Radiocarbon dating reveals Rapa Nui not as isolated as previously thought

Archaeologists have analyzed ritual spaces and monumental structures across Polynesia, questioning the idea that Rapa Nui (Easter Island) developed in isolation following its initial settlement.

The first people in Polynesia settled the islands from west to east, rapidly expanding from Tonga and Samoa across the sea to central East Polynesia and from there to distant lands such as Hawai’i, Rapa Nui and Aotearoa/New Zealand.

After this initial colonization, it was thought that the islands of East Polynesia, particularly the remote Rapa Nui, remained isolated from the wider Pacific world. However, despite their remoteness, similar ritual practices and monumental structures have been observed in East Polynesia.

One such example is the construction of marae. These rectangular clearings were communal ritual spaces that, in some places, remain sacred to this day. However, they changed over time on different islands: on Rapa Nui, the famous moai sculptures were constructed and placed on the ritual temple platforms within marae.

To re-assess how ritual expression spread and developed throughout the region, Professors Paul Wallin and Helene Martinsson-Wallin from Uppsala University compared archaeological data and radiocarbon dates from settlements, ritual spaces and monuments across East Polynesia. Their results are published in the journal Antiquity.

“The migration process from West Polynesian core areas such as Tonga and Samoa to East Polynesia is not disputed here,” say the authors. “Still, the static west-to-east colonization and dispersal suggested for East Polynesia and the idea that Rapa Nui was only colonized once in the past and developed in isolation is challenged.”

The authors identified three separate phases of ritual activity in East Polynesia. The first reflects the west-to-east expansion, during which ritual activity was focused on actions such as burials and feasting. These sites were indicated by stone uprights. These activities were formed through continuous contact within interaction networks.

The second phase saw the clearer materialization of ritual through the construction of marae. Radiocarbon dates suggest that this idea to make ritual places more visible originated on Rapa Nui, then spread west back into central East Polynesia through existing exchange networks.

Finally, the third phase was defined by increased isolation, leading to internal changes. As hierarchical social structures developed independently in Rapa Nui, Tahiti, Hawai’i etc., large, monumental structures were built to display power.

“The most important finding is that, based on C-14 dating, we can observe an initial west-to-east spread of ritual ideas,” states Professor Wallin. “However, the complex, unified ritual spaces (known as marae) show earlier dates in the east.”

Overall, while the findings do not question the idea that Polynesia was peopled from west to east, they do show how subsequent ritual developments were much more complex than previously thought.

This indicates interaction networks between islands were robust and, importantly, new ideas were also transferred from east to west.

“This paper challenges commonly accepted ideas about the movement and development of ritual temple sites in East Polynesia,” concludes Professor Wallin. “The findings suggest a more complex pattern than previously thought. Initially, it has been shown that ritual ideas spread from west to east. Later, more elaborate temple structures developed on Easter Island, which then influenced other parts of East Polynesia in an east-to-west movement.”