Inspired by art, researchers find the finger snap to have the highest acceleration the human body produces

by Georgia Institute of Technology

This comic depicts the Bhamla Lab research in an exciting and engaging way - all pointing

 back to curiosity-driven science and how it can impact scientific research.

 Credit: Lindsey Leigh for Georgia Tech

The snapping of a finger was first depicted in ancient Greek art around 300 B.C. Today, that same snap initiates evil forces for the villain Thanos in Marvel's latest Avengers movie. Both media inspired a group of researchers from the Georgia Institute of Technology to study the physics of a finger snap and determine how friction plays a critical role.

Using an intermediate amount of friction, not too high and not too low, a snap of the finger produces the highest rotational accelerations observed in humans, even faster than the arm of a professional baseball pitcher. The results were published Nov. 17 in the Journal of the Royal Society Interface.

The research was led by an undergraduate student at Georgia Tech, Raghav Acharya, as well as doctoral student Elio Challita, Assistant Professor Saad Bhamla of the School of Chemical and Biomolecular Engineering, and Assistant Professor Mark Ilton of Harvey Mudd College in Claremont, California.

Their results might one day inform the design of prosthetics meant to imitate the wide-ranging capabilities of the human hand. Bhamla said the project is also a prime example of what he calls curiosity-driven science, where everyday occurrences and biological behaviors can serve as data sources for new discoveries.

"For the past few years, I've been fascinated with how we can snap our fingers," Bhamla said. "It's really an extraordinary physics puzzle right at our fingertips that hasn't been investigated closely."

In earlier work, Bhamla, Ilton, and other colleagues had developed a general framework for explaining the surprisingly powerful and ultrafast motions observed in living organisms. The framework seemed to naturally apply to the snap. It posits that organisms depend on the use of a spring and latching mechanism to store up energy, which they can then quickly release.

Acharya and Bhamla felt a particular push to apply this framework to a finger snap after seeing the movie Avengers: Infinity War, released in April 2018 and produced by Marvel Studios. In it, Thanos, a villainous character, seeks to obtain six special stones and place them into his metal gauntlet. After collecting them all, he snaps his fingers and triggers universe-wide consequences.

But would it be possible to snap at all while wearing an armor gauntlet, the researchers asked? In the case of a finger snap, they suspected that skin friction played a more important role compared to other spring and latch systems. With the frictional properties of a metal gauntlet, they imagined it might be impossible.

Using high-speed imaging, automated image processing, and dynamic force sensors, the researchers analyzed a variety of finger snaps. They explored the role of friction by covering fingers with different materials, including metallic thimbles to simulate the effects of trying to snap while wearing a metallic gauntlet, much like Thanos.

For an ordinary snap with bare fingers, the researchers measured maximal rotational velocities of 7,800 degrees per second and rotational accelerations of 1.6 million degrees per second squared. The rotational velocity is less than that measured for the fastest rotational motions observed in humans, which come from the arms of professional baseball players during the act of pitching. However, the snap acceleration is the fastest human angular acceleration yet measured, almost three times faster than the rotational acceleration of a professional baseball pitcher's arm.

"When I first saw the data, I jumped out of my chair," said Bhamla, who studies ultrafast motions in a variety of living systems, from single cells to insects. "The finger snap occurs in only seven milliseconds, more than twenty times faster than the blink of an eye, which takes more than 150 milliseconds."

When the fingertips of the subjects were covered with metal thimbles, their maximal rotational velocities decreased dramatically, confirming the researchers' intuitions.

Saad Bhamla snapping. Credit: Georgia Tech

"Our results suggest that Thanos could not have snapped because of his metal armored fingers," said Acharya, first author of the study. "So, it's probably the Hollywood special effects, rather than actual physics, at play! Sorry for the spoiler."

They explained this decrease by considering the diminished contact area that exists between thimble-covered fingers.

"The compression of the skin makes the system a little bit more fault tolerant," said Challita, a coauthor on the work. "Reducing both the compressibility and friction of the skin make it a lot harder to build up enough force in your fingers to actually snap."

Surprisingly, increasing the friction of the fingertips with rubber coverings also reduced speed and acceleration. The researchers concluded that a Goldilocks zone of friction was necessary—too little friction and not enough energy was stored to power the snap, and too much friction led to energy dissipation as the fingers took longer to slide past each other, wasting the stored energy into heat.

The researchers experimented with a variety of mathematical models of the snapping process to explain their observations. They found that a model including a spring and a soft friction contact-latch could reproduce the qualitative features of their results.

