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Social Simulation and Social Structure

Social Simulation and Social Structure
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Dr.BenjaminClark,United States,Teacher
Published Date:21-07-2017
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Intelligent Control and Cognitive Systems Social Simulation and Social Structure Joanna J. Bryson University of Bath, United KingdomTinbergen’s Questions Evolutionary (ultimate) explanations • Function (adaptation) • Phylogeny (evolution) • Proximate explanations • Causation (proximate mechanisms) • Development (ontogeny) •Replication & Science Where there is a controversy / surprising • result, the first thing to do is try to replicate it. Fail → doubt on original result (and/or • yourself) Succeed → lets you test & extend • theory.Replication & Science Leading role for simulation in science: show • whether a parsimonious model really could explain the data. Goals of replication: • 1. validate experiment 2. extend results i. explain more data, or ii. understand model betterCase StudyCognitive Minimalism Rhesus Macaques picture: Bernard Thierry Egalitarian species show bilateral aggression, human-like reconciliation. Research Question: Is cognition necessary or incidental to their social strategy?Why model monkeys? Much better quantitative data than for • humans. Complete interaction statistics. • Not significantly affected by observers. • Understand our own origins and inclinations. • Political instability leading cause of ill health. •Macaque Social Order Some (e.g. Rhesus) show strict • dominance hierarchy; violent but infrequent conflict: “despotic”. Some (e.g. Tonkeans) show more • tolerance e.g. bilateral aggression; more frequent but less violent conflicts: “egalitarian”. van Schaik (1989), • Thierry et al. (2004)Bilateral Aggression & Reconciliation Tonkean Macaques, an Egalitarian Species (video: Bernard Thierry)Two Hypotheses of Macaque Social Order Less resources (e.g. food) ⟹ • more violence ⟹ selective pressure for social structure (Hemelrijk 2001, 2002+). New conflict resolution • behaviour ⟹ less violence ⟹ less pressure for social structure (de Waal 2001, Flack & de Waal).Hemelrijk’s Model Simple, cognitively-minimalist boids-like • model. (Reynolds 1987; Hogeweg 1988) Despotic (vs. egalitarian) attributed to • greater variety in dominance rank value, consequence of aggression level. Side-effect: dominants in centre of troop, • subordinates outside – like real troops. Convergent evidence for model. •Challenges Most researchers think something more • cognitive is going on with primates. Only scientific justification for a more • complex model is better match to data. Research question: Is there room to improve • on the match to data?Describing a Model Bryson, Ando & Lehmann (2007, 2011) Environment • Agents’ State • Agents’ Behaviour • Results & Analysis •Environment Very simple torus: no • food or shelter, only space. Big enough with respect • to troop that agents couldn’t get lost & look around & see each other “around the world”.Hemelrijk’s Agents’ State Individual: DomValue (initially determined • by gender, changes by Eq. 2); X,Y position. Experimental Condition: StepDom • (aggression)–determined by gender and species; 2002 only: attraction (boolean: ♂⇒♀). • Statics: field of view; near view; max view; • personal space.Hemelrijk’s AS Separation Cohesion No AlignmentInteraction Equations ⎡ Dom i 1 Random(0,1) Dom +Dom i j 1 ⎣ w = i 0 else " Dom i Dom =Dom + w − ∗StepDom i i i Dom +Dom i j 2 " Dom i Dom =Dom + w − ∗StepDom j j i Dom +Dom i j for bees Hogeweg & Hesper 1988Hemelrijk 2002 “Self-Organization and Natural Selection in the Evolution of Complex Despotic Societies”, Biological Bulletin, 202(3):283-288 Difference between despotic & egalitarian • only increase of aggression (StepDom). Increased tolerance of females during • tumescence due only to their attractiveness.Replication By Hagen Lehmann & JingJing WangEgalitarian, Normal Dominance Rankings