Hunter-Gatherer Behavior

Human Response During the Younger Dryas

Metin I Eren

• Publisher: Routledge
• Year: 2016
• Print ISBN:
  9781598746020
• eBook ISBN:
  9781315427119
• Topic: Social Sciences
• Subtopic: Archaeology
• Index: Social Sciences

A major global climate event called the Younger Dryas dramatically affected local environments and human populations at the end of the Pleistocene. This volume is the first book in fifteen years to comprehensively address key questions regarding the extent of this event and how hunter-gatherer populations adapted behaviorally and technologically in the face of major climatic change. An integrated set of theoretical articles and important case studies, written by well-known archaeologists, provide an excellent reference for researchers studying the end of the Pleistocene, as well as those studying hunter-gatherers and their response to climate change.

1
On Younger Dryas Climate Change as a Causal Determinate of Prehistoric Hunter-Gatherer Culture Change

Metin I. Eren

Introduction

At the terminal end of the Pleistocene there was a sharp temperature downturn that briefly reversed the general warming trends that were evident prior to the Holocene (Straus and Goebel 2011:259). This climatic cooling event, called the Younger Dryas, has received considerable attention as of late, which is significant when one contemplates that “no event in the climate record has received more attention than the Younger Dryas” (Broecker et al. 2010:1078). It was within this context that the short-lived, extraterrestrial Younger Dyras, origins hypothesis generated substantial debate (e.g., Buchanan et al. 2008; Collard et al. 2008; Firestone et al. 2007; Haynes et al. 2010; Holliday and Meltzer 2010; Paquay et al. 2009; Surovell et al. 2009). However, even more plausible, traditional explanations for Younger Dryas origins (e.g., Alley 2007) have also recently been questioned (e.g., Broecker et al. 2010; Wunsch 2010). Nevertheless, despite a lack of consensus regarding the origins of the Younger Dryas, it is still evident that between 11,000 and 10,000 BP (12,900–11,600 cal BP)¹ a singular event affected climates around the world, which in turn impacted local environments. Yet it appears that these climatic and environmental changes were not globally ubiquitous, nor uniform in strength. Thus, for the archaeologist, two questions naturally arise. First, how dramatic was Younger Dryas climate and environmental change in different geographic locations? Second, in what ways did terminal Pleistocene hunter-gatherers have to adapt behaviorally and technologically during the Younger Dryas? It was these two questions that researchers specifically addressed in a symposium entitled “Hunter-gatherer Transitions through the Younger Dryas: A Global Perspective” at the 73rd Annual Meeting of the Society for American Archaeology in Vancouver, Canada (2008). And it is these two questions that researchers elaborate upon in this volume.

Before moving on to more specific topics, it is worth briefly reflecting upon why the latter two questions necessitate a book, and what the value of this book and the contributions within it ultimately entail. After all, it has been understood by archaeologists for some time that climatic and environmental change does not “determine” prehistoric cultural and technological change. But it is for that very reason, the lack of any direct one-to-one correlation between climate and culture change, that a comparative examination of prehistoric hunter-gatherer adaptations in a global context is useful. Only through juxtaposed, focused case studies of prehistoric hunter-gatherers can we understand the diversity of adaptive responses humans can espouse, which in turn allows us to establish boundaries of behavioral variability (Shea 2011). Comprehending how much behavioral variability humans are capable of, especially in relation to the context(s) in which that variability occurs, permits us to ask broader, fundamental questions about the mechanisms of human adaptation, survival, and evolution.

The inspiration for the symposium and this volume came from research I conducted during my first two years of graduate school (2005– 2007). Having been invited to present a paper at the 2007 festschrift of my undergraduate advisor, Ofer Bar-Yosef, I wished to expand upon my nascent work in the late Pleistocene of the North American lower Great Lakes region. My graduate advisor, David Meltzer, recommended that I reexamine whether or not the Younger Dryas impacted Paleoindian behavior there, an appropriate topic for the festschrift given that Professor Bar-Yosef himself investigated the Younger Dryas impact on Levantine hunter-gatherers (e.g., Bar-Yosef 1998, 2002; BarYosef and Belfer-Cohen 2002; Bar-Yosef and Meadow 1995). To my surprise, there did not appear to be any influence of Younger Dryas climate change upon Paleoindian culture change (Eren 2009). Looking back, as with any research project, there are some things in the paper that I would have done differently², although there are several conclusions still quite valid today (see the discussion below). Regardless, the experience was overall quite positive, and given the unexpected result, I became curious as to whether or not the influence of Younger Dryas climate change upon hunter-gatherer adaptations was exaggerated in other regions of the world. Assembling some of the most innovative minds on the topic, including David Meltzer and Ofer Bar-Yosef, was the most fruitful and efficient way to attack the subject.