"We included soft frictional contact into our mathematical model, and the results reinforced the central role played by friction in achieving ultrafast motions," Ilton said. "This model can now help us understand how other animals such as termites and ants snap their mandibles, as well as rationally bioinspired actuators for engineering applications."

Ancient Greek vase depicting a finger snap. Credit: Wikicommons

John Long, a program director in the National Science Foundation's Division of Integrative Organismal Systems, oversees research in the Physiological Mechanisms and Biomechanics Program, which currently funds Bhamla's investigations into ultrafast behaviors in animals.

"This research is a great example of what we can learn with clever experiments and insightful computational modeling," he said. "By showing that varying degrees of friction between the fingers alters the elastic performance of a snap, these scientists have opened the door to discovering the principles operating in other organisms, and to putting this mechanism to work in engineered systems such as bioinspired robots."

John Long, program director in the Directorate for Biological Sciences at the National Science Foundation, oversees research in the Physiological Mechanisms and Biomechanics Program, which currently funds Bhamla's investigations into ultrafast behaviors in animals.

"The research of Dr. Bhamla and his colleagues is a great example of what we can learn with clever experiments and insightful computational modeling," he said. "By showing that varying degrees of friction between the fingers alters the elastic performance of the snap, they've opened the door for discovering these principles operating in other organisms and for putting this soft, sophisticated, and adjustable mechanism to work in engineered systems such as bioinspired robots."

The researchers believe that the results open a variety of opportunities for future study, including understanding why humans snap at all, and if humans are the only primates to have evolved this physical ability.

"Based on ancient Greek art from 300 B.C., humans may very well have been snapping their fingers for hundreds of thousands of years before that, yet we are only now beginning to scientifically study it," Bhamla said. "This is the only scientific project in my lab in which we could snap our fingers and get data."New law of physics helps humans and robots grasp the friction of touch

]More information: The ultrafast snap of a finger is mediated by skin friction, Journal of the Royal Society Interface (2021). DOI: 10.1098/rsif.2021.0672. rsif.royalsocietypublishing.or … .1098/rsif.2021.0672

Journal information: Journal of the Royal Society Interface 

Provided by Georgia Institute of Technology 

Music is more than sound waves: What you see and how you move, affects what you hear

by Mari Lilleslåtten, University of Oslo

Tejaswinee Kelkar. Credit: University of Oslo

When you hear a melody, your perception is formed by the shapes and movements you associate with it.

When you hear Beyoncé sing, how long does it take before you visualize her dancing across the stage? Or when Jimi Hendrix's guitar solos are pounding out of the speakers—can you see Hendrix posing with his guitar?

Whether you're miming in front of the mirror and using your hairbrush as a microphone or listening with one ear while cleaning the house, the movements you associate with the music play a role in what you actually hear.

That's because music is more than a good lyric or melody. Music is the interplay between everything you sense.

"Just think about how you feel when someone is singing really high notes," says music researcher Tejaswinee Kelkar, and continues:

"What we actually notice is the effort being made by the singer. We recognize it because it's physical. We don't even need to see the singer, because we are so fine-tuned to interpreting nuances in the voice—which, for example, tells us about the singer's feelings."

Kelkar studies the shapes we associate with music and has investigated this by studying what gestures people make when listening to music. Facial expressions and the position of one's legs are just a few of the things that she believes affect one's listening experience.

When singing, you also use your arms

Tejaswinee Kelkar is herself a performing singer, and her interest in gestures developed when she became aware that there is a difference between how we use our hands when singing Western and Indian music.

"As a child, I learned to sing North Indian music. It is common there to use hand gestures in order to help children when they are learning to sing. When you're on stage, you should sing in the same way as you do when you rehearse. You focus on the song as being sung between you and the room, instead of thinking about the audience."

When she was later trained in Western classical singing, she began using similar hand gestures.

"But I was told quite firmly that that was not how it was done."

She became curious: What did the hand gestures really mean?

"You might think that these movements provide you some kind of anatomical assistance, or that they shape how you use your voice. In that case some hand gestures may be suitable for Indian music and not for Western music."

To Kelkar, the different rules that applied to gestures also served as proof of something else: in order to understand music, you need to think about how it fills the space in a room.

Melodies can have different shapes

Music plays on all our senses because it is multimodal—it takes place in different modes. For Kelkar, the main mode is spatiality. She refers to the mathematician René Thom who says: "In order to understand something, we need to understand the geometry of it."

