The unexpected sophistication of Neanderthals

Discover reports: Circular structures discovered in a French cave continue to build the case that Neanderthals were more intelligent than we give them credit for.

Deep inside the Bruniquel Cave, researchers discovered two rings of stalactites and stalagmites that appeared to have been deliberately stacked and arranged to form a structure. The site also contained charred animal bones, which may have served as torches to illuminate the dark depths of the cave or keep bears at bay. The thing is, a new dating analysis suggests these structures were built more than 170,000 years ago, long before Homo sapiens arrived in the area. That means Neanderthals were the likely architects, and we didn’t expect them to be such adept builders and cave explorers.

The structures in Bruniquel were first discovered in 1990 and dated at the time to roughly 50,000 years ago based on carbon dating techniques. However, in 2013, Sophie Verheyden of the Royal Belgian Institute of Natural Sciences conducted a new study, drilling into the stalactites and stalagmites to measure differences between layers of rock that accumulated before and after they were felled. Her analysis, published Wednesday in Nature, revealed an astounding age of roughly 176,500 years, more than three times the previous estimate. By contrast, the oldest known human cave art is only around 42,000 years old. [Continue reading…]

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Rules of the underworld

Katherine Hirschfeld writes: In March 2013, a drug cartel staged a grisly tableau near a central plaza in Uruapan, Mexico. Seven dead and mutilated bodies were left sitting upright in plastic chairs. Two had crudely lettered signs pinned to their chests with ice picks that read, “Warning, this is going to happen to all muggers, pickpockets, thieves of cars, homes, and walkers — as well as kidnappers, rapists, and extortionists.” Photos found their way to CNN and other media outlets in the United States and Europe. (You may view them here if you are brave.)

Those who inhabit the upper world — law-abiding citizens who enjoy the rights and protections of government — instinctively turn away from such images of horrific violence. Not only are the photos disturbing to look at, they don’t make sense. Why would a drug cartel go to such lengths to issue a proclamation against thievery? Drug cartels are not law-abiding organizations, so why arrange a display of dead bodies with ice picks and cardboard signs in order to declare rules?

The scene at Uruapan contains a message from the underworld — the subterranean organized crime groups that control much of the world’s traffic in illicit commodities. Criminal organizations often communicate through the bodies of the dead, and we should not look away just yet, because their message contains a warning for all of us.

What the bodies in Uruapan tell us is that underworld groups are law-and-order organizations, but their laws and their order are not the same as those of the upper world. We know this because the intrepid journalists, human rights activists, and forensic anthropologists who have crossed over to explore specific examples of the global underworld have brought back stories that reveal common themes. Criminal groups may be culturally or geographically distinct, but they operate with similar rules.

The primary rule of the underworld is that the cartel (or the mafia or the warlord) makes the rules, and disobedience is a capital crime. Public displays of death convey the cartel’s power to impose the kind of lethal punishment typically reserved for the state. The public setting in Uruapan symbolizes that the Mexican government no longer has jurisdiction over matters of criminal justice in this municipality. Through these practices, the cartel reanimates the dead and compels them to speak to the living one last time: “Obey, or you will end up like us.” [Continue reading…]

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New evidence that humans settled in southeastern U.S. far earlier than previously believed

Phys.org reports: The discovery of stone tools found in a Florida river show that humans settled the southeastern United States far earlier than previously believed — perhaps by as much as 1,500 years, according to a team of scientists that includes a University of Michigan paleontologist.

Michael Waters of Texas A&M University and Jessi Halligan of Florida State University led a research team that also included U-M’s Daniel Fisher and scientists from the University of Minnesota, University of Texas, University of Arizona, Stafford Research Laboratories in Colorado, Aucilla Research Institute in Florida, and Exeter and Cambridge universities in the United Kingdom.

A report on the team’s findings appears in Science Advances. [Continue reading…]

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‘Nobody knew what you would see on the other side of a mountain’

mt-tam

Carl Zimmer writes: As a boy growing up in Denmark, Eske Willerslev could not wait to leave Gentofte, his suburban hometown. As soon as he was old enough, he would strike out for the Arctic wilderness.

His twin brother, Rane, shared his obsession. On vacations, they retreated to the woods to teach themselves survival skills. Their first journey would be to Siberia, the Willerslev twins decided. They would make contact with a mysterious group of people called the Yukaghir, who supposedly lived on nothing but elk and moose.

