Survival of the friendliest? Why Homo sapiens outlived other humans | New Scientist

2021/11/27 13(22Survival of the friendliest? Why Homo sapiens
outlived other humans
We once shared the planet with at least seven other types of human. Ironically, our successmay have been due to our deepest vulnerability: being dependent on others

HUMANS 24 November 2021
By Kate Ravilious

Simon Pemberton

HUMANS today are uniquely alone. For the majority of the existence of Homo sapiens,
we shared the planet with many other types of human. At the time when our lineage firstevolved in Africa some 300,000 years ago, there were at least five others. And if you weregoing to place a bet on which of those would outlast all the rest, you might not have put
your money on us.
The odds would have seemed more favourable for the Neanderthals, who had alreadyhttps://www.newscientist.com/article/mg25233625-000-survival-of-the-friendliest-why-homo-sapiens-outlived-other-humans/

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2021/11/27 13(22adapted to live in colder conditions and expanded to inhabit much of Eurasia. Or Homoerectus, who had made a success of living in south-east Asia. By contrast, our direct
Homo sapiens ancestors were the new kids on the block, and wouldn’t successfully settle
outside of Africa until more than 200,000 years later. Yet, by 40,000 years ago, or
possibly a bit more recently, we were the only humans left standing. Why?
Many explanations have been put forward: brainpower, language or just luck. Now, a
new idea is building momentum to explain our dominance. Ironically, it may be some ofour seemingly deepest vulnerabilities – being dependent on others, feeling compassion
and experiencing empathy – that could have given us the edge.
Today, surrounded by computers, phones and all the other clever things we haveinvented, it is easy to pin our success on our cognitive abilities. But the more we learn
about other types of human, the more they seem similar to us in this regard. In the caseof Neanderthals, and possibly the mysterious Denisovans, this includes the ability tomake sophisticated tools, such as projectile spears that enabled them to hunt large
game. Similarly, we are discovering that artistic flair – a marker for the ability to think
symbolically, and thought to be another vital ingredient for our dominance – wasn’t justthe preserve of our species. Homo erectus etched patterns onto shells some 500,000 years
ago and Neanderthals drew on cave walls.
Join expert archaeologist Louise Leakey in Kenya: Explore the origins of humanity on a Discovery Tour

More recently, the focus has shifted from intelligence to our ability to network withstrangers: the survival of the friendliest. Archaeological evidence shows, for example,
that Homo sapiens not only lived in larger groups than all other humans, but had an
unparalleled ability to form alliances beyond their immediate group. It might be thatthese social abilities helped to make us the most adaptable humans, the only ones
capable of occupying every single biome on the planet.
Other humans certainly became adept at living in particular environments. Homo
heidelbergensis and the Neanderthals, for example, had the cultural and technologicalskills – the ability to make clothing, fire and shelter – needed to branch out into colder
climes. The diminutive newly discovered Homo luzonensis, along with Homo floresiensis(aka the hobbit), thrived in woodland environments. “But it is doubtful that thesehumans would have been successful if they were magically plopped down in the other’s
habitat, whereas sapiens likely could have,” says Brian Stewart, an archaeologist at thehttps://www.newscientist.com/article/mg25233625-000-survival-of-the-friendliest-why-homo-sapiens-outlived-other-humans/

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Survival of the friendliest? Why Homo sapiens outlived other humans | New Scientist

2021/11/27 13(22University of Michigan.
Stewart, together with Patrick Roberts, an archaeologist at the Max Planck Institute for
the Science of Human History in Jena, Germany, argues that our Homo sapiens ancestors
set themselves apart by developing a new ecological niche, which they call the generalist
specialist. “Not only could Homo sapiens generalise and expand across the world, but
specific populations could also specialise in certain environments,” says Roberts.
“Together, this allowed our ancestors to thrive in the face of climatic and environmental
variability.”
However, it still isn’t clear how we became the masters of adaptability. Now, Penny
Spikins, an archaeologist at the University of York, UK, has a new explanation. She
thinks that our emotional nature and frailties gave us the edge. “Our emotional
neediness gave us the drive to connect with others,” she says. And expanding our
network made us more resilient, allowing us to flourish in many different environments.
To understand why, we have to turn the clock back around 2 million years to when thesecomplex emotions appear to have emerged, and travel to southern Africa to meet our
ape-like ancestor Australopithecus. Here, we find the earliest known examples of thepossible care for sick or injured hominins, with evidence from the skeletons ofindividuals who lived with bone problems that would have caused pain and disability,
such as a teenage boy with a spinal tumour. “They almost certainly received some levelof help, being given food and protection, to survive with these conditions,” says Spikins,
whose book exploring these ideas, Hidden Depths: The origins of human connection,
will be published next year.

