Behavioral Ecology and the Transition to Agriculture
Douglas J. Kennett and Bruce Winterhalder, eds.

Berkeley: University of California Press 2006.
394pp
ISBN: 0-520-24647-0 (£44.95)

Over the past two decades human behavioural ecology (HBE) has comprised one of the most significant developments in anthropologists' attempts to model the diversity of hunter-gatherer economies. Based on data taken from existent hunter-gatherer societies, HBE has begun to establish a robust analytical framework for examining the specific evolutionary ecological contexts generating patterns of variability in hunter-gatherer behaviour. While the efficacy of the HBE framework has been tested with much success in hunter-gatherer studies (e.g. Smith and Winterhalder 1992; Winterhalder and Smith 1981), its usefulness for the construction of archaeological models of agricultural transitions is still largely unknown.

This volume attempts to take on the difficult challenges of 1) applying an analytical framework established from research on existent hunter-gatherer societies to the archaeological record, and 2) extending the HBE framework to the complex topic of the origins of agriculture on a global scale. Douglas J. Kennett and Bruce Winterhalder have assembled an analytical tour de force stimulating the call for increasingly robust and complex approaches to the evolutionary process of agricultural transitions.

The true strength of this volume lies in its well-balanced application of the HBE framework to case studies dealing with archaeological records from diverse cultural, ecological and geographical contexts. With three theoretical chapters and eleven case studies, this volume presents an outstanding mix of breadth and analytical consistency that increases the depth at which we approach questions concerning the transition to agriculture.

The opening chapter by Winterhalder and Kennett presents a thorough introduction to the key concepts of human behavioural ecology, such as central place foraging, population ecology, diet breadth, ideal free distribution, risk sensitivity, costly signaling, and discounting. By analysing recent developments in our understanding of how human subsistence systems evolve, Winterhalder and Kennett (p. 19) make a most convincing argument for HBE as an "essential tool in the analysis of the transition from hunting and gathering to agriculture". The primary contribution of the first chapter stems from its emphasis on the flexibility of the fundamental concepts of HBE and their relation to any type of human economy, whether hunting-gathering, mixed, or fully agricultural. The very flexibility of the framework and its potential for model building is best indicated by the particular case studies that use only certain concepts of HBE which are most relevant to regional or local archaeological records.

In the second chapter, Tucker's paper on the mixed foraging-horticultural Mikea of southwest Madagascar presents the only ethnographic study of the volume. The Mikea mixed economic system is comprised of slash-and-burn cultivation of low-investment maize and manioc horticulture in the forest savanna in combination with foraging for wild tubers, honey, and small game. Tucker's use of future-discounting theory shows vividly that the Mikea cultivate due to the lower rewards of foraging, yet refrain from the intensive horticulture of their Masikoro neighbors due to immediate subsistence needs that limit their capacity for future investment within a broader resource landscape. The results of this study clearly yield the potential of future discounting theory for explaining the persistence of mixed economic systems in the "middle ground between foraging and intensive cultivation" (p. 39).

In the first of two papers to explore the application of central place foraging theory, Gremillion (Chapter 3) investigates the economic consequences of garden plot cultivation on the prehistoric people who used a rock shelter in the eastern Kentucky uplands as a storage location. Gremillion explores the different practices needed to cultivate chenopod and sumpweed, and their subsequent relative return rates of cultivation in floodplain and hillside habitats. This paper quantitatively illustrates the close relationship between the crop characteristics of particular plant species, local ecological potential of cultivation, and the costs of transport to storage locales. Central place foraging theory is used for a second time in the volume with a paper by Kennett, Voorhies, and Martorana (Chapter 6), which, combined with diet breadth models, uses a combination of palaeoecological and archaeological data to attempt to explain the long-term delay between the introduction of maize and the development of intensive maize production on the Pacific coast of southwest Mexico.

Diet breadth models are some of the most well-known and widely employed models from HBE. In this volume diet breadth models are used to examine forager choices in taking on agricultural practices. Diehl and Waters (Chapter 4) use a diet breadth model to explain the 1350 year delay between the first introduction of maize and its intensification as a floodplain crop in southeast Arizona. Employing a combination of diet breadth models and marginal value theory, Denham and Barton (Chapter 11) reveal behavioral continuity in the emergence of agriculture out of preexisting terminal Pleistocene and early Holocene foraging strategies in the Highlands of New Guinea. In this excellent empirical account of the anthropogenic transformation of environments leading to local agriculture, archaeobotanical, archaeological, geomorphological, and palaeoecological data are used to exhibit the long processes of patch creation, plant translocation, and reduced mobility that enabled taro and banana agriculture in the Highland rain forests. The final application of the diet breadth model is used in combination with costly signaling theory in Aldenderfer's (Chapter 8) paper on the origins of animal domestication in the Andean highlands. In an ambitious paper displaying the potentials of HBE models for elucidating the social interactive significance of agricultural transitions, Aldenderfer constructs an admittedly plausible yet tentative model to explain the relationship between the sexual division of labour and the domestication of the llama and the alpaca.

