Thesis
Reference
Fine-grained Evaluation of the Interactive Narrative Experience: A Continuation Desire perspective
ESTUPINAN VESGA, Sergio
Abstract
The rationale of Interactive Digital Narrative (IDN) as media is to acknowledge the user at the center of the unfolding of a story, conveying vast yet sentient Interactive Narrative Experiences (INE). However, several challenges hinder IDN from reaching its potential, including the lack of appropriate methodologies for assessing engagement of narrative events automatically triggered in reaction to the choices of the user. But how to assess engagement of such a vast range of experiences? What are the characteristics of engaging INEs? This thesis tackles the previous questions by focusing on complementing existing approaches that consider the final ‘product' measured after the task. By keeping track during runtime of the dynamics of engagement operationalized as Continuation Desire, affect, and interactivity, this thesis proposes leads to enhance the measurement tools, fit strategies to model the fluctuation of engagement over time, and discusses the reconsideration of core dimensions of the INE.
ESTUPINAN VESGA, Sergio. Fine-grained Evaluation of the Interactive Narrative Experience: A Continuation Desire perspective. Thèse de doctorat : Univ. Genève, 2020, no. FPSE 772
DOI : 10.13097/archive-ouverte/unige:147900 URN : urn:nbn:ch:unige-1479002
Available at:
http://archive-ouverte.unige.ch/unige:147900
Disclaimer: layout of this document may differ from the published version.
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Sous la direction de Nicolas Szilas, MER
FINE-GRAINED EVALUATION OF THE INTERACTIVE NARRATIVE EXPERIENCE: A CONTINUATION DESIRE PERSPECTIVE
THESE
Présentée à la
Faculté de psychologie et des sciences de l’éducation de l’Université de Genève
pour obtenir le grade de Docteur en Sciences de l’éducation par
Sergio Andrés ESTUPIÑAN VESGA de
Bucaramanga, Colombie
Thèse No 772
GENEVE Décembre 2020
15.345.713
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5 Acknowledgements
I am deeply indebted to my mentor and supervisor, Nicolas Szilas, for his kindness, availability, frankness, and for transmitting me his passion for research. Benevolent yet not complacent, no question was too trivial for you. Merci du fond du coeur, Nicolas.
I am forever thankful to my parents Luz Marina and Víctor, my nona Leonor, and to my brother Víctor Alfonso for providing the happiest place in which one could grow on in my beloved Colombia. Eternal love and gratitude to my mother to whom I deeply miss even more since 2011 and to whom I owe all the good on me. I’m also grateful to Safi, for filling my life with love and joy every single day.
A Ph.D. is often a solitary journey that finishes with a lone ‘hors catégorie’ climb to the finish line in the top of the mountain; yet the strength of a solid peloton makes the whole difference:
infinite thanks to TECFA my peloton in Geneva, headed by arguably one of the best leaders and advisors (just check the coffee mug in TECFA) Mireille Bétrancourt, and to the squad of friends Vincent Widmer, Mattia Fritz, Juliette Désiron, Julien Dacosta, Sunny Avry, Kasper Andkjaer.
I’m grateful for the support of my friends scattered around the globe (Luisk, Philippe, Sofi, Mari, Michael, Ludo, Sergio H., Carlos Jaime, Stéphanie, Coralie, Lorena… and I must stop here but the list is far from finished, you know that) and both my Vesga and Estupiñán family.
My gratitude to the amazing ICIDS research community, particularly to the amazing humans Henrik Schoenau-Fog, Christian Roth, Luis Bruni, Vincenzo Lombardo. And to Cyril Rebetez and Emmanuel Sander for agreeing in being part of my jury and commission, it means a lot to me.
Last but not least, I would like to recognize the Swiss National Science Foundation for supporting the research that got me to Switzerland in the first place via grant # 159605.
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“The right stories can open our hearts and change who we are.
Digital narratives add another powerful element to this potential by offering the opportunity to enact stories rather than merely witness them.”
(Murray, 1997)
9 Summary
The rationale of Interactive Digital Narrative (IDN) is to put the user at the center of the unfolding of a story. To do so, it capitalizes on theories of narrative mediated through intelligent digital technologies. IDN strives at conveying vast yet sentient Interactive Narrative Experiences (INE).
Despite substantial progress in the last decades, a series of challenges hinder IDN from reaching its potential, including the issue of generating engaging narrative events in reaction to the choices of the user. But what is considered an engaging narrative event? How to assess the complexity of a vast range of experiences? What are the characteristics of enjoyable INE?
This work tackles the previous questions by focusing on the evaluation of the INE, complementing existing approaches that consider the experience as a final ‘product’ measured after the task. By keeping track, during runtime, of the dynamics of engagement (operationalized as Continuation Desire) affect and interactivity, this work proposed leads to enhance the measurement tools, strategies to model the fluctuation of engagement over time, and discusses on the reconsideration of core dimensions of the INE.
Using as a base the in-house IDN system Nothing For Dinner, this dissertation featured two user studies, one using scientific crowdsourcing (online) and another using traditional user testing (onsite) for comparing the effect of the presence of interruptions vis-à-vis a control group. The studies were designed to answer research questions concerning the perception of the narrative acts, the potential disruptions caused by the measurement instruments, and the relationship between affect and engagement.
The findings of this thesis can contribute to a better understanding of positive frustration and stresses the importance of considering the affect-engagement interplay in IDN, towards more human-centered narrative experiences. Additionally, this thesis contributes a novel methodology to assess the INE at a micro-level.
11 Résumé
La raison d'être du récit numérique interactif (RNI) est de placer l'utilisateur au centre du déroulement d'une histoire. Pour ce faire, le RNI s'appuie sur les théories de la narration par le biais de technologies numériques intelligentes. Le RNI s'efforce de transmettre des expériences narratives interactives (ENI) vastes mais sensibles.
Malgré les progrès substantiels réalisés au cours des dernières décennies, une série de défis empêchent le RNI d'atteindre son potentiel, notamment la question de la génération d'événements narratifs engageants en réaction aux choix de l'utilisateur. Mais qu'est-ce qui est considéré comme un événement narratif engageant ? Comment évaluer la complexité d'un vaste éventail d'expériences ? Quelles sont les caractéristiques d'une ENI agréable ?
Ce travail aborde les questions précédentes et se concentre sur l'évaluation des ENI, en complétant les approches existantes qui se concentrent sur le "produit" final mesuré après la tâche en gardant une trace pendant l'interaction de la dynamique de l'engagement (opérationnalisée sous le nom de désir de continuité) et de l'interactivité. Ce travail propose également d'améliorer les outils de mesure, les stratégies de modélisation de la fluctuation de l'engagement au fil du temps, et discute de la reconsidération des dimensions essentielles de l’ENI.
