Monday, September 1, 2014

Groundbreaking research maps cultural history

New research from Northeastern University has mapped the intellectual migration network in North America and Europe over a 2,000-year span. The team of network scientists used the birth and death locations of more than 150,000 intellectuals to map their mobility patterns in order to identify the major cultural centers on the two continents over two millennia.

In the new paper, to be published Friday in the journal Science, the researchers found how locations such as Rome, London, and Paris have emerged as cultural hubs as more intellectuals died in these cities than elsewhere—regardless of where they were born. Additionally, the findings reveal that the distance between the birth and death locations of notable individuals has not increased much over the span of eight centuries—a remarkable showcase of human mobility patterns—despite the fact that colonization and transportation improvements have increased long-distance travel.

"By tracking the migration of notable individuals for over two millennia, we could for the first time explore the boom and bust of the cultural centers of the world," said Albert-László Barabási, Robert Gray Dodge Professor of Network Science and director of Northeastern's Center for Complex Network Research. "The observed rapid changes offer a fascinating view of the transience of intellectual supremacy."

In their paper, Maximilian Schich, the lead author and former visiting research scientist in the center, Barabási, and their co-authors presented a variety of new findings. For example, despite the arts' dependence on money, the cultural hubs that attracted the most intellectuals were not necessarily economic hubs.

In addition, they found that by the 16th century, Europe appeared to be characterized by two radically different cultural regimes: a "winner-takes-all" regime with countries where an individual city attracts a substantial and constant flow of intellectuals (i.e.: Paris, France) and a "fit-gets-richer" regime with cities within a federal region (i.e.: Germany) competing with each other for their share of intellectuals, only being able to attract a fraction of that population in any given century.

The team also found that there is no such thing as an average cultural center or average attractiveness consistent among locations. In fact, they scale and fluctuate heavily over time due to a variety of factors.

For example, while intellectuals have always flocked to New York City in great numbers, it was an even bigger source of talent in the 1920s, being the birthplace of a significant portion of individuals in the data set.

Additionally, locations like Hollywood, the Alps, and the French Riviera, which have not produced a large number of notable figures, have become, at different points in history, major destinations for intellectuals, perhaps initially emerging for reasons such as the location's beauty or climate.

The research has not only uncovered fascinating aspects of intellectual migration over two millennia, it also broke new ground in terms of its data-driven approach to understanding cultural history. The team used data going back several centuries to quantify qualitative knowledge and consulted vast amounts of literature.

They relied on large data sets, including the curated General Artist Lexicon that consists exclusively of artists and includes more than 150,000 names and Freebase with roughly 120,000 individuals, 2,200 of whom are artists. Through this novel approach, they identified a clear set of geographical patterns that would not be recognized using traditional quantitative historical methods. The third data set, the Getty Union List of Artist Names, was used to validate the results of the other two.

"We're starting out to do something which is called cultural science where we're in a very similar trajectory as systems biology for example," said Schich, now an associate professor in arts and technology at the University of Texas at Dallas. "As data sets about birth and death locations grow, the approach will be able to reveal an even more complete picture of history. In the next five to 10 years, we'll have considerably larger amounts of data and then we can do more and better, address more questions."
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References:

EurekAlert. 2014. “Groundbreaking research maps cultural history”. EurekAlert. Posted: July 31, 2014. Available online: http://www.eurekalert.org/pub_releases/2014-07/nu-grm073114.php

Sunday, August 31, 2014

Physicists create tool to foresee language destruction impact and thus prevent it

There have been numerous cases of cultural changes throughout history. Either by imposition or assimilation, cultural traits are transmitted between neighbouring regions and often one replaces the original cultural traits of the other. Physicists Joaquim Fort, from the University of Girona (UdG), and Neus Isern, from the Universitat Autònoma de Barcelona (UAB), are experts in modelling these phenomena by adequately representing a reality, as they have demonstrated with their previous projects.

In this occasion, the researchers applied their expertise to the area of language substitution, i.e. when the language of one region comes under the influence of the language of a neighbouring region considered to be at a greater social and economic advantage. The model helps to estimate the degree to which the languages are under threat and, therefore, are useful in designing actions to control or reverse language diversity destruction.

Researchers analysed the case of Welsh and its deterioration. Isern and Fort verified how, from 1961 to 1981, English took over Welsh and became the main language of communication. The researchers described the evolution in number of speakers, by reproducing the decrease over time in speakers of the native language as they substituted Welsh for the neighbouring language, English.