"I believe he's right: everything has a spatiality. Time, which is important in music, is a good example. We relate the past and future to our bodies—that something lies in front of or behind us."

In order to understand more about how music is perceived spatially, Kelkar has conducted several experiments. In one of these, she asked the participants to listen to the same piece of music several times and draw or explain what they were visualizing in their minds.

"People often perceive specific shapes or use movement metaphors. Several of the participants described or drew the music as a wave that was passing by them—like sound waves or ECG (electrocardiography)," she explains.

"While others visualized a circle, especially if they noticed that one motif in the melody kept recurring."

In another experiment, she asked participants to move their arms in a way that they felt matched the music. She documented everything by using motion capture tracking technology in order to search for patterns.

"Several tried to draw the contours of the music going up or down. This reflected the pitch, but also other characteristics of the music, such as timbre, motifs and patterns."

Facial expressions affect the sounds we hear

The fact that our brains make a connection between what we see and what we hear is something that has already been studied by language researchers.

"This has been observed as linguistic phenomena, including one called the McGurk effect," says Kelkar.

The McGurk effect describes how we can listen to a sound while observing a face that expresses a different sound and hear something which is sort of in between. A classic example of this is when we hear a B pronounced while seeing a face expressing a G, we will end up hearing a D.

Kelkar recently conducted a study with her colleagues Bruno Laeng and Sarjo Kuyateh which was designed to see if the same thing happens when we sing:

"We actually found signs to indicate that what the singer does with his or her face affects how people perceive a melody. The interval between two tones may sound different if the singer's mimicry varies."

Shazam for movement

Just as melody and rhythm allows us to recognize music, the shapes that we associate with a melody can help us with the same thing. In her research, Tejaswinee Kelkar has fed artificial intelligence with documentation of the different movements derived from her experiments, thus allowing the technology to use the movements to recognize music. This type of technology can be used for developing new tools.

"Imagine a technology similar to the music-recognition app 'Shazam' but imagine it scanning movements instead of sounds. If you were to make gestures that would be match 'Happy Birthday,' such an app might be able to find the song for you."

Although this technology is relatively new, searching for melodies based on contours is an old idea. In 1975, Denys Parsons published his "The Directory of Tunes and Musical Themes" in which he cataloged about 15,000 classical pieces based on their melodic contours—how the pitch moves up and down. The identification of music based on its contours is thus called the "Parsons Code."

Kelkar's method is also similar to other tools that are available online.

"For example, today we have musipedia.org which allows you to search for music based on its contours," she says.

Listeners change the music

Sound, text and space are some of the modes included in the music. The same applies to actions, or simply thinking about them.

"If you visualize dancing, the music you hear will probably sound different to how it would if you didn't."

The music researcher also highlights how we experience concerts, something which has changed a lot over the years.

"We have musical genres where people sit still and listen respectfully, but that's something new, because many of our classical composers created music for dancing. We now play mazurkas and minuets in concert halls while the audience sits there watching respectfully. The same applies to jazz, which was a club music genre that was intended for people to dance to."

She points out that this says something fundamental about the multimodality of music.

"Your perception of music is shaped by what you see and do, but the opposite also applies; what you do will affect the music."People listen to streamed music during specific blocks of time

More information: Tejaswinee Kelkar, Computational Analysis of Melodic Contour and Body Movement. www.duo.uio.no/bitstream/handl … quence=4&isAllowed=y

Bruno Laeng et al, Substituting facial movements in singers changes the sounds of musical intervals, Scientific Reports (2021). DOI: 10.1038/s41598-021-01797-z

Journal information: Scientific Reports 

Provided by University of Oslo 

Perceptual links between sound and shape may unlock origins of spoken words

by University of Birmingham

The "bouba/kiki effect." Credit: University of Birmingham

Most people around the world agree that the made-up word 'bouba' sounds round in shape, and the made-up word 'kiki' sounds pointy—a discovery that may help to explain how spoken languages develop, according to a new study.

Language scientists have discovered that this effect exists independently of the language that a person speaks or the writing system that they use, and it could be a clue to the origins of spoken words.

The research breakthrough came from exploring the 'bouba/kiki effect,' where the majority of people, mostly Westerners in previous studies, intuitively match the shape on the left to the neologism 'bouba' and the form on the right to 'kiki.'

An international research team has conducted the largest cross-cultural test of the effect, surveying 917 speakers of 25 different languages representing nine language families and ten writing systems—discovering that the effect occurs in societies around the world.

