Humans

adobe stock/Phoebe Watts
Nobody  doubts that Albert Einstein had a brilliant mind. But the Nobel prizewinner, famous for his theories of special and general relativity, wasn’t blessed with a big brain. “It was smaller than average,” says Jeremy DeSilva at Dartmouth College in New Hampshire.
This seems surprising. Big brains are a defining feature of human anatomy, and one we are proud of. Other species might be speedy or powerful, but we thrive using the ingenuity that comes with a large brain. Or so we tell ourselves. Einstein’s brain hints that the story isn’t so simple – and recent fossil discoveries confirm this. Over the past two decades, we have learned that small-brained hominin species survived on Earth long after big-brained ones appeared. Moreover, evidence is growing that they were behaviourally sophisticated. Some, for instance, made complex stone tools that could probably only have been fashioned by individuals with language.
These discoveries turn the question of human brain evolution on its head. “Why would selection favour big brains when small-brained humans can survive on the landscape?” says DeSilva. Neural tissue consumes lots of energy, so big brains must surely have brought benefits to the few species that evolved them. But what?
An answer to this puzzle is beginning to emerge. It looks like brain expansion began as an evolutionary accident and then led to changes that caused this growth to spiral. Surprisingly, the sorts of changes that drove this expansion could also explain a more recent 10 per cent reduction in human brain size. What’s more, this suggests our brains may shrink further still – and might even cause humanity’s demise.
It is undeniable that… More

A hoard of Roman gold coins found below the floor of a Roman house in Corbridge, UKWorld History Archive/Alamy
After the Romans conquered Britain in AD 43, the technologies and laws they introduced led to centuries of economic growth of a kind once thought to be limited to modern industrial societies. That is the conclusion of an analysis of thousands of archaeological finds from this time.
“Over that period of about 350 years, you’re looking at roughly a two and a half [fold] increase in productivity per capita,” says Rob Wiseman at the University of Cambridge.
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It has long been believed that economic growth in the ancient world depended on having more people and more resources, says Wiseman: to increase food production, say, required more land and more farm workers. This kind of growth is known as extensive growth.
By contrast, economic growth today is driven mainly by increased productivity, or intensive growth. Thanks to mechanisation and better breeds of plants and animals, for instance, more food can be produced from the same area of land with fewer workers.
Some recent studies have challenged the idea that intensive growth occurred only after the industrial age began, inspiring Wiseman and his colleagues to look at growth in Roman Britain from AD 43 to 400.
The team’s research was made possible by UK laws requiring archaeological investigations to be done when a site is developed, says Wiseman. “The result is there’s been tens of thousands of archaeological excavations done in this country. And, moreover, that data is publicly accessible.”
By looking at how the number of buildings changed over time, the researchers were able to get an idea of how the population of Roman Britain grew. There is a strong relation between the number of buildings and population size, says Wiseman.
To get an idea of economic growth, the team looked at three measures. One was the size of buildings, rather than the number of them. As people grow richer, they build bigger houses, says Wiseman.
Another measure was the number of lost coins found in digs. “These are things that have fallen through the floorboards, or they’ve been lost in the baths, or something like that,” he says.
The idea is that the more coins are in circulation, the more are likely to be lost. The team didn’t count hidden hoards of coins, as these reflect instability rather than growth.
The third measure was the proportion of crude pottery, such as cooking pots and storage pots, to more ornate pottery like decorated plates. Economic growth requires people to interact more and socialise more, which means “showing off” when guests are present, says Wiseman.
Based on these measures, the team found that economic growth exceeded that expected from population growth alone. They estimate that per capita growth was around 0.5 per cent between AD 150 and 250, slowing to around 0.3 per cent between AD 250 and 400.
“What we’re able to show is yes, after the Romans arrived, there was definitely intensive growth,” says Wiseman. The pace of growth rather than the kind of growth is what probably distinguishes the modern world from the ancient one, he says.

The researchers think that this growth was driven by factors such as the roads and ports built by the Romans, the laws they introduced making trading safer, and their technologies, such as more advanced grain mills and better breeds of animals for ploughing.
The higher growth between AD 150 and 250 may be a result of Britain catching up with the rest of the Roman world, says Wiseman. “You’re moving from a small tribal society where there’s not a lot of interaction going on to a world-spanning economy.”
What isn’t clear is whether this economic development made people happier or healthier. “Just because the productivity is going up doesn’t automatically mean that the welfare of Britons who were invaded and colonised was better under Rome,” says Wiseman. “That’s an open question.”
To investigate this, the researchers now plan to look at human remains to work out things such as how long people lived.
“I am convinced that they are right and that, indeed, intensive growth took place in Roman Britain,” says Alain Bresson at the University of Chicago, Illinois.
“A lot of archaeologists have noted compelling evidence for economic growth in Roman Britain, but this paper adds a welcome formal theoretical dimension to the discussion,” says Ian Morris at Stanford University, California.
However, Morris suspects that the lower average growth rate from AD 250 to 400 actually reflects high growth followed by rapid decline as the Roman empire began to break up. Further studies will resolve this, he says.

