Easter Island Statues
© Dale Simpson, Jr.The geology of the stone tools used to make the stone statues on Easter Island delivers tantalising clues about a bygone culture.
The remote Easter Island, known locally as Rapa Nui, lies 2,300 miles off Chile's Pacific coast, a mysterious place best known for its giant stone statues. The common narrative states that the enormous heads were built by Polynesian seafarers who, the story goes, then brought about the demise of their own society through internal squabbles and draining of the island's natural resources.

However, a new study published in the Journal of Pacific Archaeology suggests the true story of early civilisation on Polynesia's easternmost outpost is more complex. Archaeologists found evidence of a sophisticated society where the people shared information and collaborated, by analysing the chemical make-up of the tools used to build the sculptures.

"For a long time, people wondered about the culture behind these very important statues," says Laure Dussubieux, one of the study's authors and a scientist at Chicago's Field Museum of Natural History. "This study shows how people were interacting, it's helping to revise the theory."

"The idea of competition and collapse on Easter Island might be overstated," adds lead author Dale Simpson, Jr., an archaeologist from the University of Queensland. "To me, the stone carving industry is solid evidence that there was cooperation among families and craft groups."

The first settlers arrived on the island around 1200 AD. "The founding population, according to oral tradition, was two canoes led by the island's first chief, Hotu Matu'a," says Simpson. In its heyday, the island's population stood at tens of thousands, forming the complex society that carved the statues it is now most famous for.

These statues, or moai, are full-body figures that became partially buried over time, hence their common nickname of "Easter Island heads". The statues represent important ancestors of the Rapa Nui population and number almost a thousand, the largest of which is over 20 metres tall.

According to Simpson, the size and number of the moai hint at a complex society. "Ancient Rapa Nui had chiefs, priests, and guilds of workers who fished, farmed, and made the moai. There was a certain level of sociopolitical organization that was needed to carve almost a thousand statues."

Four statues in the inner region of Rano Raraku, the statue quarry, were excavated by Jo Anne Van Tilburg of Cotsen Institute of Archaeology, along with her Rapa Nui excavation team. To better understand the society responsible for their creation, Simpson, Dussubieux, and Van Tilburg closely examined 21 of about 1,600 stone tools that had been recovered in Van Tilburg's excavations.

For Van Tilburg, the goal of the project was to gain a better understanding of how tool makers and statue carvers may have interacted, thus gaining insight into how the statue production industry functioned.

The tools, also called toki, were made of a volcanic stone called basalt, and the specific composition of about half of those recovered suggested how they were used.

"Basalt is a grayish rock that doesn't look like anything special, but when you look at the chemical composition of the basalt samples from different sources, you can see very subtle differences in concentrations of different elements," explains Dussubieux. "Rock from each source is different because of the geology of each site."

"We wanted to figure out where the raw materials used to manufacture the artefacts came from [...] We wanted to know if people were taking material from close to where they lived."

There are at least three different sources on Easter Island that the Rapa Nui used for material to make their stone tools. Those different quarries, the tools that came from them, and the movement between geological locations and archaeological sites shed light on prehistoric Rapa Nui society.

Dussubieux led the chemical analysis of the stone tools. The archaeologists used a laser to cut off tiny pieces of stone from the toki, and an instrument called a mass spectrometer was used to analyse the amounts of different chemical elements present in the samples.

The results pointed to a society that Simpson believes required significant cooperation. "The majority of the toki came from one quarry complex - once the people found the quarry they liked, they stayed with it," Simpson explains.

"For everyone to be using one type of stone, I believe they had to collaborate. That's why they were so successful - they were working together."

To Simpson, this evidence of widespread collaboration contradicts the popular narrative that early Rapa Nui exhausted their natural resources and a civil war drove them into oblivion. "There's so much mystery around Easter Island, because it's so isolated, but on the island, people were, and still are, interacting in huge amounts," says Simpson.

While the society was ultimately decimated following the arrival of Europeans in the 18th century, Rapa Nui culture lives on. "There are thousands of Rapa Nui people alive today - the society isn't gone," Simpson adds.

Van Tilburg, however, urges caution in interpreting her team's findings and encourages further study, admitting that the possible use of coercion in Rapa Nui interactions cannot be ruled out. "The near exclusive use of one quarry to produce these 17 tools supports a view of craft specialization based on information exchange, but we can't know at this stage if the interaction was collaborative."

In addition to potentially introducing a more nuanced perspective on the history of the Rapa Nui, Dussubieux notes that the study is important because of its wider-reaching insights into how societies work.

"What happens in this world is a cycle, what happened in the past will happen again," says Dussubieux. "Most people don't live on a small island, but what we learn about people's interactions in the past is very important for us now because what shapes our world is how we interact."