According to John Clark (2003: 34), the key concept in trade models is that "Trade has social evolutionary consequences. Without this foundational postulate nothing else matters". While obsidian studies in the Andes can also provide important insights on historical subjects such as the early peopling of the Andean highlands, and the changes in long distance interaction due to camelid caravans, the study of ancient exchange in the south-central Andes has direct bearing on exploring the basis and development of social and political power. Beginning from the assumption that long-distance exchange of products like obsidian in Late Archaic foraging contexts was based primarily on down-the-line exchange mechanisms, it is possible to develop inferences about the contexts of early caravan transport. Drawing on earlier discussions in chapters 2 and 3, the theoretical implications of early long-distance caravan exchange will be considered in terms of three principal variables: (1) herd size and status, (2) the scale of interaction, and (3) competitive behavior and exchange.