Category Archaeology

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Journal Articles

Applying Brantingham’s Neutral Model of Stone Raw Material Procurement to the Pinnacle Point Middle Stone Age Records, Western Cape, South Africa

Oestmo, S., M.A. Janssen, and H. Cawthra

2020 Quaternary Science Reviews 235: 105901.


The Palaeo-Agulhas Plain (PAP), when exposed, presented Middle Stone Age (MSA) foragers at Pinnacle Point (PP) on the South Coast of South Africa with new sources of raw materials to make stone tools. Sea-level fluctuations and the changing size of the Paleo-Agulhas Plain throughout the Pleistocene PP record ∼165 ka to 50 ka would have altered the availability of different resources, thus potentially forcing new raw material procurement strategies. The relative frequencies of raw material throughout the PP sequence shows that frequencies of raw material types did change, especially after 90 ka. What caused these changing frequencies is debated and centers on whether targeted procurement of specific raw materials was the cause, or if simple raw material availability and abundance due to the changing environmental context in conjunction with opportunistic procurement drove such shifts. The application of a neutral model of stone raw material procurement presented here evaluates whether random walk in the region surrounding the PP site during different coastline configurations (Marine Isotope Stage 6, 5, and 4) explains the observed shifts in raw material usage. Put differently, did opportunistic acquisition of raw materials during random walk in these different environments cause the observed raw material pattern? Model simulations and a sensitivity analysis provide no convincing evidence that observed raw material frequencies at PP resulted from opportunistic acquisition during random walk.


The foraging potential of the Holocene Cape South Coast of South Africa without the Paleaso-Agulhas Plain

Wren, C.D., S. Bothaa, J. De Vynck, M.A. Janssen, K. Hill, E. Shook, J.. Harris, B.M. Wood, J. Venter, R. Cowling, J. Franklin, A. Potts, E.C. Fisher and C.W. Marean

2020 Quaternary Science Reviews 235: 105789.


The Palaeo-Agulhas Plain formed an important habitat exploited by Pleistocene hunter-gatherer populations during periods of lower sea level. This productive, grassy habitat would have supported numerous large-bodied ungulates accessible to a population of skilled hunters with the right hunting technology. It also provided a potentially rich location for plant food collection, and along its shores a coastline that moved with the rise and fall of sea levels. The rich archaeological and paleontological records of Pleistocene sites along the modern Cape south coast of South Africa, which would have overlooked the Palaeo-Agulhas Plain during Pleistocene times of lower sea level, provides a paleoarchive of this extinct ecosystem. In this paper, we present a first order illustration of the “palaeoscape modeling” approach advocated by Marean et al. (2015). We use a resourcescape model created from modern studies of habitat productivity without the Palaeo-Agulhas Plain. This is equivalent to predominant Holocene conditions before recent landscape modifications for farming. We then run an agent-based model of the human foraging system to investigate several research questions. Our agent-based approach uses the theoretical framework of optimal foraging theory to model human foraging decisions designed to optimize the net caloric gains within a complex landscape of spatially and temporally variable resources. We find that during the high sea-levels of MIS 5e (+5–6 m asl) and the Holocene, the absence of the Plain left a relatively poor food base supporting a much smaller population relying heavily on edible plant resources from the current Cape flora. Despite high species diversity of plants with edible storage organs, and marine invertebrates, encounter rates with highly profitable resources were low. We demonstrate that without the Palaeo-Agulhas Plain, human populations must have been small and low-density, and exploited plant, mammal, and marine resources with relatively low caloric returns. The exposure and contraction of the Palaeo-Agulhas Plain was likely the single biggest driver of behavioural change during periods of climate change through the Pleistocene and into the transition to the Holocene.


Paleoscape model of coastal South Africa during modern human origins: progress in scaling and coupling climate, vegetation, and agent-based models on XSEDE

Shook, E., C. Wren, C.W. Marean, A.J. Potts, J. Franklin, F. Engelbrecht, D. O?Neal, M.A. Janssen, E. Fisher, K. Hill, K.J. Esler, R.M. Cowling, S. Scheiter, G. Moncrieff

2015 Proceedings of the 2015 XSEDE Conference: Scientific Advancements Enabled by Enhanced Cyberinfrastructure 2:1-2:8.


To better understand the origins of modern humans, we are developing a paleoscape model that simulates the climatic conditions and distribution of natural resources available to humans during this critical stage of human evolution. Our geographic focus is the southern Cape region of South Africa, which was rich in natural resources for hunter-gatherer groups including edible plants, shellfish, animals, and raw materials. We report our progress in using the Extreme Science and Engineering Discovery Environment (XSEDE) to realize the paleoscape model, which consists of four components: a climate model, correlative and dynamic vegetation models, and agent-based models. We adopt a workflow-based approach that combines modeling and data analytics to couple these four modeling components using XSEDE. We have made significant progress in scaling climate and agent-based models on XSEDE. Our next steps will be to couple these models to the vegetation models to complete the workflow, which will require overcoming multiple theoretical, methodological, and technical challenges.


