Humans

By Alison George

Calcite crystals collected by humans more than 100,000 years agoJayne Wilkins
A cache of beautiful crystals collected 105,000 years ago in South Africa is shedding new light on the emergence of complex behaviours in our species.
A team led by Jayne Wilkins at Griffith University, Australia, discovered 22 distinctively shaped white calcite crystals at a site in the Kalahari desert called Ga-Mohana Hill North Rockshelter. “They are little rhomboids, really visually striking,” says Wilkins.

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These geometric crystals didn’t originate at the site and haven’t been modified, so seem to have been deliberately collected and brought to the rock shelter for ornamental purposes. “They don’t seem to have been used for everyday tasks,” she says.
The collection of beautiful items seems like a normal thing for humans to do today, but this so-called symbolic behaviour only emerged around 100,000 years ago. “Collecting these kinds of pretty objects for non-utilitarian reasons could have its roots in symbolism and arts and culture,”  says Wilkins.

Also found at the site were 42 fragments of burnt ostrich egg shell. The large egg shells may have been used by humans to store and transport water – offering more evidence of human innovation.
These discoveries in the Kalahari, 600 kilometres from the sea, are challenging the prevailing assumption that the emergence of complex behaviours like symbolism and technological innovation emerged at the coast, where humans had access to seafood containing nutrients thought to support brain growth.
Until now, the earliest evidence of symbolic behaviour was found at sites close to the sea, such as 100,000-year-old engraved ochre from Blombos cave and 60,000-year-old decorated ostrich egg shells from the Diepkloof rock shelter, both on the South African coast.
“In the Kalahari, which is really far from the coast, we are seeing the same kinds of behaviours, at the same time,” says Wilkins.
Journal reference: Nature, DOI: 10.1038/s41586-021-03419-0

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By Michael Marshall

Coarse pottery that was used to help extract salt from seawaterS.J. Sherlock
Stone Age Britons extracted salt from seawater using industrial-style processes more than 5500 years ago. The discovery means people in Great Britain were producing salt thousands of years earlier than thought, before the Bronze Age.The technology may have been brought by migrants arriving from mainland Europe.
“It changes how we think about Neolithic society,” says Stephen Sherlock, an independent archaeologist based in Redcar, UK.

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In mainland Europe, there is evidence of salt production from the heating of salty water as early as 6050 BC during the Neolithic: the last period of the Stone Age, before the invention of bronze. However, in Britain the earliest known evidence was from Brean Down in Somerset, where Bronze Age people were making salt around 1400 BC.
Sherlock has been excavating for many years at Street House, near the town of Loftus in north-east England. The site was occupied from the Neolithic, about 5700 years ago, into the later Bronze Age and the Iron Age that followed, and as recently as the 7th century AD in the Anglo-Saxon period of English history.

Geophysics revealed a buried structure about 200 metres from a Neolithic house, so Sherlock began digging.
“It was sealed by about a metre of clay,” says Sherlock. Beneath that was a distinctive pit measuring 2.8 metres by 2 metres, with a narrow trench leading into it. Three areas of the pit had been intensely burned, leaving charcoal deposits: Sherlock argues these were hearths. A hazelnut shell in the charcoal layer was radiocarbon dated to between 3766 and 3647 BC.
Similar structures are known from Iron Age deposits in Britain and are generally interpreted as “salterns” used for extracting salt from seawater. The water was placed in large ceramic pots, supported by stones over hot flames. The heat evaporated the water, leaving salt crystals. Sherlock found shards of pottery of a low quality characteristic of salt production.
“I showed these finds to salt-making experts,” says Sherlock. “They said you’d expect to find that in the Iron Age.”
Salt would have been the most valuable commodity in society, says Sherlock. It was hard to obtain and could be used to flavour or preserve food, for instance. “The people who controlled salt are going to be some of the richest.”
Journal reference: Antiquity, DOI: 10.15184/aqy.2021.25
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By Alexander McNamara
and Matt Hambly

Mohamad Haghani / Alamy
The Triassic period started 252 million years ago after the Permian-Triassic extinction event, and in the 50 million years before the next extinction event, huge reptiles evolved and ruled the planet. One particularly fearsome species known as the rauisuchians stretched 9 metres from nose to tail with teeth like steak knives. However, the dinosaurs that existed at the time were much smaller creatures, many not much bigger than a cow. Though they were lacking in stature, some had some unusual features, like Tanystropheus, with a neck twice as long as its body.
We can maintain relationships with only around 150 friends
Clare Jackson / Alamy
Although the number of friends on your Facebook profile might be a long way north of 500, there is a natural upper limit to the number of people you can maintain a stable social relationship with. This is known as Dunbar’s number, and it plays out in many more situations than you might realise. For example, historically it was the average size of English villages, the ideal size for church parishes, and the size of the basic military unit, the company.

