Group Mobility versus Interaction Networks
In Middle and Upper Palaeolithic contexts, analyzing the causes underlying raw material distributions is a major difficulty. Do observed distances correspond to the customary movements of groups across the landscape, or to displacements of items exceeding the range of such movements? A related matter is the distinction between direct acquisition and indirect acquisition through trade and exchange of raw materials, the two major types of mechanisms responsible for the presence of intrusive items in archaeological assemblages.
When distributions are interpreted in terms of group mobility, the underlying assumption is that of a procurement embedded in other subsistence-activities, and distances traveled are construed as a measure of the size of the area exploited for subsistence-related purposes. In particular, the maximum transport distance (MTD) recorded for individual lithic assemblages is used as a proxy for the maximum size of territories. Economic necessities arguably give rise to specific mobility strategies, which may vary through time and/or space, and translate into different scales and rates of movement.
When distributions are interpreted in terms of intergroup relationships, thereby implying exchange, MTDs are seen as the material correlates of the maximum extent of interaction networks expected as part of the survival and social process. Distances involved can be very great insofar as items can travel a long way through successive transfers. The existence of alliance networks is rarely contemplated for the Middle Palaeolithic. They are supposed to have developed only in the Upper Palaeolithic, along with the essential social structures making interaction possible.
Criteria for Exchange
Establishing the magnitude of Palaeolithic group mobility from the extent of interaction networks is fraught with difficulties, since direct and indirect procurement may produce similar patterns. However, in some cases, the possibility of a ‘down-the-line’ mode of distribution resulting from successive reciprocal exchanges can be considered in view of the results of a cross-cultural comparison of ethnographic records of exchange. These show that highly valued items are conveyed over extreme distances (600-3000 km) by such a mode. Archaeologically, the prerequisites for an interpretation in terms of ‘down-the-line’ trade are
(1) the presence of at least one site where the item may have been passed on, located between the source and the furthest known occurrence of that item and
(2) the presence in the ‘relay’ site of another item made from the same raw material or from a raw material of close geographical provenance (see Exchange Systems).
The Cultural Ecological Paradigm
Whether plotted transfers are interpreted as correlates of group mobility or as proxies for the extent of interaction networks, the issues are generally addressed in relation to the cultural ecological paradigm (see Cultural Ecology). Behavioral models devised to assess the size of exploited territories and the extent of spatial networks of connection among groups are mostly based on ethnographic accounts of present day hunter-gatherers and rely heavily on ecological approaches (Figure 1). Hunter-gatherer subsistence strategies are supposed to be directly influenced by the nature, abundance, and accessibility of resources. In turn, these strategies may result in different patterns, rates, and scales of movement across a landscape, as well as in variably dense and extensive interaction networks. In particular, the scale of group mobility appears indicative of adaptation to different environmental contexts, moves being longer or more frequently recorded over long distances in the most exacting environments, Similarly, risk-minimizing strategies in high-risk environments, where resources are liable to important fluctuations, promote the creation of wide-ranging social networks through which information about vital resources is dispensed, the exchange of goods forming an integral part of these strategies. When interpreting distributions of transfers, it is suggested that in both cases the frequency with which particular distances are covered is possibly more significant than the magnitude of transfers (see Hunter-Gatherers, Ancient).
Which past hunter-gatherers’ dealings with space were environmentally constrained. Drawing on bibliographical information about stone raw material transfers in 500 lithic assemblages, evidence for change and variability is presented below, and particular points are illustrated and discussed in relation to these major issues.
The methodologies used to characterize and identify sources of the lithic materials discussed in this article have changed over the years. Earlier attempts (in the 1980s) were mainly based on the sole macroscopic characterization of rocks by color, texture, and visible inclusions. This method nevertheless allows materials to be sourced with a measure of reliability when it is grounded in a thorough knowledge of the range of regionally available raw materials. In later publications (from the early 1990s to the present), the most widely used approach involves a combination of macroscopic observations and petrographic microfacies analyses, complemented by micropalaeontological analyses of thin sections. On the whole, chemical methods, more complex, costly, and time-consuming, have been less used, and either on specific materials such as obsidian and radiolarite, or to narrow the range of potential sources when other approaches were powerless to do so (see Chemical Analysis Techniques).
World History
