Artifacts shed light on social networks of the past

Researchers studied thousands of ceramic and obsidian artifacts from A.D. 1200-1450 to learn about the growth, collapse and change of social networks in the late pre-Hispanic Southwest

The advent of social networking sites like Facebook and Twitter have made us all more connected, but long-distance social networks existed long before the Internet.

An article published this week in the Proceedings of the National Academy of Sciences sheds light on the transformation of social networks in the late pre-Hispanic American Southwest and shows that people of that period were able to maintain surprisingly long-distance relationships with nothing more than their feet to connect them.

Led by University of Arizona anthropologist Barbara Mills, the study is based on analysis of more than 800,000 painted ceramic and more than 4,800 obsidian artifacts dating from A.D. 1200-1450, uncovered from more than 700 sites in the western Southwest, in what is now Arizona and western New Mexico.

With funding from the National Science Foundation, Mills, director of the UA School of Anthropology, worked with collaborators at Archeology Southwest in Tucson to compile a database of more than 4.3 million ceramic artifacts and more than 4,800 obsidian artifacts, from which they drew for the study.

They then applied formal social network analysis to see what material culture could teach them about how social networks shifted and evolved during a period that saw large-scale demographic changes, including long-distance migration and coalescence of populations into large villages.

Their findings illustrate dramatic changes in social networks in the Southwest over the 250-year period between A.D. 1200 and 1450. They found, for example, that while a large social network in the southern part of the Southwest grew very large and then collapsed, networks in the northern part of the Southwest became more fragmented but persisted over time.

"Network scientists often talk about how increasingly connected networks become, or the 'small world' effect, but our study shows that this isn't always the case," said Mills, who led the study with co-principal investigator and UA alumnus Jeffery Clark, of Archaeology Southwest.

"Our long-term study shows that there are cycles of growth and collapse in social networks when we look at them over centuries," Mills said. "Highly connected worlds can become highly fragmented."

Another important finding was that early social networks do not appear to have been as restricted as expected by settlements' physical distance from one another. Researchers found that similar types of painted pottery were being created and used in villages as far as 250 kilometers apart, suggesting people were maintaining relationships across relatively large geographic expanses, despite the only mode of transportation being walking.

"They were making, using and discarding very similar kinds of assemblages over these very large spaces, which means that a lot of their daily practices were the same," Mills said. "That doesn't come about by chance; it has to come about by interaction – the kind of interaction where it's not just a simple exchange but where people are learning how to make and how to use and ultimately discard different kinds of pottery."

"That really shocked us, this idea that you can have such long distance connections. In the pre-Hispanic Southwest they had no real vehicles, they had no beasts of burden, so they had to share information by walking," she said.

The application of formal social network analysis – which focuses on the relationships among nodes, such as individuals, household or settlements – is relatively new in the field of archaeology, which has traditionally focused more on specific attributes of those nodes, such as their size or function.

The UA study shows how social network analysis can be applied to a database of material culture to illustrate changes in network structures over time.

"We already knew about demographic changes – where people were living and where migration was happening – but what we didn't know was how that changed social networks," Mills said. "We're so used to looking traditionally at distributions of pottery and other objects based on their occurrence in space, but to see how social relationships are created out of these distributions is what network analysis can help with."

One of Mills's collaborators on the project was Ronald Breiger, renowned network analysis expert and a UA professor of sociology, with affiliations in statistics and government and public policy, who says being able to apply network analysis to archaeology has important implications for his field.

"Barbara (Mills) and her group are pioneers in bringing the social network perspective to archaeology and into ancient societies," said Breiger, who worked with Mills along with collaborators from the UA School of Anthropology; Archaeology Southwest; the University of Wisconsin; Hendrix College; the University of Colorado, Boulder; the Santa Fe Institute; and Archaeological XRF Laboratory in Albuquerque, N.M.

"What archaeology has to offer for a study of networks is a focus on very long-term dynamics and applications to societies that aren't necessarily Western, so that's broadening to the community of social network researchers," Breiger said. "The coming together of social network and spatial analysis and the use of material objects to talk about culture is very much at the forefront of where I see the field of social network analysis moving."

Going forward, Mills hopes to use the same types of analyses to study even older social networks. "We have a basis for building on, and we're hoping to get even greater time depth. We'd like to extend it back in time 400 years earlier," she said. "The implications are we can see things at a spatial scale that we've never been able to look at before in a systematic way. It changes our picture of the Southwest."
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References:

EurekAlert. 2013. “Artifacts shed light on social networks of the past”. EurekAlert. Posted: March 25, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-03/uoa-asl032513.php

Nouns before verbs?

New research agenda could help shed light on early language, cognitive development

Researchers are digging deeper into whether infants' ability to learn new words is shaped by the particular language being acquired.

A new Northwestern University study cites a promising new research agenda aimed at bringing researchers closer to discovering the impact of different languages on early language and cognitive development.

For decades, researchers have asked why infants learn new nouns more rapidly and more easily than new verbs. Many researchers have asserted that the early advantage for learning nouns over verbs is a universal feature of human language.

In contrast, other researchers have argued that early noun-advantage is not a universal feature of human language but rather a consequence of the particular language being acquired.

Sandra Waxman, lead author of the study and Louis W. Menk Professor of Psychology at Northwestern, shows in her research that even before infants begin to produce many verbs in earnest, infants acquiring either noun-friendly or verb-friendly languages already appreciate the concepts underlying both noun and verb meaning.

In all languages examined to date, researchers see a robust ability to map nouns to objects, Waxman said, but when it comes to mapping verbs to events, infants' performance is less robust and more variable. Their ability to learn new verbs varied not only as a function of the native language being acquired, but also with the particular linguistic context in which the verb was presented.

Based on new evidence, a shift in the research agenda is necessary, according to Waxman and her colleagues.

"We now know that by 24 months infants acquiring distinctly different languages can successfully map novel nouns to objects and novel verbs to event categories," Waxman said. "It is essential that we shift the research focus to include infants at 24 months and younger, infants who are engaged in the very process of acquiring distinctly different native languages."

Waxman said the implications are clear. "Rather than characterizing languages as either 'noun friendly' or 'verb friendly,' it would be advantageous to adopt a more nuanced treatment of the syntactic, semantic, morphologic and pragmatic properties of each language and the consequences of these properties on infants' acquisition of linguistic structure and meaning."
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References:

EurekAlert. 2013. “Nouns before verbs?”. EurekAlert. Posted: March 25, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-03/nu-nbv032513.php

The Picts are 'alive and well' and living in Scotland

TEN per cent of Scottish men are directly descended from the Picts, according to a new discovery by a DNA project.

Generations of historians have questioned why the Picts seemed to disappear from history after fighting the Romans and Vikings. But BritainsDNA has found a new DNA marker that suggests they are alive and well and “living among us”.

Dr Jim Wilson, chief scientist for the group, has found a new Y chromosome marker that arose among the direct ancestors of the Picts.

He tested the new “fatherline” in more than 3,000 British and Irish men and found an “amazing statistic” suggesting it was ten times more common in men with Scottish grandfathers, than in men with English grandfathers.

Ten per cent of the more than 1,000 Scottish men tested carry the R1b-S530 marker, while less than one per cent of Englishmen have it.

Dr Wilson said the difference was “highly statistically signiflicant” and could be applied to the general population. About three per cent of men in Northern Ireland also carry the marker, but it was only seen once in more than 200 men from the Republic of Ireland.

The company, which maps ancestry for individuals by looking at their DNA, said it had so far found 170 men in Scotland carrying the Pictish marker.

Dr Wilson, a lecturer in genetics at Edinburgh University, said, “The finding just popped out of the analysis. While there have been hints of this from previous data, what was surprising was the really huge difference between England and Scotland.

“It is also a clear sign that although people have moved around in recent times, there remains a core who have stayed at home, for a very long time.”

Alistair Moffat, the historian and co-founder of BritainsDNA, added, “Politically the Picts seemed to vanish after a crucial battle with the Vikings in Strathmore in 839 and the establishment of Kenneth MacAlpin and his dynasty in the middle of the 9th century.

“But what these fascinating new findings tell us is that, kings and dynasties apart, there is a hidden, people’s history of Scotland bubbling under the headlines, a history only DNA can reveal.”
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References:

Cramb, Auslan. 2013. “The Picts are 'alive and well' and living in Scotland”. The Telegraph. Posted: March 25, 2013. Available online: http://www.telegraph.co.uk/science/science-news/9953179/The-Picts-are-alive-and-well-and-living-in-Scotland.html

First Migration from Africa Less Than 95,000 Years Ago: Ancient Hunter-Gatherer DNA Challenges Theory of Early Out-Of-Africa Migrations

Recent measurements of the rate at which children show DNA changes not seen in their parents -- the "mutation rate" -- have challenged views about major dates in human evolution.

In particular these measurements have made geneticists think again about key dates in human evolution, like when modern non-Africans split from modern Africans. The recent measurements push back the best estimates of these dates by up to a factor of two. Now, however an international team led by researchers at the University of Tübingen and the Max Planck Institute for Evolutionary Anthropology in Leipzig, present results that point again to the more recent dates. The new study is published in Current Biology.

The team, led by Johannes Krause from Tübingen University, was able to reconstruct more than ten mitochondrial genomes (mtDNAs) from modern humans from Eurasia that span 40,000 years of prehistory. The samples include some of the oldest modern human fossils from Europe such as the triple burial from Dolni Vestonice in the Czech Republic, as well as the oldest modern human skeletons found in Germany from the site of Oberkassel close to Bonn.

The researchers show that pre-ice age hunter-gatherers from Europe carry mtDNA that is related to that seen in post-ice age modern humans such as the Oberkassel fossils. This suggests that there was population continuity throughout the last major glaciation event in Europe around 20,000 years ago. Two of the Dolni Vestonice hunter-gatherers also carry identical mtDNAs, suggesting a close maternal relationship among these individuals who were buried together.

