SAA conference 2015

The 80th Annual Meeting of the Society for American Archaeology, which took place from 15th to 19th April 2015 in San Francisco, included a whole symposium dedicated to the SimulPast project on 16th April. In addition to organising and presenting in this symposium, SimulPast members also delivered separate presentations in other sessions of SAA 2015.

Listed below can be found the presentations delivered in the session dedicated to the SimulPast project in the SAA 2015 conference.


Session: Symposium: "SimulPast - Simulating the past to understand human behaviour"

Session abstract: Social and environmental transitions represent key aspects to better understand human behaviour. From a complex systems perspective, the most decisive questions about human societal systems are related to the transitions between phases of equilibrium. Therefore, the study of these transitions is extremely interesting in order to move forward with our current understanding of human behaviour at macro, meso and micro-level. In that respect, ancient societies present a great opportunity to build a virtual laboratory in which to model, explore and simulate different hypotheses and theories about social and environmental transitions. This session will act as a showcase of the final results of the SimulPast project ( The philosophy on which SimulPast is based is transdisciplinary, evading the traditional division that sees the Humanities and Social Sciences and the often-called “Hard Sciences” as mutually impermeable areas of knowledge. Indeed, the research strategy on which the project has worked crossed many disciplinary boundaries to create a holistic approach.


Abstract: The aim of this study is to model resource management and decision making among hunter-gatherer and agro-pastoral groups in semi-arid zones in order to explore evolutionary trajectories in relation to (a) the appearance of other specialized groups during the mid-Holocene and (b) environmental variability. The study of coexistence and interaction between groups with different subsistence strategies and land-use behaviors represents an interesting research challenge to understand socioecological dynamics. This study deeply depends on the appreciation of past settlement dynamics and resource management and the approach is through Agent-Based Simulation. Our case study focuses in Northern Gujarat (India), a marginal environment between the Thar Desert and the more fertile area of Saurashtra. This region is an ecotone characterized by the seasonal influence of the monsoon, where contrasting ecological niches are in tension and small climatic shifts can generate significant environmental changes. Archaeological evidence points to the presence and possible coexistence in the area of groups of people with different resource management strategies and mobility behaviors during the mid-Holocene: hunter-gatherers (HG) and agropastoralists (AP).


Abstract: Following the introduction of agriculture, domestication and permanent settlement in the early Holocene, patrilinear and patrilocal models have become more common than matrilineal and matrilocal ones. While patrilocality is observed at the worldwide level, matrilocality has been associated to specific areas, e.g. sub-Saharan Africa. Matrilocal and patrilocal residence patterns indicate whether as a rule, a newly formed couple settles with or near the female’s or male’s parents respectively. In this context, mating can be seen as a sub-category of the migration process, where one of the two components of the newly formed couple moves into the household/village/city/country of the other. Where patrilocality is widespread greater female mobility is observed. The opposite is true for matrilocality. Using available ethnological data, our agent-based model (ABM) focuses on mating-migration dynamics between hunter-gatherer populations (HGP) and food-producing populations (FPP). We explore within and between population mating-migration behavior, highlighting possible tendencies for gendered ‘marriage’ migration among traditional HG and AP societies.


Abstract: Cooperation studies have become an essential area of knowledge across different disciplines. Within the humanities and the social sciences, it has been used to explain human behavior as well as the maintenance of the social tissue itself. It has also given clues to explain the variability and the plasticity of human social organization at different levels. In this presentation we focus on Yamana society a nomadic hunter-fisherer-gatherer group that inhabited the southernmost region of South America and who maintained this socio-economic organization approximately till the 30s of the last century. This society developed a range of cooperative practices (through production, distribution and consumption activities) that took place mostly during aggregation events caused by a great accumulation of resources. Through Agent Based Modelling we pretend to explore the role played by different variables that may influence the development of these cooperation practices. The aim of this paper is to present some theoretical and methodological results of this study.


Abstract: Agent-Based Models (ABMs) have been increasingly used to study social phenomena, from the emergence of social norms to population dynamics or cultural transmission processes. Key to this method of computational simulation is the tension for explaining how macroscopic phenomena emerge from the interaction of agents behaving in a plausible manner. However, the behavior is too often encoded as a simple set of condition-action rules. We consider this kind of rule-based behavior too simplistic, specifically when simulating human action and exploring the impact of decision-making processes on the simulation outcome. Therefore, we experiment with a novel type of agent whose decisions are based on casting the surrounding world as a Markov Decision Process, a decisionmaking model widely used in Artificial Intelligence. The performance of this type of agents is assessed on a simple ABM simulation and compared to that of traditional rule-based agents. We then analyze the interplay between decision-making processes and relevant simulation parameters such as the distribution of resources. Finally, we present the results of applying the insights thus gained to a concrete case study within the Simulpast project concerning the dynamics of Hunter- Gatherer populations in North Gujarat, India, in the mid and late Holocene.


