Stephen Shennan

Bio: Stephen Shennan is an academic researcher from University College London. The author has contributed to research in topics: Population & Prehistory. The author has an hindex of 52, co-authored 192 publications receiving 10207 citations. Previous affiliations of Stephen Shennan include Massachusetts Institute of Technology & Arts and Humanities Research Council.

Population-level neutral model already explains linguistic patterns

Abstract: In customizing the neutral model for language transmission, Reali & Griffiths [[1][1]] have added a new, ‘Bayesian’ learning interpretation to a neutral model that has been used in cultural evolution studies for some time (eg [[2][2]–[6][3]]) While Reali & Griffiths [[1][1], p 435] dismiss

Cultural phylogenies and explanation: Why historical methods matter

Abstract: Book description: Much of what we are comes from our ancestors. Through cultural and biological inheritance mechanisms, our genetic composition, instructions for constructing artifacts, the structure and content of languages, and rules for behavior are passed from parents to children and from individual to individual. Mapping Our Ancestors demonstrates how various genealogical or “phylogenetic” methods can be used both to answer questions about human history and to build evolutionary explanations for the shape of history. Anthropologists are increasingly turning to quantitative phylogenetic methods. These methods depend on the transmission of information regardless of mode and as such are applicable to many anthropological questions. In this way, phylogenetic approaches have the potential for building bridges among the various subdisciplines of anthropology; an exciting prospect indeed. The structure of Mapping Our Ancestors reflects the editors’ goal of developing a common understanding of the methods and conditions under which ancestral relations can be derived in a range of data classes of interest to anthropologists. Specifically, this volume explores the degree to which patterns of ancestry can be determined from artifactual, genetic, linguistic, and behavioral data and how processes such as selection, transmission, and geography impact the results of phylogenetic analyses. Mapping Our Ancestors provides a solid demonstration of the potential of phylogenetic methods for studying the evolutionary history of human populations using a variety of data sources and thus helps explain how cultural material, language, and biology came to be as they are.

Simulating Geographical Variation in Material Culture: Were Early Modern Humans in Europe Ethnically Structured?

Abstract: A high degree of structuring is seen in the spatial distribution of symbolic artefact types associated with the Aurignacian culture in Upper Palaeolithic Europe, particularly the degree of sharing of ornament types across archaeological sites. Multivariate analyses of these distributions have been interpreted as indicating ethno-linguistic differentiation (Vanhaeren and d’Errico 2006), although simpler explanations such as isolation-by-distance have not been formally discounted. In this study we have developed a spatiotemporally explicit cultural transmission simulation model that generates expectations of a range of spatial statistics describing the distribution of shared ornament types. We compare these simulated spatial statistics to those observed from archaeological data for Aurignacian Europe—using Approximate Bayesian Computation—in order to test and compare a range of hypotheses concerning group interaction dynamics for the period. Among the set of hypotheses examined, we include ones where material culture does or does not drive group interaction dynamics.

The Web of Human Sexual Contacts

Abstract: Many ``real-world'' networks are clearly defined while most ``social'' networks are to some extent subjective. Indeed, the accuracy of empirically-determined social networks is a question of some concern because individuals may have distinct perceptions of what constitutes a social link. One unambiguous type of connection is sexual contact. Here we analyze data on the sexual behavior of a random sample of individuals, and find that the cumulative distributions of the number of sexual partners during the twelve months prior to the survey decays as a power law with similar exponents $\alpha \approx 2.4$ for females and males. The scale-free nature of the web of human sexual contacts suggests that strategic interventions aimed at preventing the spread of sexually-transmitted diseases may be the most efficient approach.

Massive migration from the steppe was a source for Indo-European languages in Europe

Abstract: We generated genome-wide data from 69 Europeans who lived between 8,000-3,000 years ago by enriching ancient DNA libraries for a target set of almost 400,000 polymorphisms. Enrichment of these positions decreases the sequencing required for genome-wide ancient DNA analysis by a median of around 250-fold, allowing us to study an order of magnitude more individuals than previous studies and to obtain new insights about the past. We show that the populations of Western and Far Eastern Europe followed opposite trajectories between 8,000-5,000 years ago. At the beginning of the Neolithic period in Europe, ∼8,000-7,000 years ago, closely related groups of early farmers appeared in Germany, Hungary and Spain, different from indigenous hunter-gatherers, whereas Russia was inhabited by a distinctive population of hunter-gatherers with high affinity to a ∼24,000-year-old Siberian. By ∼6,000-5,000 years ago, farmers throughout much of Europe had more hunter-gatherer ancestry than their predecessors, but in Russia, the Yamnaya steppe herders of this time were descended not only from the preceding eastern European hunter-gatherers, but also from a population of Near Eastern ancestry. Western and Eastern Europe came into contact ∼4,500 years ago, as the Late Neolithic Corded Ware people from Germany traced ∼75% of their ancestry to the Yamnaya, documenting a massive migration into the heartland of Europe from its eastern periphery. This steppe ancestry persisted in all sampled central Europeans until at least ∼3,000 years ago, and is ubiquitous in present-day Europeans. These results provide support for a steppe origin of at least some of the Indo-European languages of Europe.

A cross-cultural analysis of the behavior of women and men: implications for the origins of sex differences.

Abstract: This article evaluates theories of the origins of sex differences in human behavior. It reviews the cross-cultural evidence on the behavior of women and men in nonindustrial societies, especially the activities that contribute to the sex-typed division of labor and patriarchy. To explain the cross-cultural findings, the authors consider social constructionism, evolutionary psychology, and their own biosocial theory. Supporting the biosocial analysis, sex differences derive from the interaction between the physical specialization of the sexes, especially female reproductive capacity, and the economic and social structural aspects of societies. This biosocial approach treats the psychological attributes of women and men as emergent given the evolved characteristics of the sexes, their developmental experiences, and their situated activity in society.