The 32 symbols of Europe caves

 There's something about caves -- a shadowy opening in a limestonecliff that draws you in. As you pass through the portalbetween light and dark, you enter a subterranean world -- a place of perpetual gloom,of earthy smells, of hushed silence. Long ago in Europe, ancient people also enteredthese underground worlds. As witness to their passage, they left behind mysteriousengravings and paintings, like this panel of humans, trianglesand zigzags from Ojo Guareña in Spain. 

You now walk the same pathas these early artists. And in this surreal, otherworldly place, it's almost possible to imagine that you hear the muffled footfallof skin boots on soft earth, or that you see the flickering of a torcharound the next bend. When I'm in a cave, I often find myself wonderingwhat drove these people to go so deep to brave dangerous and narrowpassageways to leave .

In Spain, we found a seriesof red paintings on a ceiling in a previously unexploredsection of the cave. As we crawled forward, military-style,with the ceiling getting ever lower, we finally got to a pointwhere the ceiling was so low that my husbandand project photographer, Dylan, could no longer achieve focuson the ceiling with his DSLR camera. So while he filmed me, I kept following the trail of red paintwith a single light and a point-and-shoot camerathat we kept for that type of occasion. Half a kilometer underground. 

Seriously. What was somebody doing down therewith a torch or a stone lamp? (Laughter) I mean -- me, it makes sense, right? But you know, this is the kind of question thatI'm trying to answer with my research. I study some of the oldestart in the world. It was created by theseearly artists in Europe, between 10,000 and 40,000 years ago. And the thing is that I'm not just studying itbecause it's beautiful, though some of it certainly is.

 But what I'm interested inis the development of the modern mind, of the evolution of creativity,of imagination, of abstract thought, about what it means to be human. While all species communicatein one way or another, only we humans have reallytaken it to another level. Our desire and abilityto share and collaborate has been a huge part of our success story. Our modern world is based on a globalnetwork of information exchange made possible, in large part,by our ability to communicate -- in particular, using graphicor written forms of communication.

 The thing is, though, that we've been buildingon the mental achievements of those that came before us for so long that it's easy to forget that certainabilities haven't already existed. It's one of the thingsI find most fascinating about studying our deep history. Those people didn't have the shouldersof any giants to stand on. They were the original shoulders. And while a surprising numberof important inventions come out of that distant time, what I want to talk to you about todayis the invention of graphic communication. There are threemain types of communication, spoken, gestural --so things like sign language -- and graphic communication.

 Spoken and gestural areby their very nature ephemeral. It requires close contactfor a message to be sent and received. And after the momentof transmission, it's gone forever. Graphic communication, on the other hand,decouples that relationship. And with its invention,it became possible for the first time for a message to betransmitted and preserved beyond a single moment in place and time. Europe is one of the first places that we start to see graphic marksregularly appearing in caves, rock sheltersand even a few surviving open-air sites. But this is not the Europe we know today. This was a world dominatedby towering ice sheets, three to four kilometers high, with sweeping grass plainsand frozen tundra. 

This was the Ice Age. Over the last century, more than 350 Ice Age rock art siteshave been found across the continent, decorated with animals, abstract shapesand even the occasional human like these engraved figuresfrom Grotta dell'Addaura in Sicily. They provide us with a rare glimpse into the creative world and imaginationof these early artists. Since their discovery, it's been the animals that have receivedthe majority of the study like this black horsefrom Cullalvera in Spain, or this unusual purple bisonfrom La Pasiega. 

But for me, it was the abstract shapes,what we call geometric signs, that drew me to study the art. The funny this is that at most sites the geometric signs far outnumberthe animal and human images. But when I started on this back in 2007, there wasn't even a definitive listof how many shapes there were, nor was there a strong sense of whether the same onesappeared across space or time. Before I could evenget started on my questions, my first step was to compile a database of all known geometric signsfrom all of the rock art sites. The problem was that while they werewell documented at some sites, usually the oneswith the very nice animals, there was also a large number of themwhere it was very vague -- there wasn't a lotof description or detail. 

