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Neandertals Adorned with Feathers, Thinking Symbolically September 22, 2012

Posted by Nina Rosenstand in Nina Rosenstand's Posts, Philosophy of Human Nature, Science.
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Here is a wonderful example of why I, as a philosopher, have a passion for every bit of new info and speculation coming out about human evolution. To me there is no deeper philosophical question than the one about human identity: Who are we? Who were we? And how do we differ from those who are our close relatives today (the apes), and who were our even closer living relatives in the past (now three separate relatively recent groups of hominins coexisting with early Homo sapiens: the Neandertals, the Denisovans, and the elusive “Hobbits”, Homo floresiensis)? The categories we used to indicate our human extraordinary nature have been steadily challenged in the last decades. We used to be the only tool users. Then, because we found that apes (and birds) use tools, too, we became the only tool makers. But apes and birds make tools, too. So we became the only rational species. Ah, but now it turns out that many other species are quite capable of basic reasoning. Then we were the only species that has self-recognition. But so do apes, dolphins, elephants, ravens, magpies, pigs, and maybe even (if we are to believe the very latest findings) all big-brained, social species. But aren’t we at least the only ones who deliberately create art, and use body decorations? Because a brain that can conceive of art and decorations is capable of thinking symbolically. As late as ten years ago the great anthropologist Ian Tattersall claimed that humans were the only ones with the capacity for symbolic thinking. The Neandertals, with their big brains, still didn’t count as a self-aware species because they didn’t have symbolic thinking. Well, according to Scientific American blogger Kate Wong, they did:

Experts agree that Neandertals hunted large game, controlled fire, wore animal furs and made stone tools. But whether they also engaged in activities deemed to be more advanced has been a matter of heated debate. Some researchers have argued that Neandertals lacked the know-how to effectively exploit small prey, such as birds, and that they did not routinely express themselves through language and other symbolic behaviors. Such shortcomings put the Neandertals at a distinct disadvantage when anatomically modern humans availed of these skills invaded Europe—which was a Neandertal stronghold for hundreds of thousands of years—and presumably began competing with them, so the story goes.

Over the past couple decades hints that Neandertals were savvier than previously thought have surfaced, however. Pigment stains on shells from Spain suggest they painted, pierced animal teeth from France are by all appearances Neandertal pendants. The list goes on. Yet in all of these cases skeptics have cautioned that the evidence is scant and does not establish that such sophistication was an integral part of the Neandertal gestalt.

But now some new results have come in: Neandertals, across the entire western Eurasia, wore feathers they harvested from birds of prey—in particular black feathers.

Exactly what the Neandertals were doing with the feathers is unknown, but because they specifically sought out birds with dark plumage, the researchers suspect that our kissing cousins were festooning themselves with the resplendent flight feathers. Not only are feathers beautiful, they are also lightweight, which makes them ideal for decoration, Finlayson points out. “We don’t think it’s a coincidence that so many modern human cultures across the world have used them.”

Speakers at a conference on human evolution held in Gibraltar last week extolled the study, and agreed with the team’s interpretation of the remains as evidence that Neandertals adorned themselves with the feathers as opposed to using them for some strictly utilitarian purpose. If the cutmarked bones from Gibraltar had been found in association with early modern humans, researchers would assume that the feathers were symbolic, says paleoanthropologist John Hawks of the University of Wisconsin notes. The same standards should apply to Neandertals. “We’ve got to now say that Neandertals were using birds. Period. They were using them a lot. They were wearing around their feathers,” he comments. “They clearly cared. A purely utilitarian kind of person does not put on a feathered headdress.”

So. The Neandertals had symbolic thinking after all. (And those researchers who pointed out, over ten years ago, that the jewelry found in Neandertal archeological sites would indicate as much, as well as the little fact that they buried their dead, they can now feel vindicated.) And how far back in time did the symbolic, self-aware thinking originate?

 

“[This] is something many of us thought was unique to Homo sapiens,” [John] Shea adds. “But [it] turns out to be either convergently evolved with Neandertals or more likely something phylogenetically ancient we simply haven’t picked up in the more ancient archaeological record. It’s probably something [our common ancestor] Homo heidelbergensis did, we just haven’t found archaeological evidence for it yet.”

Homo heidelbergensis. At least 500,000 years ago. So we are not unique in our symbolic thinking. Now that doesn’t mean humans are not exceptional. Of course we are. We have managed to extend our influence and interest into space (literally), and time, by our research and imagination, reaching into the dim past as well as affecting and imagining possible futures. We can leave our legacy through our languages, our imagery (provided it doesn’t all go digital and disappears), our artifacts, our music, our buildings (and also the strip mines, the polluted lakes, the mass graves of discarded civilians, and all the other less wonderful stuff that is part of human history). Our reach, for better and for worse, is far greater than the other social animals on this planet. But the point is, it now seems to be fundamentally a matter of degree, not of a radically different kind.  

