AI Design for Believable Characters via Gameplay Design Patterns

AI Design for Believable Characters via Gameplay Design Patterns

Petri Lankoski (Aalto University, Finland), Anja Johansson (Linköping University, Sweden), Benny Karlsson (Fabrication Games Europe AB, Sweden), Staffan Björk (Chalmers University of Technology, Sweden) and Pierangelo Dell’Acqua (Linköping University, Sweden)
DOI: 10.4018/978-1-60960-567-4.ch002
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We address the problem of creating human-like, believable behavior for game characters. To achieve character believability in games, the game designer needs to develop that character so that it fulfills as many aspects of believability as possible. With believable behavior we mean that the game is consistently structured in terms of narration or gameplay so that it is possible to build and maintain coherent relations between the actions of the characters. In this paper, we first analyze the general patterns for game characters design in detail concentrating on the aspects that are relevant to the AI design. Then, we present an agent architecture that we are developing, and discuss how this architecture can address the identified design patterns.
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Game characters have an important role in the playing experience, because people are fine-tuned to act in social situations. Damasio (2005) argues that a part of the brain is specialized for reasoning and making decisions in social situations. Different studies imply that people react to human-like entities similarly with how they react to people (e.g., Reeves & Nass, 1996; Schulte-Rüther, Markowitsch, & Piefke, 2007). In addition, theorists argue that understanding what other people or characters are experiencing depends on action-perception coupling and mimicry (e.g., Decety & Jackson, 2004; Niedenthal, Barsalou, Winkielman, Krauth-Gruber, & Ric, 2005). This coupling means, for example, that when one seems someone smiling happily, one tend to smile and feel happy also. Mimicry seems to be rather involuntary and autonomous; people have only limited control over mimicry (e.g., Dimberg, Thunberg, & Elmehed, 2000). Characters need not to be realistic (Mickey Mouse), but the expressions and behaviors need to resemble human ones.

To create human-like and believable behavior for a game character, the designer needs to develop that character so that it fulfills as many aspects of believability as possible. Lankoski and Björk (2007b) define believability as follows: “By believability we mean that the game is consistently structured in terms of narration or gameplay so that it is possible to build and maintain coherent event indexes (relations between the events).” Lankoski and Björk (2007a) argue that character can be looked at from three perspectives: physical (e.g., sex, health, posture, and appearance), social (friends, social standing, and family), and psychological (intelligence moral standards, skills, attitude, complexes, and goals). They base their proposal to drama theorist Lajos Egri’s (1960) method for theatre writing. These perspectives are connected and every feature in one has implications in terms of what is a possible and plausible feature in the other. As very simple examples, a skilled gymnastics moves differently than a man weighting hundred kilos, and person who is a afraid of snakes reacts to the presence of a snake differently than one who owns a snake. When non-player characters (NPCs) 1 should have emotional expressions towards events in the game word, the character design needs to be detailed enough to give basis for reasoning how the NPCs should react emotionally to the possible events.

Lankoski and Björk (2007a), following Egri (1960), look at how the character qualities can be used to create believable conflict. While conflict design is not discussed here, it is noteworthy that this character design approach extends beyond designing single characters.

Isbister (2006) describes how different attitudes (or aspects of the personality) and emotions show in the character’s facial expressions and posture. For example, a friendly person smiles and maintains eye contact (but does not stare) and a dominant person tends to control conversations and take up more physical space than a submissive one.

Lankoski and Björk (2007b) argue that a believable character is one that behaves consistently; the players are able to posit causal connections between the character’s actions. However, believable behavior is context dependent: an action hero or superhero can perform impossible actions without breaking the expectations of the player or causal logic of the game. They argue, following Murray Smith (1995), that character interpretation is based on a schema that includes qualities such as:

  • the physical body, and each human has a different body;

  • perceptual activity and self-awareness;

  • intentional actions;

  • the ability to use natural language;

  • persistent traits. (See, Smith, 1995, pp. 20-31.)

