[Paper] Geoarchaeological evidence from Angkor, Cambodia, reveals a gradual decline rather than a catastrophic 15th-century collapse

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Angkor Wat. Stock photo from Shutterstock/Intarapong
Angkor Wat. Stock photo from Shutterstock/Intarapong
Angkor Wat. Stock photo from Shutterstock/Intarapong

From PNAS, 25 Feb 2019 with links to news stories below: Analyzing sediment cores from Angkor reveal that the decline of Angkor took place over a long period of time, rather than a dramatic “fall“.

Geoarchaeological evidence from Angkor, Cambodia, reveals a gradual decline rather than a catastrophic 15th-century collapse

Alternative models exist for the movement of large urban populations following the 15th-century CE abandonment of Angkor, Cambodia. One model emphasizes an urban diaspora following the implosion of state control in the capital related, in part, to hydroclimatic variability. An alternative model suggests a more complex picture and a gradual rather than catastrophic demographic movement. No decisive empirical data exist to distinguish between these two competing models. Here we show that the intensity of land use within the economic and administrative core of the city began to decline more than one century before the Ayutthayan invasion that conventionally marks the end of the Angkor Period. Using paleobotanical and stratigraphic data derived from radiometrically dated sediment cores extracted from the 12th-century walled city of Angkor Thom, we show that indicia for burning, forest disturbance, and soil erosion all decline as early as the first decades of the 14th century CE, and that the moat of Angkor Thom was no longer being maintained by the end of the 14th century. These data indicate a protracted decline in occupation within the economic and administrative core of the city, rather than an abrupt demographic collapse, suggesting the focus of power began to shift to urban centers outside of the capital during the 14th century.

Source: Geoarchaeological evidence from Angkor, Cambodia, reveals a gradual decline rather than a catastrophic 15th-century collapse | PNAS

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Categories: Angkor Cambodia Papers


Evolutionary dynamics of language systems

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A new paper in the Proceedings of the National Academy of Science studies the rates of change between grammar and vocabulary in 81 Austronesian languages and finds that grammatical changes in language differ much quicker. The paper suggests a more nuanced reading of language evolution is needed in order to trace their movement in time.

Understanding how and why language subsystems differ in their evolutionary dynamics is a fundamental question for historical and comparative linguistics. One key dynamic is the rate of language change. While it is commonly thought that the rapid rate of change hampers the reconstruction of deep language relationships beyond 6,000–10,000 y, there are suggestions that grammatical structures might retain more signal over time than other subsystems, such as basic vocabulary. In this study, we use a Dirichlet process mixture model to infer the rates of change in lexical and grammatical data from 81 Austronesian languages. We show that, on average, most grammatical features actually change faster than items of basic vocabulary. The grammatical data show less schismogenesis, higher rates of homoplasy, and more bursts of contact-induced change than the basic vocabulary data. However, there is a core of grammatical and lexical features that are highly stable. These findings suggest that different subsystems of language have differing dynamics and that careful, nuanced models of language change will be needed to extract deeper signal from the noise of parallel evolution, areal readaptation, and contact.

Source: Evolutionary dynamics of language systems

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[Paper] Hunter-gatherer residential mobility and the marginal value of rainforest patches

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New paper in PNAS; a study of Batek Negrito lifestyle patterns in Peninsular Malaysia and what it can tell us about hunter-gatherer mobility.

Hunter-gatherers are notable for their high levels of mobility, but the ecological and social cues that determine the timing of camp movements (residential mobility) are poorly understood. Using models from foraging theory, we found that, for one population of hunter-gatherers, camp movements coincided with the point at which resource acquisition declined to a critical threshold level, but before local resources were completely depleted. These results suggest that hunter-gatherer residential mobility is constrained in a predictable fashion by rates of local resource depletion.

Source: Hunter-gatherer residential mobility and the marginal value of rainforest patches

New paper argues against claims of Hobbit Down Syndrome theory

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Skull of LB1. Source: The Conversation 20150210

A new paper in PNAS tears down the arguments made last year in the same journal about the Hobbit being a human with Down Syndrome. The arguments centre around the attributes of LB1 and LB6’s chins. The Conversation piece by the same authors breaks it down nicely.

Skull of LB1. Source: The Conversation 20150210

Skull of LB1. Source: The Conversation 20150210

Down syndrome theory on Hobbit species doesn’t hold to scrutiny
The Conversation, 10 February 2015

Mandibular evidence supports Homo floresiensis as a distinct species
Proceedings of the National Academy of Science, doi: 10.1073/pnas.1418997112

Henneberg et al. (1) and Eckhardt et al. (2) present another pathology-based alternative to the hypothesis that the “hobbit” fossils from Liang Bua, Indonesia, represent a distinct hominin species, Homo floresiensis. They contend that the Liang Bua specimens are the remains of small-bodied humans and that the noteworthy features of the most complete specimen, LB1, are a consequence of Down syndrome (DS). Here, we show that the available mandibular evidence does not support these claims.

