THE UNIVERSITY OF SOUTHERN QUEENSLAND THE SYNTHESIS OF EMOTIONS IN ARTIFICIAL INTELLIGENCES: An Affective Agent Architecture for Intuitive Reasoning in Artificial Intelligences A Dissertation submitted by Penny Baillie, B.Info.Tech. (USQ) For the award of Doctor of Philosophy 2002 Abstract This dissertation addresses several highly-critical issues in affective computing and agent architecture design including knowledge representation, motivation, emotion appraisal and affective decision making. The approach presented integrates motivational drives, goals and associated behaviours via a multi-dimensional Affective Space. The research focuses on an emotionally motivated artificial intelligence (EMAI) architecture. This architecture dispenses with the ideas implemented in contemporary affective agent architectures where individual emotional states are modelled as individual variables, integrated and processed using complex algorithms. Contemporary approaches required significant programming effort to modify them for domains outside their realm, integration of new emotional states and high-level complex affective decision making. Unlike contemporary affective agent architectures, the EMAI architecture reasons using a multi-dimensional decision making process where emotional states are modelled as coexisting locations in a six-dimensional affective continuum called the Affective Space. Through use of the Affective Space, an EMAI agent can predict the effect that certain behaviours will have on its emotional state and in turn decide how to behave. Furthermore, the agent can use the emotions produced from its behaviour to update its beliefs about particular events and entities. The nature of the Affective Space also allows an EMAI agent to deal with processes related to emotion synthesis in a more effective manner than contemporary architectures. These processes include the natural diminishing of an emotional state’s strength over time, the way in which emotions can influence an agent’s perspective of a situation and the way in which an agent can migrate from one emotional state to another. This dissertation contributes crucial and unique concepts and formalisations of emotion based intelligence for agent construction to the domain of Artificial Intelligence (in particular Affective Computing). It introduces a unique process for emotionally motivated decision making based on holistic and atomic appraisals made with respect to events. The thesis contained within has been supported through experimentation that has confirmed the effectiveness of the emotion synthesis technique in the EMAI architecture and how this is used to produce intelligent agents capable of emotional reasoning and decision making. i Certification of Dissertation I certify the ideas, experimental work, results, analyses, software and conclusions reported in this dissertation are entirely my own effort, except where otherwise acknowledged. I also certify the work is original and has not been previously submitted for any other award, except where otherwise acknowledged. __________________________________ _____________________ Signature of Candidate Date ENDORSEMENT ___________________________________ ______________________ Signature of Supervisor/s Date ii Acknowledgments I would like to take this opportunity to thank those people who have influenced me the most during the past six years of my Ph.D. studies. Foremost, I would like to thank Dr Dickson Lukose who has been there from the very beginning. At different times during the course of my studies, I had five supervisors. Many of them moved to other Universities making it difficult for them to continue their associations with my research. Although Dr. Lukose moved overseas and was no longer my principal supervisor he has continued to be an inspiration and continual mentor over the entire duration of my studies, in the capacity of Associate Supervisor. The best advice that he gave me was on day one when he said, “Start writing now. Don’t wait until the end!” Because of this, most of the work presented herein has already been published in numerous international conference proceedings, a journal and a book. I hope that I can pass this advice on someday. Dickson, I do not know how I can show my gratitude. Secondly, I would like to thank my current principal supervisor, Dr. Mark Toleman. As I had already completed a significant amount of research when I met up with Mark, I believe that he was not initially convinced that artificial intelligences should exhibit emotions. Now, I believe he is a true advocate for the affective computing domain. He has provided me with invaluable advise and support over the past two years. I know that our numerous debates and discussions about this research have helped me to develop a deeper understanding of the topic. Mark, my sincere thanks for your encouragement. I couldn’t have finished this without you. Next, I would like to thank my Mum, Dad and my brothers Tim and Craig. I know they have believed in me from the very beginning. Thank-you so much for being there through the ups and downs of the past six years. Special thanks must go to Daniel and Deefa who have never known me to be without Ph.D. study. Without them, I do not believe I would have had the motivation to make it this far. I cannot express in words the emotional support and strength that I acquire from you. LYVM And finally, to the late Gene Roddenberry, thank-you for the inspiration! iii Table of Contents CERTIFICATION OF DISSERTATION ............................................................................II LIST OF FIGURES ..........................................................................................................VIII LIST OF TABLES ...............................................................................................................XI 1. INTRODUCTION............................................................................................................1 1.1 THE ULTIMATE PUZZLE ..................................................................................................1 1.2 A NEED FOR EMOTIONAL COMPUTERS ............................................................................4 1.3 PERCEIVED SHORTFALLS OF CONTEMPORARY RESEARCH IN AFFECTIVE COMPUTING .......5 1.4 STRUCTURE OF THE DISSERTATION .................................................................................7 1.5 CASE STUDIES AND IMPLEMENTATION OF PROTOTYPES .......................................................9 2. ARTIFICIAL INTELLIGENCE AND EMOTIONS..................................................... 11 2.1 A MISSING PIECE OF THE PUZZLE ................................................................................. 11 2.2 A DEFINITION OF EMOTIONS ........................................................................................ 12 2.2.1 The Physiology of Emotion.................................................................................... 13 2.2.2 The Molecules of Emotion ..................................................................................... 16 2.2.3 Cognitive Theories of Emotion............................................................................... 18 2.2.4 Understanding the Chaos ...................................................................................... 20 2.3 AFFECTIVE COMPUTING ............................................................................................... 22 2.3.1 Emotional Behaviour............................................................................................ 23 2.3.2 Fast Primary Emotions.......................................................................................... 24 2.3.3 Emotional Experience ........................................................................................... 26 2.3.4 Body-Mind Interactions......................................................................................... 26 2.3.5 Cognitively Generated Emotions............................................................................ 27 2.4 AFFECTIVE AGENT ARCHITECTURES............................................................................ 28 2.4.1 Blumberg’s Silas T. Dog........................................................................................ 29 2.4.2 PETEEI (A PET with Evolving Emotional Intelligence).......................................... 30 2.4.3 Emotion Based Control (EBC) Framework for Autonomous Agent......................... 31 2.4.4 Minsky’s Commonsense Agent............................................................................... 32 2.5 SUMMARY .................................................................................................................. 33 3. EMOTIONALLY MOTIVATED ARTIFICIAL INTELLIGENCE............................. 34 3.1 INTRODUCTION ............................................................................................................. 34 3.2 OVERVIEW OF THE EMAI ARCHITECTURE ..................................................................... 34 3.3 THE KNOWLEDGE AREA................................................................................................ 37 3.3.1 Ontology............................................................................................................... 37 3.3.2 Motivational Drive Generator ............................................................................... 37 iv 3.3.3 Sensory Processor................................................................................................. 39 3.3.4 Emotional State and