Emergent situations in interactive storytelling

Interactive storytelling can either be based on explicit plot representations or on the autonomous behaviour of artificial characters. In such a character-based approach, the dynamic interaction between characters generates the actual plot from a generic storyline. Characters' behaviours are implemented through real-time search-based planning techniques. However, the top-down planning systems that control artificial actors need to be complemented with appropriate mechanisms dealing with emerging ("bottom-up") situations of narrative relevance. After discussing the determinants of plot variability and the mechanisms that account for the emergence of narrative situations, we introduce additional mechanisms for coping with these situations. Thes

Emergent Story Generation: Lessons from Improvisational Theater

An emergent approach to story generation by computer is characterized by a lack of predetermined plot and a focus on character interaction forming the material for stories. A potential problem is that no interesting story emerges. However, improvisational theater shows that – at least for human actors – a predetermined plot is not necessary for creating a compelling story. There are some principles that make a successful piece of improvisational theater more than a random interaction, and these principles may inform the type of computational processes that an emergent narrative architecture draws from. We therefore discuss some of these principles, and show how these are explicitly or implicitly used in story generation and interactive storytelling research. Finally we draw lessons from these principles and ask attention for two techniques that have been little investigated: believably incorporating directives, and late commitment

Using Out-of-Character Reasoning to Combine Storytelling and Education in a Serious Game

To reconcile storytelling and educational meta-goals in the context of a serious game, we propose to make use of out-of-character reasoning in virtual agents. We will implement these agents in a serious game of our design, which will focus on social interaction in conflict scenarios with the meta-goal of improving social awareness of users. The agents will use out-of-character reasoning to manage conflicts by assuming different in-character personalities or by planning to take specific actions based on interaction with the users. In-character reasoning is responsible for the storytelling concerns of character believability and consistency. These are not endangered by out-of-character reasoning, as it takes in-character information into account when making decisions

The Virtual Storyteller: story generation by simulation

The Virtual Storyteller is a multi-agent framework that generates stories based on a concept called emergent narrative. In this paper, we describe the motivation and approach of the Virtual Storyteller, and give an overview of the computational processes involved in the story generation process. We also discuss some of the challenges posed by our chosen approach

Player agency in interactive narrative: audience, actor & author

The question motivating this review paper is, how can computer-based interactive narrative be used as a constructivist learn- ing activity? The paper proposes that player agency can be used to link interactive narrative to learner agency in constructivist theory, and to classify approaches to interactive narrative. The traditional question driving research in interactive narrative is, ‘how can an in- teractive narrative deal with a high degree of player agency, while maintaining a coherent and well-formed narrative?’ This question derives from an Aristotelian approach to interactive narrative that, as the question shows, is inherently antagonistic to player agency. Within this approach, player agency must be restricted and manip- ulated to maintain the narrative. Two alternative approaches based on Brecht’s Epic Theatre and Boal’s Theatre of the Oppressed are reviewed. If a Boalian approach to interactive narrative is taken the conflict between narrative and player agency dissolves. The question that emerges from this approach is quite different from the traditional question above, and presents a more useful approach to applying in- teractive narrative as a constructivist learning activity

Facilitating open plot structures in story driven video games using situation generation

Story driven video games are rising in popularity, along with the players desire to make meaningful choice within the plot and therefore become more involved and immersed within the experience. This paper investigates the problems which arise from implementing interactive narrative within video games and potential techniques to solve those problems. The main focus of the study was the situation generation technique, used to maintain the continuity within open, emergent plot structures, using behaviour trees as a means to implement and traverse plot sequences. The ISGEngine was developed during the course of this study in order to implement and evaluate the situation generation technique

Agents for educational games and simulations

This book consists mainly of revised papers that were presented at the Agents for Educational Games and Simulation (AEGS) workshop held on May 2, 2011, as part of the Autonomous Agents and MultiAgent Systems (AAMAS) conference in Taipei, Taiwan. The 12 full papers presented were carefully reviewed and selected from various submissions. The papers are organized topical sections on middleware applications, dialogues and learning, adaption and convergence, and agent applications

