Open Research Online The Open University’s repository of research publications and other research outputs A Computational Model of Non-Cooperation in Natural Language Dialogue Thesis How to cite: Plüss, Brian (2014). A Computational Model of Non-Cooperation in Natural Language Dialogue. PhD thesis The Open University. For guidance on citations see FAQs. c 2014 Brian Plüss Version: Version of Record Link(s) to article on publisher’s website: http://dx.doi.org/doi:10.21954/ou.ro.00009d1c Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online’s data policy on reuse of materials please consult the policies page. oro.open.ac.uk A Computational Model of Non-Cooperation in Natural Language Dialogue Brian Pl¨uss Bachiller Universitario en Ciencias Exactas Licenciado en Ciencias de la Computaci´on Computing and Communications Department The Open University Athesissubmittedforthedegreeof Doctor of Philosophy September 2013 Abstract A common assumption in the study of conversation is that participants fully cooperate in order to maximise the effectiveness of the exchange and ensure communication flow. This assumption persists even in situations in which the private goals of the participants are at odds: they may act strategically pursuing their agendas, but will still adhere to a number of lin- guistic norms or conventions which are implicitly accepted by a community of language users. However, in naturally occurring dialogue participants often depart from such norms, for instance, by asking inappropriate questions, by avoiding to provide adequate answers or by volunteering information that is not relevant to the conversation. These are examples of what we call linguistic non- cooperation. This thesis presents a systematic investigation of linguistic non-coopera- tion in dialogue. Given a specific activity, in a specific cultural context and time, the method proceeds by making explicit which linguistic behaviours are appropriate. This results in a set of rules: the global dialogue game. Non-cooperation is then measured as instances in which the actions of the participants are not in accordance with these rules. The dialogue game is formally defined in terms of discourse obligations. These are actions that participants are expected to perform at a given point in the dialogue based on the dialogue history. In this context, non-cooperation amounts to parti- cipants failing to act according to their obligations. We propose a general definition of linguistic non-cooperation and give a specific instance for political interview dialogues. Based on the latter, we present an empirical method which involves a coding scheme for the manual annotation of interview transcripts. The degree to which each participant cooperates is automatically determined by contrasting the annotated tran- scripts with the rules in the dialogue game for political interviews. The ap- proach is evaluated on a corpus of broadcast political interviews and tested for correlation with human judgement on the same corpus. Further, we describe a model of conversational agents that incorporates the concepts and mechanisms above as part of their dialogue manager. This allows for the generation of conversations in which the agents exhibit varying degrees of cooperation by controlling how often they favour their private goals instead of discharging their discourse obligations. Acknowledgements These pages close a very long journey, the last part of which started in 2008 when I left Argentina and moved to Milton Keynes in the UK. I embarked on a PhD as a natural step in my education, but also as a personal challenge. And what a challenge it was! The experience was thrilling at times, but also extremely difficult. It would have been impossible to reach this point without an army of people that played essential roles in different and unique ways. To them I am deeply grateful and the following lines are my attempt to put this in writing. Still, words are nowhere nearly enough to communicate how important they have been over the years. First and foremost, I thank my supervisors, Paul Piwek and Richard Power, for their constant guidance, encouragement and understanding. They received a computer scientist with a formal background and a huge lack of knowledge in computational linguistics and took on the challenge to turn him into an independent researcher in an area that builds upon empirical evidence. Along the way, they coped with my Latin American manners and patiently taught me to listen to questions and suggestions before attempting a reply. They gave me enough freedom to do exactly the research project I wanted, but knew when to show me where I was going down potentially unfruitful paths. They taught me how to write, leaving \woolly generalisa- tions" for caf´etalks. I have immense respect for them and gratitude for the time they have