The researchers also used the radiocarbon age of the fossils to estimate human mutation rates over tens of thousands of year back in time. This was done by calculating the number of mutations in modern groups that are absent in the ancient groups, since they had not yet existed in the ancient population. The mutation rate was estimated by counting the number of mutations accumulated along descendent lineages since the radiocarbon dated fossils.

Using those novel mutation rates -- capitalizing on information from ancient DNA -- the authors cal-culate the last common ancestor for human mitochondrial lineages to around 160,000 years ago. In other words, all present-day humans have as one of their ancestors a single woman who lived around that time.

The authors also estimate the time since the most recent common ancestor of Africans and non-Africans to between 62,000-95,000 years ago, providing a maximum date for the mass migration of modern humans out of Africa. Those results are in agreement with previous mitochondrial dates based on archaeological and anthropological work but are at the extreme low end of the dates suggested from de-novo studies that suggest a split of non-Africans from Africans about thirty thousand years earlier.

"The results from modern family studies and our ancient human DNA studies are in conflict" says Krause. "One possibility is that mutations were missed in the modern family studies, which could lead to underestimated mutation rates." The authors argue that nuclear genomes from ancient modern humans may help to explain the discrepancies.
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References:

Science Daily. 2013. “First Migration from Africa Less Than 95,000 Years Ago: Ancient Hunter-Gatherer DNA Challenges Theory of Early Out-Of-Africa Migrations”. Science Daily. Posted: March 22, 2013. Available online: http://www.sciencedaily.com/releases/2013/03/130322114856.htm

Stone ships show signs of maritime network in Baltic Sea region 3,000 years ago

In the middle of the Bronze Age, around 1000 BC, the amount of metal objects increased dramatically in the Baltic Sea region. Around the same time, a new type of stone monument, arranged in the form of ships, started to appear along the coasts. New research from the University of Gothenburg, Sweden shows that the stone ships were built by maritime groups.

The maritime groups were part of a network that extended across large parts of northern Europe. The network was maintained largely because of the strong dependence on bronze.

Archaeologists have long assumed that bronze was imported to Scandinavia from the south, and recent analyses have been able to confirm this notion. The distribution of bronze objects has been discussed frequently, with most analyses focusing on the links in the networks. The people behind the networks, however, are only rarely addressed, not to mention their meeting places.

'One reason why the meeting places of the Bronze Age are not discussed very often is that we haven't been able to find them. This is in strong contrast to the trading places of the Viking Age, which have been easy to locate as they left behind such rich archaeological material,' says the author of the thesis Joakim Wehlin from the University of Gothenburg and Gotland University.

In his thesis, Wehlin has analysed the archaeological material from the Bronze Age stone ships and their placement in the landscape. The stone ships can be found across the entire Baltic Sea region and especially on the larger islands, with a significant cluster on the Swedish island of Gotland. The ships have long been thought to have served as graves for one or several individuals, and have for this reason often been viewed as death ships intended to take the deceased to the afterlife.

'My study shows a different picture. It seems like the whole body was typically not buried in the ship, and some stone ships don't even have graves in them. Instead, they sometimes show remains of other types of activities. So with the absence of the dead, the traces of the survivors tend to appear.'

One of Wehlin's conclusions is that the stone ships and the activities that took place there point to people who were strongly focused on maritime practice. Details in the ships indicate that they were built to represent real ships. Wehlin says that the stone ships give clues about the ship-building techniques of the time and therefore about the ships that sailed on the Baltic Sea during the Bronze Age.

By studying the landscape, Wehlin has managed to locate a number of meeting places, or early ports.

'These consist of areas that resemble hill forts and are located near easily accessible points in the landscape – that is, near well-known waterways leading inland. While these areas have previously been thought to be much younger, recent age determinations have dated them to the Bronze Age.'

The thesis offers a very extensive account of the stone ships. It also suggests that the importance of the Baltic Sea during the Scandinavian Bronze Age, not least as a waterway, has been underestimated in previous research.
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References:

EurekAlert. 2013. “Stone ships show signs of maritime network in Baltic Sea region 3,000 years ago”. EurekAlert. Posted: March 21, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-03/uog-sss032113.php

Best-Preserved Human Ancestor Didn't Have Bone Disorder

"Turkana Boy," an exquisitely preserved 1.5-million-year-old human ancestor found in Kenya, may not have had dwarfism or scoliosis, new research suggests.

Past studies had suggested that the ancient human ancestor, a Homo erectus, had suffered from a congenital bone disorder that made him unrepresentative of his species.

"Until now, the Turkana Boy was always thought to be pathological," said study co-author Martin Häusler, a physician and physical anthropologist at the University of Zurich. "The spine was somewhat weird, and so he couldn't be used as a comparative model for Homo erectus biology because he was so pathological."

But the new analysis, published in the March issue of the American Journal of Physical Anthropology, suggests that apart from a herniated disc in his back, Turkana Boy was a fairly healthy person with no genetic bone problems.

Exquisite find

The exquisitely preserved fossil, unearthed near the shores of Lake Turkana in Kenya in 1984, is the most complete early human skeleton ever found. The ancient hominid was likely a child or an adolescent Homo erectus who lived and died about 1.5 million years ago.

But about a decade ago, researchers proposed that Turkana Boy was suffering from a congenital deformation of the spine —possibly dwarfism or scoliosis.

To find out, Hausler and his colleagues carefully reanalyzed the skeletal bones. When they arranged the ribs as they were originally laid out, they got an asymmetrical back and rib cage.

"The ribs were arranged in the wrong way originally, and then you get this asymmetry, which is essentially not there," Häusler told LiveScience.

By rearranging the bones, the researchers found that Turkana Boy actually had a symmetrical spine and rib cage, meaning he wasn't suffering from dwarfism or scoliosis. As a result, it's fair game to make conclusions about the species' anatomy based on the skeleton, Häusler said.

The ancient hominid did show evidence of some vertebral misalignment, consistent with having a herniated disc — an injury that may have contributed to his death, Häusler said.

Controversial results

The new study is an excellent analysis, wrote Henry McHenry, an anthropologist at the University of California, Davis, who was not involved in the study. Häusler "has a special perspective in being an orthopedic surgeon with years of experience with original fossils in Africa and huge collections of modern humans and apes."

But not everyone is convinced.

"His axial skeleton is distinctive and bears evidence of some significant pathology," wrote Scott Simpson, an anthropologist at Case Western Reserve University in Ohio who was not involved in the study, in an email. "Clearly, some of the characteristics recognized in [Turkana Boy] would be characterized as congenital pathologies, perhaps in addition to traumatic injuries."
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References:

Ghose, Tia. 2013. “Best-Preserved Human Ancestor Didn't Have Bone Disorder”. Live Science. Posted: March 19, 2013. Available online: http://www.livescience.com/28016-turkana-boy-had-normal-spine.html

Return to Antikythera: what divers discovered in the deep

Divers revisiting the wreck in Greece where an ancient computer was found have discovered an array of artefacts

Divers returning to the site of an ancient wreck off the Greek island of Antikythera have found artefacts scattered over a wide area of the steep, rocky sea floor. These include intact pottery, the ship's anchor and some puzzling bronze objects. The team believes that hundreds more items could be buried in the sediment nearby.

The Antikythera wreck, which dates from the first century BC, yielded a glittering haul when sponge divers discovered it at the beginning of the 20th century. Among jewellery, weapons and statues were the remains of a mysterious clockwork device, dubbed the Antikythera mechanism.

Bar a brief visit by the undersea explorer Jacques Cousteau in the 1970s (featured in his documentary Diving for Roman Plunder), no one had visited the wreck since, leading to speculation about what treasures might still be down there. The locals told tales of giant marble statues lying beyond the sponge divers' reach, while ancient technology geeks like me wondered whether the site might be hiding another Antikythera mechanism, or at least some clues as to whom this mysterious object belonged to.

Cue all-round excitement when in October last year, a team of divers led by Brendan Foley of Woods Hole Oceanographic Institution and Aggeliki Simossi of Greece's Ephorate of Underwater Antiquities, went back for a proper look. The divers used James Bond-style propulsion vehicles equipped with high-resolution video cameras to circumnavigate the island at about 40 metres depth. Now the photos released by the team show some of what they found.

For centuries Antikythera was in a busy shipping lane, but surprisingly its treacherous underwater cliffs and reefs are not littered with sunken ships (perhaps those ancient navigators were more skilled than we thought). And there are no obvious signs of a wreck at the site supposedly excavated by Cousteau, suggesting that he recovered all of the visible items there – or that he planted some of his finds for the cameras.

But 200 metres away, the divers found artefacts spread across the rocky sea floor, on a steep slope between 35 and 60 metres deep.

The largest item recovered was a huge lead anchor stock. It was lying on a semicircular object that might be a scupper pipe, used to drain water from the ship's deck. If so, the ship may have gone down as she was sailing with the anchor stowed. The team also raised an intact storage jar (amphora), which matches those previously recovered from the wreck. DNA tests may reveal its original contents.

Most intriguing are dozens of irregular spherical objects sprinkled across the wreck site. They look like rocks but contain flecks of green, suggesting small bronze fragments, corroded and encrusted in sediment after thousands of years in the sea. This is just what the Antikythera mechanism looked like when it was discovered. Then again, they could be collections of ship's nails.

Because the artefacts the team found are a short distance from the site investigated by Cousteau, it's possible that they belong to a second ship from around the same date as the original wreck, perhaps part of the same fleet. But Foley thinks it more likely that all of the remains come from one vessel that broke up as it sank.

To confirm this, he hopes to revisit the site later this year. He wants to use metal detectors to map the distribution of metal and ceramic objects buried beneath the surface, as well as dig a few test trenches. "I'm intensely curious about what's in the sediments," he says.