En utilisant comme base le système Nothing For Dinner, cette thèse présente deux études d'utilisateurs, l'une utilisant le crowdsourcing scientifique (en ligne) et l'autre utilisant des tests d'utilisateurs traditionnels (sur site) avec comme condition la présence d'interruptions et un groupe de contrôle. Les études ont été conçues pour répondre à des questions de recherche concernant la perception des actes narratifs, les perturbations potentielles causées par les instruments de mesure et la relation entre l'affect et l'engagement.
Les résultats de cette thèse peuvent contribuer à une meilleure compréhension de la frustration positive et soulignent l'importance de considérer l'interaction entre l'affectif et l'engagement dans les RNI, vers des expériences narratives plus centrées sur l'humain. En outre, cette thèse contribue à une nouvelle méthodologie pour évaluer l'ENI à un niveau micro.
13 TABLE OF CONTENTS
Acknowledgements ... 5
Summary ... 9
Résumé ... 11
Introduction ... 20
1.1 Background ... 22
1.2 Thesis goals ... 23
1.3 Challenges ... 24
1.4 Problem statement ... 25
1.5 Outline of the dissertation ... 26
2 Literature review ... 29
2.1 Interactive Digital Narrative ... 29
2.1.1 Conciliating Narrative and Interactivity ... 30
2.1.1.1 The Narrative Paradox ... 32
2.1.1.2 Hypertext Narratives and Interactive Fiction ... 32
2.1.1.3 Choice ... 33
2.1.2 Definitions ... 34
2.1.2 Narrative Management ... 36
2.1.2.1 Coarse-grained systems ... 37
2.1.2.1.1 Implementations of Coarse-grained systems ... 37
2.1.2.2 Fine-grained systems ... 38
2.1.2.2.1 Implementations of Fine-grained systems ... 39
2.1.3 Pedagogical Applications ... 40
2.1.4 Interactive Narratives in Education and Learning ... 40
2.2 Narrative and Interactive Narrative Experience ... 42
2.2.1 Narratology ... 42
2.2.1.1 Narrative Acts ... 43
2.2.2 The Interactive Narrative Experience ... 45
2.2.2.1 Definition of INE employed in this Thesis ... 46
2.2.2.2 Dimensions of the INE ... 46
2.2.2.3 Effectance ... 48
2.3 Affect ... 49
2.3.1 Models of Emotion ... 49
2.3.1.1 Discrete Models ... 49
2.3.1.2 Dimensional models ... 50
2.3.1.3 Appraisal theories ... 51
2.3.2 Psychophysiology ... 52
2.3.2.1 Electrodermal Activity ... 53
2.3.2.2 Facial Expressions ... 53
2.4 Assessing the Interactive Narrative Experience ... 54
2.4.1 Subjective Evaluation Approaches ... 55
2.4.2 Telemetry ... 57
2.4.3 Mixed-Method Approach ... 57
2.4.4 Engagement in Interactive Digital Narrative ... 58
2.4.4.1 Engagement dynamics in Interactive Media ... 59
2.4.4.2 Player Engagement Process ... 59
2.4.4.3 Continuation Desire ... 60
3 Research Questions ... 63
3.1 RQ1: Can engagement levels and narrative perception be sampled during runtime without spoiling the Interactive Narrative Experience? ... 63
3.1.1 Methodological considerations. ... 64
3.1.2 Hypotheses. ... 64
3.1.3 Implications ... 64
3.2 Can a relation be established between patterns of user-initiated narrative acts and engagement levels sampled during runtime? ... 65
3.2.1 Methodological Considerations ... 66
3.2.2 Hypotheses ... 66
3.2.3 Implications ... 66
3.3 Can runtime-collected affective data be used to explain engagement states in an Interactive Narrative? ... 67
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3.3.1 Methodological considerations. ... 67
3.3.2 Hypotheses. ... 68
3.3.3 Implications ... 68
4 Reconsidering the Interactive Narrative Experience ... 69
4.1 The Interactive Narrative Experience as a process ... 71
4.2 Engagement: A Core Element of the INE ... 72
4.2.1 Engagement Trajectories ... 73
4.3 Consolidating the Affective Component ... 74
4.4 Salient narrative structures ... 75
4.5 Effectance and Replayability ... 76
5 Assessing the Interactive Narrative Experience: A Continuation Desire Perspective 78 5.1 Advancing Continuation Desire ... 79
5.1.1 Sampling without Spoiling ... 81
5.1.1.1 Interruption Triggering Algorithm ... 81
5.1.1.2 User Interface Design ... 83
5.1.2 Reinforcing the Affective Component ... 87
5.1.2.1 Self-Reporting ... 88
5.1.2.2 Psychophysiology ... 89
5.1.2.2.1 Electrodermal Activity (EDA) ... 90
5.1.2.2.2 Facial Expression Recognition ... 91
5.1.3 Use of Mixed Methods ... 91
5.1.4 Engagement Trajectories ... 93
5.2 Additional INE-relevant Dimensions ... 95
5.2.1 Effectance ... 95
5.2.2 Replayability ... 95
5.2.3 Usability ... 96
5.3 Methodological toolbox ... 96
5.3.1 Testbed IDN system: Nothing For Dinner ... 96
5.3.1.1 IDtension Narrative Engine ... 97
5.3.2 Process-oriented analysis ... 98
5.3.3 User Research platform ... 99
5.3.4 Biometric Data Analysis ... 102
5.3.4.1 Automated Facial Expression Recognition ... 102
5.3.4.2 Electrodermal Activity ... 103
6 Experiments ... 103
6.1 Overview of the studies ... 103
6.2 Measurement Instruments ... 105
6.3 Study One: Crowdsourced (online). ... 111
6.3.1 Introduction ... 111
6.3.1.1 Research questions ... 112
6.3.1.2 Hypotheses ... 112
6.3.2 Study Design ... 113
6.3.2.1 Participants ... 113
6.3.2.2 Study Protocol ... 114
6.3.3 Study one results ... 114
6.3.3.1 Pre-experience measures ... 114
6.3.3.1.1 Demographics ... 115
6.3.3.1.2 Gaming Frequency Questionnaire ... 116
6.3.3.1.3 Willingness to Start the Experience ... 116
6.3.3.2 Post-experience measures ... 117
6.3.3.2.1 Effectance ... 117
6.3.3.2.2 Usability ... 117
6.3.3.2.3 Perception of in-game interruptions ... 118
6.3.3.2.4 Replayability ... 120
6.3.3.2.5 Correlational Analyses ... 121
6.3.3.3 Runtime measures ... 125
6.3.3.3.1 Engagement Trajectories ... 125
6.3.3.3.1.1 Hooked (High, High, High) ... 128
6.3.3.3.1.2 Unengaged (Low, Low, Low) ... 131
6.3.3.3.1.3 Betrayed (High, High, Low) ... 134
6.3.3.3.1.4 Disappointed (High, Low, Low) ... 136
6.3.3.3.1.5 Deflated (High, High, Neutral) ... 137
6.3.3.3.2 Comparing Engagement Trajectories ... 139
6.3.3.3.2.1 Hooked Vs. Unengaged ... 139
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1. Hooked Vs. Unengaged: User-Initiated Actions (UIAs) ... 139
2. Hooked Vs. Unengaged: System Actions ... 142
6.3.3.3.2.2 Betrayed Vs. Disappointed ... 144
3. Betrayed Vs. Dissapointed: User-Initiated Actions ... 145
6.4 Study Two: Biometrics (on-site) ... 148
6.4.1 Introduction ... 148
6.4.1.1 Research questions ... 151
6.4.1.2 Hypotheses ... 151
6.4.1.3 Study Design ... 151
6.4.1.4 Participants ... 151
6.4.1.5 Study Protocol ... 152
6.4.2 Study two results ... 153
6.4.2.1 Pre-experience measures ... 153
6.4.2.1.1 Demographics ... 153
6.4.2.1.2 Gaming Frequency Questionnaire ... 154
