Relational Agents: Effecting Change Through Human-Computer Relationships
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Relational Agents: Effecting Change through Human-Computer Relationships by Timothy Wallace Bickmore Master of Science, Computer Science, Arizona State University, 1986 Bachelor of Science and Engineering, Computer Systems Engineering Arizona State University, 1985 Submitted to the Program in Media Arts and Sciences, School of Architecture and Planning, In partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology February 2003 © 2003 Massachusetts Institute of Technology, All rights reserved. Author January 31st, 2003 Certified by Rosalind W. Picard Associate Professor of Media Arts and Sciences Thesis Supervisor Certified by Justine Cassell Associate Professor of Media Arts and Sciences Thesis Supervisor Accepted by Andrew B. Lippman Chairperson, Departmental Committee on Graduate Students 2 Relational Agents: Effecting Change through Human-Computer Relationships by Timothy Wallace Bickmore Submitted to the Program in Media Arts and Sciences, School of Architecture and Planning, In partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology Abstract What kinds of social relationships can people have with computers? Are there activities that computers can engage in that actively draw people into relationships with them? What are the potential benefits to the people who participate in these human-computer relationships? To address these questions this work introduces a theory of Relational Agents, which are computational artifacts designed to build and maintain long-term, social-emotional relationships with their users. These can be purely software humanoid animated agents--as developed in this work--but they can also be non-humanoid or embodied in various physical forms, from robots, to pets, to jewelry, clothing, hand-helds, and other interactive devices. Central to the notion of relationship is that it is a persistent construct, spanning multiple interactions; thus, Relational Agents are explicitly designed to remember past history and manage future expectations in their interactions with users. Finally, relationships are fundamentally social and emotional, and detailed knowledge of human social psychology--with a particular emphasis on the role of affect--must be incorporated into these agents if they are to effectively leverage the mechanisms of human social cognition in order to build relationships in the most natural manner possible. People build relationships primarily through the use of language, and primarily within the context of face-to-face conversation. Embodied Conversational Agents--anthropomorphic computer characters that emulate the experience of face-to-face conversation--thus provide the substrate for this work, and so the relational activities provided by the theory will primarily be specific types of verbal and nonverbal conversational behaviors used by people to negotiate and maintain relationships. This work also provides an analysis of the types of applications in which having a human-computer relationship is advantageous to the human participant. In addition to applications in which the relationship is an end in itself (e.g., in entertainment systems), human-computer relationships are important in tasks in which the human is attempting to undergo some change in behavior or cognitive or emotional state. One such application is explored here: a system for assisting the user through a month-long health behavior change program in the area of exercise adoption. This application involves the research, design and implementation of relational agents as well as empirical evaluation of their ability to build relationships and effect change over a series of interactions with users. Thesis Supervisors: Rosalind W. Picard, Associate Professor of Media Arts and Sciences Justine Cassell, Associate Professor of Media Arts and Sciences 3 4 Doctoral Dissertation Committee Thesis Co-Advisor Rosalind W. Picard, Sc.D. Associate Professor of Media Arts and Sciences M.I.T. Program in Media Arts and Sciences Thesis Co-Advisor Justine Cassell, Ph.D. Associate Professor of Media Arts and Sciences M.I.T. Program in Media Arts and Sciences Thesis Reader Amanda J. Gruber, M.D. Assistant Professor of Psychiatry Harvard Medical School Thesis Reader Candace L. Sidner, Ph.D. Senior Research Scientist Mitsubishi Electric Research Laboratory January 2003 5 6 Acknowledgements Thanks, first and foremost, to a wonderfully supportive and helpful committee. Roz provided the initial inspiration that led me into the field of health behavior change, and I could not have pulled this project off without her having supported my work through to its completion. My discussions with Candy--ranging from philosophy to linguistics to artificial intelligence--were always insightful, and it has been a real pleasure to interact with someone who cares deeply about both theoretical issues and building useful systems. Amanda gave generously of her time and knowledge, even before I asked her to serve on my committee, and provided me with the crucial knowledge of how various therapeutic approaches to change are applied in a clinical setting. Justine taught me to look at human behavior in a whole new way. Thanks also to behavior change researchers at the Cancer Prevention Research Center at the University of Rhode Island, especially Wayne Velicer who helped me develop the experimental design for the behavior change study. Bryan Blissmer and Deb Riebe gave me essential tips and feedback on how to structure an exercise adoption study. My work was supported by the many wonderful sponsors of the MIT Media Lab and NSF ROLE grant REC-0087768. Development of the FitTrack system and study was a huge undertaking, involving lots of people over the year or so it was in development. Ian Gouldstone was designer and animator extraordinaire, who designed the characters used in the system, and consulted on various aspects of the system's design. Marlisa Febbriello of the Health Education department at MIT Medical provided invaluable help in developing the educational content used in the system. Julie Stalma and Dorri Lee were the exercise trainers who acted as role models for the exercise advisor character. Laura Packer wrote many of the exercise stories used in the system. Nancy Alvarado of IBM Research provided useful feedback on the facial expressions used by the character. Anna Pandolfo did most of the subject intake interviews, and provided feedback on various aspects of the experimental design. Sherry Turkle provided great suggestions for the qualitative interviews done at the end of the study. Dan Ariely provided invaluable feedback on the statistical analysis of data from the study. Noah Fields and Jeannie Finks of the Media Lab's NeCSys group provided many helpful suggestions and software and support for the web server and relational database used in the study. Karen Liu helped design some of the empathy dialogue networks in the system. Jonathan Klein provided lots of useful feedback on the system design. Thanks to Mindy Chang, Chris Cary and Temitope Sibun-- undergraduate researchers--who put many pieces of the system in place over the Summer of 2002, and to Tom Stocky for patiently tutoring them. And, thanks to the one hundred-plus study participants who proved that it was all worthwhile. The REA small talk study also involved a number of other people, including all the past developers of the REA system (notably Hannes Vilhjálmsson, Lee Campbell and Hao Yan), and folks who contributed to the design, implementation and execution of parts of the experiment, including Jennifer Smith, Elisabeth Sylvan, and Ian Gouldstone (as the "wizard"). Thanks to Linda Peterson and Pat Solakoff for essential advice on the mechanics of the Ph.D. program, and for their support through turbulent times. A warm thanks to my work buddies and moral support network for the last four-and-a- half years, Hannes Vilhjálmsson and Kimiko Ryokai. Thanks also for the support and 7 feedback from past and current members of the Gesture and Narrative Language and Affective Computing groups at the Media Lab. Thanks to my family for pretending to understand why I came back to school after a decade in industry, and to my girls, Katie and Olivia, for giving up their father during my time at MIT. Finally, my deepest gratitude goes to my partner Jennifer, who provided the emotional and social support I needed to get through this. Not only did she keep me sane during this time, but she played a substantial role as sounding board and proof-reader, and implemented and tested a significant portion of the FitTrack dialogue networks and other parts of the system. 8 Table of Contents Abstract..................................................................................................................................3 Doctoral Dissertation Committee........................................................................................5 Acknowledgements ...............................................................................................................7 Table of Contents..................................................................................................................9 Chapter 1. INTRODUCTION ...........................................................................................15 1.1 Motivation: The Importance of Personal Relationships ...........................................15 1.2 Relational Agents......................................................................................................17