Publishing their findings today in Philosophical Transactions of the Royal Society B, the team, led by experts from the University of Birmingham and the Leibniz-Centre General Linguistics (ZAS), Berlin, says that such iconic vocalizations may form a global basis for the creation of new words.

Co-author Dr. Marcus Perlman, Lecturer in English Language and Linguistics at the University of Birmingham, commented: "Our findings suggest that most people around the world exhibit the bouba/kiki effect, including people who speak various languages, and regardless of the writing system they use."

"Our ancestors could have used links between speech sounds and visual properties to create some of the first spoken words—and today, many thousands of years later, the perceived roundness of the English word 'balloon' may not be just a coincidence, after all."

The 'bouba/kiki effect' is thought to derive from phonetic and articulatory features of the words, for example, the rounded lips of the 'b' and the stressed vowel in 'bouba,' and the intermittent stopping and starting of air in pronouncing 'kiki.'

To find out how widespread the bouba/kiki effect is across human populations, the researchers conducted an online test with participants who spoke a wide range of languages, including, for example, Hungarian, Japanese, Farsi, Georgian, and Zulu.

The results showed that the majority of participants, independent of their language and writing system, showed the effect, matching 'bouba' with the rounded shape and 'kiki' with the spiky one.

Co-author Dr. Bodo Winter, Senior Lecturer in Cognitive Linguistics at the University of Birmingham, commented: "New words that are perceived to resemble the object or concept they refer to are more likely to be understood and adopted by a wider community of speakers. Sound-symbolic mappings such as in bouba/kiki may play an important ongoing role in the development of spoken language vocabularies."

Iconicity—the resemblance between form and meaning—had been thought to be largely confined to onomatopoeic words such as 'bang' and 'peep,' which imitate the sounds they denote. However, the team's research suggests that iconicity can shape the vocabularies of spoken languages far beyond the example of onomatopoeias.

The researchers note that the potential for bouba/kiki to play a role in language evolution is confirmed by the evidence they collected. It shows that the effect stems from a deeply rooted human capacity to connect speech sound to visual properties, and is not just a quirk of speaking English.

Study finds hidden emotions in the sound of words

More information: Aleksandra Ćwiek et al, The bouba/kiki effect is robust across cultures and writing systems, Philosophical Transactions of the Royal Society B: Biological Sciences (2021). DOI: 10.1098/rstb.2020.0390

Journal information: Philosophical Transactions of the Royal Society B 

Provided by University of Birmingham 

 

Pythagoras' revenge: Humans didn't invent mathematics, it's what the world is made of

by Sam Baron, The Conversation

Credit: Geralt / Pixabay

Many people think that mathematics is a human invention. To this way of thinking, mathematics is like a language: it may describe real things in the world, but it doesn't "exist" outside the minds of the people who use it.

But the Pythagorean school of thought in ancient Greece held a different view. Its proponents believed reality is fundamentally mathematical.

More than 2,000 years later, philosophers and physicists are starting to take this idea seriously.

As I argue in a new paper, mathematics is an essential component of nature that gives structure to the physical world.

Honeybees and hexagons

Bees in hives produce hexagonal honeycomb. Why?

According to the "honeycomb conjecture" in mathematics, hexagons are the most efficient shape for tiling the plane. If you want to fully cover a surface using tiles of a uniform shape and size, while keeping the total length of the perimeter to a minimum, hexagons are the shape to use.

Charles Darwin reasoned that bees have evolved to use this shape because it produces the largest cells to store honey for the smallest input of energy to produce wax.

The honeycomb conjecture was first proposed in ancient times, but was only proved in 1999 by mathematician Thomas Hales.

The hexagonal pattern of honeycomb is the most efficient way to cover a space in identical

 tiles. Credit: Sam Baron, Author provided

Cicadas and prime numbers

Here's another example. There are two subspecies of North American periodical cicadas that live most of their lives in the ground. Then, every 13 or 17 years (depending on the subspecies), the cicadas emerge in great swarms for a period of around two weeks.

Why is it 13 and 17 years? Why not 12 and 14? Or 16 and 18?

One explanation appeals to the fact that 13 and 17 are prime numbers.

Imagine the cicadas have a range of predators that also spend most of their lives in the ground. The cicadas need to come out of the ground when their predators are lying dormant.

Suppose there are predators with life cycles of two, three, four, five, six, seven, eight and nine years. What is the best way to avoid them all?

