In his best-selling book of 2005 To collapseJared Diamond offered the social collapse of Easter Island (aka Rapa Nui), circa 1600, as a cautionary tale. Diamond essentially argued that the destruction of the island’s ecological environment triggered a downward spiral of internal warfare, population decline and cannibalism, resulting in an eventual collapse of social and political structures. It is a story now being challenged by a team of researchers who have studied the archeology and cultural history of the island for many years.
In a new paper published in the Journal of Archaeological Science, the researchers offer intriguing evidence suggesting that the people of Rapa Nui are still thriving after 1600. The authors suggest this warrants a rethinking of the popular story that the island was destitute when Europeans arrived in 1722.
“The extent to which their cultural heritage was passed on — and continues to be present today through language, art and cultural practices — is quite remarkable and impressive,” study co-author Robert DiNapoli, a doctoral student in anthropology at the University of Oregon, said. said Sapiens. “This degree of resilience has been overlooked because of the collapse story and deserves recognition.”
Easter Island is famous for its giant monumental statues called moai, built by early settlers some 800 years ago. Scholars have marveled at the moai on Easter Island for decades, reflecting on their cultural significance, as well as how a Stone Age culture managed to carve and transport statues that weighed a whopping 92 tons. The moai were usually mounted on platforms called ahu†
In 2012, Carl Lipo of Binghamton University and his colleague, Terry Hunt of the University of Arizona, showed that you can use a 10-foot, 5-ton moai a few hundred meters with only 18 people and three strong ropes through a rocking motion. In 2018, Lipo proposed an intriguing hypothesis about how the islanders put red hats on some moai† they can weigh up to 13 tons. He suggested that the residents use ropes to roll the hats up a ramp. And as we reported last year, Lipo and his team concluded (based on quantitative spatial modeling) that the islanders likely chose the statues’ locations based on the availability of freshwater resources, according to their 2019 paper in PLOS One.
For this latest study, Lipo and his colleagues turned their attention to establishing a better chronology of Rapa Nui’s human habitation. While it is generally agreed that humans arrived in Eastern Polynesia and Rapa Nui sometime in the late 12th century or early 13th century, “We don’t really know much about the timing and pace of events that are in relation to ahu construction and moai transportation,” Lipo told Ars. “We generally know that this kind of construction happened sometime before the Europeans, but exactly how these events happened was vague.”
The team applied a Bayesian model-based method to existing radiocarbon dates collected from previous excavations at 11 different sites with ahu† The model also integrated the sequence and position of the island’s distinctive architecture, as well as ethnohistoric records, quantifying the beginnings of monument building, the speed at which it occurred, and when it likely ended. This allowed the researchers to test Diamond’s “collapse” hypothesis by building a more precise timeline of when construction took place at each of the sites.
“Our results show a lack of evidence for a pre-contact ‘collapse’ and instead provide strong support for a newly emerging model of resilient communities that continue their long-term traditions despite the consequences of European arrival,” the authors wrote. In addition, “Methodologically, our model-based approach to testing hypotheses regarding the chronology of collapse can be extended to other case studies around the world where similar debates remain difficult to resolve.”
The work has met with some mixed opinions from fellow Lipo archaeologists. “Their work adds to the growing body of evidence that has accumulated over the past 10 years that the earlier accounts of the Easter Island collapse are incorrect — and need to be reconsidered,” Seth Quintus, an anthropologist at the University of Hawai’ i , Mānoa, Sapiens told me. Quintus is not involved in Lipo’s investigation.
However, UCLA archaeologist Jo Anne Van Tilburg – also not involved in the study – expressed skepticism. “The collapse story as these authors describe it is a straw man they set up that doesn’t accurately reflect the actual hypothesis,” Van Tilburg told Sapiens. She thinks Diamond’s collapse hypothesis is still a viable option, arguing that his hypothesis was not based on a single collapse event, but on a series of events that led to the destruction of the social fabric, exacerbated by the arrival of European explorers.
Lipo admits that some critics have suggested that his team picked the radiocarbon dating, which he dismisses as “just baloney and misinformed thinking.” According to Lipo, some radiocarbon samples may be biased because of “old carbon” issues: that is, the samples were taken from chunks of burnt wood or charcoal, for example. “Some parts of trees may be much older than others due to the fact that they were growing when the tree was just getting started,” he said, which may skew the results of radiocarbon dating.
So he and his team filtered their radiocarbon samples down to only those they were certain to be associated with human occupation and human events, meaning they analyzed a smaller subset of all available ages — not an uncommon strategy. And the results for colonization estimates are about the same as before.
Other critics have insisted that there must be a time period preceding the earliest radiocarbon age anyone has found to date. “This is an argument based on the lack of evidence, i.e. something happened for which we will never have a record,” Lipo said. “As scientists, our strategy has been to explain the evidence we find, which involves explaining the archaeological record (and radiocarbon ages) we have available. To speculate about something that is inherently unknowable and invisible is a matter of faith instead of science.”
In addition, due to the island’s small size, Lipo says the human impact would have been “almost instantaneous.” So “unless people came to the island and hid in a single cave for centuries, we would have evidence to show their impact,” he added.
At the other end of the chronology, Lipo says his team has seen less backlash. “Others are starting to show that” ahu build, moai carving and other activities continued not only until the arrival of Europe in 1722, but also after that time,” he said. “The whole idea that all activities related to the construction and use of monumental architecture took place at some point in the late 17th century simply has no empirical basis.”
As for the Tilburg “straw man” accusation, Lipo has none. “Calling something a ‘straw man’ hypothesis is a way of changing one’s story to say that ‘we’ve been saying that all the time,'” he said. “It is a misleading statement and completely misleading.” He argues that Diamond’s “evidence” for the collapse argument was quite specific: the arrival of humans on the island as early as 700 CE, an “ecological paradise” that existed when humans arrived, huge population sizes (up to 30,000), evidence of erosion, overfishing, widespread group-level warfare and cannibalism.
“Our work consisted of examining the archaeological evidence that should be apparent to support his claims,” Lipo said. “We’re just lacking in anything remotely like what Diamond has said. Instead, we’ve learned that his reasoning is based on a deeply flawed misunderstanding of the island’s historical record (particularly the impact of post-European conditions) and also on bad assumptions about human behavior in general.”
Fieldwork is not possible at this time due to the ongoing global pandemic. But Lipo and his colleagues plan to continue their study of Easter Island and test hypotheses with data generated from the record through additional fieldwork, remote sensing and artifact analysis. According to Lipo, they will expand their analyzes to focus more on explaining why the communities on Rapa Nui have worked together so consistently to create the island’s spectacular architecture.
“Diamond (and others) tend to portray statue construction as a ‘cultural’ thing that got out of hand,” Lipo said. “But we haven’t found that answer very satisfying. Why Rapa Nui and not elsewhere on the other side of the Pacific? Why do it in the first place, and then why do it over and over again? Figuring this out is essential if we really solve the ‘mystery’ of Easter Island.”
DOI: Journal of Archaeological Science, 2020. 10.116/j.jas.2020.105094 (About DOIs).