Showing papers by "Stephen Shennan published in 2016"

Early farmers from across Europe directly descended from Neolithic Aegeans

Abstract: Farming and sedentism first appeared in southwestern Asia during the early Holocene and later spread to neighboring regions, including Europe, along multiple dispersal routes. Conspicuous uncertainties remain about the relative roles of migration, cultural diffusion, and admixture with local foragers in the early Neolithization of Europe. Here we present paleogenomic data for five Neolithic individuals from northern Greece and northwestern Turkey spanning the time and region of the earliest spread of farming into Europe. We use a novel approach to recalibrate raw reads and call genotypes from ancient DNA and observe striking genetic similarity both among Aegean early farmers and with those from across Europe. Our study demonstrates a direct genetic link between Mediterranean and Central European early farmers and those of Greece and Anatolia, extending the European Neolithic migratory chain all the way back to southwestern Asia.

Early Neolithic genomes from the eastern Fertile Crescent

Abstract: We sequenced Early Neolithic genomes from the Zagros region of Iran (eastern Fertile Crescent), where some of the earliest evidence for farming is found, and identify a previously uncharacterized population that is neither ancestral to the first European farmers nor has contributed substantially to the ancestry of modern Europeans. These people are estimated to have separated from Early Neolithic farmers in Anatolia some 46,000 to 77,000 years ago and show affinities to modern-day Pakistani and Afghan populations, but particularly to Iranian Zoroastrians. We conclude that multiple, genetically differentiated hunter-gatherer populations adopted farming in southwestern Asia, that components of pre-Neolithic population structure were preserved as farming spread into neighboring regions, and that the Zagros region was the cradle of eastward expansion.

Understanding cumulative cultural evolution.

Abstract: In a narrow critique of two early papers in the literature on cumulative cultural evolution, Vaesen et al. (1) misunderstand the work they criticize, mischaracterize multiple lines of research, and selectively ignore much evidence. While largely recycling prior criticisms, they provide no new models, evidence, or explanations (2). Not only do their criticisms of Henrich’s (3) and Powell et al.’s (4) modeling assumptions miss their mark (2), but Vaesen et al. (1) also ignore many other models that do not rely on these assumptions yet arrive at similar predictions. These other models variously include conformist transmission and explore these processes using nonnormal distributions, discrete traits, networks, etc. (2, 5). Of course, no … [↵][1]1To whom correspondence should be addressed. Email: henrich{at}fas.harvard.edu. [1]: #xref-corresp-1-1

European Neolithic societies showed early warning signals of population collapse.

Abstract: Ecosystems on the verge of major reorganization—regime shift—may exhibit declining resilience, which can be detected using a collection of generic statistical tests known as early warning signals (EWSs). This study explores whether EWSs anticipated human population collapse during the European Neolithic. It analyzes recent reconstructions of European Neolithic (8–4 kya) population trends that reveal regime shifts from a period of rapid growth following the introduction of agriculture to a period of instability and collapse. We find statistical support for EWSs in advance of population collapse. Seven of nine regional datasets exhibit increasing autocorrelation and variance leading up to collapse, suggesting that these societies began to recover from perturbation more slowly as resilience declined. We derive EWS statistics from a prehistoric population proxy based on summed archaeological radiocarbon date probability densities. We use simulation to validate our methods and show that sampling biases, atmospheric effects, radiocarbon calibration error, and taphonomic processes are unlikely to explain the observed EWS patterns. The implications of these results for understanding the dynamics of Neolithic ecosystems are discussed, and we present a general framework for analyzing societal regime shifts using EWS at large spatial and temporal scales. We suggest that our findings are consistent with an adaptive cycling model that highlights both the vulnerability and resilience of early European populations. We close by discussing the implications of the detection of EWS in human systems for archaeology and sustainability science.

The Origins and Spread of Domestic Animals in Southwest Asia and Europe

Abstract: This volume tackles the fundamental and broad-scale questions concerning the spread of early animal herding from its origins in the Near East into Europe beginning in the mid-10th millennium BC. Original work by more than 30 leading international researchers synthesizes of our current knowledge about the origins and spread of animal domestication. In this comprehensive book, the zooarchaeological record and discussions of the evolution and development of Neolithic stock-keeping take center stage in the debate over the profound effects of the Neolithic revolution on both our biological and cultural evolution.

