Category: 82

Attacks on Darwinian evolutionary theory have come from within the scientific community as well as from creationists. Much of this is the normal process of scientific scrutiny, but some bear all the hallmarks of pseudoscience.

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Of all the so-called evidence that has been presented in support of human settlement in New Zealand before the second millennium, only a set of radiocarbon-dated rat bones has appeared scientifically credible. Now even that is coming under close scrutiny.

In 1996 a paper with the rather sexy title Arrival of rats in New Zealand appeared in the journal Nature. It was by Dr Richard Holdaway and described radiocarbon studies of Pacific rat (Rattus exulans, called kiore in New Zealand) bones collected from avian predator sites, most in the South Island, which were interpreted to be evidence of the arrival of rats in New Zealand around AD 50 to AD 150, and humans as well, on the assumption that rats arrived as a human commensal. The results were very controversial because there is no supporting archaeological or ecological evidence for the presence of humans or rats in New Zealand until much later (around AD 1250). To be fair, Holdaway has always maintained that the ‘early’ humans were here only temporarily as fleeting visitors, ie it was transient contact, not settlement. But he has gone on to develop models involving rapid spread of the rats over both islands and also attributes the decline (possibly extinction) in some birds and other animals to predation by rampant rats well before c. AD 1250.

As well as lacking any archaeological or ecological evidence (such as change in vegetation as recorded by pollen profiles) for the ‘early’ arrival, problems with rat-bone ages had emerged during the dating of archaeological sites where ages of various cultural material (including charcoal, wood, eggshell, marine shell, and large bone) were all in good agreement with one another and with other sites, but rat bone ages from the same layers were sometimes older by more than 1000 years. Critics suggested various explanations for the anomalously old rat bone ages including:

• contamination of bone through dietary uptake of old carbon (eg if rats eat seal meat – note that dates on modern rats and ducks at Taupo can give ages of about 2000 years because of hydrothermally derived
• old carbon getting into the food chain and hence rat bones)
• old carbon contamination from the environment
• dating tiny jaw bones is technically very difficult and processing of bones to produce gelatin can easily produce the wrong results, as was demonstrated in an experiment conducted by Prof. Atholl Anderson (of Australian National University, formerly Otago University). He sent ‘blind’ samples of rat bones of known age to three different radiocarbon labs and one lab returned ages that were too old by more than 1000 years, ie he showed that subtle differences in pre-treatment of bones can markedly affect outcome (paper published in 2000)
• Oxford University AMS radiocarbon lab has shown that there was the possibility of contamination in the pre-treatment and filtering process involved in gelatin preparation – although probably a relatively minor effect (paper published in 2004)
• Anderson also demonstrated that dates produced on bones from one lab from both natural and archaeological sites showed a ‘production trend’ and ‘age disconformity’ pre- and post-1997, ie the ages changed (got younger) generally as samples were processed, the implication being that the pre-treatment techniques were gradually improved with time so that correct ages were obtained eventually. The ‘trend/age disconformity’ was published in two papers (2000, 2004) but its existence was denied by the lab director; Holdaway said that he (Holdaway) had caused the trend by submitting older samples first – this argument broke down because the trend existed also from archaeological sites (never studied by Holdaway) as well as natural sites such as the avian predator sites.

In 1987 Professor Doug Sutton, formerly at Auckland University and now at Waikato University, had published a paper suggesting early settlement of New Zealand (approximately AD 0-500) on the basis mainly of disturbance indicators in pollen records, primarily short-lived increases in bracken. That there was no evidence apart from the pollen record disturbances (easily accounted for by natural factors such as lightning or volcanic eruptions or storms) was explainable according to Sutton by a tiny population which was ‘archaeologically invisible’. So the ‘old’ rat-bone dates seemed to support his hypothesis (called the early settlement model).

Meanwhile, I and colleagues (including Prof Rewi Newnham of Plymouth University) had published several papers in 1998 and 2000 using volcanic-ash layers as markers to try to date the earliest archaeological and earliest sustained forest disturbance indicators from pollen profiles. We obtained a new wiggle-match date (at Waikato University Radiocarbon Dating Lab, led by Dr Alan Hogg, and facilitated by tree-ring work by Dr Jonathan Palmer) on a widespread ash layer, the Kaharoa Tephra, which was erupted from Mt Tarawera in AD 1314 ± 12 (published in 2003). This provides a maximum age for many archaeological sites in eastern parts of the North Island – no artefacts have ever been found beneath it. It also gives an approximate near-maximum age for the start of sustained disturbance by burning: out of around twenty pollen profiles which contained Kaharoa Tephra, four showed the start of sustained disturbance (presumably by people) was just before the eruption. From sedimentation rates this is likely to be around 50 years or so at most, ie some decades before AD 1300. This, then, appeared to be the most likely date for the human settlement of the eastern North Island.