A New Research Strategy for Integrating Studies of Paleoclimate, Paleoenvironment, and Paleoanthropology

Marean, C.W., R.J. Anderson, M. Bar-Matthews, K. Braun, R.M. Cowling, F. Engelbrecht, K.J. Esler, E. Fisher, J. Franklin, K. Hill, M.A. Janssen, A.J. Potts, and R. Zahn

2015 Evolutionary Anthropology 24(2): 62-72.


Paleoanthropologists (scientists studying human origins) universally recognize the evolutionary significance of ancient climates and environments for understanding human origins.[1-6] Even those scientists working in recent phases of human evolution, when modern humans evolved, agree that hunter-gatherer adaptations are tied to the way that climate and environment shape the food and technological resource base.[7-10] The result is a long tradition of paleoanthropologists engaging with climate and environmental scientists in an effort to understand if and how hominin bio-behavioral evolution responded to climate and environmental change. Despite this unusual consonance, the anticipated rewards of this synergy are unrealized and, in our opinion, will not reach potential until there are some fundamental changes in the way the research model is constructed. Discovering the relation between climate and environmental change to human origins must be grounded in a theoretical framework and a causal understanding of the connection between climate, environment, resource patterning, behavior, and morphology, then move beyond the strict correlative research that continues to dominate the field.


Population aggregation in the ancient arid environments

Janssen, M.A.

2010 Ecology and Society 5(2): 19.


Human societies have adapted to spatial and temporal variability, such as that found in the prehistoric American Southwest. A question remains as to what the implications are of different social adaptations to the long-term vulnerability of small-scale human societies. A stylized agent-based model is presented that captures small-group decision making on movements and resource use in ancient arid environments. The impact of various assumptions concerning storage, exchange, sharing, and migration on indicators of aggregation and sustainability are explored. Climate variability is found to increase the resilience of population levels at the system level. Variability reduces the time a population stays in one location and can degrade the soils. In addition to climate variability, the long-term population dynamics is mainly driven by the level of storage and the decision rules governing when to migrate and with whom to exchange.

Keywords: agent-based model; archaeology; arid landscapes; climate variability


Understanding Artificial Anasazi

Janssen, M.A.

2009 Journal of Artificial Societies and Social Simulation 12 (4) 13.


A replication and analysis of the Artificial Anasazi model is presented. It is shown that the success of replicating historical data is based on two parameters that adjust the carrying capacity of the Long House Valley. Compared to population estimates equal to the carrying capacity the specific agent behavior contributes only a modest improvement of the model to fit the archaeological records.

Keywords: Replication, Model Analysis, Model-Based Archaeology, Population Dynamics, Social-Ecological Systems


A robust budding model of Balinese water temple networks

Lansing, J.S., M.P. Cox, S.S. Downey, M.A. Janssen and J.W. Schoenfelder

2009 World Archaeology 41(1): 112-133.


Ethnohistory, genetics and simulation are used to propose a new ‘budding model’ to describe the historical processes by which complex irrigation communities may come into existence. We review two alternative theories, Wittfogel’s top-down state-formation theory and common-pool resource management, and suggest that a budding model would better account for existing archaeological and ethnographic descriptions of a well-studied network of irrigation communities on the island of Bali. The budding model is supported by inscriptions and ethnohistorical documents describing irrigation works in and around the drainage of the Petanu River, an area with some of the oldest evidence for wet-rice agriculture in Bali. Genetic analysis of Y-STR and mtDNA shows correlated demographic histories and decreased diversity in daughter villages, consistent with the budding model. Simulation results show that the network of irrigation communities can effectively adjust to repeated budding events that could potentially shock the system outside the parameter space where good harvests can be maintained. Based on this evidence we argue that the budding model is a robust explanation of the historical processes that led to the emergence and operation of Petanu irrigation communities.