Cousteau only excavated a few square metres of the site but that was enough to reveal more than two hundred items, including jewellery, coins and small bronze statues. But while previous visits to the wreck have been little more than salvage expeditions, Foley says he'd love to carry out a systematic, scientific excavation of the wreck site, if he can find anyone to sponsor him: "As soon as we have the money we'll be back."
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References:

Marchant, Jo. 2013. “Return to Antikythera: what divers discovered in the deep”. The Guardian. Posted: March 18, 2013. Available online: http://www.guardian.co.uk/science/blog/2013/mar/18/return-to-antikythera-divers

Farming has deep roots in Chinese ice age

Some ideas need time to take root. A new analysis suggests it took up to 12,000 years for people in what is now China to go from eating wild plants to farming them. Agriculture elsewhere also took time to flower.

Li Liu of Stanford University and colleagues studied three grinding stones from China's Yellow River region. They bear residues showing that they were used to process millet and other grains, as well as yams, beans and roots.

The stones date from 23,000 to 19,500 years ago, late in the last ice age. But the earliest archaeological evidence for crop cultivation in China is 11,000 years old, suggesting that farming was slow to emerge from ancient traditions of plant use.

That fits with a wider pattern, says Robin Allaby of the University of Warwick, UK. In the Middle East "we also have evidence of cereals at that 23,000-year point", he says – which is long before people were farming them. "Although this period is around the late glacial maximum, there is a blip at 23,000 years during which time it was milder." Millet and the other food plants could have flourished in the warmth, tempting people to start exploiting them.

Some of the plants, like the snakegourd root, are still used in traditional medicines. Karen Hardy at the Catalan Institution for Research and Advanced Studies in Barcelona, Spain, says she would not be surprised if ancient peoples "knew how to select plant food that benefited their health". Last year she reported evidence that Neanderthals used medicinal plants.

"We can never know for certain why a plant was ingested, but I think these early people probably had a detailed knowledge of the plants they selected and used," Hardy says. "This is likely to have included their medicinal as well as their nutritional qualities."
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References:

Barras, Colin. 2013. “Farming has deep roots in Chinese ice age”. New Scientist. Posted: March 18, 2013. Available online: http://www.newscientist.com/article/dn23290-farming-has-deep-roots-in-chinese-ice-age.html

How can we stlil raed words wehn teh lettres are jmbuled up?

Researchers in the UK have taken an important step towards understanding how the human brain 'decodes' letters on a page to read a word. The work, funded by the Economic and Social Research Council (ESRC), will help psychologists unravel the subtle thinking mechanisms involved in reading, and could provide solutions for helping people who find it difficult to read, for example in conditions such as dyslexia.

In order to read successfully, readers need not only to identify the letters in words, but also to accurately code the positions of those letters, so that they can distinguish words like CAT and ACT. At the same time, however, it's clear that raeders can dael wtih wodrs in wihch not all teh leettrs aer in thier corerct psotiions.

"How the brain can make sense of some jumbled sequences of letters but not others is a key question that psychologists need to answer to understand the code that the brain uses when reading," says Professor Colin Davis of Royal Holloway, University of London, who led the research.

For many years researchers have used a standard psychological test to try to work out which sequences of letters in a word are important cues that the brain uses, where jumbled words are flashed momentarily on a screen to see if they help the brain to recognise the properly spelt word.

But, this technique had limitations that made it impossible to probe more extreme rearrangements of sequences of letters. Professor Davis's team used computer simulations to work out that a simple modification to the test would allow it to question these more complex changes to words. This increases the test's sensitivity significantly and makes it far more valuable for comparing different coding theories.

"For example, if we take the word VACATION and change it to AVACITNO, previously the test would not tell us if the brain recognises it as VACATION because other words such as AVOCADO or AVIATION might start popping into the person's head," says Professor Davis. "With our modification we can show that indeed the brain does relate AVACITNO to VACATION, and this starts to give us much more of an insight into the nature of the code that the brain is using – something that was not possible with the existing test."

The modified test should allow researchers not only to crack the code that the brain uses to make sense of strings of letters, but also to examine differences between individuals – how a 'good' reader decodes letter sequences compared with someone who finds reading difficult.

"These kinds of methods can be very sensitive to individual differences in reading ability and we are starting to get a better idea of some of the issues that underpin people's difficulty in reading," says Professor Davis. Ultimately, this could lead to new approaches to helping people to overcome reading problems.
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References:

EurekAlert. 2013. “How can we stlil raed words wehn teh lettres are jmbuled up?”. EurekAlert. Posted: March 14, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-03/esr-hcw031313.php

Black Death Skeletons Unearthed by Crossrail Workers

Thirteen skeletons thought to be victims of the Black Death plague which swept Britain over 600 years ago have been dug up by workers on the £15 billion Crossrail project in London, archaeologists said Friday.

Up to 50,000 people may have been buried at the site in Charterhouse Square in Farringdon if it proves to be the location of a plague cemetery mentioned in ancient records.

The records refer to a burial ground in the Farringdon area that opened during the Black Death in 1348.

Over the past two weeks, the archaeologists have uncovered 13 skeletons in two carefully laid out rows 2.5 metres below the road that surrounds the gardens in Charterhouse Square.

"The depth of burials, the pottery found with the skeletons and the way the skeletons have been set out all point towards this being part of the 14th century emergency burial ground," said Jay Carver, Crossrail's lead archaeologist.

"This is a highly significant discovery and at the moment we are left with many questions that we hope to answer," he said.

"We will be undertaking scientific tests on the skeletons over the coming months to establish their cause of death, whether they were plague victims from the 14th century or later London residents, how old they were and perhaps evidence of who they were," Carver added.

The skeletons are being carefully excavated and taken to the Museum of London Archaeology for laboratory testing.

The scientists are hoping to map the DNA signature of the plague which could help uncover the cause of the Black Death.

The bones may also be radio carbon-dated to try and establish the burial dates.

These are not the first skeletons found on the Crossrail project, with archaeologists already having uncovered more than 300 at the New Cemetery near the site of the Bedlam Hospital at Liverpool Street from the 1500s to 1700s.

The Crossrail line, under construction since 2009 and due to carry its first passengers in 2017, will run across London on an east-west route.

It will be mostly overground but is going underground in the centre of the city.
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References:

Discovery News. 2013. “Black Death Skeletons Unearthed by Crossrail Workers”. Discovery News. Posted: March 15, 2013. Available online: http://news.discovery.com/history/archaeology/black-death-skeletons-130315.htm

Fish corrupt Carbon-14 dating

Danish Stone Age settlements may have been misdated by up to 2,000 years. In sites where people ate fish, there might well be errors in the Carbon-14 dating of clay vessels.

Danish Stone Age settlements may turn out to be hundreds, perhaps thousands, of years younger than we thought.

A physicist from Aarhus University has together with archaeologists at the Gottorp Castle Museum in Northern Germany made a startling discovery: if ancient people prepared their fish in clay vessels, it’s impossible to date this accurately.

It turns out that the widely-used Carbon-14 dating method may be up to 2,000 years off the mark.

”We had not expected to see an effect of 2,000 years. The discovery has some fairly frightening implications because it’s crucial to archaeology to have steady fixation points in the dating work. There’s probably no need to rewrite the history books, but it’s likely that they contain some incorrectly dated excavation sites, Associate Professor Felix Riede told Aarhus University’s newsletter Rømer.

“This is food for thought, especially in an old fishing nation like Denmark. In sites where people ate fish, we might see errors in the Carbon-14 dating of clay vessels.”

Fish contain less Carbon-14

This is due to the fact that fish contain less of the radioactive substance Carbon 14 if they have lived in hard water.

Hard water contains high levels of calcium carbonate. Carbonate contains carbon, including carbon-14. However, depending on ocean water circulation, fish and other living creatures can incorporate 'older' carbonate (with less carbon-14) into their bodies. When these organisms die and fossilise, they appear to be much older than they actually are.

And, strange as it may sound, this has an effect on the Carbon-14 content in the clay pots that were used for cooking fish.

Danish Stone Age people had a diet rich in fish, so there is a great risk that errors have been made in the dating of an unknown number of settlements. This could mean that we have an inaccurate picture of how ancient culture developed in and around Denmark.

”An error of a couple of hundred years isn’t too bad when you’re dating finds from the Early Stone Age. But an error of 2,000 years is of great importance,” says Riede.

A result of creative experiments

Before they started on the research project, the archaeologists were fully aware that dating of fish is subject to a large margin of error. They just didn’t know how big it was, nor how fish affect the Carbon-14 contents in the clay vessels that they were prepared in.

An experiment made things clearer:

The archaeologists created a clay vessel of the kind that was used in the Stone Age.

They placed it over a fire and prepared a fish dish in it.

They made sure that some of it stuck to the pot.

They then Carbon-14 dated the pot and the burnt crust at the bottom of the pot. The dating showed that the pot and the burnt fish, Carbon-14-wise, were 700 years old.

This gave the archaeologists reason to believe that they should take care not to rely too much on the Carbon-14 dating method.
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References:

Ebdrup, Niels. 2013. “Fish corrupt Carbon-14 dating”. Science Nordic. Posted: March 14, 2013. Available online: http://sciencenordic.com/fish-corrupt-carbon-14-dating

New research discovers the emergence of Twitter 'tribes'

A project led by scientists from Royal Holloway University in collaboration with Princeton University, has found evidence of how people form into tribe-like communities on social network sites such as Twitter.

In a paper published in EPJ Data Science, they found that these communities have a common character, occupation or interest and have developed their own distinctive languages.

"This means that by looking at the language someone uses, it is possible to predict which community he or she is likely to belong to, with up to 80% accuracy," said Dr John Bryden from the School of Biological Sciences at Royal Holloway. "We searched for unusual words that are used a lot by one community, but relatively infrequently by the others. For example, one community often mentioned Justin Bieber, while another talked about President Obama."

Professor Vincent Jansen from Royal Holloway added: "Interestingly, just as people have varying regional accents, we also found that communities would misspell words in different ways. The Justin Bieber fans have a habit of ending words in 'ee', as in 'pleasee', while school teachers tend to use long words."

The team produced a map of the communities showing how they have vocations, politics, ethnicities and hobbies in common. In order to do this, they focused on the sending of publically available messages via Twitter, which meant that they could record conversations between two or many participants.