Well, compare a 13-year life cycle and a 12-year life cycle. When a cicada with a 12-year life cycle comes out of the ground, the 2-year, 3-year and 4-year predators will also be out of the ground, because two, three and four all divide evenly into 12.

When a cicada with a 13-year life cycle comes out of the ground, none of its predators will be out of the ground, because none of two, three, four, five, six, seven, eight or nine years divides evenly into 13. The same is true for 17.

It seems these cicadas have evolved to exploit basic facts about numbers.

Some cicadas have evolved to emerge from the ground at intervals of a prime number of

 years, possibly to avoid predators with life cycles of different lengths. 

Credit: Michael Kropiewnicki / Pixels

Creation or discovery?

Once we start looking, it is easy to find other examples. From the shape of soap films, to gear design in engines, to the location and size of the gaps in the rings of Saturn, mathematics is everywhere.

If mathematics explains so many things we see around us, then it is unlikely that mathematics is something we've created. The alternative is that mathematical facts are discovered: not just by humans, but by insects, soap bubbles, combustion engines and planets.

What did Plato think?

But if we are discovering something, what is it?

The ancient Greek philosopher Plato had an answer. He thought mathematics describes objects that really exist.

For Plato, these objects included numbers and geometric shapes. Today, we might add more complicated mathematical objects such as groups, categories, functions, fields and rings to the list.

Plato also maintained that mathematical objects exist outside of space and time. But such a view only deepens the mystery of how mathematics explains anything.

Explanation involves showing how one thing in the world depends on another. If mathematical objects exist in a realm apart from the world we live in, they don't seem capable of relating to anything physical.

P1–P9 represent cycling predators. The number-line represents years. The highlighted 

gaps show how 13 and 17-year cicadas manage to avoid their predators. 

Credit: Sam Baron, Author provided

Enter Pythagoreanism

The ancient Pythagoreans agreed with Plato that mathematics describes a world of objects. But, unlike Plato, they didn't think mathematical objects exist beyond space and time.

Instead, they believed physical reality is made of mathematical objects in the same way matter is made of atoms.

If reality is made of mathematical objects, it's easy to see how mathematics might play a role in explaining the world around us.

In the past decade, two physicists have mounted significant defenses of the Pythagorean position: Swedish-US cosmologist Max Tegmark and Australian physicist-philosopher Jane McDonnell.

Tegmark argues reality just is one big mathematical object. If that seems weird, think about the idea that reality is a simulation. A simulation is a computer program, which is a kind of mathematical object.

McDonnell's view is more radical. She thinks reality is made of mathematical objects and minds. Mathematics is how the Universe, which is conscious, comes to know itself.

I defend a different view: the world has two parts, mathematics and matter. Mathematics gives matter its form, and matter gives mathematics its substance.

Mathematical objects provide a structural framework for the physical world.

Pythagorean pie: the world is made of mathematics plus matter. 

Credit: Sam Baron, Author provided

The future of mathematics

It makes sense that Pythagoreanism is being rediscovered in physics.

In the past century physics has become more and more mathematical, turning to seemingly abstract fields of inquiry such as group theory and differential geometry in an effort to explain the physical world.

As the boundary between physics and mathematics blurs, it becomes harder to say which parts of the world are physical and which are mathematical.

But it is strange that Pythagoreanism has been neglected by philosophers for so long.

I believe that is about to change. The time has arrived for a Pythagorean revolution, one that promises to radically alter our understanding of reality.

Studying abstract mathematical equations using tangible surfaces

Provided by The Conversation 

Were the ancient Maya an agricultural cautionary tale? Maybe not, new study suggests

by Brown University

The research team surveyed a small area in the Western Maya Lowlands situated at

 today's border between Mexico and Guatemala, shown in context here. 

Credit: Andrew Scherer/Brown University

Many believe climate change and environmental degradation caused the Maya civilization to fall—but a new survey shows that some Maya kingdoms had sustainable agricultural practices and high food yields for centuries.

For years, experts in climate science and ecology have held up the agricultural practices of the ancient Maya as prime examples of what not to do.

"There's a narrative that depicts the Maya as people who engaged in unchecked agricultural development," said Andrew Scherer, an associate professor of anthropology at Brown University. "The narrative goes: The population grew too large, the agriculture scaled up, and then everything fell apart."

But a new study, authored by Scherer, students at Brown and scholars at other institutions, suggests that that narrative doesn't tell the full story.