6.4.2.1.3 Willingness to Start the Experience ... 155
6.4.2.2 Post-experience measures ... 156
6.4.2.2.1 Effectance ... 156
6.4.2.2.2 Usability ... 157
6.4.2.2.3 Replayability ... 158
6.4.2.2.4 Perception of in-game interruptions ... 159
6.4.2.3 Runtime measures ... 160
6.4.2.3.1 Self-Assessment Manikin and Continuation Desire ... 160
6.4.2.3.2 Facial Expressions and Continuation Desire ... 163
6.4.2.3.3 EDA and Continuation Desire ... 168
7 Discussion ... 171
7.1 Research Questions revisited ... 171
7.1.1 RQ1: Can engagement levels and narrative perception be sampled during runtime without spoiling the Interactive Narrative Experience? ... 171
7.1.2 RQ2: Can a relation be established between patterns of user-initiated narrative acts and engagement levels sampled during runtime? ... 173
7.1.3 RQ3: Can runtime-collected affective data be used to explain engagement states in an Interactive Narrative? ... 176
7.2 The Interactive Narrative Experience reconsidered ... 178
7.3 Continuation Desire perspective and NFD ... 179
8 Conclusion ... 181
8.1 Key contributions and applications ... 182
8.2 Limitations ... 184
8.3 Perspectives and final remarks ... 185
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INTRODUCTION
Narrative lies at the core of the human nature. It is without a doubt a powerful vehicle of knowledge and cultural capital that could both help tracing back and shaping the destiny of entire societies.
But the right narrative at the right moment can also transform single lives, my own in this case.
Despite the fact that I had not considered pursuing a doctoral degree at the end of my master’s program, I can now say that the decision to pursue a Ph.D. was greatly influenced by the narrative of a book that my mother gave me as a child. But this was not a regular children’s book.
The book in question was called Inca Gold, written by Jim Becket in 1988 (Becket, 1988).
Part of the Choose Your Own Adventure (CYOA) American book series popular at the end of the 20th century, this book positions the reader as the protagonist of the unfolding of the diegetic universe of an archeologist in the jungle of Peru, in a fantastic quest to find a lost gold treasure of the Inca people. It has 16 endings, completely handwritten by the author, from which one leads to the coveted treasure.
This book offered to me two sensations that I had not previously experienced reading books: the sensation of being able to sit down next to the author to co-create a story, my own story, and the sensation of wanting to re-read the book to explore the other storylines and consequences of my decisions.
CYOA books have a single starting point as regular novels but the reader is soon prompted to make decisions, operationalized as options in the bottom of certain pages inviting the reader to turn to specific pages, maintaining or redirecting the reader to a certain story branch. CYOA’s book series can be depicted as a tree, with branches and nodes corresponding to the structural elements that define the advancement of the stories.
The emotional impact resulting from the interaction with the book and positioning myself as an active character was so salient that I still remember having to choose at a certain point between flying a hang glider or rushing to leap to another mountain to escape from a group of pursuers. Interactivity is the distinguishing element of the CYOA book genre, which resulted in a singular narrative experience vis-à-vis other books and novels.
Having played simple video games at that age, I had already realized that being able to interact with the narrative of a video game would be overwhelming – yet I could not get my hands on anything similar on the digital sphere back in the days. Many years and video games later, when I read about the doctoral offer I embarked myself into, and came up to the realization that people
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could in fact interact with computers not just to receive but rather to ‘co-create’ their own story, it became a substantial argument for me to pursue a doctoral research.
In literature and electronic literature, approaches for allowing users influence the evolution of the narrative are commonly represented as branching structures and directed graphs. These structures enable users to experience the perception of being capable to perform an action (to exert agency) that would intervene effectively in the unfolding of the narrative, a term known as effectance, the “perceived influence on the game world” (Klimmt, Hartmann, & Frey, 2007a).
Several efforts have tried to implement, with different levels of success, their own approach to handling and balancing user intervention to provide not only agency and effectance, but also offer an engaging and coherent experience. In the non-digital sphere, one of the most famous examples is improvisational theater, unscripted performances spontaneously created by the performers on the basis of agreeing in a series of rules, mainly the agreement rule “the notion that a very simple way to create a story – or humor – is to have characters accept everything that happens to them.” (Gladwell, 2005)
In the digital sphere, acknowledging user intervention has been longtime pursued and implemented as different endeavors including Interactive Films as Činčera’s pioneer Kinoautomat1, Interactive Series such as Netflix’s Black Mirror: Bandersnatch2, Interactive Fiction in which the use of hyperlinks allows the user to choose from a pool of potential stories, and Interactive Digital Narrative, the research area of this dissertation a novel media covering systems that employ calculations and Artificial Intelligence techniques to generate stories dynamically by acknowledging interaction with users.
Interactive Digital Narrative (IDN) is a new media whose rationale is to empower users with agency to deeply influence the course and generation narrative events. In broad, users interacting with an IDN system should be able to influence story generation, which is possible mostly thanks to the use techniques in the realm of Artificial Intelligence mainly via AI planning and decision-making, built into ‘Drama Managers.’ As a research field, it can be traced to the late
1 http://www.kinoautomat.cz/index.htm?lang=gbr
2 https://www.netflix.com/ch-en/title/80988062
80’s / early 90s with the works of (Bates, Loyall, & Reilly, 1992; B. K. Laurel, 1986) but it can be said that it mainly attracted academic interest since the 2000’s.