When the Willerslev twins reached 18, they made good on their promise. They were soon paddling a canoe up remote Siberian rivers.

“Nobody knew what you would see on the other side of a mountain,” said Eske Willerslev, who is now 44. “There were villages on the maps, and you wouldn’t even see a trace of them.”

Dr. Willerslev spent much of the next four years in Siberia, hunting moose, traveling across empty tundra and meeting the Yukaghirs and other people of the region. The experience left him wondering about the history of ethnic groups, about how people spread across the planet.

A quarter of a century later, Dr. Willerslev is still asking those questions, but now he’s getting some eye-opening answers.

As the director of the Center for GeoGenetics at the University of Copenhagen, Dr. Willerslev uses ancient DNA to reconstruct the past 50,000 years of human history. The findings have enriched our understanding of prehistory, shedding light on human development with evidence that can’t be found in pottery shards or studies of living cultures. [Continue reading…]

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Animals are us

elephant

Tania Lombrozo writes: Researchers have studied how people think about humans in relation to the natural world, and how the way we reason about humans and other animals changes over the course of development and as a function of education and culture.

The findings from this body of work suggest that by age 5, Western children growing up in urban environments are anomalous in the extent to which they regard humans as central to the biological world. Much of the rest of the world — including 3-year-olds, 5-year-olds in rural environments and adults from indigenous populations in South America — are more inclined to think about humans as one animal species among others, at least when it comes to reasoning about the properties that human and non-human animals are likely to possess.

To illustrate, consider a study by Patricia Herrmann, Sandra Waxman and Douglas Medin published in the Proceedings of the National Academy of Sciences in 2010. In one experiment, 64 urban children, aged 3 or 5, were asked a series of questions that assessed their willingness to generalize an unknown property from one object to another. For instance, they might be told that people “have andro inside,” and would then have to guess whether it’s right or wrong to say that dogs “have andro inside.”

The findings with 5-year-olds replicated classic work in developmental psychology and suggested a strong “anthropocentric” bias: The children were more likely to generalize from humans to non-humans than the other way around, consistent with a privileged place for humans in the biological world. The 3-year-olds, by contrast, showed no signs of this bias: They generalized from humans to non-humans and from non-humans to humans in just the same way. These findings suggest that an anthropocentric perspective isn’t a necessary starting point for human reasoning about the biological world, but rather a perspective we acquire through experience.

So what happens between the ages of 3 and 5 to induce an anthropocentric bias?

Perhaps surprisingly, one influence seems to be anthropomorphism in storybooks. [Continue reading…]

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Half of your friends probably don’t think of you as a friend — but don’t be sad

Cari Romm writes: Here’s a fun exercise: Take a minute and count up all your friends. Not just the close ones, or the ones you’ve seen recently — I mean every single person on this Earth that you consider a pal.

Got a number in your mind? Good. Now cut it in half.

Okay, yes, “fun” may have been a bit of a reach there. But this new, smaller number may actually be more accurate. As it turns out, we can be pretty terrible at knowing who our friends are: In what may be among the saddest pieces of social-psychology research published in quite some time, a study in the journal PLoS One recently made the case that as many as half the people we consider our friends don’t feel the same way. [Continue reading…]

Let’s suspend any questions about the validity of this research finding (even though a lot of scientific papers these days do seem more geared towards grabbing social media attention than the advance of knowledge) and let’s consider instead whether this should indeed be a cause of sadness.

If it turns out that most of us have half as many friends as we imagine, that sounds like a strong reason for an unwelcome boost in self-doubt and insecurity.

If our friends are the people we trust, does this mean that a lot of our trust is misplaced?

Maybe — but that’s not as bad as it sounds.

Trust is a gamble. If we actually had no doubt and could reliably know who was a friend and who was not, there would be no need for trust.

Trust is a relationship with the unknown, and since it’s inevitably going to extend too far or not far enough, it seems that human beings as social creatures are built to trust more rather than less.

So this proclivity to imagine our net of friendships extends further than it really does, is probably less a reason for sadness than reason to be glad that for most people, trust is stronger than fear.

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Humans paid for bigger brains with energy-hungry bodies

Ed Yong writes: Evolution works on a strict energy budget. Each adaptation burns through a certain number of calories, and each individual can only acquire so many calories in the course of a day. You can’t have flapping wings and a huge body and venom and fast legs and a big brain. If you want to expand some departments, you need to make cuts in others. That’s why, for example, animals that reproduce faster tend to die earlier. They divert energy towards making new bodies, and away from maintaining their own.

