The origins of East Polynesian culture are traced to a regional homeland that was centered on the Society Islands but which also included neighboring archipelagoes. Archaeological evidence suggests a fall-off through time in the frequency of opensea voyaging within this homeland, with marked declines in voyaging and interaction after A.D. 1450. A range of social and environmental factors may have contributed to these declines. The regional distribution of terrestrial resources is significant because the smallest islands often suffered the most acute consequences of human-induced environmental change. Tahiti, in the Society Islands, is unique in terms of the unparalleled scale of its resource base and its high degree of voyaging accessibility. If Tahiti and the Societies played the role of a regional hub in early interaction spheres, developments in Tahiti may have influenced inhabitants of the outer archipelagoes. Specifically, if circumstances restricted the flow of timber and canoes from the Societies to outlying archipelagoes, and this coincided with the depletion of forest reserves on the smaller outlying islands, these developments could help explain the contraction of early central East Polynesian interaction spheres. It is likely that voyaging patterns in the Marquesas and the Pitcairn Islands, comparatively isolated archipelagoes, were little affected by internal developments in the Societies. KEYWORDS: East Polynesia, ancient voyaging, interaction spheres.