IDN intends to be regarded as “an interdisciplinary discipline, requiring techniques from Human-Computer Interaction, Artificial Intelligence and Computer Graphics, as well as knowledge from psychology, media studies, drama theory, narratology, etc.” (“Integrating Research in Interactive Storytelling,” 2019); a media that reconsiders the role and power of interactivity mediated by computers. Chris Crawford, one of the field’s pioneers reiterated this spirit in a conference in 20163 “Interactivity is the essence of the computer as a medium of expression.”
IDN differs from linear media such as films as authors do not hold control over the events that the user will experience. This is a distinguishable characteristic of IDN, mentioned by (Roth, 2016) as “The idea behind Interactive Storytelling lies in generative content that allows for different story progressions in each play session.”
Such a promising discipline and media do not come without great challenges. Other than the problem of generation and co-creation of stories, numerous questions have arisen concerning the human factor, including how to measure something that could change even between play sessions? What are the main characteristics to assess concerning the experience of users interacting with this kind of system? Just to mention two amongst a plethora or other issues. But there is an overarching question that motivates and drives this dissertation: how to advance towards a holistic yet fine-grained estimation of the Interactive Narrative Experience?
1.1 Background
This dissertation took place in the frame of the Fine-grained EvaLuation of the Interactive Narrative Experience (FELINE) project, sponsored by the Swiss National Science Foundation 4. FELINE encompassed several scopes, from a novel authoring paradigm to the advancement of pragmatic User Research methods.
This dissertation addressed the User Research scope, which aimed at advancing the empirical evaluation of engagement and the factors of that influence the Interactive Narrative
3 https://www.youtube.com/watch?v=8_TrAEQ2qZ0
4 http://p3.snf.ch/project-159605
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Experience. This required a review of existing methods and designing a both holistic and fine- grained evaluation paradigm that could complement the limitations of the existing methods. The process and outcomes are presented in detail in this manuscript.
The theoretical scope of FELINE mainly dealt with foundations of the Interactive Digital Narrative, particularly laying a theoretical base around the concept of Narrative Act, including exploration and indexing of Narrative Acts across literature and actual implementations such as interactive artifacts. In short, Narrative Acts are narratological constructs that represents an encoded generic type of action essential to the unfolding of the plot of a story.
Narrative Acts also correspond to a logical authoring and interaction paradigm in Interactive Digital Narrative, enabling users to interact with the system at the level of some sort of narrative ‘building blocks’ employed in the generation of stories.
1.2 Thesis goals
This thesis aims at reconsidering the dimensions of the user experience when interacting with an Interactive Digital Narrative system, what I refer to as the Interactive Narrative Experience (INE) introduced by (Ruth Aylett & Louchart, 2007) as well as to complement accordingly existing global measurements of the INE, including the ‘UX-tool’ (Klimmt, Roth, & Vermeulen, 2012) issued in the frame of the joint European research initiative Integrated Research in Interactive Storytelling (IRIS), see (Cavazza et al., 2008) .
The rationale of this dissertation is that existing pre-post experience global measurements of the INE fall short at keeping track of the diversity and richness of the generated INEs, hence it is necessary to complement them with a finer-grained assessment of the experience. For this purpose, I deem essential to reconsider and strengthen a set of distinctive dimensions, in particular what I consider to be a core element of the INE: Engagement, a topic presented and developed in Section 4.2.
Understanding of the evolution of engagement and its underlying factors bear special interest to the field since it would contribute to fill the evaluation gap, which (Zagalo, Louchart,
& Soto-Sanfiel, 2010) mentioned as “a sensitive issue and hinders the field’s potential to move forward and produce further meaningful advances on interactive narratives’ design.”
This dissertation took inspiration from studies the field of Games User Research (GUR), in which it is widely accepted that “the success of a play environment is determined by the process
of playing, not the outcome of playing” (Kim et al., 2008). Extending this quest to the field of IDN requires a novel multidimensional methodology that can help keeping track, in context, of the emotional, narrative perception, and psychological impact of Interactive Digital Narratives on users, despite a potentially massive space of narratives generated by a single IDN artifact.
While this dissertation does not directly cover the evaluation of the educational outcomes or pedagogical objectives of IDN systems, investigating engagement could provide a solid basis for the design of systems that could enhance the delivery of pedagogical content, for instance by orchestrating actions for meaningful interaction and active discovery of a story world. Studying engagement is of interest for the development of educational technologies since designing educational artifacts that focus on sustained engagement could be a driver for captivating and successful learning experiences. Moreover, learners learn less adequately when they do not feel motivated.
Finally, by collecting data at a micro level both from the interplay IDN system and the user, I aim at exploring relations between perception of the experience and the underlying actions. From these traces, it could be possible to trace back the narratives that seemed to have worked better in terms of engagement and study them in order to detect the most salient narrative structures, which could add to an expanded view of narratology by integrating perceptive views in the context of interaction.
1.3 Challenges
Several challenges arise concerning the evaluation of the Interactive Narrative Experience (INE), including the high variability in the generation of stories: If the content and the experience itself may change between users and play sessions, how does one uniformly evaluate the Interactive Narrative Experience?
In this regard, I support the vision of (Ruth Aylett & Louchart, 2007) who considered that the audience creates meaning while interacting with the system. In consequence, I consider that interacting with an IDN system should be considered as a process, the focus of evaluation should be on assessing the INE, if possible, during the experience rather than the final static ‘product.’
The evaluation of the INE is an important scope of action for the advancement of the field, and such it has been recognized in different instances such as the prime conference in the field, the International Conference in Interactive Digital Storytelling (ICIDS). It is precisely in this
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conference that (Zhu, 2012) strengthened this by pointing out that “Evaluation is one of the major open problems in Interactive Digital Storytelling (IDS) research. As narrative systems grow in their capacities, the community needs a set of well-designed evaluation methods and criteria that can bring insights on the systems as well as the stories they provide.”
I deem that the fulfillment of the promise of IDN relies in integrating evaluation in the design process to create IDN systems that forge, along with the user, memorable, enjoyable, and moreover, engaging experiences.
Previous research in the evaluation of Interactive Narratives mainly dealt with the global appreciation based on a posteriori approaches, users are inquired about their experience after the session using surveys and standardized questionnaires. I claim that global experience measurements are relevant but not sufficient: fully characterizing the constituting elements of the INE requires to take a step further by investigating the effects at a smaller time-frame scale due to the nature of the media, which could include performing runtime measurements and potentially exploring the use of psychophysiological data.