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Table of Contents
Maria Manuela Cruz-Cunha, Vitor Hugo Varvalho, Paula Tavares
Maria Manuela Cruz-Cunha, Vitor Hugo Varvalho, Paula Tavares
Chapter 1
Paula Tavares, Pedro Mota Teixeira, Leonardo Pereira, Maria Manuela Cruz-Cunha
Finally, we examine the importance and function of motion graphics inside the game experience and the game contexts in which this communication... Sample PDF
Video Games as Aggregating Mediums and Resulting Products of Several Visual Communication Languages
Chapter 2
Petri Lankoski, Anja Johansson, Benny Karlsson, Staffan Björk, Pierangelo Dell’Acqua
We address the problem of creating human-like, believable behavior for game characters. To achieve character believability in games, the game... Sample PDF
AI Design for Believable Characters via Gameplay Design Patterns
Chapter 3
Giannis Milolidakis, Chris Kimble, Corinne Grenier
This chapter analyzes behaviour in on-line games from a practice-oriented perspective and focuses on how individuals create and sustain social... Sample PDF
A Practice-Based Analysis of Social Interaction in a Massively Multiplayer Online Gaming Environment
Chapter 4
Verónica Costa Orvalho, João Orvalho
Character Animation has a crucial role in modern videogames: it is essential to provide a realistic and immersive experience to the users. This... Sample PDF
Character Animation: Past, Present and Future
Chapter 5
Agostino Poggi
Online games have grown during recent years into a popular entertainment form with a wide variety of games and player communities spread across the... Sample PDF
Enhancing Online Games with Agents
Chapter 6
Mark G. Elwell
This chapter reports on movements toward de facto standards for role playing games in the freely accessible and configurable shared virtual... Sample PDF
Questing for Standards: Role Playing Games in Second Life
Chapter 7
Murillo Guimarães Carneiro
The growth of the game industry shows a great market to be conquered. However the gaming business now has consumers more demanding and hungry for... Sample PDF
Artificial Intelligence in Games Evolution
Chapter 8
Jouni Smed
Interactive digital storytelling (IDS) aims at generating dramatically compelling stories based on the user’s input. During the two decades of... Sample PDF
Once Upon a Time: The Convergence of Interactive Storytelling and Computer Games
Chapter 9
Game Led HCI Improvements  (pages 126-145)
Michael Barlow
This chapter covers these recent advances in HCI technology. It conveys the technological and engineering basis of the key current & successful... Sample PDF
Game Led HCI Improvements
Chapter 10
Vladimir Devyatkov, Alexander Alfimtsev
A primary goal of virtual environments is to support natural, efficient, powerful and flexible human-computer interaction. But the traditional... Sample PDF
Human-Computer Interaction in Games Using Computer Vision Techniques
Chapter 11
Sarajane Marques Peres, Clodis Boscarioli, Jorge Bidarra, Marcelo Fantinato
Nowadays, efforts in computer game development have been concerned to overcome entertainment objectives. In fact, there has been much effort aiming... Sample PDF
Human-Computer Interaction and Artificial Intelligence: Multidisciplinarity Aiming Game Accessibility
Chapter 12
Blaine Hoffman
The continued evolution of mobile technology provides for new means of interaction and engagement in our daily lives. The interconnectedness... Sample PDF
Mobile Gaming: Exploring Spaces and Places
Chapter 13
Henry H. Emurian, Gerald C. Canfield, Peter G. Roma, Zabecca S. Brinson, Eric D. Gasior, Robert D. Hienz, Steven R. Hursh, Joseph V. Brady
This chapter describes a Team Performance Task (TPT) that has been designed to assess the status of a three-person team operating a game-like... Sample PDF
A Multiplayer Team Performance Task: Design and Evaluation
Chapter 14
Patrick Stacey, Joe Nandhakumar
There is little research into the emotional dimension of creative industry personnel, such as computer game designers, and how emotions relate to... Sample PDF
Emotional Journeys in Game Design Teams
Chapter 15
Olga Albuquerque, Gillian Grace Moreira