Using drones and lidar, a remote sensing technology, a team led by Scherer and Charles Golden of Brandeis University surveyed a small area in the Western Maya Lowlands situated at today's border between Mexico and Guatemala. Scherer's lidar survey—and, later, boots-on-the-ground surveying—revealed extensive systems of sophisticated irrigation and terracing in and outside the region's towns, but no huge population booms to match. The findings demonstrate that between 350 and 900 A.D., some Maya kingdoms were living comfortably, with sustainable agricultural systems and no demonstrated food insecurity.

"It's exciting to talk about the really large populations that the Maya maintained in some places; to survive for so long with such density was a testament to their technological accomplishments," Scherer said. "But it's important to understand that that narrative doesn't translate across the whole of the Maya region. People weren't always living cheek to jowl. Some areas that had potential for agricultural development were never even occupied."

The research group's findings were published in the journal Remote Sensing.

When Scherer's team embarked on the lidar survey, they weren't necessarily attempting to debunk long-held assumptions about Maya agricultural practices. Rather, their primary motivation was to learn more about the infrastructure of a relatively understudied region. While some parts of the western Maya area are well studied, such as the well-known site of Palenque, others are less understood, owing to the dense tropical canopy that has long hidden ancient communities from view. It wasn't until 2019, in fact, that Scherer and colleagues uncovered the kingdom of Sak T'zi," which archeologists had been trying to find for decades.

Lidar scans of the research area revealed the relative density of structures in Piedras 

Negras, La Mar and Lacanjá Tzeltal, providing hints at these cities' respective populations

 and food needs. Credit: Brown University

The team chose to survey a rectangle of land connecting three Maya kingdoms: Piedras Negras, La Mar and Sak Tz'i," whose political capital was centered on the archeological site of Lacanjá Tzeltal. Despite being roughly 15 miles away from one another as the crow flies, these three urban centers had very different population sizes and governing power, Scherer said.

"Today, the world has hundreds of different nation-states, but they're not really each other's equals in terms of the leverage they have in the geopolitical landscape," Scherer said. "This is what we see in the Maya empire as well."

Scherer explained that all three kingdoms were governed by an ajaw, or a lord—positioning them as equals, in theory. But Piedras Negras, the largest kingdom, was led by a k'uhul ajaw, a "holy lord," a special honorific not claimed by the lords of La Mar and Sak Tz'i." La Mar and Sak Tz'i' weren't exactly equal peers, either: While La Mar was much more populous than the Sak T'zi' capital Lacanjá Tzeltal, the latter was more independent, often switching alliances and never appearing to be subordinate to other kingdoms, suggesting it had greater political autonomy.

The lidar survey showed that despite their differences, these three kingdoms boasted one major similarity: Agriculture that yielded a food surplus.

"What we found in the lidar survey points to strategic thinking on the Maya's part in this area," Scherer said. "We saw evidence of long-term agricultural infrastructure in an area with relatively low population density—suggesting that they didn't create some crop fields late in the game as a last-ditch attempt to increase yields, but rather that they thought a few steps ahead."

In all three kingdoms, the lidar revealed signs of what the researchers call "agricultural intensification"—the modification of land to increase the volume and predictability of crop yields. Agricultural intensification methods in these Maya kingdoms, where the primary crop was maize, included building terraces and creating water management systems with dams and channeled fields. Penetrating through the often-dense jungle, the lidar showed evidence of extensive terracing and expansive irrigation channels across the region, suggesting that these kingdoms were not only prepared for population growth but also likely saw food surpluses every year.

"It suggests that by the late Classic Period, around 600 to 800 A.D., the area's farmers were producing more food than they were consuming," Scherer said. "It's likely that much of the surplus food was sold at urban marketplaces, both as produce and as part of prepared foods like tamales and gruel, and used to pay tribute, a tax of sorts, to local lords."

Scherer said he hopes the study provides scholars with a more nuanced view of the ancient Maya—and perhaps even offers inspiration for members of the modern-day agricultural sector who are looking for sustainable ways to grow food for an ever-growing global population. Today, he said, significant parts of the region are being cleared for cattle ranching and palm oil plantations. But in areas where people still raise corn and other crops, they report that they have three harvests a year—and it's likely that those high yields may be due in part to the channeling and other modifications that the ancient Maya made to the landscape.

