Characterising Action Potential in Virtual Game Worlds Applied with the Mind Module

Characterising Action Potential in Virtual Game Worlds Applied With the Mind Module Mirjam Palosaari Eladhari A thesis submitted in partial fulfilment of the requirements of the University of Teesside for the degree of Doctor of Philosophy. This research programme was carried out at and with the support of Högskolan på Gotland (Gotland University) Characterising Action Potential in Virtual Game Worlds Applied With the Mind Module Mirjam Palosaari Eladhari Gotland University Press 6 Author: Mirjam Palosaari Eladhari Publisher: Gotland University Press 2011 Address: Gotland University S-62156 Visby Web: www.hgo.se Phone: +46(0)498-29 99 00 ISSN: 1653-7424 ISBN: 978-91-86343-02-6 Editorial committee: Åke Sandström and Lena Wikström Cover: Daniel Olsson and Lena Wikström Cover illustrations: Back: Mirjam P Eladhari after details in the triptych The Garden of Earthly Delights (~1500) painted by Hieronymus Bosch. Front: The illustration The Philosophical Brain first appeared in the book ”Utriusque cosmi maioris scilicet et minores metaphysica, physica atque technica historia” (1617) by Robert Fludd, Illustrated by Matthieu Merian. Declaration While registered as a candidate for the degree of Doctor of Philosophy the author has not been registered for any other award with any other university or institution. No part of the material in this thesis has been submitted for any degree or other qualification at any other institution by the author or, to the best of her knowledge and belief, by any other person. The thesis describes the author’s original work. Other persons assisted in transcribing interviews, conducting experiments and proof reading. ii Abstract Because games set in persistent virtual game worlds (VGWs) have massive numbers of players, these games need methods of characterisation for playable characters (PCs) that differ from the methods used in traditional narrative media. VGWs have a number of particularly interesting qualities. Firstly, VGWs are places where players interact with and create elements carrying narrative potential. Secondly, players add goals, motives and driving forces to the narrative potential of a VGW, which sometimes originates from the ordinary world. Thirdly, the protagonists of the world are real people, and when acting in the world their characterisation is not carried out by an author, but expressed by players characterising their PCs. How they can express themselves in ways that characterise them depend on what they can do, and how they can do it, and this characterising action potential (CAP) is defined by the game design of particular VGWs. In this thesis, two main questions are explored. Firstly, how can CAP be designed to support players in expressing consistent characters in VGWs? Secondly, how can VGWs support role-play in their rule-systems? By using iterative design, I explore the design space of CAP by building a semiautonomous agent structure, the Mind Module (MM) and apply it in five experimental prototypes where the design of CAP and other game features is derived from the MM. The term semiautonomy is used because iii the agent structure is designed to be used by a PC, and is thus partly controlled by the system and partly by the player. The MM models a PC’s personality as a collection of traits, maintains dynamic emotional state as a function of interactions with objects in the environment, and summarises a PC’s current emotional state in terms of ‘mood’. The MM consists of a spreading-activation network of affect nodes that are interconnected by weighted relationships. There are four types of affect node: personality trait nodes, emotion nodes, mood nodes, and sentiment nodes. The values of the nodes defining the personality traits of characters govern an individual PC’s state of mind through these weighted relationships, resulting in values characterising for a PC’s personality. The sentiment nodes constitute emotionally valenced connections between entities. For example, a PC can ‘feel’ anger toward another PC. This thesis also describes a guided paper-prototype play-test of the VGW prototype World of Minds, in which the game mechanics build upon the MM’s model of personality and emotion. In a case study of AI-based game design, lessons learned from the test are presented. The participants in the test were able to form and com- municate mental models of the MM and game mechanics, validating the design and giving valuable feedback for further development. Despite the constrained scenarios presented to test players, they discovered interesting, alternative strategies, indicating that for game design the ‘mental physics’ of the MM may open up new possibilities. The results of the play-test influenced the further development of the MM as it was used in the digital