Using questionnaires and interviews, the video-gaming habits of 136 youngsters, ranging from the ages of 9 to 15 years, were assessed, taking into... Sample PDF
The Contribution of Videogames to Anti-Social Attitudes and Behaviours amongst Youngsters
Chapter 16
Matthew Sharritt, R. Kelly Aune, Daniel D. Suthers
A qualitative case study of student game play is presented, describing how game player communication becomes increasingly complex, efficient, and... Sample PDF
Gamer Talk: Becoming Impenetrably Efficient
Chapter 17
Patrícia Arriaga, Augusta Gaspar, Francisco Esteves
This chapter intends to contribute to the clarification of the controversy surrounding the short-term effects of playing violent games [VG] on... Sample PDF
Playing with Violence: An Updated Review on the Effects of Playing Violent Electronic Games
Chapter 18
Julio Angel Ortiz
The chapter serves as an introduction to current thinking about the role of games in our society. It takes a measured tone in acknowledging some of... Sample PDF
Knowing the Game: A Review of Videogames and Entertainment Software in the United States - Trends and Future Research Opportunities
Chapter 19
Stephen Brock Schafer, Gino Yu
The development of more meaningful video games is becoming increasingly possible by recent advances in video game technologies, neurosciences, and... Sample PDF
Meaningful Video Games: Drama-Based Video Games as Transformational Experience
Chapter 20
Heiko Duin, Jannicke Baalsrud Hauge, Felix Hunecker, Klaus-Dieter Thoben
This chapter describes application areas for serious games in the context of such CNOs. A classification scheme for serious games has been developed... Sample PDF
Application of Serious Games in Industrial Contexts
Chapter 21
Juho Hamari, Aki Järvinen
The results provide several game mechanics that are located in the union of game design and business planning. Moreover, the results imply a new... Sample PDF
Building Customer Relationship through Game Mechanics in Social Games
Chapter 22
Games and Advertising  (pages 366-382)
Inês de Seixas Duarte, António Manuel Valente de Andrade
In this chapter we will review the state of the art in these areas and present some arguments for and against each of these strategies. Sample PDF
Games and Advertising
Chapter 23
Fernando Belfo
Computer games conceptualization and development are processes that have particular features with significant complexity. The life cycle at computer... Sample PDF
Business Process Management in the Computer Games Industry
Chapter 24
Martin Heitmann, Kay Tidten
Nowadays, managers in the computer and video gaming industry are forced to reevaluate their companies’ strategic position within the value-added... Sample PDF
New Business Models for the Computer Gaming Industry: Selling an Adventure
Chapter 25
Pluralistic Coordination  (pages 416-431)
Peter J. Denning, Fernando Flores, Gloria Flores
Two questions are examined. Why is coordination hard to achieve when teams are diverse? Are there conditions under which players of MMOGs can learn... Sample PDF
Pluralistic Coordination
Chapter 26
Danny Pannicke, Jonas Repschläger, Rüdiger Zarnekow
Virtual worlds enable new ways to create value. Recent examples from Second Life – a virtual world run by Linden Lab – have demonstrated how firms... Sample PDF
Business Opportunities in Social Virtual Worlds
Chapter 27
Kostas Anagnostou
In this chapter we review and discuss the impact of mass adoption of the Internet and its assorted technologies is having on the evolution of the... Sample PDF
How has the Internet Evolved the Videogame Medium?
Chapter 28
Pedro Pina
In the present chapter, the author briefly studies the particular tension between the current copyright paradigm, based on the dichotomy active... Sample PDF
Computer Games and Intellectual Property Law: Derivative Works, Copyright and Copyleft
Chapter 29
Peter J. Wasilko
This chapter introduces readers to a broad range of legal issues relevant to game designers and developers touching such topics as intellectual... Sample PDF
Law, Architecture, Gameplay, and Marketing
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