To group these users into communities, they turned to cutting-edge algorithms from physics and network science. The algorithms worked by looking for individuals that tend to send messages to other members of the same community.

Dr Bryden then suggested analysing the language use of these discovered communities.

Dr Sebastian Funk from Princeton University said: "When we started to apply John's ideas, surprising groups started to emerge that we weren't expecting. One 'anipals' group was interested in hosting parties to raise funds for animal welfare, while another was a fascinating growing community interested in the concept of gratitude."
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References:

EurekAlert. 2013. “New research discovers the emergence of Twitter 'tribes'”. EurekAlert. Posted: March 14, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-03/rhuo-nrd031413.php

Bringing Up Bilingual, Bigoted Baby

Two studies out of Canada this week suggest that while your cute toddler can already understand grammar in two languages, he or she may be suspicious of difference.

The first study, published in the journal Nature Communications, found children “as young as seven months can distinguish between, and begin to learn, two languages with vastly different grammatical structures.” The study found that infants in bilingual environments quickly learned to identify words that appeared frequently, like “the” or “and” in English, and used them as cues to distinguish which language was in use.

The research included languages with marked differences in grammatical structure, like Hindi and English. The children in bilingual households learned to key in on “pitch and duration cues,” and used that to develop what the researchers suggest is a child’s concept of discrete systems of grammar.

Understanding grammar doesn’t mean they will talk any better or sooner. Which is fortunate, because if nine month-olds could tell us what they are thinking, it might be scary as hell.

Research released the same time by the University of British Columbia, found that infants as young as nine months have begun to “condone antisocial behavior when it is directed at individuals who are dissimilar.”

In what sounds like a scene from a David Cronenberg movie, researchers started by putting a series of babies in front a plate of graham crackers and some green beans and let the kids choose which one they preferred. Then, they had the kids watch a puppet show in which the puppets underwent the same exercise, selecting graham crackers or green beans. Then they let the kids interact with the puppets. The kids not only gravitated toward the puppet that shared its snack preference, but appeared to grow more attached if that puppet then attacked the puppets who had expressed the other food preference. From the UBC summary:

In the experiments, other puppets harmed, helped or acted neutrally towards the puppets with different or similar food preferences. Prompted to pick their favorite puppet, infants demonstrated a strong preference for the puppets who harmed the “dissimilar” puppet and helped the “similar” one – one infant even planted a kiss on the puppet she liked.

These findings suggest that babies either feel something like schaudenfreude – pleasure when an individual they dislike or consider threatening experiences harm,” says Hamlin. “Or babies have some early understanding of social alliances, recognizing that the ‘enemy of their enemy’ is their friend.

The two studies had nothing to do with each other. It would be interesting to run one of the bilingual babies through the puppet experiment, and see if they liked both graham crackers and green beans.
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References:

Herman, Marc. 2013. “Bringing Up Bilingual, Bigoted Baby”. Pacific Standard. Posted: March 14, 2013. Available online: http://www.psmag.com/blogs/the-101/bringing-up-bilingual-bigoted-baby-54002/

Ancient Chinese coin found on Kenyan island by Field Museum expedition

A joint expedition of scientists led by Chapurukha M. Kusimba of The Field Museum and Sloan R. Williams of the University of Illinois at Chicago has unearthed a 600-year-old Chinese coin on the Kenyan island of Manda that shows trade existed between China and east Africa decades before European explorers set sail and changed the map of the world.

The coin, a small disk of copper and silver with a square hole in the center so it could be worn on a belt, is called "Yongle Tongbao" and was issued by Emperor Yongle who reigned from 1403-1425AD during the Ming Dynasty. The emperor's name is written on the coin, making it easy to date. Emperor Yongle, who started construction of China's Forbidden City, was interested in political and trade missions to the lands that ring the Indian Ocean and sent Admiral Zheng He, also known as Cheng Ho, to explore those shores.

"Zheng He was, in many ways, the Christopher Columbus of China," said Dr. Kusimba, curator of African Anthropology at The Field Museum. "It's wonderful to have a coin that may ultimately prove he came to Kenya," he added.

Dr. Kusimba continued, "This finding is significant. We know Africa has always been connected to the rest of the world, but this coin opens a discussion about the relationship between China and Indian Ocean nations."

That relationship stopped soon after Emperor Yongle's death when later Chinese rulers banned foreign expeditions, allowing European explorers to dominate the Age of Discovery and expand their countries' empires.

The island of Manda, off the northern coast of Kenya, was home to an advanced civilization from about 200AD to 1430AD, when it was abandoned and never inhabited again. Trade played an important role in the development of Manda, and this coin may show trade's importance on the island dating back to much earlier than previously thought.

"We hope this and future expeditions to Manda will play a crucial role in showing how market-based exchange and urban-centered political economies arise and how they can be studied through biological, linguistic, and historical methodologies," Dr. Kusimba said.
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References:

EurekAlert. 2013. “Ancient Chinese coin found on Kenyan island by Field Museum expedition”. EurekAlert. Posted: March 13, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-03/fm-acc031313.php

Disputed finds put humans in South America 22,000 years ago

Brazilian site may have been home to people before the Clovis hunters

Stone tools unearthed at a Brazilian rock-shelter may date to as early as 22,000 years ago. Their discovery has rekindled debate about whether ancient people reached the Americas long before the famed Clovis hunters spread through parts of North America around 13,000 years ago.

These relics of ancient South Americans add to evidence from nearby sites challenging the longstanding view of Clovis people as the first Americans (SN: 8/11/12, p. 15), a team led by geochronologist Christelle Lahaye of the University of Bordeaux 3 and archaeologist Eric Boëda of the University of Paris X reports March 4 in the Journal of Archaeological Science.

“We have new, strong evidence that the Clovis-first model is out of date,” Lahaye says.

Among other South American locations proposed as human settlements well before North America’s Clovis culture, the most controversial is Brazil’s Pedra Furada rock-shelter. There, archaeologists unearthed burned wood and sharp-edged stones and dated them to more than 50,000 years ago. Pedra Furada’s excavators regard the finds as evidence of ancient human hearths and stone tools. Critics, and especially many Clovis investigators, say the Brazilian discoveries could have resulted from natural fires and rock slides.

The new discovery came at Toca da Tira Peia rock-shelter, which is in the same national park as Pedra Furada. It also has drawn skeptics. The site’s location at the base of a steep cliff raises the possibility that crude, sharp-edged stones resulted from falling rocks, not human handiwork, says archaeologist Gary Haynes of the University of Nevada, Reno. Another possibility is that capuchins or other monkeys produced the tools, says archaeologist Stuart Fiedel of Louis Berger Group, an environmental consulting firm in Richmond, Va.

The age of Toca da Tira Peia artifacts has also drawn debate. Dating the artifacts hinges on calculations of how long ago objects were buried by soil. Various environmental conditions, including fluctuations in soil moisture, could have distorted these age estimates, Haynes says.

But archaeologist Tom Dillehay of Vanderbilt University in Nashville has seen some of the Toca da Tira Peia finds and regards them as human-made implements. Similar tools have been unearthed at sites in Chile and Peru, Dillehay says. His team previously estimated that people settled Chile’s Monte Verde site by 14,000 years ago, and possibly as long as 33,000 years ago.

An absence of burned wood or other finds suitable for radiocarbon dating at Toca da Tira Peia is a problem, because that’s the standard method for estimating the age of sites up to around 40,000 years ago, Dillehay says. But if people reached South America by 20,000 years ago, “this is the type of archaeological record we might expect: ephemeral and lightly scattered material in local shelters.”

Lahaye and Boëda’s team excavated Toca da Tira Peia from 2008 to 2011. Digging turned up 113 stone artifacts consisting of tools and tool debris in five soil layers. Using a technique that measures natural radiation damage in excavated quartz grains, the scientists estimated that the last exposure of soil to sunlight ranged from about 4,000 years ago in the top layer to 22,000 years ago in the third layer.

Lahaye says that 15 human-altered stones from the bottom two soil layers must be older than 22,000 years. The researchers plan to calculate when those artifacts were buried.
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References:

Bower, Bruce. 2013. “Disputed finds put humans in South America 22,000 years ago”. Science News. Posted: March 13, 2013. Available online: http://www.sciencenews.org/view/generic/id/348953/description/Disputed_finds_put_humans_in_South_America_22000_years_ago

Citation

C. Lahaye et al. Human occupation in South America by 20,000 BC: The Toca da Tira Peia site, Piaui, Brazil. Journal of Archaeological Science. Doi: 10.1016/j.jas.2013.02.019.

Ancient Reindeer Hunters Fished Ice Age Lakes

Scientists have unearthed six fishhooks, the oldest of which was made from a 19,000-year-old mammoth tusk.

Hunters of ice age reindeer around 12,300 years ago likely left the fishhooks, along with mammal and fish bones, in an open field in what is now Wustermark, Germany. The fishhooks, which are the oldest found in Europe, suggests humans developed fishing tools earlier than previously thought, probably to catch fast-moving fish that appeared in lakes as the climate warmed.

"These people had strong ideas to use the new resources of this changing environment," said Robert Sommer, a paleoecologist at the University of Kiel in Germany. The eel, perch and pike that entered lakes are too fast to snag with a harpoon or a spear, Sommer added.

The findings are detailed in the May 2013 issue of the Journal of Archaeological Science.

Ancient seafood

Most archaeological evidence for ancient seafood consumption has washed away with rising sea levels. In 2011, scientists discovered the world's oldest fishhooks in coastal caves in East Timor (formerly part of Indonesia). But because the hooks were not complete, they relied heavily on nearby fish bones to draw their conclusions.

And until now, archaeologists in Europe thought hunter-gatherers around 12,000 years ago speared slow-moving fish like salmon in shallow streams, but didn't use hooks until much later, Sommer told LiveScience.

Fish eaters

Sommer and his colleagues unearthed several Paleolithic finds during a routine environmental assessment prior to building a shopping mall 12.4 miles (20 kilometers) west of Berlin.

