A weekly programme featuring a mix of sound-rich stories about science, the environment and medical research, recorded around New Zealand in laboratories and in the field. Our Changing World is broadcast nationwide on Thursday nights on Radio New Zealand National, during Nights with Bryan Crump. It is preceded in this recording by a news and sports bulletin, and weather forecast. In today's programme:
21:06
Tracking the Lapita Expansion Across the Pacific
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Veronika Meduna joins Pacific archaeologists at the oldest cemetery in the pacific to find out about the Lapita and their epic voyage of discovery.
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by Veronika Meduna
The whole Lapita story is an extraordinary chapter of human history. These are the first people that get beyond the main Solomons chain.
Stuart Bedford, Australian National University, Vanuatu Cultural Centre
Stuart Bedford has spent many years scouring Vanuatu’s volcanic soil for evidence of the archipelago’s first inhabitants, but one of his best discoveries came when he wasn’t looking. A digger driver who was excavating soil for a prawn farm on Vanuatu’s main island Efate discovered a richly decorated shard of pottery – and recognised it as something unusual.
Bedford and his colleague Matthew Spriggs, both archaeologists at the Australian National University in Canberra, were called in and immediately identified it as Lapita.
The serendipitous discovery soon led to a major project which unearthed not just more pottery but human remains. More than a decade later, the site at Teouma is now famous among Pacific archaeologists as the oldest Lapita cemetery, reaching back three millennia to the very beginning of an epic voyage of discovery.
The Lapita are ancestors of modern Polynesians, who later went on to explore all corners of the Polynesian triangle, from Hawaii to Easter Island and ultimately New Zealand. But 3000 years ago it was Lapita seafarers who heralded the last major prehistoric wave of migration by sailing to Vanuatu and from there out into an area known as Remote Oceania.
In July, Vanuatu’s capital Port Vila hosted the 8th Lapita conference, which brought together scientists from disciplines as far apart as archaeology, linguistics and genetics to discuss the latest findings about the Lapita, from the techniques they used to produce their unique, elaborately decorated pottery, to their burial practices, their health, their impact on the archipelago’s ecology - and of course their Pacific sailing itinerary.
"Teouma is the first kind of really core Lapita site … so it’s given us unique insights into who the Lapita people were," says Matthew Spriggs.
From the bones and teeth, the team gleaned information about their diet and health, but most importantly perhaps, the Teouma bones confirm the Polynesian link.
We can compare the skull shape of the Lapita people and see who they resemble most among living populations today and they fit very neatly within the Polynesian/Asian mode rather than the Australian, Aboriginal and Melanesian mode.
Matthew Spriggs, Australian National University, Vanuatu Cultural Centre
Spriggs says that it was during the relatively short period of Lapita expansion that change happened and, while the people at Teouma are ancestors of Polynesians, later Lapita site are more closely linked with modern Melanesians.
“It’s only during Lapita that we have evidence of extensive interactions between all the archipelagos, so from New Guinea, the Bismarck Archipelago, through to the Solomons, Vanuatu, New Caledonia and out to Fiji. There’s extensive exchange networks, contact between these areas.”
At the Teouma cemetery, archaeologists also discovered 68 burial sites, and the bleached bones almost certainly belong to the first people to make landfall in Vanuatu. They unearthed clear evidence that the Lapita used their highly decorated pottery for ceremonies and rituals, but for Frederique Valentin, an archaeologist at the National Centre for Scientific Research in Paris, the bones tell a fascinating story of ritual burial practices – with headless skeletons and deliberately rearranged bones.
Hallie Buckley, a biological anthropologist at the University of Otago, has coordinated the excavation of the bones and has studied them for signs of disease.
These same bones also tell a story of hard work, and of people suffering from gout and what we now know as metabolic disease. But Anna Gosling, also at the University of Otago, says the gout may be an evolutionary consequence of protection against malaria.
Gout is a result, usually, of high serum urate levels. Pacific Island people, throughout the Pacific, have been found to have quite high levels of this particular chemical in their blood compared to most other populations worldwide, which is suggesting that there is some sort of genetic link.
