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.

Archaeology and evolutionary ecology.

Abstract: The evolutionary anthropologist Eric Smith has recently suggested that there are three styles in the evolutionary analysis of human behaviour (Smith 2000): evolutionary psychology, behavioural ecology and dual inheritance theory. The second style represents what we might call the classical Darwinian view, drawing its inspiration from the assumption that in evolutionary terms humans are little different from any other animal, simply another unique species. Accordingly, we can assume that, since humans are the outcome of a long history of natural selection a long line of reproductively successful ancestors they have a propensity to take decisions, consciously or unconsciously, in the light of the costs and benefits of the consequences of those decisions for their future reproductive success. What explains diversity in behaviour in the present and recent past is the different pay-offs for different courses of action in different environments. Humans can weigh up these and respond to them, often quite unconsciously, thanks to the flexibility of their behaviour. It is generally assumed that culture does not make much difference in this process because any cultural behaviour which leads to deviation from the best outcome in terms of the reproductive cost-benefit calculus will not last very long. This is the approach with which this volume of World Archaeology is concerned. The most widespread methodology based on these assumptions is optimal foraging theory and it is strongly represented here. It generates predictions about the subsistence strategies which will give people the best cost-benefit outcome in any given set of circumstances and compares them with actual subsistence strategies, or, in the case of archaeology, compares their predicted residues with those found in the archaeological record. As so often is the case, this archaeological comparison is not a trivial task and a number of the case studies presented here address it. The aim of this introduction is to briefly explain the background to the approach. It was only after World War II that biologists turned to the evolutionary study of animal behaviour. This involved looking at behaviour in terms of selection; that is to say, looking at how variations in behaviour relate to variations in survival, in reproduction and in the rearing of offspring. It assumes, therefore, that behaviour is to some extent at least genetically determined. This is quite easy for us to imagine in the case of organisms such as insects, but at first sight it is harder to conceive in relation to more complex animals, which have a capacity for learning that can give them considerable behavioural flexibility.

Innovation in cultural systems

Abstract: Leading scholars offer a range of perspectives on the roles played by innovation in the evolution of human culture.

Commodities, Transactions, and Growth in the Central-European Early Bronze Age

Abstract: This paper suggests that recent studies of the beginning of the Bronze Age and the growth of a bronze 'industry' have placed too much emphasis on the importance of social ranking and the control of resources by elites. Copper had been in demand for over 2000 years before the beginning of the Bronze Age. What changed at this time was the emergence of a technology that gave access to virtually unlimited copper supplies and contributed to a process of economic growth. Circulating metal took on the role of a proto-currency in certain areas and had a significant effect on local patterns of social organisation. It was not centrally controlled. Eventually, the end of the growth process led to increased competition and warfare. Studies of these processes are illuminated by looking at the circulation of metal and money in medieval Europe and by thinking of the social changes in terms of Douglas's' grid' and 'group' dimensions.

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.