Demonstrating that the Younger Dryas Impacted Hunter-gatherer Behavior

Up-to-date syntheses on the causes of, and debates surrounding, the Younger Dryas itself can be found in Meltzer and Holliday (2010), Fiedel (2011), Alley (2007), Broecker et al. (2006), Broecker et al. (2010), and Wunsch (2010). The goal in this introductory chapter will be to explore a generalized, scientific framework for establishing climate and environmental change as a causal determinate of hunter-gatherer behavior.

There was great diversity of evolving hunter-gatherer adaptations between 11,000 and 10,000 BP (12,900–11,600 cal BP). Determining whether or not these changes were directly in response to Younger Dryas climate and environmental change is challenging, to say the least. How should a researcher who suspects Younger Dryas climate to be causal factor of hunter-gatherer culture change go about proving it? I suggest that the systematic examination of three increasingly complex “if-then” statements may be the most robust way to support prehistoric climate-induced, culture change. The implementation of such a program is no easy task, but required if one is to move beyond mere assertion.

If-then Statement 1

If Younger Dryas climate change is influencing culture change, then there should be evidence of both environmental change and culture change.

This first expectation may appear simplistic, but it is the foundation upon which a casual relationship between Younger Dryas climate and terminal Pleistocene culture must rest. Demonstrating change, either environmental or cultural, can be a tricky endeavor. In terms of climatic and environmental change (or at least the establishment of change in ecological parameters directly salient to mobile hunter-gatherers), the fact of the matter is that the Younger Dryas does not currently appear to have been an invariable global force (in addition to papers in this volume, see Straus and Goebel 2011). In fact, it appears to have affected adjacent regions differently (compare Ellis et al. 2011 vs. Lothrop et al. 2011), and some regions not at all. As such, Younger Dryas environmental change should never be taken as a given and should be explicitly demonstrated.

While determining a temporal scale of analysis for environmental change during the Younger Dryas is certainly challenging (i.e., should change be measured every 1000, 500, or 100 years?), archaeologists are in the difficult position of also inferring what level of environmental shift would have been perceptible enough to humans (consciously or unconsciously) to provoke long-term behavioral responses. For example, Meltzer and Holliday’s (2010) exhaustive examination of environmental change and the archaeological record in the Rocky Mountains and Great Plains indicate that in those regions “Paleoindians were not constantly scrambling to keep up with Younger Dryas age climate changes” (p. 31). In those r egions, climate and environmental change simply were not as extreme as in other locations. Thus, for a group of flexible hunter-gatherers who frequently responded to daily, weekly, and seasonal weather patterns, adapting to extended climatic and environmental variation “would have been nothing new to them” (Meltzer and Holliday 2010:31–32).

In addition to understanding the range of challenges inherent in studying Younger Dryas climate and environmental change, it is also important for researchers to understand differing scales and types of analyses in documenting hunter-gatherer culture change. In regard to late Pleistocene hunter-gatherers of the North American, lower Great Lakes region, I argued that there was no change in broad categories of tool classes from early to late Paleoindian times during the Younger Dryas (Eren 2009). Ellis et al. (2011:537) criticized the approach of using broad tool categories, arguing that “such gross categories could mask a wide range of activity variability.” Although this may be so, categories that are too narrowly defined might mask important similarities as well. For an illustrative example, we can briefly look at Great Lakes Paleoindian toolstone procurement distances. Using a 50 km-scale of analysis, Ellis et al. (2011) show that the early Paleoindian record in the lower Great Lakes seems to be biased toward shorter average toolstone procurement distances than later times (e.g., Figure 1.1a). While small, biased sample sizes are certainly playing their part in this pattern, it is interesting to note that if the scale of analysis changes from 50 km to 100 km, some of the differences between early and middle Paleoindian groups nearly disappear (Figure 1.1b). The point here is not to say that any one scale of analysis is right or wrong, but instead that different scales of analysis are arbitrarily determined by the researcher and ultimately provide different types of information, be it for tool classes or toolstone procurement distances.

Figure 1.1 The number of early Paleoindian (black) and middle Paleoindian (grey) sites at varying toolstone procurement distances. When the toolstone, procurement distance scale is set at 50 km (a), early Paleoindian sites appear to be closer to toolstone sources (0–50 km), while middle Paleoindian sites do not (see Ellis et al. 2011:539). But when the toolstone procurement distance scale is set at 100 km (b), there is little to no difference between the number of early and middle Paleoindian sites in the 0–100 km- and 101–200 km-categories. Note that at either scale, only early Paleoindian sites appear to possess toolstone, procurement distances over 250 km (a) [recreated from Ellis et al. 2011: 539].