Care in the community
Examples in the archaeological record of caring for fellow hominins increase over timeand are commonplace by the time Neanderthal communities emerge. One Neanderthal
skeleton found in Shanidar cave in Iraq and dated to about 50,000 years ago shows signsof multiple severe injuries, including the loss of the right forearm and hand. But
remarkably, this individual survived for 10 to 15 years after his accident, and was
carefully buried when he died aged between 40 and 50. “His care must have been
extensive,” says Spikins.
This investment in caring brought benefits for the group as well as the individual. “Itallowed humans to hunt dangerous animals whilst living with the consequences interms of injury risks. And it also allowed longer lifespans, enabling grandparents to behttps://www.newscientist.com/article/mg25233625-000-survival-of-the-friendliest-why-homo-sapiens-outlived-other-humans/

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Survival of the friendliest? Why Homo sapiens outlived other humans | New Scientist

2021/11/27 13(22involved in infant care, as well as passing on knowledge and skills,” she says.
Explore key Neanderthal sites with archaeologist Rebecca Wragg-Sykes: On a Discovery Tour ofFranceArchaeological evidence of those benefits becomes increasingly apparent as we getcloser to the present day, showing humans hunting animals larger than themselves andworking together to tackle particularly dangerous beasts, such as woolly rhinoceros,
mammoths and giant Cape buffalo.
But when Homo sapiens emerged, they took these collaborative skills one step further
and began to extensively interact with others outside their own immediate group –something not seen before. Exactly what drove this is unclear, but large swings inclimate in Africa would have made life difficult, and those who collaborated may havebeen more likely to survive. Around 320,000 years ago, in the Olorgesailie basin in what
is now southern Kenya, people began to transfer obsidian – a highly valued volcanic
glass used for spear points – over longer distances, up to 90 kilometres in some cases.
This suggests that interactions were occurring with neighbouring groups. Over time,these long-distance networks expanded. By 30,000 years ago, Stewart and his colleagues
have shown that Homo sapiens in southern Africa were exchanging ostrich eggshellbeads over distances of more than 300 kilometres.
This expansion of our social networks was a significant part of our success, says Chris
Stringer at the Natural History Museum, London. “Interacting with more people allowed
us to acquire behaviours and inventions from neighbouring groups, which may haveaided survival.” By contrast, the Neanderthal’s apparently insular way of life may havecost them dear. Ten wooden throwing spears, excavated from a mine in Schöningen, near
Hannover in Germany, and dated to around 300,000 years ago, would have enabled those
who used them – perhaps early Neanderthals – to hunt big game from a distance. “Youwould assume that such a good invention could never be lost, but maybe within 10,000
years of the Schöningen people living there, the entire area was covered by an ice sheet
and all these humans were gone,” says Stringer. “If these people weren’t part of a muchwider social network then the technology that was special to their group would havedied with them.”“If things had turned out differently, would it be Neanderthals’
ancestors here today?”https://www.newscientist.com/article/mg25233625-000-survival-of-the-friendliest-why-homo-sapiens-outlived-other-humans/

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Survival of the friendliest? Why Homo sapiens outlived other humans | New Scientist