Keywords: Bali, irrigation, genetics, pre-colonial, inscriptions, complex adaptive systems


Overexploitation of renewable resources by ancient societies and the role of sunk cost effects

Janssen, M.A. and M. Scheffer

2004 Ecology and Society 9(1): 6.


What makes social-ecological systems (SESs) robust? In this paper, we look at the institutional configurations that affect the interactions among resources, resource users, public infrastructure providers, and public infrastructures. We propose a framework that helps identify potential vulnerabilities of SESs to disturbances. All the links between components of this framework can fail and thereby reduce the robustness of the system. We posit that the link between resource users and public infrastructure providers is a key variable affecting the robustness of SESs that has frequently been ignored in the past. We illustrate the problems caused by a disruption in this link. We then briefly describe the design principles originally developed for robust common-pool resource institutions, because they appear to be a good starting point for the development of design principles for more general SESs and do include the link between resource users and public infrastructure providers.

Keywords: institutions, resilience, robustness, social-ecological systems.


Sunk-cost effects and vulnerability to collapse in ancient societies

Janssen, M.A., T.A. Kohler, and M. Scheffer

2003 Current Anthropology 44(5): 722-728.

Book Chapters

What makes a forager turn coastal? An agent-based approach to coastal foraging on the dynamic South African Paleoscape

Wren, C.D., C.W. Marean, K. Hill, K., and M.A. Janssen

2023 In Human Behavioral Ecology at the Coastal Margins Global Perspectives on Coastal & Maritime Adaptations, edited by H Thakar and C. Flores, 172-198, University of Florida Press.

An agent-based approach to weighted decision making in the spatially and temporally variable South African Palaeoscape

Wren, C.D., C. Atwater, K. Hill, M.A. Janssen, J.C. De Vynck, and C.W. Marean

2018 In Proceedings of the 44th Computer Applications and Quantitative Methods in Archaeology Conference (CAA 2016), edited by Mieko Matsumoto and Espen Uleberg, 507–522, Archaeopress.


Even a simple human foraging system has a large number of moving parts. Foragers require a complex decision making process to effectively exploit the spatially and temporally variable resources in an environment. Here we present an agent-based modelling framework, based in optimal foraging theory, for agent foragers to make mobility and foraging decisions by weighing expected caloric returns against geographic and social factors, and forecasted future return rates. We apply our Paleoscape model to a spatially explicit South African coastal landscape to better understand the human foraging system of the Middle Stone Age, when foragers began systematically exploiting a wide variety of flora and fauna in both terrestrial and inter-tidal environments. We also discuss the broader importance of agent-based models of foraging systems for a wide variety of archaeological research questions.


Testing Brantingham’s neutral model: the effect of spatial clustering on stone raw material procurement

Oestmo, S., M.A. Janssen, C.W. Marean

2016 In Simulating Prehistoric and Ancient Worlds, edited by J.A. Barceló and F. Del Castillo, 175-188, Springer.

Stylized Models to Analyze Robustness of Irrigation Systems

Janssen, M.A. and J.M. Anderies

2007 In The Model-based Archaeology of Socionatural Systems, edited by T.A. Kohler and S.E. van der Leeuw , pp. 157-173,  School for Advanced Research Press.

Hominids Foraging in a Complex Landscape: Could Homo ergaster and Australopithecus boisei Meet their Calorie Requirements?

Janssen, M.A., J.M Sept and C.S. Griffith

2007 In Advancing Social Simulation, edited by S. Takahashi, D. Sallach and J. Rouchier, pp. 307-318, Springer.


In this paper, we present the results of an agent-based model of foraging of hominids. The model represents foraging activities in a landscape that is based on detailed measurements of food availability in the modern East African environments. These current landscapes are used as a model for the environment of the hominids one million years ago. We use the model to explore possible rankings of food preferences for different types of hominids (Homo ergaster and Australopithecus boisei) in different types of semi-arid landscapes. We let the agents adjust their preferences to maximize their calorie intake and show that A. boisei could not meet its calorie requirements in different landscapes.



Foraging of Homo ergaster and Australopithecus boisei in East African environments

Janssen, M.A., J.M. Sept and C.S. Griffith
2005 paper presented at the Center for Computational Analysis of Social and Organizational Systems (CASOS) Summer Institute. June 25 - 30. Pittsburgh, PA.


In this paper, we present the initial results of an agent-based model of foraging of hominids. The model represents foraging activities in a landscape that is based on detailed measurements of food availability in the modern East African environments. These current landscapes are used as a model for the environment of the hominids one million years ago. We explore the spatial and temporal consequences of foraging patterns in different types of semi-arid landscapes and different types of hominids (Homo ergaster and Australopithecus boisei) who are defined with different abilities and preferences.

Keywords: foraging, hominids, field data


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