The perceived extent of Younger Dyras environmental change may be inaccurate due to the nature of proxy data or the collection of that data (Grimm et al. 2009; Wunsch 2010). Radiocarbon dating and calibration can be extremely problematic due to the well-known radiocarbon “plateau,” making it difficult to chronologically covary hunter- gatherer adaptations with environmental change (Meltzer and Holliday 2010). Likewise, the demonstration of culture change can be just as challenging as the demonstration of environmental change, in no small part due to the nature of late Pleistocene hunter-gatherer data. For instance, in my previous investigation of lower Great Lakes Paleoindians of the Younger Dryas Chronozone, I examined five material characteristics of Paleoindian behavior (Eren 2009): 1) the type composition of stone-tool assemblages; 2) site/assemblage sizes; 3) kinds of subsurface cultural features documented; 4) toolstone procurement distance; and 5) the geographic location of sites. Ellis et al. (2011) asserted that some of the selected traits I investigated were analytically frail in comparison to three they examined, which in addition to toolstone procurement distance included the frequency of Paleoindian site presence and the geographic distribution of Paleoindian sites. But in the same way that the identification of subsurface features may be influenced by postde-positional processes (explicitly acknowledged in Eren 2009), both frequency and distribution of Paleoindian sites can be severely skewed by collector bias, postdepositional processes, or misinterpretations of time-depth (all explicitly acknowledged by Ellis et al. 2011, but still taken at “face value,” p. 539). The fact of the matter is that there is currently no empirical way to argue that any one of these traits is “more robust” than another. Indeed, while archaeologists studying Younger Dryas hunter-gatherers should always strive for rigor, if we start to selectively disdain the accumulated [archaeological] record because of its imperfections (Shott 1997), we eventually will end up with nothing left to analyze. A more positive and productive way forward, indeed the only way forward, is to explicitly acknowledge biases in any and all traits we wish to examine, rather than subjectively eschewing particular ones we believe to be problematic. Making conclusions from the data we have now does not prevent the collection of new data in future, nor does it hamper different conclusions to be made from that new data, whether we are talking about sub-plowzone features, site frequency, or some other analytical category.

In the event that researchers can demonstrate environmental and culture change during the Younger Dryas, they will be ready to tackle the next if-then statement.

If-then Statement 2

Assuming evidence of climate and culture change is demonstrated, if Younger Dryas climate change is influencing culture change, there should be tight temporal covariance of climatic/environmental events with behavioral changes.

Researchers who suspect Younger Dryas, climate change influenced hunter-gatherer culture change need to demonstrate chronological covariance between the two, in some cases taking into consideration time lags. However, covariance can be difficult to substantiate given that dates for geological, environmental, and archaeological events can be notoriously imprecise (Dillehay 2009). Such difficulty is exemplified by the meticulous work of Jones (2009), who examined climate change, patch choice, and subsistence intensification at the French terminal upper Paleolithic site of Pont d’Ambon. In the Dordogne River valley, she documented a decline in patch evenness between 13,000 and 9500 BP, resulting in increased grassland. In response, it appears that prehistoric hunter-gatherers over time intensified their use of the grassland patch, as evidenced by the increasing abundance of grassland fauna (spe...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Contents
• List of Illustrations
• 1. On Younger Dryas Climate Change as a Causal Determinate of Prehistoric Hunter-Gatherer Culture Change
• 2. Climate, Technology, and Society during the Terminal Pleistocene Period in South America
• 3. The Human Colonization of the High Andes and Southern South America during the Cold Pulses of the Late Pleistocene
• 4. Kelp Forests, Coastal Migrations, and the Younger Dryas: Late Pleistocene and Earliest Holocene Human Settlement, Subsistence, and Ecology on California's Channel Islands
• 5. Evaluating the Effect of the Younger Dryas on Human Population Histories in the Southeastern United States
• 6. Hunter-Gatherer Adaptations of the Central Plains and Rocky Mountains of Western North America
• 7. Coping with the Younger Dryas in the Heart of Europe
• 8. Europe in the Younger Dryas: Animal Resources, Settlement, and Funerary Behavior
• 9. The Younger Dryas and Hunter-Gatherer Transitions to Food Production in the Near East
• 10. The Younger Dryas in Arid Northeast Asia
• 11. Looking for the Younger Dryas
• Index
• About the Authors