invested in me. I hope to do them justice in the next stages of my academic and professional life. The Open University is a great environment to study and work. Its unique mission of spreading higher education to \all who wish to realise their ambitions and fulfil their potential" is beautiful and hugely necessary. It fills me with pride to be part of this institution. I am thankful to the Faculty of Mathematics, Computing and Technology for funding my studies, especially into the initially unplanned fourth year. Many academics in the Department of Computing and Communications played an essential role in my progress. Marian Petre and Robin Laney dedicated much time and effort in teaching me and my colleagues how to do good research. I thank Marian for having taken an exaggerate amount of time to push me forward when the task ahead looked impossible. Also Michel Wermelinger, Leonor Barroca, Anne De Roeck and Alistair Willis helped at different stages along the way. I am thankful to Hugh Robinson who \grilled" me the first time I presented my research, with questions that ultimately shaped the project to a great extent. The members, past and present, of the Natural Language Generation group were \home", academically speaking, and provided a safe environment where I could present my often unpolished ideas. They are Donia Scott, Sandra Williams, Svetlana Stoyanchev, Allan Third, Eva Banik, Richard Doust, Sharon Moyo and Tu Anh Nguyen. Half-way through my studies, I was immensely lucky to take part in a summer internship at the University of Southern California's Institute for Creative Technologies. Working under the supervision of David DeVault, with David Traum and the rest of the Natural Language Dialogue Group, was an excellent opportunity, professionally and also personally. I also thank David DeVault, David Traum, Ron Artstein and Kalliroi Georgila for illu- minating discussions of my own research. Milton Keynes would not have been the happy memory it is today without my dear friends, who would turn any city into the best place to be. I thank Bethany for her constant company during the first three years while we shared 36 Warren Bank. She turned an otherwise uneventful flat into a fairground full of excitement and endless fun, as we built a unique connection that will last for the rest of our lives. I thank Koula and Jo for being the other two legs of that sturdy table of friendship and mutual under- standing. It is impossible for me to name everyone else in the Milton Keynes gang without forgetting someone. I implicitly and wholeheartedly thank all of them and here attempt a necessarily incomplete list: Sam, Dave, Lionel, Andr´es,Katarina, Davey, Paul W, Ben R, Ben D, Marc, Andy C, Andy M, Adam, Miriam, Jakub, Dinar, Giorgos, Mariano, Lucas, Stephen, Minh, Tu Anh, Laura, Stefan, Macarena, Joan, Lana, Alexandra, Nadia, Jen, Anna, Carlos, Sally, Eva, Alba, Thomas, Saad, Vanessa, Philippe, Liliana, Carmen, Rob, Beck, Amanda, Zdenek, Mic, Carolyn. And Paul T. I also thank those friends elsewhere in the UK: Alejandra, Leandro, Ros, Duncan, Charlie, Andy, Sergio, Santiago, Tasha and Kirsty. And those around the world: Ana, J~oao,Tiago, Cristina, Francisca, Fernando, Pablo and Luis in Portugal; Quitterie, Jano and Nache in France; Abdul, Matias, Virpa, Peikko and Em in Finland; Aly and Rachel in the US; Dami´anand Mercedes in Italy; and about a thousand in Argentina. I am thankful to Maxi, my teacher and friend, for opening so many doors and for recent collaborations which will hopefully continue for years to come. I thank those who opened their homes and provided a safe haven for me to work during the long writing up stage: Bethany and Dave, Miriam and Jakub, Alejandra and Leandro, Laura and Luciano, Chicho and Silvina. Diego not only opened his home, but also allowed for a profound connection that has been essential all along, especially in turbulent times. Over the years and despite the ocean in between, Dani remained that soulmate I can go to, whatever the matter and without fear of judgement or incomprehension. Dermot showed up right before things started to get complicated and walked with me through the hardest last two years. Without his company, understanding and support { in every imaginable way { I would have cer- tainly failed. A lifetime will not be enough to pay back his immense effort. And finally, I need to thank my beloved family. My parents, Gabriel and Graziela, endured the distance and were there whenever I needed them, without necessarily understanding what I was working on and why I was a student well into my thirties. I thank my brother, Alan, the architect and traveller who in these years grew up into a man with an amazingly wise and soothing approach to life. My grandmother, Raquel, endless in her wisdom, has been my life coach for as many years as I can remember.