But humans, on the face of it, are exceptional. Compared to other apes, we reproduce more often (or, at least, those of us in traditional societies do) and our babies are bigger when they’re born and we live longer. And, as if to show off, our brains are much larger, and these huge organs sap some 20 percent of our total energy.

“We tend to have our cake and eat it too,” says Herman Pontzer from Hunter College. “These traits that make us human are all energetically costly. And until now, we didn’t really understand how we were fueling them.” [Continue reading…]

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What I learned from tickling apes

chimp

Frans de Waal writes: Tickling a juvenile chimpanzee is a lot like tickling a child. The ape has the same sensitive spots: under the armpits, on the side, in the belly. He opens his mouth wide, lips relaxed, panting audibly in the same “huh-huh-huh” rhythm of inhalation and exhalation as human laughter. The similarity makes it hard not to giggle yourself.

The ape also shows the same ambivalence as a child. He pushes your tickling fingers away and tries to escape, but as soon as you stop he comes back for more, putting his belly right in front of you. At this point, you need only to point to a tickling spot, not even touching it, and he will throw another fit of laughter.

Laughter? Now wait a minute! A real scientist should avoid any and all anthropomorphism, which is why hard-nosed colleagues often ask us to change our terminology. Why not call the ape’s reaction something neutral, like, say, vocalized panting? That way we avoid confusion between the human and the animal.

The term anthropomorphism, which means “human form,” comes from the Greek philosopher Xenophanes, who protested in the fifth century B.C. against Homer’s poetry because it described the gods as though they looked human. Xenophanes mocked this assumption, reportedly saying that if horses had hands they would “draw their gods like horses.” Nowadays the term has a broader meaning. It is typically used to censure the attribution of humanlike traits and experiences to other species. Animals don’t have “sex,” but engage in breeding behavior. They don’t have “friends,” but favorite affiliation partners.

Given how partial our species is to intellectual distinctions, we apply such linguistic castrations even more vigorously in the cognitive domain. By explaining the smartness of animals either as a product of instinct or simple learning, we have kept human cognition on its pedestal under the guise of being scientific. [Continue reading…]

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In order for our minds to go beyond syntax to semantics, we need feelings

tufted-capuchin-monkey

Stephen T Asma writes: After you spend time with wild animals in the primal ecosystem where our big brains first grew, you have to chuckle a bit at the reigning view of the mind as a computer. Most cognitive scientists, from the logician Alan Turing to the psychologist James Lloyd McClelland, have been narrowly focused on linguistic thought, ignoring the whole embodied organism. They see the mind as a Boolean algebra binary system of 1 or 0, ‘on’ or ‘off’. This has been methodologically useful, and certainly productive for the artifical intelligence we use in our digital technology, but it merely mimics the biological mind. Computer ‘intelligence’ might be impressive, but it is an impersonation of biological intelligence. The ‘wet’ biological mind is embodied in the squishy, organic machinery of our emotional systems — where action-patterns are triggered when chemical cascades cross volumetric tipping points.

Neuroscience has begun to correct the computational model by showing how our rational, linguistic mind depends on the ancient limbic brain, where emotions hold sway and social skills dominate. In fact, the cognitive mind works only when emotions preferentially tilt our deliberations. The neuroscientist Antonio Damasio worked with patients who had damage in the communication system between the cognitive and emotional brain. The subjects could compute all the informational aspects of a decision in detail, but they couldn’t actually commit to anything. Without clear limbic values (that is, feelings), Damasio’s patients couldn’t decide their own social calendars, prioritise jobs at work, or even make decisions in their own best interest. Our rational mind is truly embodied, and without this emotional embodiment we have no preferences. In order for our minds to go beyond syntax to semantics, we need feelings. And our ancestral minds were rich in feelings before they were adept in computations.

Our neo-cortex mushroomed to its current size less than one million years ago. That’s a very recent development when we remember that the human clade or group broke off from the great apes in Africa 7 million years ago. That future-looking, tool-wielding, symbol-juggling cortex grew on top of the limbic system. Older still is the reptile brain — the storehouse of innate motivational instincts such as pain-avoidance, exploration, hunger, lust, aggression and so on. Walking around (very carefully) on the Serengeti is like visiting the nursery of our own mind. [Continue reading…]

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‘Hobbits’ may have died out before the arrival of humans

Science News reports: Hobbits disappeared from their island home nearly 40,000 years earlier than previously thought, new evidence suggests.