Anna Gosling, University of Otago
Urate has several important function: it helps maintain blood pressure, it is an anti-oxidant, and it plays a role in the body's innate immune response. During a Malaria infection, urate levels increase to stimulates an immune response.
"The argument we're trying to make here is that if you already have slightly higher urate levels in your blood, you need less red blood cells to ... burst apart before your immune system kicks in and tries to resolve the infection, which would give you quite an advantage."
The human settlement of the Pacific and the origins of the Polynesian people have been topics of intense debate for decades, and scientists have sought to chart the path of the Lapita expansion. Collectively they have accumulated evidence that points to an origin in island Southeast Asia, but with more clarity in some of the detail comes increasing complexity of the total picture.
The first wave of colonisation in the Pacific region began when people fanned out across an area known as Near Oceania, sometime around 40,000 years ago. Sea levels were lower then – New Guinea, Australia and the island of Tasmania were still one landmass – and these first explorers had to navigate smaller gaps of ocean. They spread as far as the Bismarck Archipelago north of Papua New Guinea and the Solomon Islands in the Pacific.
Patrick Kirch, an anthropologist at the University of California at Berkeley and an expert in Pacific prehistory, says for 30,000 years, the sea gap between the main chain of the Solomon Islands and Vanuatu was an invisible boundary. But then, around 3000 years ago, the Lapita, breached this voyaging barrier. Their unmistakable comb-toothed pottery is the most distinctive cultural signature they left behind, and it now helps to reconstruct their journey.
You can use the pottery and other material culture to trace the movement very clearly and with the assistance of radio carbon dating we’ve put a timeframe on that.
Patrick Kirch, University of California at Berkeley
This Lapita “bursting out into this part of the Pacific that had never been occupied by humans” ended at about 800BC in Tonga and Samoa, but just what motivated the rapid expansion is still a point of debate.
Population pressure is often discussed as one option, but Kirch thinks people were pulled rather than pushed. “By pull I mean things like new resources. We know in Vanuatu they had these tortoises and pigeons, they were great food items.”
Also, he says, there could be social factors such as a hierarchical clan structure in which younger sons may have wanted to establish elsewhere.
Although the dentate pottery – edged with toothlike projections – is the most consistent Lapita identifier, it’s clear that the people carried with them a suite of other skills, including open-ocean navigation, boat-building, fishing and agriculture. Archaeologists prefer to use the term Lapita Cultural Complex, rather than implying that Lapita was a homogenous group of people defined largely by their pottery design style.
Linguistically, the origins are clear. Lapita is just one chapter in the Austronesian diaspora.
Austronesian is unusual among language families: it’s extremely large, with more than a thousand modern languages, and it’s the most widely dispersed in the world (until the post-Columbus expansion of Indo-European languages). It extends from Madagascar to Rapa Nui, or Easter Island, and spans over 70 degrees of latitude, from Hawaii to the southern tip of New Zealand. All modern Polynesian languages are daughters of this family.
Like drawing up an evolutionary tree from the genetic diversity found in living organisms, modern languages can also be used to reconstruct ancestral proto languages and their relationships to each other. When this is done, Taiwan emerges as the most likely origin of Austronesian.
The archaeological record supports the notion that the Lapita journeys were a deliberate effort to colonise new land. Lapita sites discovered so far are close to the beach and, in Near Oceania they are mostly on small off-shore islands. The choice of coastal sites also suggests a dual subsistence economy, relying on both fishing and agriculture. Excavations have also revealed that the Lapita toolbox included a range of fish hooks made from shell, nets, spears and different types of stone adzes.
Intriguingly, the most complex patterns of decoration are associated with the oldest sites, and plain ware and more simply decorated pots make up a growing proportion of assemblages found in later settlements.
Why the Lapita might have abandoned the rituals and practices they had so treasured remains a mystery. Matthew Spriggs says once you move beyond Samoa and Tonga, the area of sea compared to the area of land “increases massively and there was probably a threshold of relatively easy travel back and forth”.