  • Modelling Group Formation in Small Scale Societies.

Abstract: Several human activities require an optimal number of individuals to maximize their utility, often leading to the coexistence of positive and negative frequency dependence. This generates unstable equilibria, as group close to the optimal size will be invaded by joiners who will increase their fitness by becoming new members, leading either beneficial or detrimental effects to the incumbent members. If a group is optimally sized, incumbent member will experience a decline in fitness, while joiners will increase its fitness by joining the group. This leads to an Evolutionary Stable Strategy (ESS) where group sizes are greater than the optimal size in the case of ideal free individuals. This outcome will be different if the acceptance of a new member can be blocked by the receiving group. The group members will face a volunteer's dilemma, as any cost of rejecting incoming individuals will be benefited by the entire group. This paper examines the role of this ESS in group formation dynamics. The decision-making process of individuals is explored, focusing on situations where members of a group can choose to reject new members for a given cost. Different scenarios are considered, including individual and shared costs, and macro scale implications are discussed.


  • Land Use Patterns in the Arid Eurasia. Models and Historical Examples.

Abstract: The relation between the main variants of pre-industrial economic production in arid Eurasia, from nomadic pastoralism to irrigated agriculture, is known to have been unstable, with abundant examples of conflict and shifting patterns of land use right up to contemporary times. We present a brief review of our experience using Agent-Based models to identify mechanisms and system dynamics that could help explain the different land use configurations, which have been recorded archaeologically for all periods from the Bronze Age up until the contemporary period. Our models helped us to explore the conditions for the stabilization of land use, simplified as discrete portions of land reserved to either mobile livestock breeding and sedentary agriculture. Assuming there is a general economic growth, we experiment with different theoretical solutions to how local stakeholders may respond to a basic economic conflict: matching an ever pushing demand with a limited resource. By simulating these mechanisms, we achieved insights on the role of environmental, technological and social constraints in land use dynamics.


Abstract: We review a method to estimate the percentages of demic and cultural diffusion in Neolithic transitions (Fort, PNAS 2012). We extend that method and identify mainly demic and mainly cultural regions in Europe.


Apart from the above symposium, additional contributions by members of the SimulPast project were made throughout the overall conference:


  • Past human activities: ethnographic and geostatistical models from North Gujarat (India).

Abstract: The main aim of archaeological research is the reconstruction of past human activities. So far this has been achieved mostly through the study of material culture. However, activities related to food production and consumption represent an important part of human life and leave microscopic and chemical traces. The use of ethnography and geostatistical approaches can help in unlock the patters and identify activity areas in a controlled environment. We present here results from a multidisciplinary study in carried out in north-west India where domestic structures and activities can represent good proxies for prehistoric life-ways. Our experiment is not intended to create direct parallelisms between present and past-times, but to test the reliability of our methodology against known activities. We combined multi-element geochemistry, spot tests and phytolith analyses with a geostatistical approach to identify activities areas in a domestic compound (house and courtyard). Results show the validity of the methodology proposed and the potential of a multi-proxy approach to the study of human activities.


  • Agent Based Modelling on the origins of the sexual division of labour.

Abstract: Social differences between men and women are still an object of debate among several areas of knowledge. These differences are the result of a long historical process that led to the establishment of the sexual division of labour as we know it, although we do not know the original cicumstances and steps that initially originated it. In order to throw light on this, we are focusing on hunter-gather societies; ethnographic and historical documentation about these human societies points to sexually differentiated cooperative strategies. This paper presents the first theoretical and methodological results of a research project that aims at evaluating the role of the variables that could have been involved in the original design of the sexual division of labour, and its subsequent ‘institutionalization’ as a social rule. Social simulation, as a kind of virtual laboratory, allows to generate an "ad-hoc" scenario and a set of agents in order to explore a question like this. By means of artificial intelligence, diferente starting scenarios will be created, considering either specific intentional direction coming from each sex in order to shape the sexual division of labour.


  • An ethnoarchaeological study on anthropic markers from a shell-midden in Tierra del Fuego: Lanashuaia II.

Abstract: Hunter-gatherer sites constitute often challenging research contexts within the discipline of archaeology; identifying and even defining whom Tierra del Fuego constitute an optimum arena for studying anthropic markers in hunter-gatherers sites for two reasons: a) good preservation of archaeological remains; b) a rich ethnographic record about hunter-fisher-gatherer societies who inhabited this region. The aim of this work is to present the first results of an intrasite spatial analysis, based on the distribution of different proxies and archaeological materials, carried out on a layer from the site Lanashuaia II, a shell midden located on the Beagle Channel coast (Tierra del Fuego, Argentina). Ethnoarchaeology is used as a methodological tool to give content to the concept of anthropic markers by means of formulating archaeological hypothesis on the basis of ethnological information. Geostatistical results are expected to be representative of the social uses of space, such us productive or consumption areas within the habitat and its surroundings.


In general, any one of the abstracts of the conference can be found at the tDAR repository.