Topics:archaeology/economics More

Tonje Bøe Birkeland as Tuva Tengel on a camel in Mongolia.Tonje Bøe Birkeland
The imagined female scientists, explorers and adventurers seen in Tonje Bøe Birkeland’s photographs are echoes from a footnote in women’s history. In her ongoing series, The Characters, the photographer frames herself in the guise of Victorian and early-20th century pioneers – dressed in period costume, holding binoculars and bellows cameras – snapped in widescreen vistas of mountains, fjords and ice flows. Each picture is a performance.
Tonje Bøe Birkeland
The project began in 2008, when Birkeland was on a course about photography’s role in shaping historical truths. “It was all about did Neil Armstrong go to the moon? Did Roald Amundsen actually get to the Pole first?” she recalls. “That made me want to do something about women.” Her first character was a glaciologist.Advertisement
Tonje Bøe Birkeland
Her photographs are puzzles and her work taps into the names, appearances and biographies of real, unrecognised women, such as Louise Arner Boyd, a polar scientist who traversed the north-east coast of Greenland in the 1920s. As well as stepping into the boots of her creations, Birkeland writes their journals and creates installations of their travel cases (packed with maps and geological samples), which she both photographs and exhibits. She has immortalised her intrepid alter egos in various settings, from the snowdrifts of Svalbard to the foothills of Bhutan.
Tonje Bøe Birkeland
In the top photo, she is seen as desert traveller Tuva Tengel on a camel in Mongolia. The three other photos show her as Arctic explorer Anna Aurora Astrup in Greenland.
Birkeland’s work will be at Forum Box in Helsinki, Finland, from 22 August to 19 September.

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Tracing of the cave painting showing a pig and human-like figures from Leang Karampuang on Sulawesi, IndonesiaGriffith University
A painting of a pig with human-like figures in an Indonesian cave is at least 51,200 years old, making it the earliest known example of representational art in the world.
“We like to define ourselves as a species that tells stories, and this is the oldest evidence of that,” says Maxime Aubert at Griffith University in Gold Coast, Australia.
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The pig artwork was discovered in 2017 on the ceiling of the limestone cave of Leang Karampuang on the island of Sulawesi.
In 2019, Aubert and his colleagues dated a hunting scene from a nearby cave named Leang Bulu’ Sipong 4 to a minimum of 43,900 years old.
Now, they have used a new, more accurate technique to estimate the ages of both artworks. They found that the image at Leang Bulu’ Sipong 4 is actually more than 4000 years older than previously thought – and the Leang Karampuang art is even older.
The artworks at both locations are at least 10,000 years older than the oldest European rock art, says Aubert.
Modern humans, Homo sapiens, had reached Australia by 60,000 to 65,000 years ago, so we know they were in the region at this time, says Aubert. “We assume these paintings were made by modern humans.”
In the same caves, there are depictions of creatures with both human and animal attributes, indicating spiritual beliefs.
“This rock art is not just small symbols,” says team member Renaud Joannes-Boyau at Southern Cross University in Lismore, Australia. “They were actually painting hunting and life scenes and they were already telling stories with their art, living in a spiritual world and trying to make sense of the environment around them. That tells us a lot about the evolution of Homo sapiens.”
The previous method of dating the artworks relied on the chemical extraction of samples and a large portion of the rock had to be crushed and destroyed.
In the new technique, a 5-millimetre diameter core is extracted from the crust on the rock. From the surface of this core, material that is less than half the thickness of a human hair is removed by a laser and tested to measure the decay of isotopes in the mineral. Once this is done, the core can be plugged back into the rock art, resulting in far less destruction compared with the previous method.
Karampuang Hill, location of Leang Karampuang caveGoogle Arts & Culture
Joannes-Boyau says the new technique is likely to lead to major revisions of rock art history around the world.
Kira Westaway at Macquarie University in Sydney, Australia, says the refined dating technique has provided a more accurate assessment of when the Sulawesi art was actually painted.
“This is hugely significant, when the original age was already considered groundbreaking,” she says. “This has massive implications for our understanding of the capabilities of the early artists moving through Indonesia and the type of skills and tool kit they already possessed when entering Australia.”
Homo sapiens probably wasn’t the only species with the capacity for complex symbolic practices, says Martin Porr at the University of Western Australia. “It is very likely that other hominins at least had some capabilities in this respect as can be inferred from the highly sophisticated material culture of Neanderthals.”
“It will be important to do more work in the future on the archaeological evidence in the region to understand and confirm the social, economic and cultural contexts of the images during the late Pleistocene,” says Porr.