Interactive Digital Storytelling: Towards a Hybrid Conceptual Approach

1 Introduction In this contribution, Interactive Digital Storytelling is viewed as a hybrid form of game design and cinematic storytelling for the understanding and making of future learning and entertainment applications. The paper shall present formal design models that provide a conceptual bridge between both traditional linear narrative techniques as well as agent-based emergent conversations with virtual characters. In summary, a theoretical classification of thinking models for authors and interactive experiences for users will be presented. The conceptual work is based upon practical experiments within several research projects on edutainment, which employ conversations with virtual characters to convey information and to entertain. By building several prototypes, two different approaches where explored to combine plot-based interactive storytelling with character-based emergent conversations. Visual impressions of the examples are shown in Fig. 1 and will be explained in more detail in the full paper. In both examples, several virtual animated characters converse digitally with each other and with a user who mainly types text with the keyboard, optionally complemented by choice functionality and special hardware interfaces. The resulting conversations differ in their direction of approaching a middle ground between predefined narrative presentations and emergent conversations with a user, by combining emerging chatterbot dialogues with a story structure. The user experiences a semi-autonomous behaviour of interacting agents. This paper is not about the difference between stories and games. The motivation is on the potential of both to offer structures for learning and entertainment. Instead of trying to draw a distinct line between them, conceptual models for authors have to be defined, who are responsible to flesh out a suitable design within a variability of forms. Design elements include aspects of drama and filmmaking, dialogue design, as well as game design and game tuning. The actual challenge for the design of learning applications with conversational agents is the necessity that authors have to take on responsibility concerning the intended outcome and effect. In fact, they have to balance the bias between a pre-structured storyline (and possibly a timeline) which they may have strictly defined, and the agency that users shall experience through the design of the author. However, there is no one-dimensional borderline between both. In the following, the paper presents a model with several levels which shall help to form a more differentiated picture. 2 Conceptual Models for Storytelling and Agency In Fig. 2, a traditional modus operandi is sketched at four abstract levels. The distinction between levels may vary from project to project. The four levels were found to be suitable for the addition of interaction at each of the levels to form a classification of genres. On the top level of highest story abstraction, the overall dramatic outline is sketched. For example, there may be a hero’s journey in 3 acts, or a Propp model. Further, authors break down the story into scenes which are handled at the next level. Each scene will be defined by a scene script. Within a scene, dialogues and interactions between actors are defined, and lead to stage directions. If producing for an animated film, these directions are strictly mapped onto virtual actors by a skilled animator, who defines the way the virtual actors move and behave. When storytelling gets interactive, the user can influence the storytelling. In fact, in games as well as in constructivist scenarios for learning, users need to experience agency within a story. However, there are different levels at which to affect the outcome. In Fig. 3, the first author model (compare Fig. 2) has been extrapolated according to the need of introducing agency at each level. Opposed to the author, a participant is modelled who now may contribute to each level. The first implication for the author is that it’s not enough to just model a database of descriptions, but to add rules and models, which control an autonomous behaviour at each level in reaction to the participants. Then, it is possible to think of gradations of granted agency versus authored determination. Within Fig. 3 this is indicated by the sliders between control and autonomy at each level. The levels rather represent conceptual stages for authoring than elements of software architecture, though there are parallels to architectures of a number of existing systems of game and story engines. Semi-autonomy occurs on the edge between predefined factual information and rules for each level. The more rules on one level, the more agency can be experienced by potentially affecting the respective level. For example: It is imaginable that participants only experience agency on the lowest level, as a feeling of presence in a scenario. In this case, everything is predefined, but avatars would still react with nonverbal cues to the visitor and recognize her, comparable to a virtual cursor that shows a live status. At the conversation level, participants can for example have agency in an entertaining and informative chatbot dialogue with the characters. They may even not be able to affect anything in the story logic, but participate at dialogue level with speech acts. Agency at scene level would mean to have real choices about the outcome of a scene, for example, the story of the game would have to change according to user’s actions. On the top level, players would influence the whole story of the application, if the "agency slider" would be at a 100% to the right. For example, a simulation such as "The Sims" (Electronic Arts) can be put into the classification here. For factual knowledge transfer in a didactic lesson situation, the highest level could stay predefined, while the lower levels allow for conversational interaction, however constrained. If authors only provide a rule base with little pre-scripted structuring, they achieve a conceptual model more like an exploration or gaming experience depending completely on the action of the player. While arranging the bias at each level to various slider positions, several abstract genres of Interactive Digital Storytelling can be rebuilt in the model, which helps to specify exactly what kind of user experience an application shall provide. It is a conceptual model that can be used to classify story-related games, and it particularly supports authors coming from linear media, stepping into interactive storytelling. 3 Further Work In the full paper, I will also tackle related work while comparing with other theoretical models between games and stories, including references of the taxonomies of C. Lindley, M. Leblanc, J. Klabbers, B. Laurel, C. Pearce, and traditional classifications such as of R. Caillois. I will give more examples how existing products of Interactive Storytelling fit into the classification, and raise the question if new genres have to be defined particularly for Interactive Digital Storytelling. Literature Caillois, Roger: Man, Play and Games. (orig.: Les Jeux Et Les Hommes 1958) University of Illinois Press, Reprint (2001) Hunicke, Robin; LeBlanc, Marc; Zubek, Robert: MDA: A Formal Approach to Game Design and Game Research. In: Workshop Proceedings: Challenges in Game AI. 19th National Conference on Artificial Intelligence AAAI (2004) Klabbers, Jan H.G.: The gaming landscape: A taxonomy for classifying games and simulations. In Copier & Raessens (Eds.) Level up: Digital Games Research Conference. Utrecht University (2003) Lindley, Craig: Narrative, Game Play and Alternative Time Structures for Virtual Environments. In: Proc. TIDSE 2004, Technologies for Interactive Digital Storytelling and Entertainment, Darmstadt, Springer LNCS vol. 3105, 2004 Pearce, Celia: Emergent authorship: The next interactive revolution. In: Computers & Graphics 26, p. 21-29 (2002) Spierling, U.: Conceptual Models for Interactive Digital Storytelling in Knowledge Media Applications. In: Proc. TIDSE 2004, Technologies for Interactive Digital Storytelling and Entertainment, Darmstadt, Springer LNCS vol. 3105, 200