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There is also a correlation between primate brain size and the size of their social groups. Extrapolate this relationship to the size of a human brain and guess where that leads us? Yes,  around 150 social contacts.
Mount Everest’s summit would be 2 kilometres underwater at the ocean’s deepest spot
Alexmumu/Getty Images
At its deepest point, in an area known as the Challenger Deep, the Mariana trench plunges to a depth of 10,984 metres (36,037 feet) below sea level. This is roughly the same distance below the waves that commercial airliners fly above them, and if Mount Everest were to start at the ocean’s lowest point, at 8849 metres it would still be more than 2000 metres below the surface.

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By Karina Shah

A deed written on sheepskin parchment from 1499David Lee
Sheepskin was the most commonly used parchment for legal deeds over the past five centuries in Great Britain, even though it is quite fragile. This is most likely because fraud can be more easily detected on it than on vellum.
Sean Doherty at the University of Exeter in the UK and his colleagues analysed 645 pages from 477 legal deeds concerning property in England, Scotland and Wales dating from 1499 to 1969.

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They first cut a 2-square-millimetre sample of parchment from the edge of the documents. “We made sure to be well away from the text, any stamps and wax seals,” says Doherty.
The team then chemically treated the animal skin to isolate the protein collagen, which is made up of a mix of sub-units called peptides. “Each animal has a different set of peptides that make up collagen – it is species variable,” says Doherty. This let the researchers work out what type of parchment each deed was written on.
They found that 622 of the 645 pages were made from sheepskin, which was a surprise, as previous research suggested these types of documents were made with a variety of animal skin – most commonly vellum, which is made from calfskin.
“We expected to see a wide range of animals, but they pretty much all turned out to be from sheep,” he says.

Doherty and his team suspect that sheepskin was used for important deeds because it is difficult to alter without being noticed due to its high fat content.
When animal skin is first processed, it is submerged into an alkaline solution of chalk. This draws out the fat and removes any hair, leaving behind the dermis layer of the skin which is then stretched into parchment.
Sheepskin is between 30 to 50 per cent fat, compared to just 2 to 3 per cent in cattle and 3 to 10 per cent in goats. The removal of the fat causes sheepskin parchment to be very fragile. “The layers will detach because it has all these holes in it where the fat once was,” says Doherty.
As a result, you can see a visible mark where text has been altered on sheepskin more easily than other animal skins, which is useful for important documents.
“If someone intentionally tried to alter a word on a deed made of sheepskin, they would leave behind a telltale smudgy residue,” says Heather Wolfe at Folger Shakespeare Library in Washington DC, who wasn’t involved in the research.
Journal reference: Heritage Science, DOI: 10.1186/s40494-021-00503-6

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By Krista Charles

Charred remains of millet, a cereal grain, found in the Eastern AlpsHeiss et al, 2021, PLOS ONE
People working on mining sites in the Eastern Alps during the Bronze Age had cooked, bread-based meals delivered to them during the day.
Andreas Heiss at the Austrian Academy of Sciences and his colleagues studied cooked food remains, including refined cereals and finely ground grains, obtained from Prigglitz-Gasteil in the Eastern Alps, a copper mine that was active between 1100 and 900 BC, during the Late Bronze Age.

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These types of cereal-based food require preparation to make them edible, including separating grains from husks and then cooking them, but the team found no signs of this kind of work being done at the mine. There was also no evidence of harvesting nearby, suggesting the food must have come from elsewhere.

“All the early stages from processing were entirely missing and this is usually a good indicator for a consumer habit that people did not produce themselves, but they received stuff that was already pre-processed,” says Heiss.
Since wet ingredients like milk weren’t preserved, the researchers can’t say exactly which dishes the miners were being served, but they were likely to be bread based. Previous research has shown that these miners had pork delivered to them, but the new findings suggest that plant-based foods were a major part of their diet too.
Lara González Carretero at the Museum of London Archaeology says this isn’t surprising. “It would be very time-consuming and there would be clear logistical issues for them to be able to cook their own meals in such a work setting.”
Journal reference: PLOS One, DOI: 10.1371/journal.pone.0248287
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The Neanderthals, Denisovans and many others once shared Earth with us. What happened – and where are they now? Archaeologist Tom Higham has written a great insider account

Humans

24 March 2021

By Michael Marshall

Archaeologist Tom Higham, with a skull from a modern humanMark Hardy
The World Before Us
Tom Higham

