Easter Island, also known as Rapa Nui, is a small island in the Pacific Ocean that is famous worldwide for the hundreds of large stone monoliths (moai) found across the island. Although popularly referred to as stone ‘heads’, most of the monoliths actually possess long bodies, with the largest constructed standing over 30 feet tall and weighing 82 tons. The mystery of how almost 900 moai were carved and transported, mostly between 1250 CE and 1500 CE, only to be toppled and abandoned by the time Europeans arrived in the 18th century has long been a source of fascination for researchers, explorers, and the general public (particularly in the West).
Recently, I wrote a short article for the online magazine Aeon discussing research on the island’s history. In particular I discussed the misrepresentation that surrounds an ongoing academic debate over whether there was ever a historical ‘collapse‘ of the population of Easter Island caused by the overexploitation of environmental resources and intense tribal conflicts. This is the thesis summarised by Jared Diamond in his popular science book Collapse (2005), but it represents a view which has come under increasing criticism over the past decade from a group of scholars led by the anthropologists Terry Hunt and Carl Lipo. This alternative group question the validity of the evidence cited for a population decline and instead argue that settlement on the island, up until the arrival and destructive slave raids of European colonialists, was marked not by environmental mismanagement and disastrous decline but by sustainable practices and a remarkable degree of continuity.
The arguments and counter arguments that make up this debate are fascinating but they would require a much longer article, or series of articles, to do proper justice to their complexity. However, my article in Aeon provides a good introduction for those that are curious about the topic and I would also heartily recommend Will Kirkland’s neat overview of the controversy and the environmental blogger Michael Tobin’s critical commentary of the Lipo and Hunt thesis (including the lengthy discussion in the comments) from a few years back.
I wrote about the topic on the basis of a flurry of articles (such as this one in Ars Technica) that appeared earlier in the year and overhyped the results from a single new study by Lipo, Hunt and colleagues as if it resolved the debate. The study analysed the shapes of obsidian artefacts found across the island, which were previously believed to be remnants of weapons, and argued that their shapes meant that they were more likely to be agricultural or ritual implements (available here). This is an interesting finding, and it certainly adds an interesting new piece of evidence to the research literature about the island, but it hardly constitutes definitive proof for any broader theory.
And this was (and remains) my core point: the complexity of the research evidence and the lack of a clear consensus amongst the relevant experts means that we (researchers and readers) need to be very wary of how overhyped media reporting and slickly produced documentaries can severely misrepresent the status of particular theories. A nice illustration of this that I came across in my research for the Aeon piece concerns two popular science documentaries that were produced about a decade apart but were both promoted as finally unravelling the mystery of how the massive moai were transported into place.
NOVA and Van Tilburg have accomplished their purpose. She has moved a statue replica in reality rather than via computer, and has stood it up on a platform. But there are serious errors of omission that almost negate the science that was accomplished. Was there simply not time for it? Or was this part of NOVA’s production philosophy?
For an American audience, NOVA has reached its apogee in desperation as it tries to choreograph an event that will be reshown, marketed and touted, as the latest “truth” on how Easter Island statues have been moved. Though credit is never given, Van Tilburg borrowed heavily from ideas already either shown by NOVA, other films, or on other documentaries and publications.
The thrust of Van Tilburg’s moai moving experiments, in spite of much archaeological evidence to the contrary, is to lower them out ofthe quarry onto a sledge and move them horizontally. In the program, the archaeological evidence supporting Van Tilburg’s horizontal moving method and the raising of the statue and pukao on the ahu is never explored or even touched on
Skip forward to 2012 and we find the mystery of how the moai were transported again being ‘solved’ in a National Geographic documentary called the The Statues that Walked (available online here). This time another replica moai is moved a few hundred feet using a vertical transport method, in which a team use ropes to rock the statue back and forth to make it ‘walk’, a method based primarily on the theories of Terry Hunt and Carl Lipo (see below).
However, not everyone was convinced by this display. The aforementioned Jo Anne Van Tillburg was one such critic quoted in a Nature article as saying:
“What they did was a stunt and not an experiment,” says Jo Anne Van Tilburg, director of the Easter Island Statue Project at the University of California, Los Angeles. The shape of the team’s model statue is not an accurate facsimile of the moai, she says, so any conclusions drawn from it are irrelevant. “What this work has done is disengaged the statues from the archaeological context, and I think any time you do that, you enter, however gingerly, into fantasy and speculation on a level that isn’t scientific,” says Van Tilburg, whose own team has demonstrated that moai can be moved horizontally along logs.
The clear lesson here is that, regardless of whether you find Van Tilburg’s or Lipo and Hunt’s theories more compelling (and I happen to think the field more broadly supports a horizontal or combined horizontal/vertical transport methods), we really should not simply accept that documentaries, even ostensibly ‘science’ documentaries, will provide an accurate overview of the status of the theories they have been created to promote. This doesn’t mean that we need to stop watching them, many documentaries do provide accurate overviews or at least compelling introductions to otherwise obscure and technical research. But when we do watch them we should always be critical of what is being presented and (ideally) use it as a jumping off point for further independent research into the validity of the theories presented. It’s not feasible for people to become experts in every topic they see in a documentary but even just a few minutes of googling through reliable sources (and google scholar!) can help to get a more accurate view of the general consensus in a field.