So Did or Did We Not Interbreed with Neandertals? August 26, 2011

Posted by Nina Rosenstand in Nina Rosenstand's Posts, Philosophy of Human Nature, Science.
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Back on the perch, folks–time for a new season of occasional insights or at least sharing of interesting stories from the web!

Only last week I watched another show in a long line of mocumentaries/supposedly nonfictional shows with a good deal of play-acting about Neandertals and early humans, the Cro-Magnons. I’m a sucker for those. I love to see human actors in some kind of crude make-up depicting the latest ideas of what our closest relatives ever on this planet may have looked and acted like. I also love to see the scientists act in front of the camera, in fairly minimal make-up. But I was surprised to see that the scientists interviewed came down massively against the idea that there might be Neandertal DNA in the human gene pool—after all, in 2010, after the Neandertal genome was decoded, researcher at the Max Planck Institite Svante Paabo was quoted as saying that 1-4 percent of genetic material in the human population that left African around 60,000 years ago came from sexual encounters with Neandertals. So why the categorical denial? Of course it could have been a dated show, but my impression was that it was recent. The fact that the show was centered around renowned paleoanthropologist Ian Tattersall could have had something to do with it—he has, for years, argued that (1) there is in all likelihood no genetic connection between living humans and Neandertals, and (2) Neandertals probably couldn’t speak or even think rationally because they lacked symbolic thinking. (The fact that crude jewelry has been found among Neandertal remains apparently hasn’t been enough to change his mind, although philosophically I’d have to say that deliberately adorning oneself with body art/ornaments shows some kind of symbolic thought, and their brain and throat structures do not exclude the power of speech.) Otherwise the show had interesting moments, such as floating the theory that perhaps Cro-Magnons didn’t actually exterminate the Neandertals by force, but by transferring diseases to them to which they had no immunity, much like it happened to the American Indian population in the 19th century.

And then we have the news, now quoted and tweeted all over cyberspace, that it seems that we—at least the descendants of those who migrated out of Africa—have Neandertal DNA in our genes after all! And it may have helped us become the extraordinarily successful species that we are (at least in the short term–who knows how long we’ll last?) by adding an immunity boost to our constitution. That, and possible interbreeding with that mysterious new-found Siberian hominin species the Denisovans may have secured our survival:

Indeed, DNA inherited from Neanderthals and newly discovered hominids dubbed the Denisovans has contributed to key types of immune genes still present among populations in Europe, Asia and Oceania. And scientists speculate that these gene variants must have been highly beneficial to modern humans, helping them thrive as they migrated throughout the world.

This DNA has had “a very profound functional impact in the immune systems of modern humans,” said study first author Laurent Abi-Rached, a postdoctoral researcher in the lab of senior author Peter Parham of the Stanford University School of Medicine.

From the analysis, the scientists estimated, for example, that more than half of the genetic variants in one HLA gene in Europeans could be traced to Neanderthal or Denisovan DNA. For Asians, that proportion was more than 70%; in people from Papua New Guinea, it was as much as 95%.

“We expected we’d see some, but the extent that these contributed to the modern [genomes] is stunning,” Abi-Rached said of the findings, released Thursday by the journal Science.

Though the researchers haven’t proved it, the vast reach of these gene variants in people today suggests that they probably gave some early modern humans an advantage over others, he said.

Our ancestors’ HLA systems may have been perfectly tailored for Africa but naive to bacteria, viruses and parasites that existed in Europe or Asia, rendering them susceptible to disease.

Mating and mixing their genomes with those of their Neanderthal and Denisovan relatives could have been a speedy way to set up their immune systems to combat new, unencountered threats.

What is philosophically interesting from the point of view of speculations about human nature (philosophical anthropology) is not so much whether we slept with Neandertals or not. My own hunch is that we did interbreed and created viable offspring, but like I posted in an earlier blog entry, it was probably because of hunters raping women of the other species rather than nice, romantic interspecies marriages. What is philosophically interesting is our reaction to these theories: Why is it so important for some people to see it verified that we didn’t interbreed? And what makes it so vital for others that we did? I’m not saying that the scientists work out theories that fit their preferred view, but many laypeople (such as myself) who follow these stories have usually taken sides. Can this be boiled down to on the one hand a wish to keep human nature separate and special, and on the other hand a wish to see us closely related to all life on this planet? Competing visions of exclusivity vs. inclusivity? And where will such visions take us? Just remember Kennewick Man and the battle over his origins: Was he an early European, an American Indian ancestor, or perhaps a visitor from Asia? Each explanation carries its own political slant. Ask yourself, in your heart, would you rather that humans who migrated out of Africa were distantly related to Neandertals, or would you rather they/we weren’t? And then ask yourself, Why?