The site, which was once an open field near an ancient lake, revealed six fishhooks, along with animal and fish remains. One of the fishhooks was carved from ivory from a mammoth tusk, while the rest were made of reindeer or elk bones closer to 12,300 years of age.

Because mammoths went extinct before the fishermen lived, the people probably found a whole tusk and used it millennia later, Sommer told LiveScience.

Confirms fishing

The fishhooks are impressive because they show the sophistication of ancient hunters, said Sue O'Connor, an archaeologist at the Australian National University, who found the East Timor fishhooks, but was not involved in this study.

"There's a lot of planning that's gone into the development of these particular hook shapes," O'Connor told LiveScience. "You've got to have it at the right angle so it actually hooks the fish, otherwise the fish just gets off."
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References:

Ghose, Tia. 2013. “Ancient Reindeer Hunters Fished Ice Age Lakes”. Live Science. Posted: March 8, 2013. Available online: http://www.livescience.com/27744-oldest-fish-hooks-unearthed-europe.html

High-Res Brain Scans to Reveal Personality Traits

U.S. researchers published incredibly detailed images of the human brain as part of an international project aimed at uncovering how brain architecture influences personality.

The five-year "Human Connectome Project" or HCP -- being conducted at 10 research centers in the United States and Europe -- will use advanced brain imaging technology to collect vast amounts of data on healthy adults and make it freely available to researchers worldwide.

"The HCP will have a major impact on our understanding of the healthy adult human brain," said David Van Essen, of the Washington University School of Medicine in St. Louis.

It will enable "the scientific community to immediately begin exploring relationships between brain circuits and individual behavior," he said.

"And it will set the stage for future projects that examine changes in brain circuits underlying the wide variety of brain disorders afflicting humankind."

Tuesday's initial release includes scans of 68 healthy adults, along with behavioral information, including individual differences in personality, cognitive capabilities, emotional characteristics and perceptual function.

The extremely high-resolution brain scans were achieved using two techniques of magnetic resonance imaging. Each have limitations, the researchers said, but taken together, they should give a more complete picture of what goes on in the brain.

The researchers also performed scans of the test subjects while performing specific tasks.

The resulting dataset is massive -- comprising two terabytes (2 trillion bytes) of computer memory, or the equivalent of more than 400 DVDs.

Over the next five years, the researchers hope to release similar information on a total of 1,200 individuals, including siblings and twins, which will help determine which brain circuitry traits might be inherited.
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References:

Discovery News. 2013. “High-Res Brain Scans to Reveal Personality Traits”. Discovery News. Posted: March 6, 2013. Available online: http://news.discovery.com/tech/biotechnology/high-res-brain-scans-personality-traits-130306.htm

How science debunked the ancient Aztec crystal skull hoax

They may have gained fame in the Steven Spielberg adventure film "Indiana Jones and the Kingdom of the Crystal Skull," but those quartz-crystal skulls that once ranked as a great enigma of archaeology are certifiably fake. And the current edition of Chemical & Engineering News, (C&EN) the weekly news magazine of the American Chemical Society, the world's largest scientific society, recalls the details of their rise and fall.

In the article, Sarah Everts, C&EN's European science correspondent, delves back into history, explaining that the skull sculptures — supposedly crafted before the Spanish conquest in the 16th century — began appearing on the art market in the 1860s. They graced collections of institutions as renowned as the British Museum in London, the Quai Branly Museum in Paris and Washington, D.C.'s Smithsonian Institution.

Experts began doubting the authenticity of the skulls as long ago as the 1930s. Everts describes how experts at those three museums have used scientific instruments to show that the skulls are post-Columbian fakes. French antiquities dealer Eugène Boban played a major role in sparking public fascination with the skulls by getting some of the first fakes placed in major museums.
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References:

EurekAlert. 2013. “How science debunked the ancient Aztec crystal skull hoax”. EurekAlert. Posted: March 7, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-03/acs-hsd030713.php

Grotesque Mummy Head Reveals Advanced Medieval Science

In the second century, an ethnically Greek Roman named Galen became doctor to the gladiators. His glimpses into the human body via these warriors' wounds, combined with much more systematic dissections of animals, became the basis of Islamic and European medicine for centuries.

Galen's texts wouldn't be challenged for anatomical supremacy until the Renaissance, when human dissections — often in public — surged in popularity. But doctors in medieval Europe weren't as idle as it may seem, as a new analysis of the oldest-known preserved human dissection in Europe reveals.

The gruesome specimen, now in a private collection, consists of a human head and shoulders with the top of the skull and brain removed. Rodent nibbles and insect larvae trails mar the face. The arteries are filled with a red "metal wax" compound that helped preserve the body.

In the second century, an ethnically Greek Roman named Galen became doctor to the gladiators. His glimpses into the human body via these warriors' wounds, combined with much more systematic dissections of animals, became the basis of Islamic and European medicine for centuries.

Galen's texts wouldn't be challenged for anatomical supremacy until the Renaissance, when human dissections — often in public — surged in popularity. But doctors in medieval Europe weren't as idle as it may seem, as a new analysis of the oldest-known preserved human dissection in Europe reveals.

The gruesome specimen, now in a private collection, consists of a human head and shoulders with the top of the skull and brain removed. Rodent nibbles and insect larvae trails mar the face. The arteries are filled with a red "metal wax" compound that helped preserve the body.

The preparation of the specimen was surprisingly advanced. Radiocarbon dating puts the age of the body between A.D. 1200 and A.D.1280, an era once considered part of Europe's anti-scientific "Dark Ages." In fact, said study researcher Philippe Charlier, a physician and forensic scientist at University Hospital R. Poincare in France, the new specimen suggests surprising anatomical expertise during this time period.

"It's state-of-the-art," Charlier told LiveScience. "I suppose that the preparator did not do this just one time, but several times, to be so good at this."

Myths of the middle ages

Historians in the 1800s referred to the Dark Ages as a time of illiteracy and barbarianism, generally pinpointing the time period as between the fall of the Roman Empire and somewhere in the Middle Ages. To some, the Dark Ages didn't end until the 1400s, at the advent of the Renaissance.

But modern historians see the Middle Ages quite differently. That's because continued scholarship has found that the medieval period wasn't so ignorant after all.

"There was considerable scientific progress in the later Middle Ages, in particular from the 13th century onward," said James Hannam, an historian and author of "The Genesis of Science: How the Christian Middle Ages Launched the Scientific Revolution" (Regnery Publishing, 2011).

For centuries, the advancements of the Middle Ages were forgotten, Hannam told LiveScience. In the 16th and 17th centuries, it became an "intellectual fad," he said, for thinkers to cite ancient Greek and Roman sources rather than scientists of the Middle Ages. In some cases, this involved straight-up fudging. Renaissance mathematician Copernicus, for example, took some of his thinking on the motion of the Earth from Jean Buridan, a French priest who lived between about 1300 and 1358, Hannam said. But Copernicus credited the ancient Roman poet Virgil as his inspiration.

Much of this selective memory stemmed from anti-Catholic feelings by Protestants, who split from the church in the 1500s.

As a result, "there was lots of propaganda about how the Catholic Church had been holding back human progress, and it was great that we were all Protestants now," Hannam said.

Anatomical dark ages?

From this anti-Catholic sentiment arose a great many myths, such as the idea that everyone believed the world to be flat until Christopher Columbus sailed to the Americas. ("They thought nothing of the sort," Hannam said.)

Similarly, Renaissance propagandists spread the rumor that the Medieval Christian church banned autopsy and human dissection, holding back medical progress.

In fact, Hannam said, many societies have banned or limited the carving up of human corpses, from the ancient Greeks and Romans to early Europeans (that's why Galen was stuck dissecting animals and peering into gladiator wounds). But autopsies and dissection were not under a blanket church ban in the Middle Ages. In fact, the church sometimes ordered autopsies, often for the purpose of looking for signs of holiness in the body of a supposedly saintly person.

The first example of one of these "holy autopsies" came in 1308, when nuns conducted a dissection of the body of Chiara of Montefalco, an abbess who would be canonized as a saint in 1881. The nuns reported finding a tiny crucifix in the abbess' heart, as well as three gallstones in her gallbladder, which they saw as symbolic of the Holy Trinity.

Other autopsies were entirely secular. In 1286, an Italian physician conducted autopsies in order to pinpoint the origin of an epidemic, according to Charlier and his colleagues.

Some of the belief that the church frowned on autopsies may have come from a misinterpretation of a papal edict from 1299, in which the Pope forbade the boiling of the bones of dead Crusaders. That practice ensured Crusaders' bones could be shipped back home for burial, but the Pope declared the soldiers should be buried where they fell.

"That was interpreted in the 19th century as actually being a stricture against human dissection, which would have surprised the Pope," Hannam said.

Well-studied head

While more investigation of the body was going on in the Middle Ages than previously realized, the 1200s remain the "dark ages" in the sense that little is known about human anatomical dissections during this time period, Charlier said. When he and his colleagues began examining the head-and-shoulders specimen, they suspected it would be from the 1400s or 1500s.

"We did not think it was so antique," Charlier said.

But radiocarbon dating put the specimen firmly in the 1200s, making it the oldest European anatomical preparation known. Most surprisingly, Charlier said, the veins and arteries are filled with a mixture of beeswax, lime and cinnabar mercury. This would have helped preserve the body as well as give the circulatory system some color, as cinnabar mercury has a red tint.

Thus, the man's body was not simply dissected and tossed away; it was preserved, possibly for continued medical education, Charlier said. The man's identity, however, is forever lost. He could have been a prisoner, an institutionalized person, or perhaps a pauper whose body was never claimed, the researchers write this month in the journal Archives of Medical Science.

The specimen, which is in private hands, is set to go on display at the Parisian Museum of the History of Medicine, Charlier said.