2021/11/27 13(22Not only did such networks allow Homo sapiens to pass knowledge on, but they were an
insurance policy for when times are bad. “If a drastic climate change occurred, thensome populations might struggle, but others living in a different region might thrive,and may have been able to help out their neighbours. This would have allowed us tobecome incredibly resilient,” says Roberts.
He and his colleagues have found evidence for this kind of supporting collaboration in
the dense jungle environments of south Asia, some 50,000 years ago, when Homosapiens first settled this region. These pioneers spread across this challenging
environment with unprecedented speed. The isotope chemistry of bones found deep
within the jungles of Sri Lanka reveal that Homo sapiens inhabited the rainforest all year
round. “They became rainforest specialists, using bow and arrow to hunt monkeys andgiant squirrels,” says Roberts. But artefacts found alongside their bones, such as marine
shell beads and sharks’ teeth, indicate that they also had contact with populations fromcoastal regions. “What you end up with is a beautiful picture of two different
populations – one in the forest and one on the coast – and they are communicating,”says Roberts.
The more we look, the more we see evidence for increased social interaction and wider
networks when Homo sapiens first emerge. But what gave us the courage to interact with
our neighbours in a way not seen in other human lineages? Genomic analysis of a rare
genetic condition known as Williams syndrome has recently shed light on this question.
People with Williams syndrome are often hyper-social – trusting and happy to hug
strangers. The condition is also associated with a range of health risks, including heart
issues, and a distinct physical appearance, including delicate facial features such as
smaller teeth.
The syndrome is caused by small deletions of genetic material, of which one gene –BAZ1B – has been the subject of much research during the past decade. This gene isassociated with the control of neural crest cells, which form the basis for many tissues
during embryonic development and create the adrenal glands that influence ourhormonal response to stressful events. The absence of this gene results in reduced
migration of the cells, providing an explanation for the delicate facial features andhealth issues associated with Williams syndrome, as well as the reduced levels of fear,leading to hyper-social behaviour.
The genetic changes associated with Williams syndrome caught the attention of CedricBoeckx at the Catalan Institution for Research and Advanced Studies in Barcelona,https://www.newscientist.com/article/mg25233625-000-survival-of-the-friendliest-why-homo-sapiens-outlived-other-humans/

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Survival of the friendliest? Why Homo sapiens outlived other humans | New Scientist

2021/11/27 13(22Spain. He wondered if they could help explain why our Homo sapiens ancestors started to
expand their social networks in the past. Working with Giuseppe Testa at the Universityof Milan, Italy, the researchers compared the modern human genome with that of ourclosest relatives, the Neanderthals and Denisovans, and found that BAZ1B had
undergone many more mutations in Homo sapiens, suggesting strong evolutionary
selection pressure for traits associated with this gene. “It gives us a handle on the
direction of genetic change that may have made us more tolerant of strangers,” says
Boeckx.

Compared with Homo erectus (left) and Homo Neanderthalensis (right), Homo sapiens (centre) has more delicate facial features
Natural History Museum, London/Science Photo Library

What’s more, the same mutations may explain why Neanderthals are sometimes
described as looking brutish, with their heavy brow ridges and robust jawline. “As well as
making us less aggressive, these genetic changes seem to result in physical features thatmake us appear less threatening,” says Spikins.
Essentially, it seems that our Homo sapiens ancestors “domesticated” themselves.
Archaeological finds confirm that the softening of our facial features, with thedevelopment of smaller skulls, flatter faces and tinier teeth, starts to occur in our lineage
https://www.newscientist.com/article/mg25233625-000-survival-of-the-friendliest-why-homo-sapiens-outlived-other-humans/

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2021/11/27 13(22around 300,000 years ago.
The question then becomes what effect these changes had. To find out, scientists havelooked at other species that have also undergone similar genetic changes and evolved in
the “friendly” direction, such as bonobos – a highly social ape – and animals that havebeen deliberately domesticated, including dogs, sheep and cows.
Compared with chimpanzees, which haven’t undergone self-domestication, bonobos areless scared of strangers and more willing to share and interact in a positive way withothers at the borders of their territory. Similarly, dogs are more tolerant than wolves ofliving in a group with unrelated animals, and dogs have evolved flatter faces that arecapable of more expression. “Being expressive enables greater communication andmakes you less threatening,” says Spikins.