In this research, the physics defined parameters which allow them to estimate the speed - in kilometres per year - in which the stronger language expands geographically over the native language. Their work has also focused on observing the evolution of other languages such as Quechua and Scottish Gaelic. Neus Isern explains that "these parameters can be applied to languages spoken in countries where the governments are not concerned about their conservation, while they are more difficult to use with languages such as Catalan, which is protected under a series of linguistic policies".

In a wider context, this type of model could be applied to other examples of cultural changes in which the more favourable traits expand and abolish the predominance of a native cultural trait.
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References:

EurekAlert. 2014. “Physicists create tool to foresee language destruction impact and thus prevent it”. EurekAlert. Posted: July 25, 2014. Available online: http://www.eurekalert.org/pub_releases/2014-07/uadb-pct072514.php

Saturday, August 30, 2014

Fire ecology manipulation by California native cultures

California's tribal peoples utilized wildfire to diversify resources

Before the colonial era, 100,000s of people lived on the land now called California, and many of their cultures manipulated fire to control the availability of plants they used for food, fuel, tools, and ritual. Contemporary tribes continue to use fire to maintain desired habitat and natural resources.

Frank Lake, an ecologist with the U.S. Forest Service's Pacific Southwest Station, will lead a field trip to the Stone Lake National Wildfire Refuge during the Ecological Society of America's 99th Annual Meeting, in Sacramento, Cal. this August. Visitors will learn about plant and animal species of cultural importance to local tribes. Don Hankins, a faculty associate at California State University at Chico and a member of the Miwok people, will co-lead the trip, which will end with a visit to California State Indian Museum.

Lake will also host a special session on a "sense of place," sponsored by the Traditional Ecological Knowledge section of the Ecological Society, that will bring representatives of local tribes into the Annual Meeting to share their cultural and professional experiences working on tribal natural resources issues.

"The fascinating thing about the Sacramento Valley and the Miwok lands where we are taking the field trip is that it was a fire and flood system," said Lake. "To maintain the blue and valley oak, you need an anthropogenic fire system."

Lake, raised among the Yurok and Karuk tribes in the Klamath River area of northernmost California, began his career with an interest in fisheries, but soon realized he would need to understand fire to restore salmon. Fire exerts a powerful effect on ecosystems, including the quality and quantity of water available in watersheds, in part by reducing the density of vegetation.

"Those trees that have grown up since fire suppression are like straws sucking up the groundwater," Lake said.

The convergence of the Sacramento and San Joaquin rivers was historically one of the largest salmon bearing runs on the West Coast, Lake said, and the Miwok, Patwin and Yokut tribal peoples who lived in the area saw and understood how fire was involved.

California native cultures burned patches of forest in deliberate sequence to diversify the resources available within their region. The first year after a fire brought sprouts for forage and basketry. In 3 to 5 years, shrubs produced a wealth of berries. Mature trees remained for the acorn harvest, but burning also made way for the next generation of trees, to ensure a consistent future crop. Opening the landscape improved game and travel, and created sacred spaces.

"They were aware of the succession, so they staggered burns by 5 to 10 years to create mosaics of forest in different stages, which added a lot of diversity for a short proximity area of the same forest type," Lake said. "Complex tribal knowledge of that pattern across the landscape gave them access to different seral stages of soil and vegetation when tribes made their seasonal rounds."

In oak woodlands, burning killed mold and pests like the filbert weevil and filbert moth harbored by the duff and litter on the ground. People strategically burned in the fall, after the first rain, to hit a vulnerable time in the life cycle of the pests, and maximize the next acorn crop. Lake thinks that understanding tribal use of these forest environments has context for and relevance to contemporary management and restoration of endangered ecosystems and tribal cultures.

"Working closely with tribes, the government can meet its trust responsibility and have accountability to tribes, and also fulfill the public trust of protection of life, property, and resources," Lake said. "By aligning tribal values with public values you can get a win-win, reduce fire along wildlife-urban interfaces, and make landscapes more resilient."
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References:

EurekAlert. 2014. “Fire ecology manipulation by California native cultures”. EurekAlert. Posted: July 25, 2014. Available online: http://www.eurekalert.org/pub_releases/2014-07/esoa-fem072514.php

Friday, August 29, 2014

Cultural stereotypes may evolve from sharing social information

Millenials are narcissistic, scientists are geeky and men like sports — or so cultural stereotypes would have us believe.

Regardless of whether we believe them to be true, we all have extensive knowledge of cultural stereotypes. But how does this information become associated with certain groups in the first place?

Research published in Psychological Science, a journal of the Association for Psychological Science, suggests that cultural stereotypes are the unintended but inevitable consequence of sharing social information.