Elsewhere in New Zealand the earliest known archaeological sites are dated reliably (using moa eggshells) from the late 13th Century to AD 1300 (eg the Wairau Bar site in Marlborough). Hence the current model for settlement (called the late settlement model) is set at c. AD 1250-1300.

New approaches

So, how to test the two competing hypotheses and especially to verify or otherwise the ‘old’ rat bone ages? One way was to obtain more dates from the original sample material that led to the 1996 paper. However, it was embargoed by Te Papa, and then when that lapsed it was reported that ‘no further material is available’. Two scientists, Dr Janet Wilmshurst (Landcare Research, Lincoln) and Dr Tom Higham at Oxford University (formerly at Waikato University) came up with two approaches.

The first was to use an alternative method for dating the arrival of rats which bypassed the need for bone dating. This was done by obtaining AMS (accelerator-based) radiocarbon ages on unequivocally rat-gnawed woody seed cases preserved in sediments. Wilmshurst and Higham dated numerous seeds at three sites, one on Coromandel Peninsula and two in Taranaki (ie opposite sides of North Island). The results were extremely clear: all rat-gnawed seeds were younger than about 750 years old. The results at the Coromandel sites were confirmed by my unequivocal identification of Kaharoa Tephra there – no rat-gnawed seeds were found beneath the Kaharoa layer, but plenty above it which had given the young ages. The conclusion from this work (published in 2004) was that rats arrived after c. AD 1250, and not before. The rat-gnawed seeds dating was supported by a similar study by Dr Fred Brook who dated rat-gnawed landsnail shells in Northland – his results (published in 2000) were the same: no snail shells had been nibbled before c. AD 1250-1300. His dates were done at the Waikato University Radiocarbon Lab.

Together, the newly dated rat-gnawed seeds and snail shells (from widely spaced sites) showed it was extremely unlikely that there were any rats in the North Island before c. AD 1250-1300, but plenty after that date.

Otago revisited

The second approach was to re-examine independently the original avian predator deposits and collect new materials for dating and re-analysis. The results from one site have been published by Anderson and Higham (in 2004) – that site was called Earthquakes #1, north Otago, one of Holdaway’s key 1996 sites.

They obtained two new radiocarbon dates for pigeon bones and two on rat bones: the pigeon-bone dates were as reported in the first series (ie ‘young’) but the two rat-bone dates were much younger than in the first series, suggesting that the ‘old’ rat-bone ages from that site were not reliable for estimating the timing of human settlement.

Wilmshurst, Higham, Anderson and Trevor Worthy (Adelaide University) have collected rat-bone and bird-bone samples from other avian predator sites in the South Island, including Holdaway’s original sites. The results, as for the new seed dating work, were presented at a conference in Oxford in April and are in the process of being written up and so are not yet available.

Holdaway attempted to re-date his sites using another technique called optical luminescence dating (OSL), which involves dating quartz grains. He claimed to have verified the ‘old’ rat-bone ages with OSL dates (in 2002). OSL dating relies on the assumption that the luminescence signal of grains is fully reset to zero by sunlight exposure before deposition. If this requirement is not fulfilled, ages may be grossly overestimated. In particular, poor bleaching can significantly affect age estimations of young sediments (especially within the last 3000 years). Because the sites are so disturbed and because the technique has uncertain (at best) to virtually zero reliability for such young deposits, the OSL dates have zero credibility.

My position has been one of scepticism for the early settlement model because of the lack of hard unequivocal evidence for it, but a reasonably open position regarding the ‘transient contact’ model, and the ‘old’ rat bone dates were intriguing. The wiggle-match date for the Kaharoa Tephra helped cement the late settlement story.

But I believe Anderson especially was unconvinced from the start by the ‘old’ rat bone dates hence he set about his examination of the literature and discovered the ‘dating trend’ from one laboratory and set up the ‘blind sample’ test. It seemed that it would be impossible to establish the truth when it was announced that no material was available for re-testing – but then the prescient rat-gnawed seeds and snails work came along.

The rat-gnawed seeds paper of 2004 especially, plus the re-dating of rat bones at Earthquakes #1 site paper, convinced me and most others that the ‘old’ rat-bone dates were highly questionable. Our ‘gnawing’ (!) doubts about the possibility of erroneous ages were confirmed.

