1. Simulating social, economic and political decisions in a hunter-gatherer group. The case of “Prehistoric” Patagonia. Juan A. Barceló, Florencia del Castillo, J.A.Cuesta, J.M.Galán, L. Mameli, F.Miguel, J.I. Santos, X.Vila UNIVERSITAT AUTONOMA DE BARCELONA UNIVERSIDAD DE BURGOS UNIVERSIDAD CARLOS III - Madrid

2. THE NATURE OF THE PROBLEM Ethnicity as Cultural Differentiation An ethnic group is a group of people whose members explicitly regard themselves and are regarded by others as truly distinctive, through a common heritage that is real or assumed- sharing “cultural” characteristics. Processes that result in the emergence of such identification are called ETHNOGENESIS

3. Casamiquela R. Los pueblos indígenas. Ciencia Hoy, vol. 2 N° 7. 1990. OBSERVING ETHNICITY IN THE PRESENT: Nations / Language OBSERVING ETHNICITY IN THE PAST: Cultures / Artefacts ETHNOGENESIS: ETHNICITY IS PERPETUALLY IN NEGOTIATION AND RENEGOTIATING BY BOTH EXTERNAL ASCRIPTION AND INTERNAL SELF-IDENTIFICATION

4. Our research goal Why groups of people are the way they are? in terms of how agents acted when they became integrated into a single group. The concept of Productivity The complex interplay of social actions, agents and their products explains ethnicity by showing how social aggregation fit into a causal structure, that is to say, a vast network of interacting actions and entities, where a change in a property of an entity dialectically produces a change in a property of another entity.

5. Observing Ethnicity PRESENTPAST Social /Political Science History EthnographyArchaeology SocioLinguisticsPhysical Anthropology

6. Ethnicity in Patagonia: The classical view

7. OBSERVING ETHNICITY IN THE PAST: Archaeological information

8. BEYOND CULTURAL SIMILARITY Simulating requires to execute a mechanism, which, given the properties of the constituent components and of the environment, gives rise to the phenomena of interest.

9. An ARTIFICIAL prehistoric society

11. Netlogo Implementation http://ingor.ubu.es/models/patagonia/simple1.0/

14. AN ENHANCED MODEL Model : bayesian network Probability for survival INITIAL_PHUNTING INITIAL_ PGATHERING. POSTERIOR_PHUNTING / POSTERIOR_PGATHERING. PSHARING / PEXCHANGE. Environmental Resources Labor: Hunting Gathering Child care Socializing

16. RESULTS (i) ETHNICITY IS AN EMERGENT PROPERTY OF SOCIAL GROUP DYNAMICS ETHNICITY is not the direct consequence of territorial mobility, because agent mobility is not a pure random walk, but it is mediated by. 1) the history of previous interactions, 2) the degree of cultural similarity, 3) the payoffs derived from cooperation (collective hunting, material exchange, social reproduction) and 4) the costs generated by internal social conflict.

17. RESULTS (ii) Historically, aggregated social groups have been less frequent than small bands of individuals, basically by the cost due to inequalities arising in all social conglomerates. Only if some individuals within the group increase their own productivity and the absolute volume of their production above a critical threshold, they can invest such a plus-value to increase coercion, and hence maintain ever increasing levels of social inequality. Without a dramatic change in technology (i.e. agriculture, pastoralism) we think that this social change is mostly infrequent.

18. RESULTS (iii) Contrary to traditional Fisher / Cavalli-Sforza “wave of advance” model, population dispersal not only depends on demography, but it is socially mediated. This is a complex social mechanism characterized by the dialectical relationship between. A) the higher payoffs of cooperation, B) the local carrying capacity, C) the level of technological development and D) the risk of increasing social stress when surplus accumulates and wealth became unequally distributed.

19. Sugarscape. (Epstein and Axtell 1996)

20. CONFRONTING THE MODEL WITH ETHNO-ARCHAEOLOGICAL DATA

22. 3A. 3B WÜNÜN A KENA 4-5. AONIKENK 10. CHONO 2. PEHUENCHE 1. MAPUCHE 6. SELKNAM 7 HAUSH 8. YAMANA 9. ALAKALUF

23. ANCIENT PATAGONIA: A Case-Study

24. CONCLUSIONS Bounded rationality in ethnicity formation The similarity between two interacting individuals is increased as a consequence of repeated interactions, and that the probability of positive interactions increase as a result of the increase of cultural similarity seems a good starting point for simulating the emergence of ethnic and cultural differentiation in the prehistoric past.

25. CONCLUSIONS: A group of X people, culturally homogenous moves across a territory conditioned by the existing resources (wanaco, fish/seafood, water, vegetable fuel, raw material) and establishing: -positive relationships (exogamy, interaction, exchange, collective labor, reciprocity) - or negative relationships (conflicts) with other families. THE PRODUCTION OF SUBSISTENCE AND INSTRUMENTS + REPRODUCTION OF PEOPLE AND SOCIAL NORMS SOCIAL, CULTURAL, POLITICAL, ECONOMIC DECISIONS BASED IN CRITERIA OF BOUNDED RATIONALITY Increasing Segregation Increasing cultural drift Increasing Mobility Increasing conflict Model Assumptions

26. ¿WHAT EMERGES? Agregation Social Heterogeneity Segregation Social Homogeneity Territorial mobility Social mobility

27. HUNTER-GATHERERS IN PREHISTORY: The Complexities of Apparent Simplicity Thanks!