"We examined how social information evolves when it is repeatedly passed from person to person," explained psychological scientist Doug Martin, who leads the Person Perception Laboratory at the University of Aberdeen. "As it passes down a chain of individuals, social information that is initially random complex and very difficult to remember becomes a simple system of category stereotypes that can be learned easily."

According to Martin and colleagues, stereotypes may have negative consequences when they contribute to prejudice, but they can also help us make sense of the world around us, helping us in "the way we organize, store, and use information about other people."

"For example, if we meet a stranger, stereotypes provide us with a foundation on which we can begin to build an impression of this person and therefore guide our behaviour towards them," says Martin.

Martin and colleagues conducted lab experiments in which they asked people to remember information about novel alien characters and then pass this information from person to person. Like the game "Telephone," they expected the information to change as it travelled down the chain of people.

Volunteers were asked to learn personality attributes that described the aliens, all of whom shared certain physical features such as their color, their shape, or the way they moved.

Each person was then tested to see what they could remember. Whatever information they produced was then passed on to be learned by the next volunteer and so on until a chain of information was created.

"As information is passed from person to person, what begins as a chaotic and random association of aliens and attributes becomes simpler, more structured and easier to learn," says Martin. "By the end of the chain we have what look very much like stereotypes with physical features — such as color — strongly associated with the possession of specific personality attributes."

The researchers say stereotypes appear to form and evolve because people share similar cognitive limitations and biases.

People are more likely to confuse the identity of individuals when they belong to the same social category than when they belong to different categories. Similarly, people are more likely to mistakenly think that individuals who belong to the same social category also share the same attributes. Because we all experience the same category-based memory biases, when social information is repeatedly shared it is continually filtered as it passes from one mind to the next until eventually it becomes organised categorically and a stereotype has formed.

The scientists say their research appears to explain why some stereotypes have a basis in reality while others have no obvious origin.

"For example, the cultural stereotype of Scottish people includes attributes that are overrepresented among Scots, such as wearing kilts and having red hair, but also attributes that seemingly have no basis in reality, such as being miserly or dour," says Martin.

"Where a genuine relationship exists between social categories and attributes, people are very good at detecting this, remembering it and then passing this information on. Equally, however, where there is no existing relationship between social categories and attributes, we see this association emerging spontaneously over time as the social information evolves," Martin explains. "If we can understand how cultural stereotypes form and naturally evolve then we might be able to positively influence their content in the future."
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References:

EurekAlert. 2014. “Cultural stereotypes may evolve from sharing social information”. EurekAlert. Posted: July 24, 2014. Available online: http://www.eurekalert.org/pub_releases/2014-07/afps-csm072414.php

Thursday, August 28, 2014

Tonga May Have Been a Vast Seafaring Empire

The seafaring empire of Tonga in the South Pacific Ocean once spanned more than a thousand miles, serving as the hub through which distant settlements exchanged artifacts and ideas, researchers say. This finding could help explain the rise of monumental structures throughout the Pacific starting about 700 years ago, scientists added.

Tonga is an archipelago of about 160 Polynesian islands, with the core of the kingdom covering an area of about 195,000 square miles (500,000 square kilometers). The islands, located about two-thirds of the way from Hawaii to New Zealand, were first settled about 2,800 years ago by the Lapita people.

Beginning about 800 years ago, a powerful chiefdom arose in Tonga, unique in Oceania — that is, the islands of the South Pacific — in how it successfully united an entire archipelago of islands. However, much remained unknown about how far Tonga's influence actually reached.

"How much voyaging and interaction occurred in the prehistoric Pacific has been debated for centuries," said lead study author Geoffrey Clark, an archaeologist at the Australian National University in Canberra.

To learn more about the extent of Tonga's empire, scientists chemically analyzed nearly 200 stone tools excavated from the centers of its leaders, especially artifacts from the royal tombs on Tongatapu, the main island of Tonga. They also chemically analyzed more than 300 stone artifacts and rock samples taken from other Pacific islands, such as Samoa.

"All of the work has been done with a large Tongan workforce from the community who are now being funded to conserve many of the monumental tombs," Clark said.

They found that stone artifacts in Tonga often matched rock samples from Samoa and Fiji — in fact, 66 percent of stone tools analyzed from Tonga were long-distance imports. One tool apparently was made from rock that came from as far away as Tahiti, about 1,550 miles (2,500 km) east of Tongatapu. In contrast, stone tools from a monumental stone mound in Samoa were made from local sources of rock.

These findings revealed that Tonga was the center of a maritime empire that goods flowed toward as tribute from distant locales. The researchers suggest these exotic artifacts may have served as status symbols among Tongan elites.