Sutton’s paper certainly has stimulated a lot of work and he may well still be right. But the evidence is very strong now for late settlement. The next move is to publish the South Island nibbled seeds and rat-bone and avian-bone data from re-examined sites. That might be the end of the story.

Claims about pre-Maori colonisation of New Zealand refuse to go away.

There’s one born every minute. Former Act MP Muriel Newman appears to be the latest convert to the view that New Zealand was colonised thousands of years ago. Nowadays Newman runs a website-based forum called the New Zealand Centre for Political Debate (www.nzcpd.com), for which she writes a weekly column called the Newman Weekly. In January this year she posted an article called “History in the Making” arguing that recent alternative interpretations of world history challenge the view that Maori are Tangata Whenua. She wrote:

Claims have been made that New Zealand was discovered from as early as 600 BC by Phoenician, Indian, Greek and Arab explorers. In fact claims of their visits help to explain the existence in the South Island of the fossilised remains of rats that have been carbon dated at 160 BC — more than 1000 years before Maori! There are further claims that before Maori arrived in New Zealand settlements had already been established by the Waitaha, the peace-loving fair skinned ancestors of the Moriori, by Chinese miners, and by the celts.

Newman has obviously been reading the fanciful inventions of Martin Doutré (she lists his website as a ‘useful’ reference), Barry Brailsford and Ross Wiseman, whose writings have no credibility among historians and scientists and have been roundly debunked in the NZ Skeptic and other journals (see NZ Skeptic 68, 72 and 73).

Newman also cited Gavin Menzies, the author of the best selling book 1421 which argues that the Chinese mariner Zheng He discovered America in 1421, 71 years before Columbus. She quoted Menzies’ remarks that:

The New Zealand Government possesses several skeletons carbon dated to centuries before the Maori claimed to have reached the North and South Islands. These skeletons should have their DNA examined … however, we need the consent of the New Zealand Government who, as might be expected, have passed the buck by saying we need Maori consent.

Newman also cited an article in the Economist which discussed Menzies’ claims.

Muriel Newman’s agenda is not hard to discern. The burden of her song is that if evidence emerged that non-Polynesian people settled in New Zealand before the Maori it would negate the Treaty of Waitangi. She cited claims (not sourced, but clearly echoing Martin Doutré) that the New Zealand Government and officials censor the historical record by refusing to allow alleged non-Polynesian human remains to be carbon dated and DNA tested. The intended implication is that the New Zealand Government is deliberately suppressing an alternative version of New Zealand history that would rewrite the New Zealand history books to better fit with Muriel Newman’s dream of a New Zealand without the Treaty of Waitangi. Newman is clutching at straws and her arguments fall apart as soon as you examine the detail. Let me elaborate.

She misused the Economist article. That article was entitled China beat Columbus to it – perhaps (12 Jan 2006) and was about a 1763 map of the world thought to be (but not yet authenticated as) an accurate copy of a 1418 Chinese map. Newman cited this article as support for Gavin Menzies’ belief that Chinese colonies existed in New Zealand hundreds of years before Maori arrived. The Economist article said no such thing. It was about historical events in the early 1400s and only referred to possible Chinese visits to New Zealand in the twelfth to fifteenth centuries (when New Zealand was already settled by Maori forebears). Newman read what she wanted into the Economist article.

She misconstrues, or misunderstands, the Treaty of Waitangi. Evidence that non-Polynesian people inhabited New Zealand before Maori would certainly be an exciting discovery (no hard evidence exists yet), but it would not negate the Treaty of Waitangi, which was between the British Crown and the large population of Maori tribes inhabiting New Zealand in the early 1800s. The validity of this treaty is not dependent on who inhabited New Zealand prior to AD 1000, it is dependent on who signed it in 1840. Treaties are between the signatories.

In another non sequitur Newman said, “The testing of Maori DNA … would go a long way towards confirming or refuting these claims, but sadly many Maori appear to be opposed to its use.” She adds that some Maori were unwilling to participate in the National Geographic Genographic Project. Exactly what point she was trying to make here escapes me. Since Maori DNA can only indicate where Maori originated (the whole point of the Genographic project) it is not going to tell us anything about whether non-Maori were in New Zealand earlier.

Newman appealed to Gavin Menzies’ writings as if they are exciting new evidence that rewrites history. They are not. They use the same methods as other fringe theorists – misrepresentations of other authors, unverifiable conspiracy theories about suppressed evidence, logical fallacies, long strings of speculative argumentation, uncited sources, invented evidence, impressive-looking long lists of supporting evidence that fall apart when subjected to expert scrutiny, and contempt for mainstream scholarship. (See historian Robert Finlay’s detailed critique of Menzies’ book at www.historycooperative.org/journals/jwh/15.2/finlay.html See also David Riddell’s review of Menzies’ book in NZ Skeptic Number 67, Autumn 2003.)

