Migration was a key social process contributing to the creation of the ‘Chaco World’ between AD 800 and 1200. Dynamic social network analysis allows for evaluation of several migration scenarios, and demonstrates that Chaco’s earliest ninth-century networks show interaction with areas to the west and south, rather than migration to the Canyon from the Northern San Juan. By the late eleventh century, Chaco Canyon was tied strongly to the Middle and Northern San Juan, while a twelfth-century retraction of networks separated the Northern and Southern San Juan areas prior to regional depopulation. Understanding Chaco migration is important for comprehending both its uniqueness in U.S. Southwest archaeology and for comparison with other case studies worldwide.

Ritual practices and their associated material paraphernalia played a key role in extending the reach and ideological impact of early states. The discovery of a leather bag containing snuffing tablets and traces of psychoactive substances at Cueva del Chileno in the southern Andes testifies to the adoption of Tiwanaku practices by emergent local elites. Tiwanaku control spread over the whole of the south-central Andes during the Middle Horizon (AD 500–1100) but by the end of the period it had begun to fragment into a series of smaller polities. The bag had been buried by an emergent local elite who chose at this time to relinquish the former Tiwanaku ritual practices that its contents represent.