«By Nathan B. Goodale A dissertation submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY WASHINGTON STATE ...»
Population size is strongly interconnected with the transition to agriculture largely based upon the link between food production and subsistence requirements of living organisms. In social terms, this relationship provided dynamic change within past societies including the number of roles (niches) for individuals to occupy, the situations that structure the nature of teaching and learning, and the number of people to interact with in social situations.
Anthropologists and archaeologists have long recognized that fluctuating population densities had an intricate association with the long-term process of humans settling into semi-permanent to permanent residences (Cohen 1977a, b). In most instances, the origin of these communities is associated with the transition to agriculture (Flannery 1972:1) and in others; the transition to resource intensification (Kramer and Boone 2002). This study focuses on population dynamics and the transition to agriculture/resource intensification in the Near East, where it took place leaving behind abundant archaeological data to interpret the role of population densities during the transition.
As agreed upon by most archaeologists, the origin of agriculture was associated with demographic change, or a significant increase in the number of humans defined as the Neolithic demographic transition (NDT) (Bocquet-Appel 2002). While we maintain this general agreement and definition, we currently need to explore more specifically why fertility increased and how human behavior shifted to invest in more children and larger families, ultimately allowing populations to grow. Bocquet-Appel (2002) suggests that fertility increase was linked to food quality and Kohler et al. (2008) specifically link the introduction of efficient storage technology that allowed upland dry farming to expand in the American Southwest.
The result of this expansion of dry farming comes in the form of a population explosion in many areas of the Southwest (Kohler et al. 2008).
The goal of this study is to build upon these hypotheses and explore in a more specific manner how food may be linked to increased fertility and why populations subsequently grew when they did, and not before. While this topic has been previously addressed, other proposals emphasize environmental factors (e.g., Richerson et al. 2001) and a significant departure from this is warranted to hypothesize the degree to which other factors contributed to population growth. This study represents a departure from environmental catalysts as a significant contributor and instead examines the food nutrient content, technology, and human behaviors that could have worked together to increase fertility and permit population growth.
shifting resource bases and their sensitivity (although maybe not in a conscious manner) to diets that enhance fertility (as other organisms are). These conclusions are supported by recent research which indicates certain foods provide nutrients that increase fertility in women. Additional archaeological evidence outlines that the advent of technology allowing those specific foods to be part of a stable diet likely contributed toward increased fertility. In other words, these foods associated with fertility were available on a longer basis than just the harvest season through the use of storage technology. Yet, just because people can have more children, this does not necessarily mean that they will invest more energy in their rearing. Subsequently, the demographic transition had to incorporate a change in human behavior allowing population growth. I suggest one potential explanation for this change is the introduction of younger age classes into the labor force, essentially underwriting the costs of having larger families (Hassan 1981; Kramer and Boone 2002).
In this study I utilize abundant archaeological data to model population growth rates from 20,000 to 8,000 years ago in the southern Levant of the Near East.
By utilizing new techniques and multiple variables as proxies for human population growth, we can demonstrate that population mimicked zero growth until approximately 11,200 cal BP, when the first growth rate increase is detected that is significantly larger than any before. I argue that this coincided with the development of food storage technology, allowing certain foods associated with increasing fertility to be available on a longer than seasonal basis, thus stabilizing human diet. Utilizing
models of the Neolithic demographic transition (e.g., Bocquet-Appel 2002 and others) but also complement and provide a potentially more detailed representation of population growth during the transition.
Dissertation Organization This study is organized into eight chapters and the following is a brief outline of the topics covered. Chapter Two covers evolutionary theory by presenting a generalized model of energetic budgets and nutrition utilizing optimality theory which I use to explore the nature of humans negotiating their diets and the potential that we will optimize behaviors to exploit the nutrients that will increase fertility.
Chapter Three defines demographic transitions in general, as well as how the Neolithic demographic transition has been defined, detected and understood. This allows for the argument to be made that additional data and analytical techniques can greatly enhance our understanding of the NDT. Chapter Four discusses the interconnection of the invention of storage technology, nutrition, and fertility. This chapter also examines ethnographic examples of labor force composition with specific attention to the age classes that are included in forager and farmer economic strategies. This sets the stage for providing an explanatory framework for why population increased when it did, and not before. Chapter Five provides the archaeological context for the southern Levantine NDT by focusing on the culture history and archaeological record of the area. Chapter Six presents the methods used
techniques utilized to argue that the variables of population proxies are monitoring and tracking population growth in a similar manner through time and thus, we are able to utilize them simultaneously to examine population growth rates. Chapter Seven presents the results and the overall characteristics of the Near East NDT and how it articulates with evolutionary trends revealed by population modeling. Chapter Eight then provides a discussion regarding the NDT and the convergence of fertility, food nutrition, storage technology, and labor organization with population growth.
Chapter Eight also provides the conclusions to this study and argues for the utility of this approach to understand the past. Ultimately, while it has become clear to archaeologists that the Neolithic Revolution was a long process, it is still highlighted by several revolutions and is clearly associated with a significant increase in fertility.
Due to the flexible nature of human behavior and associated foods that enhance fertility the NDT incorporated a substantial increase in the number of humans.