If one underlying tenet of the HBE framework could be emphasised, it would most likely be optimal foraging theory (OFT). Two papers in this volume give lucid accounts of the flexibility of optimal foraging theory that yield enormous potentials for modeling the origins of agriculture within specific environmental circumstances. Barlow's (Chapter 5) formal model incorporates optimisation hypotheses in order to explain the economic diversity and the persistence of a mixed economy among the Fremont (eastern Great Basin and northern Colorado Plateau). In an excellent empirical overview of plant domestication in the Neotropics, Piperno (Chapter 7) uses OFT to answer some of the 'why' questions concerning prehistoric peoples choices to domesticate so few plants, particularly, what selection requirements came into play to spark the first steps of domestication. Interpreting domestication as a complex evolutionary process, Piperno provides the most thorough application of HBE to the question of agricultural origins in the entire volume.

With a model to explain the differential spreads of domesticated animals and plants to southern Arabia, McCorriston (Chapter 10) produces the only chapter of the volume focused specifically on the importance of HBE for explaining the relationship between climate change and the transition to agriculture. This model argues that domesticated herd animals from the Near East were incorporated earlier than plants due to the impact that high temperatures and summer rainfall would have played on early crop production.

An HBE model with special applicability not only to the origins but the subsequent spread and evolution of agricultural practices is the ideal free distribution (IFD) model, due in particular to its emphasis on the relation of habitat choice to local resource abundance and population density. In the first paper applying IFD to agricultural transitions, McClure, Jochim, and Barton (Chapter 9) examine archaeofaunal and floral data in eastern Spain in order to emphasize the role of different animal husbandry practices (sheep and goat dominant in 'Neolithic I' versus cattle and pig dominant in 'Neolithic II') in changing land use strategies. This paper exhibits how changes in husbandry practices sparked the transition from dispersed valley settlements where intensive agriculture was practiced, to aggregated villages where more extensive practices became the norm. In the final case study chapter of the volume, Kennett, Anderson, and Winterhalder (Chapter 12) use IFD to develop an integrative model for the colonisation of Oceania by examining the impact of food production on decisions to disperse and colonise remote islands. Kennett, Anderson, and Winterhalder produce a thorough model correlating appropriately with available archaeological data, in order to explain the colonization of remote Oceania as an episodic, not continuous process.

The final two chapters provide insightful layouts for future archaeological research employing human behavioural ecology theory to questions concerning the transition to agriculture from any cultural, ecological, or geographic context worldwide. Despite the striking depth of approach, Smith (Chapter 13) produces a widely accessible paper seeking to establish the relevant parameters for using HBE theory with archaeological datasets to construct models for the origins of domestication. Addressing the possible problem relating to the short-term, small-scale origin of most HBE concepts, Smith emphasizes the importance of HBE and foraging theory for addressing the full complexity of the entire developmental sequences leading to independent agricultural transitions around the globe. Moving from Smith's thorough examination of the challenges for applying HBE to archaeological data, Bettinger (Chapter 14) poses the ultimate challenge for future research on agricultural transitions: "how to think about the archaeological record in evolutionary terms". In a perfect closing paper to what will soon become a 'watershed volume' (as stated by Fitzhugh on the back cover), Bettinger proposes that the transition to agriculture be approached in a well-balanced neo-Darwinian framework able to identify the adoption of domesticates as a complex process of group selection. In order for group selection to be deciphered amongst the staggering diversity of the archaeological record, cultural transmission theory must be pared in tandem with human behavioural ecology to produce the analytical tools necessary for sorting out parts of the dynamic interchange between cultural selection, mutation, and drift.

While it is clear that many future challenges await the application of a neo-Darwinian framework to agricultural transitions worldwide, Kennett and Winterhalder have assembled a cornerstone displaying the utility of the framework as well as the parameters needed to employ it in future research from other regions. Once paired alongside cultural transmission theory, human behavioural ecology offers exciting ways to invigorate the study of agricultural transitions taking into account the myriad of affects that caused foragers to begin farming. The empirical studies in this volume establish the path for more model building and hypothesis testing in the future. Indeed, the greatest contribution to the neo-Darwinian analytical framework and our knowledge of the transition to agriculture will be adapting theory to lower-resolution datasets from important regions highlighting one of the most significant evolutionary processes in human, and global history.

About the reviewer:
Erick N. Robinson is currently undertaking PhD research in archaeology at the University of Sheffield on the cultural transmissions of Neolithic society in northeast France, Belgium, and the Netherlands. His primary interests lie in Mesolithic and Neolithic chipped stone tool industries, cultural transmission theory, and evolutionary ecology.