Absence of chins in the two mandibles recovered at Liang Bua, LB1 and LB6, is a key issue (1, 3). That these specimens lack chins has been argued to preclude their attribution to Homo sapiens, because a chin is widely accepted to be a defining characteristic of our species (3). Henneberg et al. reject this argument on the grounds that a chin is often absent in living Australo-Melanesians. However, the evidence they present does not support their assertion regarding Australo-Melanesian mandibular morphology. One of two studies they cite has not been peer reviewed (the publication is just a conference abstract), whereas the other one has been severely criticized (4). Henneberg et al. also imply that a mandible from Roonka, Australia, supports their claim, but a CT scan of this specimen shows that it has a positive chin (Fig. 1). Thus, there is no reason to believe that living Australo-Melanesians often lack chins and therefore no reason to overturn Brown and Tomoko’s (3) assessment that the absence of chins in LB1 and LB6 precludes their attribution to H. sapiens.

The link to the paper here.

Criticisms over the hobbit-Down Syndrome paper

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There seems to be more than meets the eye with the latest paper in PNAS on the ‘hobbit’ as a person with Down syndrome. The Guardian has a story on the criticism and reactions to this paper.

Homo floresiensis

Homo floresiensis: scientists clash over claims ‘hobbit man’ was modern human with Down’s syndrome
The Guardian, 17 August 2014
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More Hobbit stories

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Two articles on the New York Times and the Daily Mail about the recent papers in PNAS suggesting that the ‘Hobbit’ is person with Down syndrome and not a new species.

LB1 skull

A New Explanation for ‘New’ Man
New York Times, 04 August 2014

The oldest case of Down’s syndrome? 15,000-year-old ‘Flores man’ bones are not evidence of a new human species, study reveals
Daily Mail, 05 August 2014
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New study suggests Hobbit was a person with Down syndrome

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A new study in PNAS suggests that Homo floresiensis may not be a new species, but the skeletal features resemble a normal human with Down syndrome. This one is bound to be controversial for sure!


Evolved developmental homeostasis disturbed in LB1 from Flores, Indonesia, denotes Down syndrome and not diagnostic traits of the invalid species Homo floresiensis
Proceedings of the National Academy of Sciences, 04 August 2014
doi: 10.1073/pnas.1407382111

The “hobbit” human not a separate species, say scientists
Popular Archaeology, 04 August 2014

Flores bones show features of Down syndrome, not a new ‘Hobbit’ human
Science Daily, 04 August 2014

‘Hobbit’ had Down syndrome
The Australian, 05 August 2014

Did the ‘Hobbit’ have Down syndrome?
ABC Science, 05 August 2014
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Asians and Native Americans share common ancestry in China

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Genetic study with possible implications for the origins of populations in Southeast Asia.

DNA shows ancestry of present-day Asians, Native Americans
Channel NewsAsia, via AFP, 23 January 2013

DNA analysis of an early modern human from Tianyuan Cave, China
PNAS January 22, 2013
doi: 10.1073/pnas.1221359110

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The world's first megapolis

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15 August 2007 (The Independent) – I seem to see two main recurrent themes emanating from the Angkor stories that have popped up over the last two days. The first is the fall of Angkor, now with greater evidence to its apparent failing water management system. The second theme is the enormity of the ‘city’ (incidentally, the word “Angkor” is a variant of the sanskrit word meaning ‘city’), now seen as at least 3-10 times larger than originally thought. This new shift has also meant that the temple complexes are not cities unto themselves, but nodes in a larger network of an entire ginormous city.

Metropolis: Angkor, the world’s first mega-city
The discovery that the famous Cambodian temple complex sits in the midst of a vast settlement the size of London, which flourished until the 15th century, has astounded archaeologists – but also baffled them: why did it disappear? By Kathy Marks

The huge sandstone temples of Angkor, built nearly 1,000 years ago and unearthed from the Cambodian jungle in the last century, are considered one of man’s most outstanding architectural achievements. Last year more than a million tourists wandered through the ruins and watched the sun rise over the main temple’s distinctive towering spires.

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Australia's raiders of the lost wat

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14 Aug 2007 (The Canberra Times) – Unsurprisingly, the Canberra Times focuses more on the Australian archaeologists who worked on this project, however the map was a collaborative effort between Australian, French and Cambodian archaeologists.

REVEALED: Australia’s raiders of the lost wat

Australian archaeologists using complex radar and satellite technology to map the medieval city of Angkor have discovered more than 70 new temples scattered across a vast area of farmland and forests in north-west Cambodia.

University of Sydney archaeologist Damian Evans said, “It’s huge. We’ve mapped a massive settlement stretching well beyond the main temples of the World Heritage tourist area in Siem Reap.

“We’ve found the city was roughly five times bigger than previously thought.”

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