Revealing patterns of cultural transmission from frequency data: equilibrium and non-equilibrium assumptions.

Abstract: A long tradition of cultural evolutionary studies has developed a rich repertoire of mathematical models of social learning. Early studies have laid the foundation of more recent endeavours to infer patterns of cultural transmission from observed frequencies of a variety of cultural data, from decorative motifs on potsherds to baby names and musical preferences. While this wide range of applications provides an opportunity for the development of generalisable analytical workflows, archaeological data present new questions and challenges that require further methodological and theoretical discussion. Here we examine the decorative motifs of Neolithic pottery from an archaeological assemblage in Western Germany, and argue that the widely used (and relatively undiscussed) assumption that observed frequencies are the result of a system in equilibrium conditions is unwarranted, and can lead to incorrect conclusions. We analyse our data with a simulation-based inferential framework that can overcome some of the intrinsic limitations in archaeological data, as well as handle both equilibrium conditions and instances where the mode of cultural transmission is time-variant. Results suggest that none of the models examined can produce the observed pattern under equilibrium conditions, and suggest. instead temporal shifts in the patterns of cultural transmission.

The Cultural Evolution of Neolithic Europe. EUROEVOL Dataset 1: Sites, Phases and Radiocarbon Data

Abstract: The datasets described in this paper comprise the core spatial and temporal structure of the Cultural Evolution of Neolithic Europe project (EUROEVOL), led by Professor Stephen Shennan, UCL. This is one of three datasets resulting from the EUROEVOL project, the other two comprising the faunal (EUROEVOL Dataset 2) and archaeobotanical (EUROEVOL Dataset 3) data ( http://discovery.ucl.ac.uk/1469811/ ). The dataset offers the largest repository of archaeological site and radiocarbon data from Neolithic Europe (4,757 sites and 14,053 radiocarbon samples), dating between the late Mesolithic and Early Bronze Age (Figure 1). It also offers the core archaeological information structured at the site and phase level, which provide the primary links between the datasets.

Multilevel processes and cultural adaptation: Examples from past and present small-scale societies

Abstract: Cultural adaptation has become central in the context of accelerated global change with authors increasingly acknowledging the importance of understanding multilevel processes that operate as adaptation takes place. We explore the importance of multilevel processes in explaining cultural adaptation by describing how processes leading to cultural (mis)adaptation are linked through a complex nested hierarchy, where the lower levels combine into new units with new organizations, functions, and emergent properties or collective behaviours. After a brief review of the concept of "cultural adaptation" from the perspective of cultural evolutionary theory and resilience theory, the core of the paper is constructed around the exploration of multilevel processes occurring at the temporal, spatial, social and political scales. We do so by examining small-scale societies' case studies. In each section, we discuss the importance of the selected scale for understanding cultural adaptation and then present an example that illustrates how multilevel processes in the selected scale help explain observed patterns in the cultural adaptive process. We end the paper discussing the potential of modelling and computer simulation for studying multilevel processes in cultural adaptation.

Appendix to Understanding Cumulative Cultural Evolution: A Reply to Vaesen, Collard, Et Al.

Abstract: The appendix replies to a critique published by Vaesen et al. (2016) on the influence of effective cultural population size on cumulative cultural evolution.

The Cultural Evolution of Neolithic Europe. EUROEVOL Dataset 1: Sites, Phases and Radiocarbon data. Journal of Open Archaeology Data

Abstract: The datasets described in this paper comprise the core spatial and temporal structure of the Cultural Evolution of Neolithic Europe project (EUROEVOL), led by Professor Stephen Shennan, UCL. This is one of three datasets resulting from the EUROEVOL project, the other two comprising the faunal (EUROEVOL Dataset 2) and archaeobotanical (EUROEVOL Dataset 3) data ( http://discovery.ucl.ac.uk/1469811/ ). The dataset offers the largest repository of archaeological site and radiocarbon data from Neolithic Europe (4,757 sites and 14,053 radiocarbon samples), dating between the late Mesolithic and Early Bronze Age (Figure 1). It also offers the core archaeological information structured at the site and phase level, which provide the primary links between the datasets.