This revised timeline doesn’t erase uncertainty about the evolutionary origins of these controversial Indonesian hominids. Nor will the new evidence resolve a dispute about whether hobbits represent a new species, Homo floresiensis, or were small-bodied Homo sapiens.

Hobbits vanished about 50,000 years ago at Liang Bua Cave on Flores, an island situated between Borneo and Australia’s northern coast, say archaeologist Thomas Sutikna of the University of Wollongong, Australia, and his colleagues.

Cave sediment dating to about 12,000 years ago, which lies just above soil that yielded H. floresiensis remains, provided an initial estimate of when these diminutive hominids with chimp-sized brains died out. But that sediment washed into the cave long after H. floresiensis was gone, covering much older, hobbit-bearing soil, the researchers report in the March 31 Nature. [Continue reading…]

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How the tribal warfare of our ancestors explains the rise of ISIS

ISIS-catwalk

Luke Glowacki writes: Humans are hard-wired to adopt their communities’ norms, and these norms can include rules for how to treat others — including whether to tolerate differences or attack outsiders. When norms provide status, material rewards or membership in a privileged group, they become even more potent.

Cultures are able to hijack this psychology for violent ends by providing status, promises of an afterlife and a sense of meaning. People belonging to communities that advocate violence will adopt norms of violence, whether those communities are tribal societies, neighbors and family, or Facebook friends. Cross-cultural research I’ve conducted shows that the most important predictor of warfare in a society is a cultural system that awards warriors with social benefits.

In East Africa, where groups battle each other for livestock, access to grazing lands and water, conflicts are fought with modern weapons such as AK-47s but occur along tribal borders and resemble the dynamics of ancestral warfare in important ways. Access to resources such as livestock and water can be critical for a group’s survival, and so these cultures award status and livestock to successful warriors. Such warriors are able to marry more wives and have more children than other men. Half a world away, in the Venezuelan Amazon, researchers found that warriors also ended up better off than non-warriors. Over the time scales at which humans and cultures evolve, benefits such as these may have had profound significance in the development of human behavior.

Such incentives help explain how people can be lured into supporting the Islamic State. The group promises its recruits prestige, a sense of community and the possibility of glory — the same types of incentives that cultures across the globe have historically used to motivate youth to take up arms. [Continue reading…]

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What makes fighters risk their lives?

Harvey Whithouse writes: Misrata, Libya, 2011. I am ushered into the boardroom of what was once an oil investment corporation. I am surrounded by youths with Kalashnikovs. On the other side of the table are several of Libya’s most respected rebel leaders, foremost among them Salim Jawha, a former colonel in Muammar Gaddafi’s army who defected on the first day of the revolution.

In the preceding months, over 1,000 rebels have been killed and many thousands more horrifically injured. Stories of heroism are commonplace. For example, on March 6, Gaddafi’s forces — supported by seven tanks and some 25 or so vehicles with mounted machine guns — attempted to re-take the city but were ambushed and overcome by rebels. Despite the imbalance of military hardware and heavy loss of life, the rebels prevailed through astonishing courage and determination.

I’m here because I want to know what motivated thousands of civilians, most of whom had never even held a gun before, to take up arms as part of a popular uprising in which death was far likelier than victory. A more general version of this question has been guiding my research for some years, in my work with a wide variety of military groups ranging from tribal warriors in the rainforests of Papua New Guinea to highly trained soldiers in the British special forces and Royal Marines. One of the themes that continually surfaces in these conversations is that fighters don’t put their lives on the line for abstract values like “king and country” or “God, freedom, and democracy.” They do it for each other.

At the University of Oxford, I lead an international network of researchers dedicated to understanding what makes bonds so strong that people will fight and die for the group when it is threatened. Our research suggests that one of the most powerful causes of extreme pro-group action is the sharing of self-defining experiences. If so, this has profound implications for the way we should approach conflict resolution and counter-terrorism. Public debate and policymaking has been dominated for years by the view that extreme beliefs are what motivate extreme behaviors. I disagree — but with such a tide of popular opinion against me, I need evidence not only from the laboratory or even from the assault course and training camp, but also from the frontlines. This has brought me to Libya. [Continue reading…]

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Slaughter at the bridge: Uncovering a colossal Bronze Age battle

Andrew Curry reports: About 3200 years ago, two armies clashed at a river crossing near the Baltic Sea. The confrontation can’t be found in any history books — the written word didn’t become common in these parts for another 2000 years — but this was no skirmish between local clans. Thousands of warriors came together in a brutal struggle, perhaps fought on a single day, using weapons crafted from wood, flint, and bronze, a metal that was then the height of military technology.

