Beyond the Dyad: The Role of Groups and Third-Parties in the Trajectory of Violence Submitted by Richard Philpot to the University of Exeter as a thesis for the degree of Doctor of Philosophy in Psychology in June 2017 This thesis is available for Library use on the understanding that it is copyright material and that no quotation from the thesis may be published without proper acknowledgement. I certify that all material in this thesis which is not my own work has been identified and that no material has previously been submitted and approved for the award of a degree by this or any other University. Signature: …………………………………. Acknowledgements This thesis is dedicated to those who have provided invaluable support, guidance, and motivation towards its development over the past three (and a one-third) years. However, prior to first panting up the Washington Singer mound (perhaps indicative of the incremental pressures to come), I had already a lot to be thankful for. I am indebted to my parents, Kevin and Linda, for their self-sacrifice to provide my sisters and I with the opportunities that they themselves truly deserve. I am sincerely grateful for the unconditional love of my two beloved children, Yena and Teeuw, both of whom motivate me in every productive thing I do. I am eternally indebted to my brilliant wife Leah, not only for her unwavering support throughout my postgraduate pursuits but also for her incalculable sacrifices. To be willing to move away from her family and invest all of our post-marital savings, just so I can wake up every day and enjoy my work—I am truly blessed. I also thank my parents-in-law, Gilbert and Sunny, for always believing in me, and for always worrying about my weight and wellbeing. I would like to express my gratitude to my previous MSc supervisor Steve Reicher, who convinced me not to settle for any postgraduate job but to follow my academic interests. Here in Exeter, I wholeheartedly thank my three supervisors Mark, Miriam, and Richard—without whom none of this thesis would exist. I sincerely thank Mark Levine, not only for his remarkable academic support but also for his contagious relaxant properties. I would also like to thank Mark for giving me confidence as a developing researcher, and for providing numerous opportunities to meet interesting new people. Similar, profound gratitude goes to Miriam Koschate-Reis, for her gentle rigorousness and for always encouraging me to be critical of my own work and that of others. I express sincere thanks to Richard Everson, who not only survived three years in a room with three psychologists (something that sounds like a bad joke) but who also had incredible patience guiding me through the mathematical and computational modelling aspects of this project. These three luminaries delivered the perfect measures of inspiration, challenge and good humour—I will truly miss our meetings together. I would also like to take the opportunity to thank the University of Exeter Psychology department, and the SEORG research group, for providing me with a comfortable and stimulating working environment in which to conduct my research. I would like to extend a huge thank you to Karen Swanston for always being so friendly and helpful (and for providing me with the information no one else seems to know). I am also hugely appreciative to Rachel Arthur, for sharing her expertise in visual data analysis, and for being an interrater for this research project. I am grateful to Lancaster City Council and Barrow Borough Council for providing the CCTV footage that made so much of this empirical work possible. Thank you also to Lasse Liebst, Marie Rosenkrantz Lindegaard, Wim Bernasco, Don Weenink, Kim Møller, and all other members of the Interactionist Analyses of Violence Workgroup, for all of their valuable feedback on my research. I am grateful to the Engineering and Physical Sciences Research Council for financially supporting this research and its dissemination. Throughout the PhD process, I have appreciated the camaraderie and friendship of the South Tower Crew. Therefore, I would like to extend my warmest thanks to Denise, Felicity, Matt, Melika, Merve, Modi, (lots of M’s), Natasha and Tina. Tina Lina Agnes Frieda Keil (yes all just one person), you honestly need an entire page of dedication! Not only because your name is unusually long, but because you are an unusually wonderful person. You have been a true friend, my best friend, and you are a selfless angel—what would I do without you?... drink less coffee probably. This thesis would not have been possible without all of the remarkable support, from all of these remarkable people, and for this, I will always be grateful. Dedicated to my little Kimpots Abstract Episodes of aggression and violence continue to beset our public spaces. This thesis explores how well we understand the transition to violence—and how aggression and violence in public spaces can be managed or controlled. We begin by arguing that established social psychological approaches to aggression and violence are inadequate for the task. Existing models explain violence through the failure of individuals to inhibit their own impulses or control their own emotions sufficiently. At best the models allow for the importance of dyadic interactions as individuals provoke each other as part of an escalation cycle. We argue that public space aggression and violence involves multiple parties and more complex sets of social dynamics. We suggest that, at the very least, the roles of third-parties and social categories need to be at the heart of theorising about violence in public spaces. To support our arguments, we examined violence directly through detailed behavioural microanalyses of real-life aggressive incidents captured on CCTV footage. We also built agent-based models (ABM) to explore different theoretical approaches to the impact of groups and third-parties on aggression and violence. The thesis contains seven studies. We begin with a CCTV behavioural microanalysis (Study 1) that showed collective group self-regulation of aggressive and violent behaviour in both within- and between-group conflicts. This study demonstrated an ‘intergroup hostility bias’, showing a greater likelihood of aggressive, escalatory acts towards outgroup members in intergroup conflicts than towards ingroup members in intragroup conflicts. Furthermore, this study demonstrated an ‘intragroup de-escalatory bias’, showing a greater likelihood of peace-making, de-escalatory behaviours towards ingroup members in intragroup conflicts than towards outgroup members in intergroup conflicts. Overall, we found that the majority of coded actions were acts of de-escalation performed by third-parties. With evidence stressing the importance of social dynamics, we compared dyadic models of aggression against an alternative social model (which allowed normative influence of others) in a dynamic agent-based modelling environment. We modelled the dynamics of metacontrast group formation (Studies 2 and 3), and found that group processes can produce both escalation of violence and inhibition of violence (Study 4). We found greater polarisation of violent positions in intergroup interactions than in intragroup interactions (Studies 5a and 5b). However, an emergent intergroup hostility bias did not emerge from this polarisation process. In Study 6, we re-examined the intergroup hostility bias present in our CCTV footage. We found an intergroup hostility bias for non-physical escalatory acts but not for physical escalatory acts. We examined the standardised number of actions contributed by third-parties and assessed the relationship between specific third-party conflict management strategies (policers and pacifiers) and conflict violence severity (Study 7). Overall, our results showed that third-parties and groups are integral features of the dynamics of violence. Third-parties largely attempt to de-escalate conflict, and the conflict management strategy they employ has a direct relationship to the violent outcome. Groups have a tendency to de-escalate their own members, and self-policing and collective inhibition take place. These findings have importance for current models of aggression and violence and also for evidence-based violence reduction initiatives. Table of Contents Acknowledgements ................................................................................................................... ii Abstract ..................................................................................................................................... v List of Tables ............................................................................................................................ xi List of Figures ......................................................................................................................... xii Thesis Aims and Overview ..................................................................................................... 14 1 Literature Review .............................................................................................................. 19 1.1 Definitions of Aggression and Violence ....................................................................... 20 1.1.1 Aggression as a Construct ................................................................................. 20 1.1.2 Violence as a Physical Representation of Extreme Aggression ........................ 22 1.1.3 Social Psychological Explanations of Aggression and Violence—The Individual Balance