Despite designers and authors of IDN systems may have conceptions about certain success factors of their systems, there is a lack of pragmatic evidence in the IDN research community concerning the factors that determine if and what part of an Interactive Narrative is, in fact, perceived as meaningful and engaging by the users.
1.4 Problem statement
A rationale of generative IDN systems is that authors do not exert control over the actual
‘downstream’ since the influence of users is taken deeply into account by an IDN system. Ideally, an IDN system should provide users with opportunities to exert agency in a way that is perceived as meaningful, coherent, and engaging.
But to reach this level of maturity it is consequential to plan and execute user testing early in the development phase to understand the range of experiences perceived by the users. This is particularly relevant given the complexity of the systems as this feedback could drive the development of future iterations.
In this quest, surveys and questionnaires are generally employed in IDN to the image of games user research. Usually administered pre and/or post task hence at a different time than interaction, these self-reporting methodologies target recollections of the lived experience.
Yet given the nature of the new media, I consider that solely relying on these approaches to assess and characterize the Interactive Narrative Experience (INE) is not enough, since temporal variations are of utmost importance for researchers or authors of the IDN system.
Post-experience instruments rely heavily on the user’s cognitive and recalling capacities with, normally, no visual aid to memory. Asking users to retell or to comment on aspects of their gaming experience is normally perceived as a more difficult endeavor in comparison to re-telling a film or an episode of a series.
An alternative to these methodologies could be to probe the user for certain experiential dimensions during runtime, briefly pausing the course of the experience. This approach would provide a rich amount of highly contextual information and insights on the range of emotional responses and narrative perception. Naturally, one could argue that it is difficult not to affect the experience when interrupting, spoiling the very thing one intends to measure – this dissertation aims at finding a tradeoff between the two approaches. But this leads to the issue of what to measure, what are the ‘core’ dimensions to characterize the nature of the INE in light its unique features.
In sum, advancing on the empirical evaluation of the INE is key to “provide detailed knowledge about which elements of games make players want to continue playing” (Schoenau- fog, 2012). This dissertation tackles the previous considerations and problems by reconsidering the core dimensions that compose the Interactive Narrative Experience (the ‘what’), capitalizes on grounded-theory research towards a fine-grained evaluation of the INE (the ‘how’), and attempts at identifying the narrative elements that appear to contribute to the presence of engagement.
1.5 Outline of the dissertation
This dissertation is divided in eight chapters, as follows:
Chapter 1: Introduction. This chapter presents the overarching motivation of this work, introduces the notion of interactivity as a driving force of computers as medium of expression, provide details about the background in which this work was carried on, a brief introduction to the field of Interactive Digital Narrative and to the problems tackled in this dissertation. It also instantiates the challenges and presents an outline of the unfolding of this dissertation.
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Chapter 2: Literature Review. Chapter 2 covers the existing works this dissertation builds upon, in the areas of Interactive Digital Narrative and pedagogical applications, narrative and narrative structures, theories of affect, and evaluation of the Interactive Narrative Experience.
Chapter 3: Research Questions. This chapter presents and develop the four guiding research questions that steered this dissertation, their corresponding operational hypotheses and discusses the potential implications if their resolution is confirmed.
Chapter 4: Reconsidering the Interactive Narrative Experience. This chapter introduce and develop the dimensions that I argue could be re-examined when assessing the Interactive Narrative Experience, the main subject of study of this dissertation. This chapter presents these considerations in detail, with the goal to be experimentally tested.
Chapter 5: Assessing the Interactive Narrative Experience: A Continuation Desire perspective. This chapter deals with the methodological scope for the fine-grained evaluation of the Interactive Narrative Experience in light of dimensions advanced in Chapter 4. This chapter also presents the mechanisms that could serve to advance the sampling of engagement during runtime using Continuation Desire theory.
Chapter 6: Experiments and Results. This chapter presents and reports the results of the two experimental studies: Study one: Crowdsourced (carried online) and Study two: Biometrics taking place onsite, which employed the method presented in Chapter 5 for evaluating the reconsideration of the Interactive Narrative Experience, presented in Chapter 4.
Chapter 7: Discussion. Chapter 7 presents and elaborates on the transversal results obtained in the two experimental studies and recapitulates on the resolution of the research questions using as base the operational hypotheses.
Chapter 8: Conclusion. The last chapter of this dissertation discusses the implications of the results by vis-à-vis the aim of this dissertation, the key contributions and limitations that could serve as a guide for future work in this direction.
Note: Despite being uncommon practice in academic writing, this dissertation employs the pronoun “I” in order to maintain a reporting tone from the author, and to make a distinction from the efforts in which there the author collaborated with other researchers. Since Interactive Digital Narrative is a relatively recent and multidisciplinary field, dissertations do not observe yet particular writing style guidelines on the matter.
29 2 LITERATURE REVIEW
2.1 Interactive Digital Narrative
To understand Interactive Digital Narrative (IDN) as media and a field of research entails reconsidering the very notion of interactivity in digital media, particularly the active role of the interactor in the construction of the narrative, as presented by (Koenitz, Ferri, Haahr, & Sezen, 2015).
Grasping this specificity is not a trivial task. To start, one faces a multitude of denominations including Interactive Storytelling, Interactive Drama, and Interactive Narrative.
Yet, these designations could be problematic since they could also engulf human-based storytelling, the oldest form of transmission of knowledge and culture, which do not necessarily consider technology. Even though each term designates a particular community and research perspective and despite the apparent divergence, a common trait surges in every definition:
Interactivity.
Adding ‘Digital’ to each denomination could help setting the medium apart from purely analogous storytelling forms such as improvisational theater (Magerko et al., 2009; Swartjes, Kruizinga, & Theune, 2008) or interactive theater (Zhu, Ingraham, & Moshell, 2011). As a result, I subscribe in the frame of this dissertation to the term Interactive Digital Narrative as it designates the medium and the field built around the orchestration of two elements often regarded as inversely proportional: Narrative and Interactivity.
Also known as ‘Narrative Vs. Play,’ this differentiation encapsulates a debate well known to the researchers in the field. It designates a long-standing discourse between ludologists, studying games, and narratologists, studying the structure and function of narrative. The discussion sparked due to the a priori inversely proportional nature of narrative and play – see (R. Aylett & Louchart, 2003; Crawford, 1996) – and how apparently irreconcilable are these two: if there is a push for either end, then the other will be naturally impacted, diminished.