Topics: science, environment
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Tags: Pacific migration, Lapita, human migration, Pacific, Teouma, Vanuatu, Lapita pottery, burial rituals, Austronesian languages, archaeology, gout, Polynesian ancestors
21:46
'Air Puffs', Speech and Mobile Phones
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Adding air puffs that we produce during speech to mobile phones and hearing aids might make understanding conversations in noisy environments easier
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By Alison Ballance
“We’re looking at how the airflow that comes from people’s lips can be used to help them understand speech better.”
Donald Derrick, University of Canterbury
Here’s a new idea that might make it easier to make a phone call in a noisy place. When we talk face-to-face with someone we don't just listen with our ears, we also listen with our skin. Tiny puffs of air from speech land on us and can help us understand what we’re hearing. So what if we could feel appropriate air puffs as we listen to someone on a mobile phone in a noisy environment? Would that help us make out those tricky differences between the letters ‘b’ and ‘p’, for example?
Donald Derrick, a linguist at the New Zealand Institute of Language, Brain and Behaviour, believes the answer to this is ‘yes’, and he’s developing a technology that could, in future, be used with devices such as mobile phones, headphones and hearing aids.
To do this, Donald has had to develop novel ways of recording air puff information, separating it from the speech and then finding ways to deliver it. This stage of the project involves an innovative piece of equipment that has been developed at the University of Canterbury, called the ‘ping pong puff air flow meter’. It is, literally, a ping pong ball mounted on a carbon fibre rod, and at its base is a system for measuring the displacement of the ping pong ball by a speaker’s by air flow. This system has allowed Derrick to characterise the different air flows that are produced by words such as ba, pa, fa, sa and ta, as well as shh and chh.
You can try for yourself by holding the back of your hand in front of your mouth as you say those syllables, and you’ll get a sense of the strong wind created by pa, for example (which is an aspirated syllable), compared to almost no air produced by the very similar sounding but unaspirated ba.
“The air puffs are designed to simulate what lips about four or five centimetres away from a speaker would feel like,” and they are delivered through a small piezoelectric pump.
For the next stage of the experiment, Derrick says that it took him about six weeks to write a story that he could get study participants to listen to. “On the surface it’s an incredibly cheesy fantasy story,” he says, but it enabled him to use a whole lot of paired words that sound very similar and are commonly misunderstood in noisy environments. The word pairs included blowing and flowing, burrow and furrow, birch and perch, bumbling and fumbling, piles and vials, bills and pills, and plot and flop. More importantly, the story allowed him to use the words in continuous speech, not just as individual words.
In the study people listen on headphones to the story presented as a series of short excerpts. After each excerpt they are then asked to select which of two words they heard. The story is barely audible above a noisy background – Derrick says he used a signal to noise ratio of zero as this is a commonly encountered ratio in the real world – but the participants are also getting air puff information that they feel on their forehead.
Donald says that in experiments to date the addition of air puffs allows people to recover about one out of every four words that they would have lost. “So the enhancement is not the hugest in the world but it’s significant enough to be worthwhile. It’s similar, by the way, to the enhancement you’d get if you were looking at someone’s face while they were talking to you.”
Donald says the air puffs don’t have to be delivered to the face – they work just as well at the neck, hands and ankles – and no training is needed.
Donald is part of a University of Canterbury team working on the second phase of a science and innovation project funded by the Ministry of Business Innovation and Employment. The collaboration with colleagues Jen Hay, Scott Lloyd and Greg O'Beirne is called ‘Aero-tactile enhancement of speech perception’, and the aim is to commercialise the resulting technology. Tom De Rybel is the project's lead engineer.
This study builds on previous work by Donald and colleagues in Canada: in 2009 he co-authored a Nature paper titled ‘Aero-tactile integration in speech perception’ which involved applying slight, inaudible air puffs onto participants’ skin, either the right hand or the neck.
Topics: science, technology
Regions:
Tags: mobile phones, speech, hearing aids, air puffs, aero-tactile, listening
Duration: 13'28"