly being used as a pedagogical tool in a wide variety of computer-based learning environments (e.g., [5,6,9,10]). In an interactive pedagogical drama (IPD), the learner interacts with the characters in a story and the story unfolds based on those interactions. Ideally, an IPD combines the pedagogical power of drama with a more active learning experience that allows learners to explore a simulated story world and see the effect of their actions. The engaging nature of drama and the direct link between actions and outcomes ideally engages students more, motivates them to spend more time learning (e.g., to explore possible paths in the story), and appropriately contextualizes the experience. However, the creation of interactive pedagogical drama faces several challenges. Up to now, the effort required to design and build interactive dramas is quite signifi cant [3,8], potentially requiring man-years of design and implementation. Further, effective design for relatively open-ended user interactivity is still an open research issue. And there is often a tension between the goal of interactivity and the goal of creating an engaging drama with consistent, well-motivated characters. Satisfying both goals can be a signifi cant technological and creative challenge. For example, writers often do not have expertise in designing interactive stories, which is still largely a nascent art form. More fundamentally, in an interactive pedagogical drama, pedagogical goals must also be achieved. This raises the question of how the pedagogy is embedded in the environment,