VGW prototype the Pataphysic Institute. In the Pataphysic Institute the CAP of PCs is largely governed by their mood. Depending on which mood PCs are in they can cast different ‘spells’, which affect values such as mental iv energy, resistance and emotion in their targets. The mood also governs which ‘affective actions’ they can perform toward other PCs and what affective actions they are receptive to. By performing affective actions on each other PCs can affect each others’ emotions, which - if they are strong - may result in sentiments toward each other. PCs’ personalities govern the individual fluctuations of mood and emotions, and define which types of spell PCs can cast. Formalised social relationships such as friendships affect CAP, giving players more energy, resistance, and other benefits. PCs’ states of mind are reflected in the VGW in the form of physical manifestations that emerge if an emotion is very strong. These manifestations are entities which cast different spells on PCs in close proximity, depending on the emotions that the manifestations represent. PCs can also partake in authoring manifestations that be- come part of the world and the game-play in it. In the Pataphysic Institute potential story structures are governed by the relations the sentiment nodes constitute between entities. v Acknowledgements I would like to thank my supervisors, Clive Fencott, Paul Van Schaik and Michael Mateas, for their support and advice during the work presented in this thesis. I am greatly indebted to Paul for the substantial time and energy he has spent in giving me clear advice regarding the write-up, organisation and content of this thesis, and even suggestions of phrasings. I would like to give Michael special thanks for welcoming me as a visiting scholar, both at the Emergent Game Group of Georgia Institute of Technology in 2005 and at the Expressive Intelligence Studio of University of California Santa Cruz in 2008 and 2009. I also want to thank professor Nakajima who welcomed me in his laboratory at Tokyo Institute of Technology in 2006. These periods as visiting scholar were important for inspiration, perspective and for further directions in the work. I also want to thank everyone I learned to know in these studios — I have felt so welcome. My deep gratitude goes to my home university, Gotland University, and all my colleagues at the department of game development. I especially want to thank my colleague and friend Jenny Brusk for her continuous support and for lifting my spirits during this whole time. I am also especially grateful to Steven Bachelder and Don Geyer who have organised such a creative and dynamic working environment. I want to thank everyone who I have co-operated with in realising the prototypes vi described in this thesis. It was in the inspiring discussions in the Zero Game studio and the in the challenges involved in the development of the prototype Ouroboros that the first seeds to this thesis were sowed. I would like to thank everyone in the MMRO work-package of the IPeRG project who took part in the development and testing of the prototype Garden of Earthly Delights. Very special thanks go to Elina Ollila (formerly Koivisto) who taught me a lot about methods for testing game prototypes, and to Rik Nieuwdorp for the music he composed for the Mind Music prototype. Regarding the development of the Pataphysic Institute prototype I am eternally grateful to Christoph Pech who programmed, to Ola Persson who created the graphics, and to Musse Dolk who did level-design and various other things in the project. I also want to thank everyone who has participated in the play tests of the prototypes. I am grateful to those in the game industry who have given me advice in game design related issues, many of who I met at Project Horseshoe in 2007 and 2008, such as Mike Sellers who I ended up co-authoring a paper with. I would like to specially thank Sam Lewis who, since 2005, has saved me from a number of design-related pit-falls when I was developing the later prototypes. I would like to thank Svenska Spel who funded research in the field of games at Gotland University between 2004 and 2006. I am also grateful to the Sweden-Japan Foundation who supported the period that I was a visiting scholar at Tokyo Institute of Technology, and to Kungliga Ingeniörsvetenskaps Akademien (IVA, Royal Swedish Academy of Engineering Sciences) for supporting the period as visiting scholar at University of California of Santa Cruz. Close friends and family, thank you for being there and for accepting silences and vii absences. Special thanks to my friend Lena Wikström for being my family on Gotland. The biggest thanks of all go to my husband, who makes everything worthwhile. viii Abbreviations AA Affective Action AOE Area of Effect

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