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Snow leopards were among the animals hunted by DenisovansKlaus Honal / Alamy
Ancient humans known as Denisovans hunted a wide range of animals on the Tibetan plateau, including blue sheep, yaks and snow leopards. This varied diet enabled them to thrive in the high-altitude region for tens of thousands of years before the arrival of modern humans.
“Denisovans were behaviourally quite flexible,” says Frido Welker at the University of Copenhagen in Denmark. “They’re able to really adapt to the local environment and the species that are present there.”
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The Denisovans are one of the most mysterious groups of hominins with which we once shared the planet. They were first described in 2010, based on DNA extracted from a fragment of finger bone found in Denisova cave in the Altai mountains, Russia. It was the first time a hominin group had been identified solely based on DNA.
It is likely that Denisovans were once widespread in southern Asia because today many people in southern Asia and South-East Asia carry Denisovan DNA, indicating that Denisovans interbred with Homo sapiens tens of thousands of years ago. However, Denisova cave has only yielded teeth and other fragments. As a result, we don’t know much about what Denisovans looked like.
In 2019, researchers including Welker described a jawbone from Baishiya Karst cave in Xiahe in the north-east Tibetan plateau dated to 160,000 years ago. Protein from one of the teeth was identified as Denisovan.
The following year, another group found Denisovan DNA in the sediments of the cave. The DNA was variously 100,000, 60,000 and possibly 45,000 years old – implying that Denisovans lived there for over 100,000 years.
The Tibetan plateau is 4000 metres above sea level. The air is thin and it is cold and dry, making it a challenging place to live. To find out how the Denisovans survived for so long, Welker and his colleagues studied the animal bones from Baishiya Karst cave. By looking at the shapes of the bones and extracting telltale proteins, they identified 2005 out of 2567 bones or bone fragments.
The most numerous animals were blue sheep (Pseudois nayaur), or bharal. They and other sheep and goat relatives “make up around half of the assemblage”, says Welker. Other medium-sized plant-eaters included wild yak, Tibetan gazelles and red deer. There were also small animals like groove-toothed flying squirrels and porcupines. What’s more, there were some large carnivores, including spotted hyenas, wolves and snow leopards, plus some birds such as golden eagles.
Most of the bones seem to have been brought in by Denisovans: 19 per cent had clear evidence of this, such as cut marks made by stone tools, and less than 1 per cent showed signs – such as tooth marks – of being carried in by rodents or carnivores.
The setting of Baishiya Karst cave on the Tibetan plateauDongju Zhang’s group (Lanzhou University)
“This would be the second site where we can be absolutely certain that there are Denisovans present and that the associated assemblages specifically represent their behaviours,” says Samantha Brown at the University of Tübingen in Germany.
Other sites on the Tibetan plateau have stone tools but no hominin remains, so we don’t know who lived there. Further afield, a single molar tooth described in 2022 from Tam Ngu Hao 2 limestone cave in Laos has been tentatively identified as Denisovan.
We can’t draw too many inferences about Denisovans’ capabilities based on so few sites, says Brown. “However, we expect that Denisovans would once have been found as far north as Siberia and potentially as far south as [the islands of] South-East Asia. It could be that, as we find more of their sites, we really begin to see that Denisovans were highly adaptable.”
One of the bones from Baishiya Karst cave, a piece of rib, turned out to be another Denisovan. It was found in a layer of sediments dated to between 48,000 and 32,000 years ago – making it the youngest known Denisovan specimen. Welker says stone tools from Nwya Devu on the plateau are evidence that modern humans were also living there by 40,000 years ago – hinting that Denisovans and modern humans co-existed in the area.