"This is really interesting from a historical and archaeological point of view," Charlier said, adding, "We really have a lack of skeletons and anthropological pieces."
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References:

Pappas, Stephanie. 2013. “Grotesque Mummy Head Reveals Advanced Medieval Science”. Live Science. Posted: March 5, 2013. Available online: http://www.livescience.com/27624-mummy-head-middle-ages-anatomy.html

Human Y chromosome much older than previously thought

A newly discovered Y chromosome places the most recent common ancestor for the Y chromosome lineage more 100,000 years before the oldest known anatomically modern human fossils

UA geneticists have discovered the oldest known genetic branch of the human Y chromosome – the hereditary factor determining male sex.

The new divergent lineage, which was found in an individual who submitted his DNA to Family Tree DNA, a company specializing in DNA analysis to trace family roots, branched from the Y chromosome tree before the first appearance of anatomically modern humans in the fossil record.

The results are published in the American Journal of Human Genetics: http://www.cell.com/AJHG/abstract/S0002-9297(13)00073-6

"Our analysis indicates this lineage diverged from previously known Y chromosomes about 300,000 ago, a time when anatomically modern humans had not yet evolved," said Michael Hammer, an associate professor in the University of Arizona's department of ecology and evolutionary biology and a research scientist at the UA's Arizona Research Labs. "This pushes back the time the last common Y chromosome ancestor lived by almost 70 percent."

Unlike the other human chromosomes, the majority of the Y chromosome does not exchange genetic material with other chromosomes, which makes it simpler to trace ancestral relationships among contemporary lineages. If two Y chromosomes carry the same mutation, it is because they share a common paternal ancestor at some point in the past. The more mutations that differ between two Y chromosomes the farther back in time the common ancestor lived.

Originally, a DNA sample obtained from an African American living in South Carolina was submitted to the National Geographic Genographic Project. When none of the genetic markers used to assign lineages to known Y chromosome groupings were found, the DNA sample was sent to Family Tree DNA for sequencing. Fernando Mendez, a postdoctoral researcher in Hammer's lab, led the effort to analyze the DNA sequence, which included more than 240,000 base pairs of the Y chromosome.

Hammer said "the most striking feature of this research is that a consumer genetic testing company identified a lineage that didn't fit anywhere on the existing Y chromosome tree, even though the tree had been constructed based on perhaps a half-million individuals or more. Nobody expected to find anything like this."

About 300,000 years ago falls around the time the Neanderthals are believed to have split from the ancestral human lineage. It was not until more than 100,000 years later that anatomically modern humans appear in the fossil record. They differ from the more archaic forms by a more lightly built skeleton, a smaller face tucked under a high forehead, the absence of a cranial ridge and smaller chins.

Hammer said the newly discovered Y chromosome variation is extremely rare. Through large database searches, his team eventually was able to find a similar chromosome in the Mbo, a population living in a tiny area of western Cameroon in sub-Saharan Africa.

"This was surprising because previously the most diverged branches of the Y chromosome were found in traditional hunter-gatherer populations such as Pygmies and the click-speaking KhoeSan, who are considered to be the most diverged human populations living today."

"Instead, the sample matched the Y chromosome DNA of 11 men, who all came from a very small region of western Cameroon," Hammer said. "And the sequences of those individuals are variable, so it's not like they all descended from the same grandfather."

Hammer cautions against popular concepts of "mitochondrial Eve" or "Y chromosome Adam" that suggest all of humankind descended from exactly one pair of humans that lived at a certain point in human evolution.

"There has been too much emphasis on this in the past," he said. "It is a misconception that the genealogy of a single genetic region reflects population divergence. Instead, our results suggest that there are pockets of genetically isolated communities that together preserve a great deal of human diversity."

Still, Hammer said, "It is likely that other divergent lineages will be found, whether in Africa or among African-Americans in the U.S. and that some of these may further increase the age of the Y chromosome tree."

He added: "There has been a lot of hype with people trying to trace their Y chromosome to different tribes, but this individual from South Carolina can say he did it."
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References:

EurekAlert. 2013. “Human Y chromosome much older than previously thought”. EurekAlert. Posted: March 4, 2013. Available online: http://www.eurekalert.org/pub_releases/2013-03/uoa-hyc030413.php

Hagia Sophia: Facts, History & Architecture

The Hagia Sophia, whose name means “holy wisdom,” is a domed monument originally built as a cathedral in Constantinople (now Istanbul, Turkey) in the sixth century A.D.

It contains two floors centered on a giant nave that has a great dome ceiling, along with smaller domes, towering above.

“Hagia Sophia’s dimensions are formidable for any structure not built of steel,” writes Helen Gardner and Fred Kleiner in their book "Gardner’s Art Through the Ages: A Global History." “In plan it is about 270 feet [82 meters] long and 240 feet [73 meters] wide. The dome is 108 feet [33 meters] in diameter and its crown rises some 180 feet [55 meters] above the pavement.”

In its 1,400 year life-span it has served as a cathedral, mosque and now a museum. When it was first constructed, Constantinople was the capital of the Byzantine Empire. This state, officially Christian, originally formed the eastern half of the Roman Empire and carried on after the fall of Rome.

Born out of riots

The story of the construction of the Hagia Sophia began in A.D. 532 when the Nika Riots, a great revolt, hit Constantinople. At the time Emperor Justinian I had been ruler of the empire for five years and had become unpopular. It started in the hippodrome among two chariot racing factions called the blue and green with the riot spreading throughout the city the rioters chanting “Nika,” which means “victory,” and attempting to throw out Justinian by besieging him in his palace.

“People were resentful of the high taxes that Justinian had imposed and they wanted him out of office,” said University of London historian Caroline Goodson in a National Geographic documentary. After moving loyal troops into the city Justinian managed to put down the rebellion with brute force.

In the wake of the uprising, and on the site of a torched church that had been called the Hagia Sophia, a new Hagia Sophia would be built. To the ancient writer Paul the Silentiary, who lived when the cathedral was completed, the building represented a triumph for both Justinian and Christianity.

“I say, renowned Roman Capitol, give way! My Emperor has so far overtopped that wonder as great God is superior to an idol!” (Translation by Peter Bell, from the book "Three Political Voices from the Age of Justinian," Liverpool University Press, 2009)

Building the Hagia Sophia

To build his cathedral, Justinian turned to two men named Anthemius and Isidore the Elder.

“Contemporary writers do not refer to Anthemius and Isidore as architects, though the term was common in the sixth century, but as mechanikoi or mechanopoioi,” writes Indiana University professor W. Eugene Kleinbauer in a section of the book "Hagia Sophia" (Scala Publishers, 2004). “These terms denote a very small number of practitioners of the arts of design, whether of buildings or of machines or other works ...”

They built the Hagia Sophia in great haste, finishing it in less than six years. To put this in comparison it took nearly a century for medieval builders to construct the Notre Dame cathedral in Paris.

This short construction period appears to have led to problems. Ancient sources, such as the writer Procopios, write that the builders had problems with the dome roof, the structure almost collapsing during construction. The dome used a system of piers to channel its weight.

“The piers on top of which the structure was being built, unable to bear the mass that was pressing down on them, somehow or other suddenly started to break away and seemed to be on the point of collapsing...” writes Procopios (translation republished on Columbia University’s website).

Eventually Anthemius and Isidore did get the domed roof to stand and it was a magnificent sight indeed. “It seems not to be founded on solid masonry, but to be suspended from heaven by that golden chain and so cover the space,” wrote Procopios.

Unfortunately this roof did not stand. It collapsed about two decades later and it fell to a man named Isidore the Younger to build a new domed roof. It has lasted, with some repairs, nearly 1,400 years, down to the present day.

“The dome rests not on a drum but on pendentives, spherical triangles that arise from four huge piers that carry the weight of the cupola. The pendentives made it possible to place the dome over a square compartment,” writes researcher Victoria Hammond, who describes the structure of the surviving Hagia Sophia dome, in a chapter of the book "Visions of Heaven: The Dome in European Architecture" (Springer, 2005).

Beneath the dome are 40 windows with sunlight coming through. “The sunlight emanating from the windows surrounding its lofty cupola, suffusing the interior and irradiating its gold mosaics, seemed to dissolve the solidity of the walls and created an ambience of ineffable mystery,” she writes. “On the completion of Hagia Sophia, Justinian is said to have remarked, ‘Solomon, I have outdone thee’.”

Imperial seating

Modern-day visitors will note that the Hagia Sophia has two levels, the ground floor and a gallery above. The presence of the two levels may mean that people were organized according to gender and class when services were held at the cathedral.

In Byzantine churches “galleries seem to have been used as a means of segregation of genders and of social classes,” writes Vasileios Marinis in a chapter of the book "The Byzantine World" (Routledge, 2010). “In Hagia Sophia a part of the gallery was used as an imperial lodge, from which the empress and occasionally the emperor attended the services.”

This lodge wasn’t the only benefit the emperor got. Antony White writes in another chapter of the 2004 "Hagia Sophia" book that to enter the cathedral’s nave from the narthex there are nine doorways. “The central or Imperial Door was reserved for the use of the emperor and his attendants, and provides the most perfect approach to the interior of the church.”

Decorations and iconoclasm

The decorations within the Hagia Sophia at the time of construction were probably very simple, images of crosses for instances. Over time this changed to include a variety of ornate mosaics.

“There are a number of mosaics that have been added over the centuries, imperial portraits, images of the imperial family, images of Christ and different emperors, those have been added since Justinian’s day,” said Goodson in the documentary.

During the eighth and ninth centuries A.D., there was a period of iconoclasm in the Byzantine Empire that resulted in some of the mosaics being destroyed.

“The controversy spanned roughly a century, during the years 726–87 and 815–43. In these decades, imperial legislation barred the production and use of figural images; simultaneously, the cross was promoted as the most acceptable decorative form for Byzantine churches,” writes Sarah Brooks, of James Madison University, in a Metropolitan Museum of Art article.

“Fear that the viewer misdirected his/her veneration toward the image rather than to the holy person represented in the image lay at the heart of this controversy.”