Development of an Emergent Narrative Generation Architecture for Videogames

Emergent narratives can enhance a video gaming experience. However, the use of this storytelling form in videogames is in its infancy. Many existing emergent narrative generation systems are limited in authorial creative control, story world flexibility, user freedom and/or general storyline maintenance. In this thesis, we designed a robust architecture for generating emergent narratives to use in videogames, and tested the architecture in a prototype game simulation. The architecture continuously presents pre-written plot fragments with fulfilled preconditions, providing authorial control over the story’s components and general direction. The user navigates the plotlines and shapes the story through their unrestrained decisions. Architectural components monitor these actions and respond appropriately to ensure a cohesive story. Yet, the narrative generation framework remains separate from specific Game World mechanics, maintaining compatibility with any story world. The proposed architecture offers flexible emergent narrative generation and can provide a framework for future emergent videogame development

‘IMPLICIT CREATION’ – NON-PROGRAMMER CONCEPTUAL MODELS FOR AUTHORING IN INTERACTIVE DIGITAL STORYTELLING

Interactive Digital Storytelling (IDS) constitutes a research field that emerged from several areas of art, creation and computer science. It inquires technologies and possible artefacts that allow ‘highly-interactive’ experiences of digital worlds with compelling stories. However, the situation for story creators approaching ‘highly-interactive’ storytelling is complex. There is a gap between the available technology, which requires programming and prior knowledge in Artificial Intelligence, and established models of storytelling, which are too linear to have the potential to be highly interactive. This thesis reports on research that lays the ground for bridging this gap, leading to novel creation philosophies in future work. A design research process has been pursued, which centred on the suggestion of conceptual models, explaining a) process structures of interdisciplinary development, b) interactive story structures including the user of the interactive story system, and c) the positioning of human authors within semi-automated creative processes. By means of ‘implicit creation’, storytelling and modelling of simulated worlds are reconciled. The conceptual models are informed by exhaustive literature review in established neighbouring disciplines. These are a) creative principles in different storytelling domains, such as screenwriting, video game writing, role playing and improvisational theatre, b) narratological studies of story grammars and structures, and c) principles of designing interactive systems, in the areas of basic HCI design and models, discourse analysis in conversational systems, as well as game- and simulation design. In a case study of artefact building, the initial models have been put into practice, evaluated and extended. These artefacts are a) a conceived authoring tool (‘Scenejo’) for the creation of digital conversational stories, and b) the development of a serious game (‘The Killer Phrase Game’) as an application development. The study demonstrates how starting out from linear storytelling, iterative steps of ‘implicit creation’ can lead to more variability and interactivity in the designed interactive story. In the concrete case, the steps included abstraction of dialogues into conditional actions, and creating a dynamic world model of the conversation. This process and artefact can be used as a model illustrating non-programmer approaches to ‘implicit creation’ in a learning process. Research demonstrates that the field of Interactive Digital Storytelling still has to be further advanced until general creative principles can be fully established, which is a long-term endeavour, dependent upon environmental factors. It also requires further technological developments. The gap is not yet closed, but it can be better explained. The research results build groundwork for education of prospective authors. Concluding the thesis, IDS-specific creative principles have been proposed for evaluation in future work