EVOLUTIONARY THEORY AND FOOD ACQUSITION: THE TRANSITION
FROM FORAGING TO FARMINGThe Neolithic period was specifically defined as the New Stone Age (Childe 1925), yet this period, more importantly, also incorporated a significant change in human subsistence strategies – namely, the transition from hunting and gathering to agriculture. The Neolithic transition around the world is regularly regarded by researchers as 1) the first time that people started to plant crops, which 2) led to a morphological change in those plants over time making them more productive, resulting in 3) a dramatic increase in human population. A central question in the evolution of human societies is how nutrition may affect human fertility and why it appears that agriculture provided the possibility of decreasing birth spacing;
ultimately setting the stage for population growth.
Evolutionary theory has been utilized to address many questions regarding human behavior. Yet it has seldom been applied to the understanding the forager farmer transition. It is important to develop a theoretical perspective from Human Behavioral Ecology (HBE) which, with its economic orientation, can be applied to understand the transition in adaptive strategies from foraging to farming. In this way we may be able to provide a greater understanding of some of the circumstances that encouraged population growth to be associated with the transition to food production.
I argue that significant new insights can be gained by understanding why there was a large-scale demographic change associated with the transition to food
detecting the demographic transition associated with the onset of the Neolithic (Bocquet-Appel 2002), yet we lack a clear understanding of why it happened when it did and what parameters outside of environmental shifts potentially influenced demographic change.
As a potential solution to this problem, in this chapter I examine the evolutionary costs and benefits of participating in social and economic behaviors and their association with both food quantity and quality. In other words, food nutrient quality may be just as, if not more, important as food quantity which is the traditional focus of HBE research. At the same time I highlight the competitive social nature of engaging in activities related to acquiring food. I argue that building theoretical models that incorporate both resource quantity (a traditional focus of HBE) and quality (minimally addressed by HBE) are necessary for providing explanatory frameworks regarding why the transition to agriculture resulted in a substantial increase in population.
Evolutionary Theory Applied to the Origins of Agriculture The transition to agriculture, most notably in the Fertile Crescent, has been explained by an almost countless number of theories ranging from crowding of people and potential domesticates into oases (Childe 1925), population pressure and food stress (Cohen 1977a, b), marginality models and population expansion (Binford 1968; Flannery 1973), culturally and socially driven origins model (Braidwood
coevolution and incidental domestication (Rindos 1980, 1984); and over-zealous entrepreneurs whose appetites for surplus set the stage for competitive feasting (Hayden 1990). While this only highlights the broad range of perspectives, it is not the goal here to provide a detailed overview of these or other theories, as this has recently been accomplished (Bar-Yosef and Meadows 1995; Kuijt and Goring-Morris 2002; Twiss 2007; Verhoeven 2004).
In the Near East, the application of evolutionionary models to understanding the transition to food production has been primarily a descriptive endeavor, focused on how artifact assemblages, mobility patterns, and site morphologies change through time (i.e. Bar-Yosef 1998). In contrast, there has been limited application of the actual principles of evolution via processes of natural selection and drift to understand the broad-scale adaptive changes associated with the transition (although see Munro 2004; Russell 1988; Zeder 2009).
Kennett and Winterhalder (2006) recently brought together researchers utilizing HBE (most consistently optimal foraging and patch choice) to discuss circumstances under which humans shifted from utilizing foraged resources to those that are cultivated. Interestingly, not one paper in the volume is dedicated to the origins of agriculture in the Near East, nor more specifically, the Fertile Crescent. In actuality, only one paper, McCorriston (2006), directly attests to the significance of this area and the adoption of agriculture throughout Arabia. None of the papers specifically apply theories from HBE to the transition to agriculture in this area of the
understanding the transition to agriculture in the Near East.
The tradition of using Darwinian principles to understanding the origins of food production has been situated within the framework of HBE (Cowan and Watson 1992; Gremillion 1996; Kennett and Winterhalder 2006 and papers therein; Rindos 1980, 1984; Smith 2002). Within this paradigm, food production has been considered as “a long-term uncertainty that promotes short-term tactics” (Bettinger 2006:314) where cultivation is associated with efficiency maximization in times of plenty and risk minimization in times of scarcity (Gremillion 1996). This finding demonstrates the implicit importance of applying an evolutionary understanding to the possible reasons why food production began because it posits the explicit importance of optimization (whether sensitivity to risk or efficiency) in relation to human decisionmaking practices (Winterhalder and Goland 1997:126).
Optimization and Energy Budget One of the base assumptions of evolution via natural selection is the importance of the energy budget, since it is assumed a person who allocates time and energy efficiently will be more reproductively fit. The energy budget encompasses both reproductive effort, including time spent obtaining mates and providing for offspring, and somatic effort, or maintenance of oneself in terms of growth, development, and resource procurement (Boone 2002). Although reproductive and somatic efforts support the same ultimate goal of fitness, actions to achieve one or the
as to when it is more advantageous to invest in one arena to the possible detriment of the other.
A central focus of HBE and the energy budget concept is the idea of optimization. A researcher utilizing optimality reasoning will directly ask how an individual decides when to invest in one effort at the possible detriment to another (Foley 1985). Optimization is a process whereby humans weigh the cost, risk, and benefit of a behavior before making the decision to participate, when to participate, or at what level they will participate. HBE suggests that in food-acquisition activities, humans will tend towards optimization (Winterhalder and Kennett 2006)s when deciding whether (and how) to expend energy on food gathering or any other efforts.