At the end of this period decoration of the interior of Hagia Sophia resumed, each emperor adding their own images. One of the most well-known mosaics is located on the apse of the church showing a 13-foot-tall (4 meters) Virgin Mary with Jesus as a child. Dedicated on March 29, 867, it is located 30 meters (almost 100 feet) above the church floor, notes University of Sussex professor Liz James in a 2004 article published in the journal Art History.

Conversion to mosque

Another chapter in the Hagia Sophia’s life began in 1453. In that year the Byzantine Empire ended, with Constantinople falling to the armies of Mehmed II, sultan of the Ottoman Empire.

The Byzantine Empire had been in decline for centuries and by 1453 the Hagia Sophia had fallen into disrepair, notes researcher Elisabeth Piltz in a 2005 British Archaeological Reports series book. Nevertheless, the Christian cathedral made a strong impression on the new Ottoman rulers and they decided to convert it into a mosque.

“What a dome, that vies in rank with the nine spheres of heaven! In this work a perfect master has displayed the whole of the architectural science,” wrote Ottoman historian Tursun Beg during the 15th century (translation from Piltz’s book).

Outside the church, four minarets would eventually be added, Kleiner writes (in a 2010 edition of his book) that these “four slender pencil-shaped minarets” are more than 200 feet (60 meters) tall and are “among the tallest ever constructed.”

Changes occurred on the inside as well. Piltz writes that “after the Ottoman conquest the mosaics were hidden under yellow paint with the exception of the Theotokos [Virgin Mary with child] in the apse.” In addition “Monograms of the four caliphs were put on the pillars flanking the apse and the entrance of the nave.”

The style of the Hagia Sophia, in particular its dome, would go on to influence Ottoman architecture, most notably in the development of the Blue Mosque, built in Istanbul during the 17th century.

Present-day museum

In 1934, the government of Turkey secularized the Hagia Sophia and turned it into a museum. The Turkish Council of Ministers stated that due “to its historical significance, the conversion of the (Hagia Sophia) mosque, a unique architectural monument of art located in Istanbul, into a museum will please the entire Eastern world and its conversion to a museum will cause humanity to gain a new institution of knowledge.” [From Robert Nelson, "Hagia Sophia: 1850-1950: Holy Wisdom Modern Monument," University of Chicago Press, 2004)

Research, repair and restoration work continues to this day and the Hagia Sophia is now an important site for tourism in Istanbul. It is a place that has been part of the cultural fabric of the city in both ancient and modern times.
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References:

Jarus, Owen. 2013. “Hagia Sophia: Facts, History & Architecture”. Live Science. Posted: March 1, 2013. Available online: http://www.livescience.com/27574-hagia-sophia.html

Did a Comet Really Chill and Kill Clovis Culture?

A comet crashing into the Earth some 13,000 years ago was thought to have spelled doom to a group of early North American people, and possibly the extinction of ice age beasts in the region.

But the space rock was wrongly accused, according to a group of 16 scientists in fields ranging from archaeology to crystallography to physics, who have offered counterevidence to the existence of such a collision.

"Despite more than four years of trying by many qualified researchers, no unambiguous evidence has been found [of such an event]," Mark Boslough, a physicist at Sandia National Laboratories in New Mexico, told LiveScience.

"That lack of evidence is therefore evidence of absence."

Changing times

Almost 13,000 years ago, a prehistoric Paleo-Indian group known as the Clovis culture suffered its demise at the same time the region underwent significant climate cooling known as the Younger Dryas. Animals such as ground sloths, camels and mammoths were wiped out in North America around the same period.

In 2007, a team of scientists led by Richard Firestone of the Lawrence Berkeley National Laboratory in California suggested these changes were the result of a collision or explosion of an enormous comet or asteroid, pointing to a carbon-rich black layer at a number of sites across North America. The theory has remained controversial, with no sign of a crater that would have resulted from such an impact.

"If a four-kilometer [2.5-mile] comet had broken up over North America only 12.9 thousand years ago, it is certain that it would have left an unambiguous impact crater or craters, as well as unambiguous shocked materials," Boslough said.

Boslough, who has spent decades studying the effects of comet and asteroid collisions, was part of a team that predicted the visibility of plumes from the impact of the 1994 Shoemaker-Levy 9 comet with Jupiter.

"Comet impacts may be low enough in density not to leave craters," Firestone told LiveScience by email.

He also points to independent research by William Napier at the University of Cardiff in the United Kingdom that indicates such explosions could have come from a debris trail created by Comet Encke, which also would not have left a crater.

A large rock plunging into the Earth's atmosphere may detonate in the air without coming into contact with the ground. Such an explosion occurred in Siberia in the early 20th century; the explosive energy of the so-called Tunguska event was more than 1,000 times more powerful than the atomic bomb dropped on Hiroshima.

"No crater was formed at Tunguska, or the recent Russian impact," Firestone said.

But Boslough said this math doesn't add up. The object responsible for the Tunguska event was very small, about 130 to 160 feet (40 to 50 meters) wide, while the recent explosion over Russia was smaller, about 56 feet (17 meters). The proposed North American space rock linked with the Clovis demise is estimated to have been closer to 2.5 miles (4 kilometers) across.

"The physics doesn't support the idea of something that big exploding in the air," he said, noting that the original research team doesn't provide any explanation or models for how such a breakup might occur.

If such a large object crashed into the Earth, the resulting crater would be too large to miss, particularly when it was only a few thousand years old, Boslough said. He pointed to Meteor Crater in Arizona, which is three times as old and formed by an object "a million times smaller in terms of explosive energy."

"Meteor Crater is an unambiguous impact crater with unambiguous shocked minerals," Boslough said. If a 2.5-mile comet had broken into pieces, it could have made a million Meteor Craters, he added.

Firestone argued that water or ice could have absorbed the impact, possibly leaving behind no crater.

Boslough disagreed. Even if the comet had plunged into the ice sheet covering much of North America, the crater formed beneath it would still be sizable. "We wouldn't be able to miss that right now — it would be obvious," Boslough said.

The arguments and evidence against the impact were published in the December 2012 American Geophysical Union monograph.

Earliest Americans Arrived Even Earlier

"Extraordinary claims require extraordinary evidence"

Powerful impacts are Boslough's field, but the other 15 scientists working on the paper offered up other sources of counterevidence for the existence of a collision.

"We all independently came to the conclusion that the evidence doesn't support a Younger Dryas impact," Boslough said.

"We all came to this based on our own very narrow piece of the puzzle."

For instance, the initial team studying the event announced the discovery of a carbon-rich black layer, colloquially known as a "black mat," at a number of sites in North America. Containing charcoal, soot and nanodiamonds, such material could be formed by a violent collision.

But this isn't the only possible source.

"The things they call impact markers are not necessarily indicators of high-pressure shocks," Boslough said. "There are other processes that potentially could have formed them."

Speaking of the black mat found in central Mexico, Firestone said, "Boslough is correct that there are other black mats, but these are dated to 12,900 years ago at the time of impact." He points to independent research published this fall that located hundreds to thousands of samples.

However, radiocarbon dating of one of the sites in Gainey, Mich., suggested its samples were contaminated.

Melted rock formations and microscopic diamonds found in a lake in Central Mexico last year were also suggested as evidence for the collision, but Boslough's team disagrees with the age of the sediment layer in the region.

Boslough said the standard for indicating a strong shock occurred is pretty high in the impact community, and the findings by the original team don't meet them. Nor do they offer up any physical models that propose how an impact or airburst would have occurred — and the ones Boslough has run just don't pan out.

"It's really a stretch to claim that there was this large impact event with no crater and no unambiguous shock material, because large impacts are such rare events," Boslough said.

"When somebody is making a claim that something extraordinary happened, something out of the ordinary and with a very low probability, and they have ambiguous evidence, then the default is that it didn't happen," he continued.

"Extraordinary claims require extraordinary evidence."

Firestone stands firm.



"All the evidence has now been confirmed by others," he said.

"Boslough has no data supporting his arguments, and ignores the counter arguments of Bill Napier."
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References:

Livescience. 2013. “Did a Comet Really Chill and Kill Clovis Culture?”. Discovery News. Posted: March 1, 2013. Available online: http://news.discovery.com/human/life/did-a-comet-really-chill-and-kill-clovis-culture-130301.htm

Lost and Found: Ancient Shoes Turn Up in Egypt Temple

More than 2,000 years ago, at a time when Egypt was ruled by a dynasty of kings of Greek descent, someone, perhaps a group of people, hid away some of the most valuable possessions they had — their shoes.

Seven shoes were deposited in a jar in an Egyptian temple in Luxor, three pairs and a single one. Two pairs were originally worn by children and were only about 7 inches (18 centimeters) long. Using palm fiber string, the child shoes were tied together within the single shoe (it was larger and meant for an adult) and put in the jar. Another pair of shoes, more than 9 inches (24 cm) long that had been worn by a limping adult, was also inserted in the jar.

The shoe-filled jar, along with two other jars, had been "deliberately placed in a small space between two mudbrick walls," writes archaeologist Angelo Sesana in a report published in the journal Memnonia.

Whoever deposited the shoes never returned to collect them, and they were forgotten, until now.

In 2004, an Italian archaeological expedition team, led by Sesana, rediscovered the shoes. The archaeologists gave André Veldmeijer, an expert in ancient Egyptian footwear, access to photographs that show the finds.

"The find is extraordinary as the shoes were in pristine condition and still supple upon discovery," writes Veldmeijer in the most recent edition of the Journal of the American Research Center in Egypt. Unfortunately after being unearthed the shoes became brittle and "extremely fragile," he added.

Pricey shoes

Veldmeijer's analysis suggests the shoes may have been foreign-made and were "relatively expensive." Sandals were the more common footwear in Egypt and that the style and quality of these seven shoes was such that "everybody would look at you," and "it would give you much more status because you had these expensive pair of shoes," said Veldmeijer, assistant director for Egyptology of the Netherlands-Flemish Institute in Cairo.

The date of the shoes is based on the jar they were found in and the other two  jars, as well as the stratigraphy, or layering of sediments, of the area. It may be possible in the future to carbon date the shoes to confirm their age.