The positioning of computers as a powerful mean for conveying stories, fueled by the spectacular advancement of video games and their use as a medium of expression, encouraged the pursue of more complex means of narrative generation techniques beyond the use of ‘fixed’, linear structures. These advancements pushed the boundaries of generative systems towards the crafting of entertainment software that could allow users to influence the course of events, the unfolding
of the story. Growing efforts in computer-supported human expression and creativity seemed to have followed Brenda Laurel’s inspiring vision of ‘Computers as theatre’ (B. Laurel, 1993).
It is precisely the rise and omnipresence of video games that raises the subject of the distinction of IDN systems and video games. In this regard (Roth, 2015) says that video games are one of the implementations of IDN systems, arguably the most targeted one. But IDN systems could be designed in a way that they do not necessarily target enjoyment-first. For instance, applications like the University of Southern California’s Dimensions in Testimony 5 project allow participants to “Speak with survivors and other witnesses to the Holocaust and other genocides through their interactive biographies”, targeting curiosity and character identification.
While the theoretical debate is likely to remain open, the advancement of expressive technologies mediated by computers shed a new light into the discussion and gestated the field of Interactive Digital Narrative, that “pursues the vision of making the experience of narratives truly interactive, by letting users make meaningful decisions, e.g., influence the fate of characters, and thus co-create the story.” (Roth, 2015). Roth argues that this influence over the unfolding of the narrative must be intentional and entertaining.
2.1.1 Conciliating Narrative and Interactivity
At the end of the twentieth century, Janet Murray published her seminal book Hamlet on the Holodeck (Murray, 1997) in which she portrayed her vision of future interactive digital media as pursuing the “universal fantasy machine” in which the boundaries of expression and interaction are practically non-existent. As a result of the rise of ‘truly expressive’ storytelling technologies, researchers and enthusiasts started pursuing implementations of some sort of universal expression machine, to the image of the Star Trek’s Holodeck 6.
But considering narrative and interactivity as intertwined elements is far from a trivial endeavor; according to M.-L. Ryan “Narrative meaning, moreover, is the product of the top-down planning of a storyteller or designer, while interactivity requires a bottom-up input from the user.
It will consequently take a seamless (some will say miraculous) convergence of bottom-up input and a certain kind of user involvement.” (Ryan, 2006)
5 https://sfi.usc.edu/dit
6 https://en.wikipedia.org/wiki/Holodeck
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In the field of Game Design, tools for designing and analyzing video games such as the Mechanics-Dynamics-Aesthetics (MDA) framework (Hunicke, LeBlanc, & Zubek, 2004) consider narrative as one of the eight components of Aesthetics, as part of the emotional dimension experienced by the players. The story and the game are often considered as two separate components that require a smooth integration, it is necessary to inquiry the game designer during development to verify that an implementation ‘complies’ with the authorial intent.
In parallel to the rise of action-oriented video games, a number of titles such as Heavy Rain and Fahrenheit became famous since they provided users with the possibility to interact with the narrative. Mainstream video game players started to experience the Interactive Narrative Experience, which in turn reinforced the opportunity and relevance of more narrative-oriented applications.
In response, the video game industry realized the potential of taking into account the actions of the player to tailor the unfolding narrative, classically achieved using branching story structures (Gordon, Van Lent, Van Velsen, Carpenter, & Jhala, 2004; Riedl & Young, 2006). Entire companies were created to exploit the universe of narrative videogames such as Telltale Games 7, giving rise to commercial games such as Life is Strange 8 and Detroit: Become Human 9, that quickly became landmark examples of this genre, which have been well generally acclaimed and commercially successful. Users reportedly feeling the story as their own, experienced character identification, emotional involvement; but this came at a very high production cost as result of extremely demanding efforts in authoring.
Interactive Digital Narrative systems aim at making possible a vast space of dynamically created narratives – often thousands of different variations generated automatically as the intervention of the user is acknowledged. A narrative space of such characteristics could not be possibly handwritten by an author as he would rapidly face a dramatic growth in branches and content to be authored, a mathematical phenomenon called the Combinatorial Explosion (Stern, 2008).
7 https://en.wikipedia.org/wiki/Telltale_Games
8 https://lifeisstrange.square-enix-games.com/en-us/games/life-is-strange
9 https://www.playstation.com/en-us/games/detroit-become-human-ps4/
2.1.1.1 The Narrative Paradox
The author’s lack of control over the unfolding of the narrative creates a tension between narrative intent and user intervention over the course of the events (Louchart & Aylett, 2003). Known as the Interactive Narrative Paradox, it basically states that the more freedom of interaction a narrative experience proposes, the less control its author or designer will have over what the user will experience at a narrative level, and ultimately the nature of the experience they will have. With this kind of freedom and as the complexity of the possible narratives increases, it becomes equally complex to keep the structure of the narrative engaging and comprehensive.
2.1.1.2 Hypertext Narratives and Interactive Fiction
Figure 1. Graph of the CYOA book Inca Gold, from https://jeremydouglass.github.io/transverse- gallery/gamebooks/04-55.html
Branching or ‘tree’ structures (Figure 1) have been extensively used to create simple and effective interactive applications. Their success is mostly due to their simplicity in authoring as long as they target a small to medium-size story space, as in the Choose Your Own Adventure (CYOA) book series.
In the digital sphere, the invention of hypertext gave rise to hypertext narratives, in which an author would define where a click on a piece of text would lead the user in the story structure.
This narrative environment has found great success in part thanks to visual tools such as Twine 10, which use does not require the mastery of a programming language.
Yet this authoring paradigm turns out inconvenient for more comprehensive story worlds since it limits the space of scenarios and user agency (Murray, 1997); implementation becomes
10 twinery.org
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costly as every branch and node require authoring specific content, which must maintain narrative coherence with the preceding narrative path.
Advancements in the field of Natural Language Processing in the 1960s (ELIZA project
11) opened new horizons to Human-Computer Interaction, which in turn led the way to Interactive Fiction (IF). IF offer users the possibility to interact, primarily via text commands, with a story structure that is not explicit: users discover the plot and how to advance in the story by interacting with the system, trying multiple strategies that could provide leads into the resolution of an enigma, for instance.
By typing commands and interpreting the feedback provided by the system, users create a mental representation of how to navigate spatially and the possible course of actions in the story world, and what perform actions could help in advancing the narrative.
2.1.1.3 Choice
"A game, fundamentally, is a series of interesting choices." 12
Expressive systems that acknowledge the influence of the users in the development of the experience offer and adopt an interaction paradigm enabling this involvement. In most of the cases, it considers offering visible options from which the users can choose from – such as in hypertext narratives– but interactive systems such as Façade also rely on Natural Language Processing techniques, inferring the intention of the user from parsing different signals such text, voice, even gesture input, and respond accordingly.