"In conversations about contemporary climate or ecological crises, the Maya are often brought up as a cautionary tale: "They screwed up; we don't want to repeat their mistakes,'" Scherer said. "But maybe the Maya were more forward-thinking than we give them credit for. Our survey shows there's a good argument to be made that their agricultural practices were very much sustainable."In Guatemala, archaeologists uncover hidden neighborhood in ancient Maya city

More information: Charles Golden et al, Airborne Lidar Survey, Density-Based Clustering, and Ancient Maya Settlement in the Upper Usumacinta River Region of Mexico and Guatemala, Remote Sensing (2021). DOI: 10.3390/rs13204109

Provided by Brown University 

Skull found on Caribbean island shows evidence of leprosy

by University of Oregon

Petite Mustique 1. A, norma frontalis. B, right norma lateralis (All photos by GCN). 

Credit: DOI: 10.1016/j.ijpp.2021.10.004

A skull unearthed on an uninhabited Caribbean island is a rare find: It's one of just a few examples of leprosy identified on a skeleton in the western hemisphere.

And it's the only one that's been directly dated using radiocarbon, by analyzing a fragment of the skull itself rather than estimating an age using nearby artifacts or materials. The bones are from the late 18th or early 19th century, reports a team led by UO archaeologist Scott Fitzpatrick.

Fitzpatrick's team, which also included lead author and skeletal biologist Greg Nelson and former UO honors student Taylor Dodrill, detailed their findings in a paper published online Nov. 13 in the International Journal of Paleopathology.

The specimen was found on Petite Mustique, a rugged uninhabited island. Historical records suggest that the island might have been the site of a leprosarium in the early 1800s, when people with leprosy could be isolated to prevent spread of disease.

"There are a number of pretty well-known cases in the Caribbean and Pacific where smaller islands were used as places to segregate people with leprosy, such as Molokai in Hawaii," said Fitzpatrick, who is also the associate director for research at the Museum of Natural and Cultural History.

But while leprosy has been documented in the Caribbean via written evidence beginning around the mid-17th century, those reports have been incomplete. Archaeologists have found scant skeletal evidence of the disease that could help trace its pattern of spread. This new find adds to that picture.

Leprosy causes dramatic disfigurement of the hands, feet and face, and those changes show up in bones. Nelson determined that the person had leprosy based on the pattern of skeletal deformation in the nose and upper jaw of the skull.

The disease spreads through prolonged close contact with someone who is sick, but "the fact that leprosy can also lead to noticeable disfigurement of the hands, feet and particularly the face made it a very scary disease and likely precipitated moves to isolate people with leprosy," Nelson said.Leprosy confirmed in wild chimpanzees

More information: Greg C. Nelson et al, A probable case of leprosy from colonial period St. Vincent and the Grenadines, Southeastern Caribbean, International Journal of Paleopathology (2021). DOI: 10.1016/j.ijpp.2021.10.004

Provided by University of Oregon 

Genetic changes in Bronze Age Southern Iberia

by Autonomous University of Barcelona

The fortified settlement of La Bastida (Totana, Murcia). This is one of the largest and best 

excavated settlements of El Argar. Credit: ASOME-UAB

The third millennium BCE is a highly dynamic period in the prehistory of Europe and western Asia, characterized by large-scale social and political changes. In the Iberian Peninsula, the Copper Age was in full swing in around 2500 years BCE with substantial demographic growth, attested by a large diversity of settlements and fortifications, monumental funerary structures, as well as ditched mega-sites larger than 100 hectares. For reasons that are still unclear, the latter half of the millennium experienced depopulation and the abandonment of the mega-sites, fortified settlements and necropolis.

In southeastern Iberia, one of the most outstanding archaeological entities of the European Bronze Age emerged around 2200 BCE. Known as the El Argar culture, one of the first state-level societies on the European continent, it was characterized by large, central hilltop settlements, distinct pottery, specialized weapons and bronze, silver and gold artifacts, alongside an intramural burial rite.

A new study led by researchers from the Universitat Autònoma de Barcelona and the Max Planck Institutes for the Science of Human History (Jena) and Evolutionary Anthropology (Leipzig) and published in Science Advances, explores the relation between dynamic shifts at population scale and the major social and political changes of the third and second millennia BCE by analyzing the genomes of 136 ancient Iberians, ranging from 3000 to 1500 BCE.

Genetic turnover and melting pot

Including published genomes from Iberia, the new study encompasses data from nearly 300 ancient individuals and focuses specifically on the Copper to Bronze Age transition around 2200 BCE.