Struggling to find solid footing on the banks of the Tollense River, a narrow ribbon of water that flows through the marshes of northern Germany toward the Baltic Sea, the armies fought hand-to-hand, maiming and killing with war clubs, spears, swords, and knives. Bronze- and flint-tipped arrows were loosed at close range, piercing skulls and lodging deep into the bones of young men. Horses belonging to high-ranking warriors crumpled into the muck, fatally speared. Not everyone stood their ground in the melee: Some warriors broke and ran, and were struck down from behind.

When the fighting was through, hundreds lay dead, littering the swampy valley. Some bodies were stripped of their valuables and left bobbing in shallow ponds; others sank to the bottom, protected from plundering by a meter or two of water. Peat slowly settled over the bones. Within centuries, the entire battle was forgotten. [Continue reading…]

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How we forgot how to feed ourselves

Karen Coates writes: Late in January, I boarded a long-haul flight, 27 hours and 5 minutes, 9,405 miles, three connections. I packed emergency Larabars (food for quick energy), ordered gluten-free meals (a topic for discussion another day), and thought about my meeting with the king of Boti.

Boti is a small kingdom in the Indonesian state of East Nusa Tenggara on the island of Timor. Centuries ago, this region was populated by dozens of small indigenous kingdoms, but most no longer exist in this vast and multicultural republic now united under the flag of Indonesia. Still, the villagers of Boti hold tight to their traditional customs and life from the land: They weave clothes from cotton they grow, and they never wear shoes. They make dishes from coconut shells, bags from banyan roots, candles from nuts, and tools from wood.

In 2002, my husband and I trekked 6 miles through parched, deforested hills, toward the secluded village, to meet the king, who was 96 at the time. He greeted us on his front porch. There, at his home, we were served coffee alongside bananas and sweet potatoes grown on site. The bananas were plump and juicy, not at all mealy or dull. There is a complexity to the flavor of a great banana—plucked fresh—that is experienced only in the tropics, eaten at the origins. So many wonderful bananas never make it to stores in the West.

The king, Ama Nune Benu, sat on a painted wooden chair on his porch, twisting a long root into a rope, as he told us about his way of life. “We are close with the nature,” he said. City folk are not. City folk do not work the land and grow their own food, he told us. “I have 10 fingers. If I use these 10 fingers to get something to eat, I feel better.” Processed, store-bought foods are humanity’s downfall, according to the king. [Continue reading…]

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400,000-year-old fossils from Spain provide earliest genetic evidence of Neandertals

Phys.org reports: Previous analyses of the hominins from Sima de los Huesos in 2013 showed that their maternally inherited mitochondrial DNA was distantly related to Denisovans, extinct relatives of Neandertals in Asia. This was unexpected since their skeletal remains carry Neandertal-derived features. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have since worked on sequencing nuclear DNA from fossils from the cave, a challenging task as the extremely old DNA is degraded to very short fragments. The results now show that the Sima de los Huesos hominins were indeed early Neandertals. Neandertals may have acquired different mitochondrial genomes later, perhaps as the result of gene flow from Africa.

Until now it has been unclear how the 28 400,000-year-old individuals found at the Sima de los Huesos (“pit of bones”) site in Northern Spain were related to Neandertals and Denisovans who lived until about 40,000 years ago. A previous report based on analyses of mitochondrial DNA from one of the specimens suggested a distant relationship to Denisovans, which is in contrast to other archaeological evidence, including morphological features that the Sima de los Huesos hominins shared with Neandertals.

“Sima de los Huesos is currently the only non-permafrost site that allow us to study DNA sequences from the Middle Pleistocene, the time period preceding 125,000 years ago”, says Matthias Meyer of the Max Planck Institute for Evolutionary Anthropology, lead author of an article that was published in Nature today. “The recovery of a small part of the nuclear genome from the Sima de los Huesos hominins is not just the result of our continuous efforts in pushing for more sensitive sample isolation and genome sequencing technologies”, Meyer adds. “This work would have been much more difficult without the special care that was taken during excavation.” [Continue reading…]

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