You don’t have to read very far in Menzies’ writings to detect the fanciful and far-fetched. Thirty Chinese ships containing 7000 people, trained otters (to herd fish into nets) and thousands of horses (to stock the Americas) visited almost every part of the world including Antarctica in the three years between 1421 and 1423, establishing scores of colonies and metal mining operations along the way? As Robert Finlay demonstrated, such an absurd scenario never happened. As is well documented in the contemporary Chinese records, and in the substantial scholarly literature on the subject, of the seven expeditions of Zheng He’s fleets between 1405 and 1433 only one occurred between 1421 and 1423, and its ports of call were confined to the Indian Ocean. The rest is a figment of Menzies’ imagination.

Muriel Newman’s innuendo that the New Zealand Government is deliberately suppressing a possible alternative view of history by refusing to allow alleged carbon dated pre-Maori human remains to be DNA tested is a gross distortion she has picked up from Martin Doutré. Doutré is obviously driven by his own agenda to prove that Maori are not Tangata Whenua. He has complained in his writings that efforts by him and his friends to have human remains radiocarbon dated have been blocked by the protocols in place at laboratories requiring human remains to be appropriately documented to verify where and how they were obtained and who authorised the laboratory analysis work (which sometimes requires destruction of the sample). Doutré thinks that when some wandering amateur finds a European jaw bone in a remote cave it is essential to have it carbon dated in case it proves his pet theory that non-Polynesians inhabited New Zealand thousands of years before Maori. Archaeological methods demand somewhat more rigour than this to reach valid conclusions, not to mention the need for human remains to be suitably respected and for police interests to be eliminated.

There are, of course, hundreds of human remains stored in New Zealand museums. Many of them have been there for more than 100 years and they have arrived in the museums by all sorts of routes – some proper, some improper, some innocent, some dubious, some unknown. In recent times those whose origins have been authenticated have been rightly released to their Maori owners when requested. These skeletal remains have always been available to science via the proper channels and protocols, which are quite rightly strict. Dr Philip Houghton published definitive textbooks in the 1970s and 1990s based on his scientific analysis of the skeletal remains of over 90 human individuals in New Zealand repositories. His work clearly identified the earliest inhabitants of New Zealand as Polynesian. Over the past 100 years archaeologists have excavated hundreds of human occupation sites throughout New Zealand yielding thousands of artefacts and hundreds of radiocarbon dates. All this archaeological, genetic and phenotypic evidence indicates that these inhabitants came from the Pacific Islands. From a scientific viewpoint this body of evidence is overwhelming. As yet, no evidence of human settlement of New Zealand has been found earlier than about AD 1000. Such evidence may be forthcoming in the future, but meantime the speculations of Martin Doutré, Gavin Menzies, and other wishful alternative theorists, should be treated with great suspicion and certainly don’t constitute evidence of the sort useful to science. (For a succinct and well-documented overview of the current understanding of the human settlement of New Zealand read KR Howe, The Quest for Origins.)

Muriel Newman waxes indignant about the suppression of alternative views of history and the dire implications of this for freedom of expression. Yet a cursory glance at the mass media confirms that crackpot theories get aired even more than orthodox ones because people love a juicy yarn. The Menzies book has been on the New York best seller list for a long time. Doutré, Wiseman and their bedfellows have self-published their books without any prior expert evaluation. Like Muriel Newman they have their own websites where they can write what they like for the whole world to read. Newman should be grateful for such freedom to peddle distortions.

The New Zealand Skeptics have launched a competition to encourage critical thinking among Auckland high school students. Entrants are to submit a 100-word summary outlining their proposal for a 10-12 minute presentation on some topic relevant to skeptical inquiry. Suggested topics include:

• Are we sensible about science?
• The biggest superstition today is…
• How can we tell what is science and what is pseudo-science?
• What do students learn about critical thinking?

Short-listed entrants will make their presentations in late August before a judging panel who will invite the best three to present their talks at the 2006 Skeptics’ Conference. Power point or overhead projection slides may be used, but talks without visual aids are also welcomed.

Prizes for first, second and third places are vouchers of $250, $100 and $50 for Real Groovy’s selection of books, music, DVDs and games. Further information is available at www.skeptics.org.nz/SK:SKEPCONFERENCE