On complementary note, inspired by a landmark study in this regard carried out by Mawhorter and colleagues (Mawhorter, Mateas, Wardrip-Fruin, & Jhala, 2014) that identified a series of elements and patterns that characterize the options presented to users in entertainment media, we (Estupiñán, Maret, Andkjaer, & Szilas, 2018) decided to study the topic of choice presentation in existing IDN works to came up with a multidimensional taxonomy of choice in
11 https://en.wikipedia.org/wiki/ELIZA
12 Quote by Mars Jokela, from https://boingboing.net/blog/page/2538
IDN based on this survey. We tackled this question by analyzing a corpus of 31 works, including The Stanley Parable, The Wolf Among Us, and Heavy Rain, from which we created the following taxonomy:
Figure 2: Taxonomy of choice presentation in Interactive Narrative.
This taxonomy is divided between Basic and Optional elements, and it is intended to be used as an informative guide for authors for designing and incorporating elements for presenting options in their IDN applications. To illustrate even more its function, a wizard-like software application was developed in which the author can select a certain number of elements that will be rendered in a small interactive story afterwards.
2.1.2 Definitions
Numerous efforts to define what Interactive Digital Narrative (also called Interactive Digital Storytelling) stands for and encompasses can be observed in literature. In 2008, the IRIS European
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project defined Interactive Digital Narrative as “a major endeavour to develop new media which could offer a radically new user experience, with a potential to revolutionise digital entertainment”
(Cavazza et al., 2008). As a field, it has also been defined as “an interdisciplinary discipline, requiring techniques from Human-Computer Interaction, Artificial Intelligence and Computer Graphics, as well as knowledge from psychology, media studies, drama theory, narratology, etc.”13.
In 2010, Porteous et al. defined it as is a new medium where “the narrative, and its evolution, can be influenced in real-time by a user” (Porteous, Cavazza, & Charles, 2010). Also in 2010, Pope instantiated the role of Artificial Intelligence for narrative generation and balancing as
“It is notable that the inclusion of artificial intelligence separates IS from hypertext narrative”
(Pope, 2010). In 2014, Ware envisioned an IDN where users as active parts of a dynamic process
“in which the author, the audience (the user), and the machine all participate in the story composition process” (Ware, 2014).
Similar visions of the medium can be traced even earlier in which the user takes the role of a main character in a story and acts in behalf of the player character to ‘shape the story’ in an intentional fashion (B. K. Laurel, 1986; Mateas & Stern, 2003b; Szilas, 2003; Weyhrauch & Bates, 1997). These visions are relied on the identification of the user with the role of a diegetic character.
Despite a lack of official consensus, IDN can be considered to be a new medium and a discipline – see (Cavazza et al., 2008) – pursuing a distinctive experience than ‘linear’ media such as television, cinema, etc. since the latter lead users towards pre-defined narrative paths produced by one or many authors. Generative Interactive Digital Narrative could deliver ‘highly interactive’
narrative experiences by accommodating user participation in the narrative generation process.
Definition employed in this Thesis
More recently in 2015, Roth defined Interactive Digital Narrative as “Computer-based interactive entertainment media that allow users to intentionally influence a non-linear narrative, mediated by a storytelling engine.” (Roth, 2015)
13 https://cordis.europa.eu/project/id/231824
I consider this definition successfully integrates several core elements that are intrinsic to the medium: ‘entertainment media’ relates to enjoyment – a core dimension of the Interactive Narrative Experience–, ‘intentionally influence’ relates to the perception of effectance, recognizing how one’s actions affect the unfolding of the narrative, ‘storytelling engine’ relates to the use of Artificial Intelligence capable of assist the co-creation of stories – as opposed to more
‘linear’ or branching-based experiences.
This dissertation adopts and follows the aforementioned definition. It is worth noting at this stage that this dissertation covers only the scope of fine-grained, highly interactive ‘generative’
Interactive Digital Narrative systems.
2.1.2 Narrative Management
A unique aspect of ‘highly interactive’ versus ‘quasi-linear’ or ‘multi-linear’ Interactive Digital Narrative (IDN) is acknowledging and accommodating user intervention in the generation of story plots. To do this, IDN systems employ techniques in the realm of Artificial Intelligence, primarily search, automated planning algorithms, rule-based systems, and autonomous intelligent agents (Schoenau-Fog, Bruni, Khalil, & Faizi, 2013).
A defining characteristic is that plot elements are the outcome of calculations (Szilas, 2014), which should both respond to author-defined constraints and be coherent at a narrative level to the previous elements of the delivered experience. In this endeavor, the component in charge of this author-machine-user orchestration tasks receives several names, including Experience Manager, Narrative Engine, Drama Manager, and Storytelling Engine.
Elaborating on this orchestration component (Schoenau-Fog, Bruni, et al., 2013) describe the functions of a Drama Manager as to “organize and trigger specific events depending on the executed actions and navigational choices made by the interacting subjects.” Bulitko refers to the Experience Manager as an “a surrogate for the human author by representing his or her authorial intentions in the face of player autonomy. However, different users may have different preferences over how the narrative unfolds. An experience manager may also take user’s preferences into account by modeling and predicting the user’s preferences for different narrative futures while attempting to preserve the author’s intent” (Riedl & Bulitko, 2013). Finally, a third term appears for designating this component: Narrative Engine. In practical terms, the previous terms represent a component that performs a similar function and might be used interchangeably.
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In brief, narrative coordination is achieved by this scheduling component referred as narrative engine in this dissertation. In an attempt to simplify the description of the works of the narrative engines, Szilas established a two-element classification of the underlying functioning of such component: coarse-grained, and fine-grained systems. Other classifications were proposed in (Arinbjarnar, Barber, & Kudenko, 2009) but this work follows Szilas’ classification.
2.1.2.1 Coarse-grained systems
According to Szilas, Coarse-grained systems correspond to a narrative orchestration approach in which the Narrative Engine reasons in terms of more or less advanced beats, narrative ‘packages’
created by authors or designers containing collections of behaviors.
In coarse-grained systems, the author creates the rules that should be met to ‘activate’
certain plot points, putting them in a list of candidate narrative plots to be triggered, such as (Weyhrauch, 1997). Some IDN systems rely on this pre-post conditioning to plan the unfolding of the narrative: Mateas described the functioning of Façade’s narrative engine “To select a beat, the drama manager constructs a probability distribution over the set of satisfied beats (beats in the pool with satisfied preconditions) and draws a beat from this distribution” (Mateas, 2002).
In general, Coarse-grained systems employ an approach in which the Narrative Engine inspects the state of the experience to reprogram it according to a predefined narrative arc or dramatic shape defined beforehand, by offering suitable plot points that could be triggered afterwards.