"Complex societies like the Tongan maritime chiefdom had extensive contacts with other island groups," Clark told Live Science. "The chiefdom was an important interaction hub through which ideas, goods and people could move over large distances."

In addition, these findings could help explain puzzling discoveries seen elsewhere in Oceania.

"It has been observed that many of the significant chiefdoms in the Pacific began to build monumental architecture around the same time as one another — 1300 to 1500 A.D. — and it's been unclear why this should be, as the societies are often separated by thousands of kilometers of ocean," Clark said. This new work suggests the formation of the Tongan state may have stimulated these widespread changes in the Pacific.

In the future, the researchers want to find and examine stone tools from before the rise of the Tongan state to understand how interactions between Tonga and other islands changed over time.

"At the moment there are few sites and no significant stone assemblages from this important period," Clark said. "We also want to know whether the high proportion of exotic tools found at the central place of the Tongan state [Tongatapu] exists at other sites in Tonga of the same age. For example, did everyone in Tonga have access to stone tools from Samoa and other places, or did the central place have a higher proportion because exotic stone tools were chiefly valuables?"

The scientists detailed their findings online July 7 in the journal Proceedings of the National Academy of Sciences.
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References:

Choi, Charles Q. 2014. “Tonga May Have Been a Vast Seafaring Empire”. Live Science. Posted: July 23, 2014. Available online: http://www.livescience.com/46954-tonga-was-seafaring-empire.html

Wednesday, August 27, 2014

Essays in English yield information about other languages

Computer scientists at MIT and Israel's Technion have discovered an unexpected source of information about the world's languages: the habits of native speakers of those languages when writing in English

The work could enable computers chewing through relatively accessible documents to approximate data that might take trained linguists months in the field to collect. But that data could in turn lead to better computational tools.

"These [linguistic] features that our system is learning are of course, on one hand, of nice theoretical interest for linguists," says Boris Katz, a principal research scientist at MIT's Computer Science and Artificial Intelligence Laboratory and one of the leaders of the new work. "But on the other, they're beginning to be used more and more often in applications. Everybody's very interested in building computational tools for world languages, but in order to build them, you need these features. So we may be able to do much more than just learn linguistic features. … These features could be extremely valuable for creating better parsers, better speech-recognizers, better natural-language translators, and so forth."

In fact, Katz explains, the researchers' theoretical discovery resulted from their work on a practical application: About a year ago, Katz proposed to one of his students, Yevgeni Berzak, that he try to write an algorithm that could automatically determine the native language of someone writing in English. The hope was to develop grammar-correcting software that could be tailored to a user's specific linguistic background.

Family resemblance

With help from Katz and from Roi Reichart, an engineering professor at the Technion who was a postdoc at MIT, Berzak built a system that combed through more than 1,000 English-language essays written by native speakers of 14 different languages. First, it analyzed the parts of speech of the words in every sentence of every essay and the relationships between them. Then it looked for patterns in those relationships that correlated with the writers' native languages.

Like most machine-learning classification algorithms, Berzak's assigned probabilities to its inferences. It might conclude, for instance, that a particular essay had a 51 percent chance of having been written by a native Russian speaker, a 33 percent chance of having been written by a native Polish speaker, and only a 16 percent chance of having been written by a native Japanese speaker.

In analyzing the results of their experiments, Berzak, Katz, and Reichart noticed a remarkable thing: The algorithm's probability estimates provided a quantitative measure of how closely related any two languages were; Russian speakers' syntactic patterns, for instance, were more similar to those of Polish speakers than to those of Japanese speakers.

When they used that measure to create a family tree of the 14 languages in their data set, it was almost identical to a family tree generated from data amassed by linguists. The nine languages that are in the Indo-European family, for instance, were clearly distinct from the five that aren't, and the Romance languages and the Slavic languages were more similar to each other than they were to the other Indo-European languages.

What's your type?

"The striking thing about this tree is that our system inferred it without having seen a single word in any of these languages," Berzak says. "We essentially get the similarity structure for free. Now we can take it one step further and use this tree to predict typological features of a language for which we have no linguistic knowledge."

By "typological features," Berzak means the types of syntactic patterns that linguists use to characterize languages -- things like the typical order of subject, object, and verb; how negations are formed; or whether nouns take articles. A widely used online linguistic database called the World Atlas of Language Structures (WALS) identifies nearly 200 such features and includes data on more than 2,000 languages.