Some of them hadn't been visitedin half a century or more. These were the onesthat I targeted for my field work. Over the course of two years, my faithful husband Dylan and Ieach spent over 300 hours underground, hiking, crawling and wrigglingaround 52 sites in France, Spain, Portugal and Sicily. And it was totally worth it. We found new, undocumented geometric signsat 75 percent of the sites we visited. This is the level of accuracyI knew I was going to need if I wanted to start answeringthose larger questions. So let's get to those answers. Barring a handful of outliers,there are only 32 geometric signs. 

Only 32 signs across a 30,000-year time spanand the entire continent of Europe. That is a very small number. Now, if these were randomdoodles or decorations, we would expect to seea lot more variation, but instead what we findare the same signs repeating across both space and time. Some signs start out strong,before losing popularity and vanishing, while other signs are later inventions. But 65 percent of those signs stayedin use during that entire time period -- things like lines, rectanglestriangles, ovals and circles like we see herefrom the end of the Ice Age, at a 10,000-year-old sitehigh in the Pyrenees Mountains. 

And while certain signsspan thousands of kilometers, other signs had much morerestricted distribution patterns, with some being limitedto a single territory, like we see herewith these divided rectangles that are only found in northern Spain, and which some researchers have speculated could be some sortof family or clan signs. On a side note, there is surprising degreeof similarity in the earliest rock art found all the way from France and Spainto Indonesia and Australia. With many of the same signsappearing in such far-flung places, especially in that 30,000to 40,000-year range, it's starting to seem increasingly likely that this invention actually traces backto a common point of origin in Africa. 

But that I'm afraid,is a subject for a future talk. So back to the matter at hand. There could be no doubt that these signswere meaningful to their creators, like these 25,000-year-oldbas-relief sculptures from La Roque de Venasque in France. We might not know what they meant,but the people of the time certainly did. The repetition of the same signs,for so long, and at so many sites tells us that the artistswere making intentional choices. If we're talking about geometric shapes, with specific, culturally recognized,agreed-upon meanings, than we could very well be looking at one of the oldest systemsof graphic communication in the world. I'm not talking about writing yet. There's just not enoughcharacters at this point to have represented all of the wordsin the spoken language, something which is a requirementfor a full writing system. 

Nor do we see the signsrepeating regularly enough to suggest that they weresome sort of alphabet. But what we do haveare some intriguing one-offs, like this panel from La Pasiega in Spain,known as "The Inscription," with its symmetrical markings on the left, possible stylized representationsof hands in the middle, and what looks a bitlike a bracket on the right. The oldest systems of graphiccommunication in the world -- Sumerian cuneiform, Egyptian hieroglyphs,the earliest Chinese script, all emerged between 4,000and 5,000 years ago, with each coming into existencefrom an earlier protosystem made up of counting marksand pictographic representations, where the meaningand the image were the same. 

So a picture of a bird would reallyhave represented that animal. It's only later that we start to seethese pictographs become more stylized, until they almost become unrecognizable and that we also start to seemore symbols being invented to represent all those othermissing words in language -- things like pronouns, adverbs, adjectives. So knowing all this, it seems highly unlikely thatthe geometric signs from Ice Age Europe were truly abstract written characters. Instead, what's much more likely is that these early artistswere also making counting marks, maybe like this row of linesfrom Riparo di Za Minic in Sicily, as well as creatingstylized representations of things from the world around them. Could some of the signsbe weaponry or housing? 

Or what about celestial objectslike star constellations? Or maybe even rivers, mountains,trees -- landscape features, possibly like this black penniformsurrounded by strange bell-shaped signs from the site of El Castillo in Spain. The term penniformmeans "feather-shaped" in Latin, but could this actually bea depiction of a plant or a tree? Some researchers have begunto ask these questions about certain signs at specific sites, but I believe the time has cometo revisit this category as a whole. The irony in all of this, of course, is that having just carefully classifiedall of the signs into a single category, I have a feeling that my next stepwill involve breaking it back apart as different types of imageryare identified and separated off. 

Now don't get me wrong, the later creationof fully developed writing was an impressive feat in its own right. But it's important to remember that those early writing systemsdidn't come out of a vacuum. And that even 5,000 years ago, people were already buildingon something much older, with its origins stretching backtens of thousands of years -- to the geometric signsof Ice Age Europe and far beyond, to that point, deepin our collective history, when someone first came up with the ideaof making a graphic mark, and forever changed the natureof how we communicate. Thank you.