2.1.2.1.1 Implementations of Coarse-grained systems
Arguably, the most famous implementation of this category is Façade. Created in 2003 by Michael Mateas and Andrew Stern (Mateas & Stern, 2003a, 2005), Façade is coined as ‘Interactive Drama’
that takes place in the apartment of Grace and Trip (the two Non-Player Characters), a married duo who seemingly have ‘couple’ issues; the player’s role is a friend or mediator of some sort. The player has no instructions nor directions on what to achieve or to do, it is the interactions from the NPCs that invite to interaction.
In Façade, there is no traditional gamification mechanisms such as scores, bonuses, challenges. Interaction is achieved via free text, handled by Natural Language Processing component to map input to one of 36 discourse acts shown next.
Figure 3: Discourse acts in Façade, from (Mateas & Stern, 2003a).
Player input always occurs in the context of a narrative beat, the associated discourse act is then interpreted in that context by the narrative engine to elicit a response that can vary from one narrative beat to another. Interestingly, Façade allows the interruption of the plot point execution from the user, the narrative engine rapidly reprograms and selects the next plot point (called ‘beat’), which enables rapid exchanges and an elevated perception of agency.
In addition to Façade, other implementations of Coarse-grained systems trigger plot points in partially ordered graphs (Machado, Brna, & Paiva, 2004; Porteous et al., 2010; Skorupski, Jayapalan, Marquez, & Mateas, 2007; Weyhrauch, 1997) as well as more rigid narrative structures (Ruth Aylett, Figueiredo, Louchait, Dias, & Paiva, 2006; Silverman, Johns, Weaver, & Mosley, 2003b; Spierling, Grasbon, Braun, & Iurgel, 2002)
2.1.2.2 Fine-grained systems
Fine-grained systems are part of Szilas’ classification of Interactive Digital Narrative systems.
Opposed to Coarse-grained systems, they employ primitive narrative actions that are coordinated by a narrative engine to build a coherent and interesting story.
Fine-grained systems face a complexity problem since they reason in terms of simple, atomic narrative acts (e.g., to inform, to influence) that do not correspond to narrative ‘beats’ but rather rely on the narrative engine to be organized in a coherent manner. Users initiate actions in the story world, the narrative engine calculates on-the-fly the impact and the possible narrative implications of these actions.
Fine-grained systems employ narrative engines that rely eminently on AI planning algorithms, which, from a starting state of the story world and given a final or ‘goal state’ or states,
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and the narrative actions available in a repertory, it computes and presents the possible actions that the player and the NPCs could take to reach their goals (Cavazza, Charles, & Mead, 2001) or to reach an overall narrative target state (Young et al., 2004).
Also in the fine-grained category are to be found IDN systems that rely on agent-based approaches with built-in decision making strategies. In this quest, planning has been used in IDN since it relies on discrete actions, which can in turn be “individually assigned to and executed by characters” (El Rhalibi, Goudoulakis, & Merabti, 2012).
Being able to act such a ‘low’ level would provide users the possibility to control precisely the actions that the player character performs. But this comes at the cost of highly complex computations that should strive to provide users with a meaningful narrative. The generated actions should take into account the narrative context so that the system could increase the chances of inducing an engaging Interactive Narrative Experience. Consequently, due to their complexity, Szilas advances that fine-grained systems tend to be perceived as less engaging than coarse-grained systems.
In sum, fine-grained systems could technically offer greater variety than their coarse- grained counterpart, but they face the challenge of incorporating meaningful rules and constraints to orchestrate the narrative acts in the system’s repertory.
2.1.2.2.1 Implementations of Fine-grained systems
A first example of system can be defined as a fine-grained is Mimesis (Young et al., 2004). The story revolves around a single objective that relies on planning strategies such as accommodation and intervention to present events that react to the actions of the user. Following an agent-based approach, other implementations of fine-grained IDN systems are FearNot! (R. S. Aylett, Louchart, Dias, Paiva, & Vala, 2005a), the Virtual Storyteller (Swartjes & Theune, 2008), ActAffAct (Rank & Petta, 2005), and NetworkING (Porteous, Charles, & Cavazza, 2013).
Chris Crawford (Crawford, 1999) developed a series of systems that could be considered as fine-grained since, in general terms, they rely on the use of verbs as means of interaction to story events. Crawford’s systems under this paradigm are Erasmatron and The Legacy of Siboot.
Interestingly, these systems provide an authoring tool in which the verbs can be created and parameterized, to be included back in the IDN systems for interaction.
Finally, Nothing for Dinner, the IDN system used in this dissertation is based on the narrative engine IDtension created by Szilas (Szilas, 2003; Szilas, Barles, & Kavakli, 2007) relies on a narrative structure composed by character goals and values, a repertory of narrative actions called Narrative Acts (similar to the verbs used by Crawford in his systems), and a set of constraints to guide the Narrative Engine to plan the unfolding of the narrative so it is dramatically interesting.
2.1.3 Pedagogical Applications
Interactive Digital Narrative systems distinguish themselves from traditional linear pedagogical simulations and video games in different dimensions such as replayability, active participation of users in the story, dramatic management. It enables users to start over, making it possible to vary the course of actions and to explore the causal effect of new actions in a ‘safe’ setting.
Pedagogical video games, also known as serious games, exploit the characteristic of video games of being appealing and intrinsically motivating (Przybylski, Rigby, & Ryan, 2010). In the field of Education Sciences, motivation is often pointed out as an essential requirement for the fulfillment of learning objectives, numerous researchers have further elaborated on this direction, coinciding that “if a student is not motivated to learn or to perform an activity, there is less chance of a successful learning outcome” (Gunter, Kenny, & Vick, 2006). Yet, it seems relevant to mention that motivated students do not necessarily learn more effectively or that they reach deeper stages of cognitive engagement.
In consequence, I argue that successful interactive digital pedagogical applications should be designed to maximize experiential engagement, they should induce volition and users to repeat the experience of playing once it has finished until a learning objective is deemed accomplished.
This dynamic should be further studied to delineate heuristics and design features that would allow either the transmission or direct exposure of learners to pedagogical content.
2.1.4 Interactive Narratives in Education and Learning
Narrative is a powerful vehicle for conveying information. Analogously, interactivity holds a strong potential in education since it enables the internalization of an experience, transforming observation into action. Researchers in Education Sciences have been investigating how to harness the power of narrative and interaction for education and learning.
A good deal of efforts in this direction decide to privilege one dimension over the other:
Interactivity-oriented applications employ predefined graph-based scenarios where learners are