But, Berzak says, for some of those languages, WALS includes only a handful of typological features; the others just haven't been determined yet. Even widely studied European languages may have dozens of missing entries in the WALS database. At the time of his study, Berzak points out, only 14 percent of the entries in WALS had been filled in.

The new system could help fill in the gaps. In work presented last month at the Conference on Computational Natural Language Learning, Berzak, Katz, and Reichart ran a series of experiments that examined each of the 14 languages of the essays they'd analyzed, trying to predict its typological features from those of the other 13 languages, based solely on the similarity scores produced by the system. On average, those predictions were about 72 percent accurate.

Branching out

The 14 languages of the researchers' initial experiments were the ones for which an adequate number of essays -- an average of 88 each -- were publicly available. But Katz is confident that given enough training data, the system would perform just as well on other languages. Berzak points out that the African language Tswana, which has only five entries in WALS, nonetheless has 6 million speakers worldwide. It shouldn't be too difficult, Berzak argues, to track down more English-language essays by native Tswana speakers.
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References:

Science Daily. 2014. “Essays in English yield information about other languages”. Science Daily. Posted: July 23, 2014. Available online: http://www.sciencedaily.com/releases/2014/07/140723111305.htm

Tuesday, August 26, 2014

'Family That Walks on All Fours' Not Evolutionary Throwbacks

When Turkish evolutionary biologist Uner Tan introduced the world to a Turkish family with some members who could walk only on all fours, in a "bear crawl," he and other scientists speculated this odd gait was the resurgence of a trait lost during human evolution. Not so, a new study finds.

The family and other people with Uner Tan syndrome do not represent "a backward stage in human evolution," as Tan wrote in a 2006 paper in the International Journal of Neuroscience, said Liza Shapiro, a professor of anthropology at the University of Texas at Austin. In new research, Shapiro and her colleagues compared videos of the family's gait with the gaits of nonhuman primates, such as chimpanzees or gorillas. They found the gait patterns did not match. Instead of recreating ape walks, people with Uner Tan are simply adapting to their disorder, Shapiro and her colleagues reported July 16 in the journal PLOS ONE.

On all fours

Tan first noticed the syndrome that now bears his name in a family of 19 living in rural southern Turkey. Five of the family members walk using their feet and hands, and also have cognitive disabilities. The family was the subject of the 2006 BBC2 documentary, "The Family That Walks on All Fours."

Research has since revealed that the disorder is caused by a genetic mutation on chromosome 17, which affects the cerebellum, part of the brain responsible for movement and balance. From the beginning, Tan's statements about the evolutionary nature of the affected family's walking patterns were controversial. The affected children never had physical therapy or adaptive technology such as wheelchairs, making their gait a necessity.

But no one ever challenged the primary claim: that the affected children walked like nonhuman primates. Primates that walk on all fours do so differently than most other mammals, Shapiro told Live Science. Primates walk in a diagonal sequence, putting down a hind limb and then the opposite front limb: left foot, right hand, right foot, left hand.

Most other mammals walk in a lateral sequence, with the same-side limbs following each other: left foot, left hand, right foot, right hand. Human babies and adults asked to "bear crawl" on hands and feet typically walk in a lateral sequence, too, Shapiro said.

Adapting, not devolving

Shapiro said she became interested in studying the gait of people with Uner Tan Syndrome in 2006 after seeing the documentary on the Turkish family.

"It was all about whether or not it was evolutionary reversal, which kind of horrified me," she said. Immediately, though, she could see that the family was not using the primate diagonal gait.

Shapiro did not have access to good video of the family's walking patterns until recently, when one of her co-authors told her he had footage from the BBC. From that video, she and her colleagues were able to analyze more than 500 strides made by the five family members with the disorder.

About 99 percent of the strides were lateral, not diagonal — a blow against the notion that the family members had "rediscovered" an ancestral primate way of walking. Instead, they were walking like any typical adult would if asked to move on hands and feet.

A lateral gait is handy for long-limbed animals (such as humans) when walking on all fours, she said, because it helps keep the limbs from bumping into one another.

"They're doing what any human does in that situation where they can't stand up," Shapiro said.

Shapiro emphasized that even if the family had moved with a diagonal gait, the pattern would not prove anything about human evolution or the origins of bipedalism.

"Bipedalism requires a lot of changes, physical and anatomical changes in the body," she said. "Neurological changes. Motor changes. It's not just one thing."
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References:

Pappas, Stephanie. 2014. “'Family That Walks on All Fours' Not Evolutionary Throwbacks”. Live Science. Posted: July 22, 2014. Available online: http://www.livescience.com/46944-family-walks-on-fours-evolutionary-throwbacks.html