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Viking
ASK any well-informed human living up to 40,000 years or so ago if they were the only intelligent being around, and they would have answered, “No”. That is because at that (geologically) recent time, our ancestors would still have been sharing Earth with several other human groups. In a very real sense, we were not alone.
Today we are. The Neanderthals who roamed Europe and western Asia are long gone. So are the Denisovans of east Asia, the “hobbits” of Flores Island in Indonesia and many more. Who were they? What were they like? What happened to them?
Archaeologist Tom Higham at the University of Oxford tackles these questions in his first book for a popular audience, The World Before Us: How science is revealing a new story of our human origins. It is a slightly misleading main title because Higham barely discusses the world before Homo sapiens emerged about 300,000 years ago: you won’t find Lucy or any other ape-like australopithecines. But he does deliver on the subtitle, with a fascinating insight into groups belonging to the same Homo genus as us that lived alongside us for much of their existence.
Higham has been involved in many of the biggest discoveries in human evolution in recent decades. A specialist in dating methods, he helped trace the Neanderthal extinction, studied the mysterious Denisovans, who are mostly known from DNA extracted from bone fragments, and helped push back the date H. sapiens arrived in the Americas.
“When it comes to what happened to groups like the Neanderthals, Higham wisely embraces nuance”
The book gets off to a shaky start, as the opening chapters are overstuffed with unnecessary detail that isn’t immediately explained. For example, Higham repeatedly mentions nuclear and mitochondrial DNA, but doesn’t explain them until chapter 5 – although at one point there is an apologetic footnote directing readers to that part.
However, once past these bumps the book settles into a lively groove. Higham devotes whole chapters, sometimes multiple chapters, to each extinct hominin group. He packs in startling discoveries, impressive insights and the occasional debunking of a foolish idea.
Higham’s personal involvement means he has lots of good stories. He vividly describes Denisova cave in Siberia, Russia – where the first traces of Denisovans were found – along with its adjacent field camp.
There are also thumbnail portraits of the scientists involved. A highlight is Higham’s account of the discovery of Denny, a girl who lived in or around Denisova cave, with a Neanderthal mother and a Denisovan father. One of Higham’s students, Samantha Brown (now at the Max Planck Institute for the Science of Human History, Germany), spent weeks testing bone fragments before identifying one that belonged to a hominin.
Higham reproduces the flurry of excited, expletive-ridden texts he sent after being told the news. The reader gets a real sense of what it is like to “do” science as Higham emphasises Brown’s boring, reward-free slog before she finally struck pay dirt.
When it comes to the perennial question of what happened to groups like the Neanderthals, Higham wisely embraces nuance and complexity. It is unlikely there is a single explanation for the extinction of such a group as widespread and adaptable as the Neanderthals – and conservation biologists tend to find that species experience a multitude of threats.
For groups like the Denisovans, of whom we have barely any remains, he refuses to commit himself at all. He knows it is too early to make a big claim about what happened when we don’t even know the extent of their range or what they looked like.
In any case, many of them haven’t entirely gone. Thanks to interbreeding, the DNA of Neanderthals and Denisovans lives on. In our genes, at least, we still share the world with them.

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Beyond the headline breakthroughs, artificial intelligence is a global industrial complex. Having explored its political and social implications, Kate Crawford at Microsoft Research is now focusing on the infrastructure underpinning AI

Technology

24 March 2021

By Timothy Revell

Rocio Montoya
ARTIFICIAL intelligence is everywhere these days, from the Alexa virtual assistant in your kitchen to the algorithms that decide on your suitability for a job or a mortgage. But what exactly is it? The definition matters because to a great extent it dictates how we think about AI’s impact.
If AI is something that outperforms humans by definition, it seems logical to trust it to identify people who should be stopped and searched via facial recognition, say, or to make judgements on which offenders should get probation. If it is solely about algorithms, it becomes a lot easier to sweep aside issues of bias and injustice as mere technical issues.
Kate Crawford takes a broader view. Co-founder of the AI Now Institute at New York University and a researcher at Microsoft Research and the école Normale Supérieure in Paris, she has spent the best part of two decades investigating the political and social implications of AI. In her new book, Atlas of AI, she also looks at the global infrastructure that underpins the rise of this technology.
She argues that AI, far from being something abstract and objective, is both material and intrinsically linked to power structures. The way it is made involves extracting resources from people and the planet, and the way it is used reflects the beliefs and biases of those who wield it. Only when we come to terms with this, says Crawford, will we be able to chart a just and sustainable future with AI.
Timothy Revell: What is AI?
Kate Crawford: I think of it in three ways. Technically speaking, it is … More

Read
The Best of World SF: Volume 1 contains 26 sci-fi stories, some celebrated and others new, representing 21 countries and five continents. Edited by writer Lavie Tidhar, the collection is a celebration of a truly global genre.

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Overloaded is science writer Ginny Smith’s exploration of how our lives are influenced by neurotransmitters, the brain chemicals behind everything, from what we remember and who we love to basic drives such as hunger, fear and sleep.
Pixabay
Watch
Our Future Planet: Global greenhouse gas removal, the latest in the climate talk series from the UK-based Science Museum Group sees scientists and engineers discuss carbon capture. Watch online at 7.30 pm BST on 31 March.

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