Why they were left in the temple in antiquity and not retrieved is a mystery. "There's no reason to store them without having the intention of getting them back at some point," Veldmeijer said in an interview with LiveScience, adding that there could have been some kind of unrest that forced the owners of the shoes to deposit them and flee hastily. The temple itself predates the shoes by more than 1,000 years and was originally built for pharaoh Amenhotep II (1424-1398 B.C.).

Design discoveries

Veldmeijer made a number of shoe design discoveries. He found that the people who wore the seven shoes would have tied them using what researchers call "tailed toggles." Leather strips at the top of the shoes would form knots that would be passed through openings to close the shoes. After they were closed a long strip of leather would have hung down, decoratively, at either side. The shoes are made out of leather, which is likely bovine.

Most surprising was that the isolated shoe had what shoemakers call a "rand," a device that until now was thought to have been first used in medieval Europe. A rand is a folded leather strip that would go between the sole of the shoe and the upper part, reinforcing the stitching as the "the upper is very prone to tear apart at the stitch holes," he explained. The device would've been useful in muddy weather when shoes are under pressure, as it makes the seam much more resistant to water.

In the dry (and generally not muddy) climate of ancient Egypt, he said that it's a surprising innovation and seems to indicate the seven shoes were constructed somewhere abroad.

Health discoveries

The shoes also provided insight into the health of the people wearing them. In the case of the isolated shoe, he found a "semi-circular protruding area" that could be a sign of a condition called Hallux Valgus, more popularly known as a bunion.

"In this condition, the big toe starts to deviate inward towards the other toes," Veldmeijer writes in the journal article. "Although hereditary, it can also develop as a result of close fitting shoes, although other scholars dispute this ...."

Another curious find came from the pair of adult shoes. He found that the left shoe had more patches and evidence of repair than the shoe on the right. "The shoe was exposed to unequal pressure," he said, showing that the person who wore it "walked with a limp, otherwise the wear would have been far more equal."

Still, despite their medical problems, and the wear and tear on the shoes, the people who wore them were careful to keep up with repairs, Veldmeijer said. They did not throw them away like modern-day Westerners tend to do with old running shoes.

"These shoes were highly prized commodities."

Veldmeijer hopes to have the opportunity to examine the shoes, now under the care of the Ministry of State for Antiquities, firsthand.
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References:

Jarus, Owen. 2013. “Lost and Found: Ancient Shoes Turn Up in Egypt Temple”. Live Science. Posted: February 26, 2013. Available online: http://www.livescience.com/27464-ancient-egypt-shoes-discovered.html

Babies' brains may be tuned to language before birth

Brain imaging shows that premature babies process speech in similar ways to adults.

Despite having brains that are still largely under construction, babies born up to three months before full term can already distinguish between spoken syllables in much the same way that adults do, an imaging study has shown¹.

Full-term babies — those born after 37 weeks' gestation — display remarkable linguistic sophistication soon after they are born: they recognize their mother’s voice², can tell apart two languages they’d heard before birth³ and remember short stories read to them while in the womb⁴. 

But exactly how these speech-processing abilities develop has been a point of contention. “The question is: what is innate, and what is due to learning immediately after birth?” asks neuroscientist Fabrice Wallois of the University of Picardy Jules Verne in Amiens, France. 

To answer that, Wallois and his team needed to peek at neural processes already taking place before birth. It is tough to study fetuses, however, so they turned to their same-age peers: babies born 2–3 months premature. At that point, neurons are still migrating to their final destinations; the first connections between upper brain areas are snapping into place; and links have just been forged between the inner ear and cortex.

Colourful sounds

To test these neural pathways, the researchers played soft voices to premature babies while they were asleep in their incubators a few days after birth, then monitored their brain activity using a non-invasive optical imaging technique called functional near-infrared spectroscopy. They were looking for the tell-tale signals of surprise that brains display — for example, when they suddenly hear male and female voices intermingled after hearing a long run of simply female voices.

The young brains were able to distinguish between male and female voices, as well as between the trickier sounds ‘ga’ and ‘ba’, which demands even faster processing. What is more, the parts of the cortex used were the same as those used by adults for sophisticated understanding of speech and language. 

The results show that linguistic connections inside the cortex are already “present and functional” and did not need to be gradually acquired through repeated exposure to sound, Wallois says. This suggests at least part of these speech-processing abilities is innate. The work could also lead to better techniques caring for the most vulnerable brains, Wallois adds, including premature babies. The team's results appear in Proceedings of the National Academy of Sciences¹.

These are “remarkable findings”, says Janet Werker, a developmental psychologist at the University of British Columbia in Vancouver, Canada. They are, she says, the first evidence that brains can distinguish between difficult consonants even before a full-term birth, hinting at greater brain sensitivities than previously imagined⁵. 

Yet this does not fully answer the innate-versus-learned question, Werker says. “It is possible that the experience of birth triggers a set of processes that prime the brain of a premature infant to respond to language in ways that a same-aged fetus will not.”
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References:

Nuzzo, Regina. 2013. “Babies' brains may be tuned to language before birth”. Nature. Posted: February 25, 2013. Available online: http://www.nature.com/news/babies-brains-may-be-tuned-to-language-before-birth-1.12489

Journal References:

1.Mahmoudzadeh, M. et al. Proc. Natl Acad. Sci. USA
http://dx.doi.org/10.1073/pnas.1212220110 (2013).
2.DeCasper, A. J. & Fifer, W. P. Science 208, 1174–1176 (1980).
3.Byers-Heinlein, K., Burns, T. C. & Werker, J. F. Psychol. Sci. 21, 343–348 (2010).
4.DeCasper, A. J. & Spence, M. J. Infant Behav. Dev. 9, 133–150 (1986).
5.Weikum, W. M., Oberlander, T. F., Hensch, T. K. & Werker, J. F. Proc. Natl Acad. Sci. USA, 109, 17221–17227 (2012).

Hidden Landscapes: LiDAR survey allows public to discover new sites

Caithness, in the far northern mainland of Scotland is well known for its spectacular archaeology but a recent LiDAR survey carried in the north of the county has allowed the opportunity to glimpse the wider, hidden landscapes that are less easily appreciated. This survey is beginning to rewrite the history of northern mainland Scotland.

In response to a requirement to record the landscape surrounding the nationally significant cluster of Neolithic chambered cairns at Hill of Shebster, Baillie Windfarm Ltd. commissioned AOC Archaeology Group to carry out a LiDAR survey, the result was stunning and they decided to create a new website to let people explore the ancient landscape hidden beneath fields and woodland in north-west Caithness.

The main focus of the survey was Cnoc Freiceadain, a prominent ridge which is the site of a spectacular group of Neolithic monuments including two long cairns and a series of stone settings.

The 21-turbine project at Baillie Hill, west of Thurso, was granted permission subject to a number of conditions, one of which was to improve public access to the Hill of Shebster and Cnoc Freicedain scheduled ancient monuments, incorporating the results of a LiDAR laser scanning survey.

A billion individual points

LiDAR – which stands for ‘Light Detection and Ranging’ – works by illuminating the ground with laser light and analysing the backscattered light. Modern scanners can fire thousands of laser pulses per second, and by mounting the instrument on an aircraft, large areas can be covered in high resolution in short spaces of time.

Nearly a billion points were collected during the recent LiDAR survey. Once the raw data was gathered it was processed to create very high-resolution elevation models, detailed enough to record field boundaries, walls and ancient monuments – giving an unparalleled view of the archaeology in the area.  Features that are difficult to distinguish on the ground or even through aerial photography can be identified by overlaying hillshades of the DEM model created with artificial illumination from various angles, as with this example.

With LiDAR the ability to produce high-resolution datasets quickly and relatively cheaply is a massive advantage and the ability to penetrate forest canopy has led to the discovery of features that were not distinguishable through traditional methods.

Over 300 new sites

As well as providing spectacular new images of the previously-known monuments around Cnoc Freiceadain the survey has so far revealed over 300 new sites.

The most prominent archaeological features detected by the survey relate to settlement and agriculture dating to around 3000 years ago on one hand, and to post-medieval farming on the other. In many areas, the survey has allowed the identification of palimpsests of agriculture and settlement, where medieval and later rig and furrow systems overlie much earlier cairnfields, interspersed with the fragmentary remains of 3000 year old hut-circles and associated enclosures.

Archaeologist Andy Heald from AOC Archaeology Group said the survey was the first of its kind in the far north of mainland Scotland.

Sites include Sithean Dubh, a chambered cairn where in 1831 it was said two skeletons of “gigantic size” were found.

An opportunity for exploration

This ground-breaking survey offers an unparalleled opportunity for further study of the development of the modern Caithness landscape.

It becomes clear from the LiDAR survey that reanalysis of large parts of Highland Scotland is likely to produce numerous new monuments, and fragments of the prehistoric farming landscape may still remain beneath areas of later activity but unrecognised until this form of survey allows us to view the landscape as a 3D model.

The dataset, therefore, constitutes an invaluable research tool and an unparalleled means of preserving the landscape of 21st century Caithness by record and provides another tool for archaeological research.

One of the main aims of the project was to present the results of the Baillie survey online, in a format that allows different users to explore the data, identify features of interest and explore monuments that are familiar to them.

A dedicated website which showcases the survey results has been produced, linked to the Highland Council’s Historic Environment Record and gives visitors a ‘virtual tour’ of Caithness archaeology.

The website provides information that illustrates the time depth of the land use over thousands of years and becomes a unique window onto Caithness’s past, acting as a valuable resource for archaeological research and interested visitors alike. The archaeologists are already working on the next project to open up data recovered from projects such as this to citizen scientists across the globe.

You can access the web resource and begin your exploration here at www.aocarchaeology.com/Baillie
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References:

Past Horizons. 2013. “Hidden Landscapes: LiDAR survey allows public to discover new sites”. Past Horizons. Posted: February 23, 2013. Available online: http://www.pasthorizonspr.com/index.php/archives/02/2013/hidden-landscapes-lidar-survey-allows-public-to-discover-new-sites