The Final Volume of the Groundbreaking Trilogy on Agent-Based ModelingIn this pioneering synthesis, Joshua Epstein introduces a new theoretical entity: Agent_Zero. This software individual, or "agent," is endowed with distinct emotional/affective, cognitive/deliberative, and social modules. Grounded in contemporary neuroscience, these internal components interact to generate observed, often far-from-rational, individual behavior. When multiple agents of this new type move and interact spatially, they collectively generate an astonishing range of dynamics spanning the fields of social conflict, psychology, public health, law, network science, and economics.Epstein weaves a computational tapestry with threads from Plato, Hume, Darwin, Pavlov, Smith, Tolstoy, Marx, James, and Dostoevsky, among others. This transformative synthesis of social philosophy, cognitive neuroscience, and agent-based modeling will fascinate scholars and students of every stripe. Epstein's computer programs are provided in the book or on its Princeton University Press website, along with movies of his "computational parables.?Agent_Zero is a signal departure in what it includes (e.g., a new synthesis of neurally grounded internal modules), what it eschews (e.g., standard behavioral imitation), the phenomena it generates (from genocide to financial panic), and the modeling arsenal it offers the scientific community. For generative social science, Agent_Zero presents a groundbreaking vision and the tools to realize it.

Foreword xiPreface xiiiAcknowledgments xvINTRODUCTION 1MOTIVATION 1Generate Social Dynamics 2A Core Target 2THE MODEL COMPONENTS 5Model Overview 6Skeletal Equation 8Specific Components 9ORGANIZATION 10Part I: Mathematical Model 10Part II: Agent-Based Model 11Part III: Extensions 13Replicability and Research Resources on the Princeton University Press Website 16Part IV: Future Research and Conclusions 17PART 1. MATHEMATICAL MODEL 19I.1. THE PASSIONS: FEAR CONDITIONING 19Fear Circuitry and the Perils of Fitness 20Nomenclature of Conditioning 29The Rescorla-Wagner Model 33Social Examples 37Fear Extinction 41I.2. REASON: THE COGNITIVE COMPONENT 46I.3. THE SOCIAL COMPONENT 51Simple Version of the Core Target 55Examples of Fear Contagion 57Mechanisms of Fear Contagion 59Conformist Empirical Estimates 63Generalizing Rescorla-Wagner 67The Central Case 69Tolstoy: The First Agent Modeler 71A Mathematical Aside on Social Norms as Vector Fields 74Extinction of Majorities 78I.4. INTERIM CONCLUSIONS 80PART II. AGENT-BASED COMPUTATIONAL MODEL 81Affective Component 84"Rational" Component 85Social Component 88Action 89Pseudocode 89II.1. COMPUTATIONAL PARABLES 90Parable 1: The Slaughter of Innocents through Dispositional Contagion 90Parable 2: Agent_Zero Initiates: Leadership as Susceptibility to Dispositional Contagion 94Run 3. Information Cuts Both Ways 96Run 4. A Day in the Life of Agent_Zero: How Affect and Probability Can Change on Different Time Scales 98Run 5. Lesion Studies 102PART III. EXTENSIONS 107III.1. ENDOGENOUS DESTRUCTIVE RADIUS 107III.2. AGE AND IMPULSE CONTROL 109III.3. FIGHT VS. FLIGHT 110Case 1: Fight 111Case 2: Flight 112Capital Flight 114III.4. REPLICATING THE Latané-DARLEY EXPERIMENT 114Threshold Imputation 115The Dialogue 118III.5. MEMORY 118III.6. COUPLINGS: ENTANGLEMENT OF PASSION AND REASON 122Mathematical Treatment 124III.7.ENDOGENOUS DYNAMICS OF CONNECTION STRENGTH 128Affective Homophily 128General Setup 130Agent-Based Model: Nonequlibrium Dynamics 135III.8. GROWING THE 2011 ARAB SPRING 138III.9. JURY PROCESSES 143Phase 1. Public Phase 143Phase 2. Courtroom Trial Phase 145Phase 3. Jury Phase 147III.10. EMERGENT DYNAMICS OF NETWORK STRUCTURE 152Network Structure Dynamics as a Poincaré Map 153Relation to Literature 159III.11. MULTIPLE SOCIAL LEVELS 160Agent_Zero as Witness to History 161III.12. THE 18TH BRUMAIRE OF AGENT_ZERO 165III.13. INTRODUCTION OF PRICES AND SEASONAL ECONOMIC CYCLES 168Prices 168A Christmas Story 173III.14. SPIRALS OF MUTUAL ESCALATION 176PART IV. FUTURE RESEARCH AND CONCLUSION 181IV.1. FUTURE RESEARCH 181IV.2. CONCLUSION 187Civil Violence 187Economics 188Health Behavior 189Psychology 190Jury Dynamics 191The Formation and Dynamics of Networks 191Mutual Escalation Dynamics 192Birth and Intergenerational Transmission 192IV.3. TOWARD NEW GENERATIVE FOUNDATIONS 192Appendix I. Threshold Imputation Bounds 195Appendix II. Mathematica Code 197Appendix III. Agent_Zero NetLogo Source Code 213Appendix IV. Parameter Settings for Model Runs 221References 227Index 243