"While we knew that the so-called 'steppe'-related ancestry, which had spread across Europe during the third millennium BCE, eventually reached the northern Iberian Peninsula around 2400 BCE, we were surprised to see that all prehistoric individuals from the El Argar period carried a portion of this ancestry, while the Chalcolithic individuals did not," says Max Planck researcher Wolfgang Haak, senior author and principal investigator of the study.

Female (right) and male (left) individuals of burial 38 of the settlement of La Almoloya

 (Pliego, Murcia). This is one of the richest burials found in an El Argar settlement. 

Credit: ©ASOME-UAB

The genomic data reveals some of the processes underlying this genetic shift. While the bulk of the genome shows that Bronze Age individuals are a mix of local Iberian Chalcolithic ancestry and a smaller part of incoming ancestry from the European mainland, the paternally inherited Y chromosome lineages show a complete turnover, linked to the movement of steppe-related ancestry that is also visible in other parts of Europe.

The rich new data from the El Argar sites also show that these two components do not fully account for the genetic make-up of the early Bronze Age societies. "The causes of this disappearance of the previous diversity of the Y chromosome are still very difficult to explain," says Cristina Rihuete Herrada, UAB researcher and co-author of the study.

"We also found signals of ancestry that we traced to the central and eastern Mediterranean and western Asia. We cannot say exactly whether these influences arrived at the same time as the steppe-related ancestry, but it shows that it formed an integrative part of the rising El Argar societies, attesting to continued contacts to these regions," adds Vanessa Villalba-Mouco, postdoctoral researcher and lead author of the study.

UAB researchers already pointed to possible Mediterranean connections when they discovered in 2013 the monumental fortification of the Argaric settlement of La Bastida, in Murcia, to explain the originality of some architectural elements. "The genetic study argues in favor of this hypothesis: the data show that this unknown Mediterranean connection would have been sustained over time until the end of the period of El Argar, around 1500 BCE," says Rafael Micó, UAB researcher and co-author of the study.

Social implications

"Whether the genetic shift was brought about by migrating groups from North and Central Iberia or by climatic deteriorations that affected the eastern Mediterranean around 2200 BCE is the million-dollar question," says co-principal investigator and senior author Prof Roberto Risch from the Universitat Autònoma de Barcelona. "It would be foolish to think that it can all be explained by a simple, one-factor model. While the temporal coincidence is striking, it is likely that many factors played a role."

Copper Age collective burial of Camino del Molino (Caravaca de la Cruz, Murcia), where a

 total of ~1300 individuals were buried between 2900-2300 BCE. The image shows the

 last burial layer, dated between 2500-2300 BCE, from which six individuals have been 

analysed. Credit: Universidad de Murcia. Fotografía de Francisco Ramos

One of these factors could be pandemics, such as an early form of the Plague, which has been attested to in other regions of Europe around that time. While not found directly among the tested individuals in southern Iberia, it could be a cause or driver for the movement or disappearance of other groups in the region.

"In any case, we can now conclude that the population movement starting in the eastern European steppe zones around 3000 BCE was not a single migratory event, but required over four centuries to reach the Iberian Peninsula and another 200 years to appear in present-day Murcia and Alicante," adds Risch.

The archaeological record of the El Argar group shows a clear break with previous Chalcolithic traditions. Burial rites, for example, changed from communal to single and double burials within the building complexes. Elite burials also indicate the formation of strong social hierarchies. Testing for biological relatedness, the researchers found that males are on average more closely related to other people at the site, indicating that the group was likely patrilineally structured. Such a social organization could explain the stark reduction of the Y-lineage diversity.

"We observe similar patterns of social organization and increasing stratification also in other parts of Early Bronze Age Europe, in fact broadly around the same time and with similar characteristics of early state-like formations. This suggests a structured restart or resetting following some form of crisis or unstable, highly dynamic times," summarizes Haak.

In the research have participated, among others, these institutions: Adelaide University, Danube Private University, Basel University, Fundación Vasca para la Ciencia, Universidad de Valencia, Cape Town University, Universidad de Alicante, Museo Arqueológico de Alicante, Museo Arqueológico Municipal de Lorca, Universidad de Murcia, Harvard Medical School, Harvard University, Howard Hughes Medical Institute y Universidad de Sevilla.

Central European prehistory was highly dynamic

More information: Vanessa Villalba-Mouco et al, Genomic transformation and social organization during the Copper Age-Bronze Age transition in southern Iberia, Science Advances (2021). DOI: 10.1126/sciadv.abi7038. www.science.org/doi/10.1126/sciadv.abi7038

Journal information: Science Advances 

Provided by Autonomous University of Barcelona