“Our emotional neediness may have been our trump card during
climate changes”
In the case of Homo sapiens, it appears that we took expressiveness to another level, withthe development of language. “It seems likely that language helped us to maintain oursocial networks and was one of the skills that enabled us to adapt to lots of different
environments,” says Boeckx.
There are, however, downsides to the social traits acquired during our long-running
process of self-domestication. “Becoming more connected and tolerant towards otherpeople gave us greater strength as a community, but our underlying drive to please
others and belong to a group also makes individuals vulnerable to being lonely,
depressed and anxious,” says Spikins.
By 50,000 years ago, Homo sapiens had become well established across Eurasia, having
finally burst successfully out of Africa. Then, between 50,000 and 40,000 years ago, there
seems to have been a crunch, from which the Neanderthals and Denisovans were neverable to recover. There was an intense cooling of the climate and a major volcanic
eruption in Italy around 39,000 years ago, and a reversal of Earth’s magnetic field around
42,000 years ago, which together are thought to have caused major climate changes
around the world.
It is possible that our emotional neediness was our trump card during this difficult
period. “Our drive to connect with others may have helped us to network more widelyand cope better with the immense environmental changes at that time,” says Spikins.
Luck certainly played a part too. Perhaps our emotional skills just happened to be thehttps://www.newscientist.com/article/mg25233625-000-survival-of-the-friendliest-why-homo-sapiens-outlived-other-humans/

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2021/11/27 13(22best tool to navigate this particular challenge. Had the environment been different, it
might have been other types of human that were better equipped to cope. “If things hadturned out differently, for example with a more stable climate, would it be Neanderthals’
ancestors here today?” says Spikins.
As Boeckx says: “The history of humans is full of fits and starts, and we are just looking
at a snapshot of the last time we got lucky.”
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The others
New Scientist audio Many other types of human existed at the same time as us. The best known
are outlined below, but there are likely to be more, as yet undiscovered.
Homo erectus
The first of our ancestors to develop shorter arms and longer legs, and to expand beyond Africa~1.8 million years ago (ya)When: 1.89 million to 110,000 ya
Where: Africa, western and eastern Asia, perhaps Europe
Homo heidelbergensis
The first humans to live in colder climates and routinely hunt large animals. Thought to haveeventually evolved into Homo neanderthalensis in Europe and Homo sapiens in Africa
When: 700,000 to 200,000 ya
Where: Eastern and southern Africa, Europe and possibly Asia
Homo neanderthalensis (Neanderthal)
Shorter and stockier than us, with a protruding brow ridge and brains as large as ours, if notlargerWhen: 400,000 to 40,000 ya
Where: Europe, south-western to central Asia
Denisovan (no formal species name due to lack of fossil material)
Identified in 2010 from DNA in a finger bone found in Siberia. Denisovan populations overlappedand interbred with Neanderthals and Homo sapiens
When: Highly uncertain – at least 300,000 ya to as recent as 15,000 ya
Where: East Asia
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2021/11/27 13(22Where: East Asia
Homo naledi
Discovered in 2013. Displays a mix of ancient and modern human features (small brain, very long
fingers but modern human-like hands and feet). Its anatomy suggests it walked on two legs, but
could climb and hang from trees.
When: 335,000 to 235,000 ya
Where: South Africa
Homo luzonensis
First identified in 2019 from a few bones, this diminutive human has a blend of ancient andmodern features, hinting that it might have been a descendant of an early pre-Homo erectus
dispersal out of Africa.
When: ? to 50,000 ya
Where: The island of Luzon in the Philippines
Homo floresiensis (nickname: the hobbit people)
Discovered in 2003, these small yet capable people, with tiny brains, large teeth, no chin and areceding forehead, used stone tools, hunted small elephants and may have used fire. Theirdiminutive stature might have been a form of island dwarfism, or it could reflect a sharedancestry with Homo luzonensis, from an early wave of small humans that ventured into Asia.
When: 190,000 to 50,000 ya
Where: Flores island, Indonesia

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2021/11/27 13(22Magazine issue 3362 , published 27 November 2021
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