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Skulls found in the banks of the river Thielle in Cornaux/Les Sauges in Switzerland are now stored at the Laténium Museum in HauteriveSchweizerischer Nationalfonds/Fonds national suisse
For decades, scientists have wondered about the history of 20 people, as well as a handful of farm animals, who seemingly drowned 2000 years ago in a Swiss river. One idea is that these individuals were sacrificed from a bridge, which later collapsed. But new evidence supports the notion that, for at least some of them, their demise – along with the bridge’s – was due to a natural disaster.
In 1965, archaeologists uncovered… More

Sasithorn Phuapankasemsuk/Getty Images
Try to imagine an environment largely untouched by humans and the Amazon rainforest might spring to mind. After all, large swathes of this South American landscape are blanketed in thick vegetation, suggesting it is one corner of the world that humans never managed to tame. Here, there must have been no deforestation, no agricultural revolution and no cities. It seems like a pristine environment.
Or so we thought. But a very different picture is emerging. Archaeologists working with Indigenous communities have been shown crumbling urban remains and remote sensing technologies such as lidar are revealing the footprints of vast ghost cities. With so much evidence of ancient human activity, it is now thought the pre-Columbian Amazon was inhabited by millions of people – some living in large built-up areas complete with road networks, temples and pyramids.
But that’s not all this research reveals. Paradoxically, it also provides evidence that the traditional view of the Amazon isn’t completely wide of the mark. For instance, while the ancient Amazonians managed their landscape intensively, they didn’t deforest it. And although they developed complex societies, they never went through a wholesale agricultural revolution. This might suggest that the pre-Columbian Amazonians broke the mould of human cultural development, which is traditionally seen as a relentless march from hunting and gathering to farming to urban complexity. The truth is more surprising. In fact, we are now coming to understand that there was no such mould – civilisation arose in myriad ways. What looks like an anomaly in the Amazon is actually a shining example of a process that was as vibrant and diverse as the rainforest itself.
Despite… More

Ancient ritual stick discovered in Cloggs cave, AustraliaGunaikurnai Land and Waters Aboriginal Corporation
Wooden artefacts found in an Australian cave suggest that an Indigenous ceremony documented in the 19th century may have been practised 12,000 years ago, making it possibly the oldest known cultural ritual anywhere in the world.
Between 2019 and 2020, a team of archaeologists and members of a local Indigenous community called the GunaiKurnai from south-eastern Australia conducted an excavation at Cloggs cave, near the Snowy river in Victoria.
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The site had been partly dug in the 1970s, but during the new work the team discovered two preserved fireplaces, which contained mostly unburnt artefacts made of wood from local Casuarina trees. Chemical analysis revealed these artefacts were smeared with animal or human fat and dated to between 11,000 and 12,000 years ago, making them among the oldest wooden artefacts found in Australia.
On its own, this would have been a major but mysterious discovery. However, the researchers and community members were at the same time examining an ethnographic report by 19th-century anthropologist Alfred Howitt, who researched the customs and traditions of tribes in south-eastern Australia in the 1880s.
In 1887, very close to Cloggs cave, he recorded the practices of Indigenous “wizards”, now referred to as “mulla-mullung”, who are powerful GunaiKurnai medicine men and women. He wrote a detailed account of one ceremony that involved smearing animal or human fat on throwing sticks made of Casuarina wood and placing them in small ceremonial fires as a magic charm or curse. He understood the ritual to be used against an enemy or someone whom those conducting the ritual wished to harm.
“The wizard has during this time been singing his charm; as it is usually expressed, he ‘sings the man’s name,’ and when the stick falls the charm is complete. The practice still exists,” wrote Howitt.
Bruno David at Monash University in Melbourne and Russell Mullett, a GunaiKurnai elder, say the similarities between the archaeological discoveries and the ethnographic account have convinced them that the same ritual was used for up to 12,000 years.
Mullett says he was convinced of the connection because Howitt’s account so closely matched what they had found in the cave – the type of wood and the fats smeared on the stick, positioned exactly as Howitt had described.
“This cements the longevity of our oral traditions and knowledge and the transferral of that knowledge from generation to generation,” says Mullett.
David says the conclusions grew slowly following the discovery of such rare timber artefacts.
“Archaeologists never get to see the performances behind such ancient deposits,” he says. “To me, it’s absolutely remarkable the physical evidence that corresponds so closely to the cultural knowledge has survived virtually intact, and for so long. It exactly matches the practices described by Howitt.”
“The team’s methods are meticulous and remarkable,” says Paul Taçon at Griffith University in Brisbane, Australia.
There were lots of changes to these communities over time, says Taçon, but this ritual seems to have stayed the same. “What strikes me about this case is that this same form of ritual practice must have been considered to have been important and effective to have been perpetuated over such a long period of time.”

Topics:archaeology/anthropology More