Examensarbete LITH-ITN-MT-EX--07/032--SE EMO - A Computational Emotional State Module. Emotions and their influence on the behaviour of autonomous agents Jimmy Esbjörnsson 2007-05-28 Department of Science and Technology Institutionen för teknik och naturvetenskap Linköpings Universitet Linköpings Universitet SE-601 74 Norrköping, Sweden 601 74 Norrköping LITH-ITN-MT-EX--07/032--SE EMO - A Computational Emotional State Module. Emotions and their influence on the behaviour of autonomous agents Examensarbete utfört i medieteknik vid Linköpings Tekniska Högskola, Campus Norrköping Jimmy Esbjörnsson Handledare Pierangelo Dell'Acqua Examinator Pierangelo Dell'Acqua Norrköping 2007-05-28 Datum Avdelning, Institution Date Division, Department Institutionen för teknik och naturvetenskap 2007-05-28 Department of Science and Technology Språk Rapporttyp ISBN Language Report category _____________________________________________________ Svenska/Swedish Examensarbete ISRN LITH-ITN-MT-EX--07/032--SE x Engelska/English B-uppsats _________________________________________________________________ C-uppsats Serietitel och serienummer ISSN x D-uppsats Title of series, numbering ___________________________________ _ ________________ _ ________________ URL för elektronisk version Titel Title EMO - A Computational Emotional State Module. Emotions and their influence on the behaviour of autonomous agents Författare Author Jimmy Esbjörnsson Sammanfattning Abstract Artificial intelligence (AI) is already a fundamental component of computer games. In this context is emotions a growing part in simulating real life. The proposed emotional state module, provides a way for the game agents to select an action in real-time virtual environments. The modules function has been tested with the open-source strategy game ORTS. This thesis proposes a new approach for the design of an interacting network, similar to a spreading activation system (Maes, 1991), of emotional states that keeps track of emotion intensities changing and interacting over time. The network of emotions can represent any number of persisting states, such as moods, emotions and drives. Any emotional signal can affect every state positively or negatively. The states' response to emotional signals are influenced by the other states represented in the network. The network is contained within an emotional state module. This interactions between emotions are not the focus of much research, neither is the representation model. The focus tend to be on the mechanisms eliciting emotions and on how to express the emotions. Nyckelord Keyword artificial intelligence (AI), emotions, feelings, mood, sigmoid function, response curve, behaviour, autonomous agents, real-time strategy game (RTS), open real-time strategy (0RTS) Upphovsrätt Detta dokument hålls tillgängligt på Internet – eller dess framtida ersättare – under en längre tid från publiceringsdatum under förutsättning att inga extra- ordinära omständigheter uppstår. Tillgång till dokumentet innebär tillstånd för var och en att läsa, ladda ner, skriva ut enstaka kopior för enskilt bruk och att använda det oförändrat för ickekommersiell forskning och för undervisning. Överföring av upphovsrätten vid en senare tidpunkt kan inte upphäva detta tillstånd. 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For additional information about the Linköping University Electronic Press and its procedures for publication and for assurance of document integrity, please refer to its WWW home page: http://www.ep.liu.se/ © Jimmy Esbjörnsson EMO - A Computational Emotional State Module Emotions and their influence on the behaviour of autonomous agents Jimmy Esbjörnsson VITA - Visual Information Technology and Applications Linköping University [email protected] Abstract Artificial intelligence (AI) is already a fundamental component of computer games. In this context is emotions a growing part in simulating real life. The proposed emotional state module, provides a way for the game agents to select an action in real-time virtual environments. The modules function has been tested with the open-source strategy game ORTS. Extensive research work on the subject of emotions is available in literature, and different models of emotional systems are debated. The material have been reviewed the material and a model have been constructed based on psychological studies by Picard, Minsky, Pinker and others. Especially the work of Picard has been very influential. This thesis proposes a new approach for the design of an interacting network, similar to a spreading activation system (Maes, 1991), of emotional states that keeps track of emotion intensities changing and interacting over time. The network of emotions can represent any number of persisting states, such as moods, emotions and drives. Any emotional signal can affect every state positively or negatively. The states© response to emotional signals are influenced by the other states represented in the network. The network is contained within an emotional state module. This interactions between emotions are not the focus of much research, neither is the representation model. The focus tend to be on the mechanisms eliciting emotions and on how to express the emotions. Key words: artificial intelligence (AI), emotions, feelings, mood, sigmoid function, response curve, behaviour, autonomous agents, real-time strategy game (RTS), open real-time strategy (ORTS) Table of Contents Glossary.....................................................................................................................................................1 1 Introduction............................................................................................................................................3 1.1 Preface............................................................................................................................................3 1.2 Audience.........................................................................................................................................4 1.3 Overview and Goals.......................................................................................................................4 1.4 Achievements.................................................................................................................................4 1.5 Acknowledgements........................................................................................................................5 2 The Concept of Emotions .....................................................................................................................7 2.1 A brain to simulate.........................................................................................................................7 2.2 Emotional genes.............................................................................................................................8 2.3 The purpose of emotions.............................................................................................................11 2.4 Why machines need emotions.....................................................................................................14 2.5 The classification of emotions and feelings................................................................................16 2.6 Basic Emotions............................................................................................................................17 2.7 Appraisal Theory.........................................................................................................................18 The OCC Model........................................................................................................................19 The Roseman Model.................................................................................................................19 2.8 Temperament and Mood..............................................................................................................20 2.9 Models with Multiple Emotion Layers........................................................................................21