East Polynesian Islands as Models of Cultural Divergence: The Case of Rapa Nui and Rapa Iti

ABSTRACT

The diverse island societies of East Polynesia are well-suited as models for comparative evolutionary analysis. Settled ca. 750 BP by a common ancestral population, colonists of the remote corners of the Pacific shared a pool of cultural traits that included commensal species, language, technology, and other cultural practices. Following colonization however, island populations diverged in language, subsistence practices, degree of territoriality, settlement patterns, investment and forms of monumental architecture, and social organization. Driven by historical circumstances and varied environmental conditions, this divergence presents evolutionary case studies of alternative paths of cultural change. One explanatory approach to this evolutionary divergence involves isolating the critical ecological parameters that likely constrained and shaped the diverse history of island populations. Here, we offer a comparative evolutionary analysis that explores the divergent histories of two marginal East Polynesian islands: Rapa Nui and Rapa Iti.

Keywords:

• costly signaling
• Easter Island
• evolutionary ecology
• Polynesia
• settlement patterns
• territoriality

ACKNOWLEDGEMENTS

We thank Jessica Stone and two anonymous reviewers for helpful suggestions that improved the content of the manuscript.

Notes

1. Although there is little ethnohistorical support for the name “Rapa Iti” (Anderson et al. 2012a), we use the name here rather than simply “Rapa” for ease of comparison.

2. In addition to human land-clearing for agriculture, the introduction of rats contributed to the massive deforestation of both islands (Hunt 2007; Prebble et al. 2013).