For decades, archaeologists have pored over the spectacular images of stampeding horses and charging bison left by Ice Age artists on European cave walls more than 10,000 years ago. But few researchers have paid much attention to the simple geometric signs that often accompany the art. Unable to interpret or decipher these markings, many archaeologists dismissed them as mere decorations.

Now, paleoanthropologist Genevieve von Petzinger, a Ph.D. student at the University of Victoria in Canada and a National Geographic Emerging Explorer, has conducted a new study of the signs, gleaning fresh clues to their purpose. In a forthcoming book entitled The First Signs, von Petzinger reports that Ice Age Europeans used just 32 distinct types of geometric symbols over a period of 30,000 years, suggesting that the markings were “meant to transmit information”—an early step on humanity’s long road to developing writing.

Von Petzinger, the granddaughter of a World War II codebreaker at Bletchley Park in England, began her study nearly a decade ago. “I was interested in finding patterns in the signs across time and space,” she says. France’s well-dated Ice Age rock art sites seemed the best place to start, so she combed through inventories of the cave paintings and engravings for records of geometric signs. Then she classified the markings by type, entered them in a relational database, and looked for patterns in the data.

View Images Paleoanthropologist Genevieve von Petzinger studied rock art sites across Europe and discovered that Ice Age Europeans employed just 32 distinct geometric sign types from 40,000 to 10,000 years ago. Photograph by D. von Petzinger

The preliminary findings took her by surprise. She thought that the Ice Age artists would begin with just a few sign types and gradually add more symbols to their repertoire over time—a trend towards complexity that other researchers observed in the development of tools. But that didn’t happen in France. Instead, the Canadian researcher found that nearly three-quarters of the sign types were already in use during the Aurignacian period, which lasted from 40,000 to 28,000 years ago. This early complexity didn’t look like the start of a tradition. It suggested instead that the signs’ origins lay somewhere else.

Intrigued, von Petzinger expanded her study to all of Europe, scouring reports of 367 Upper Paleolithic rock art sites from northern Spain to the Ural Mountains in Russia. In addition, she looked for mentions of markings on portable art, such as a deer-tooth necklace found in the grave of an Ice Age woman known as the Lady of St. Germaine-la-Rivière.

Two Weeks Underground

But many of the existing inventories lacked details von Petzinger needed to classify the symbols. So she journeyed to Europe with her photographer-husband Dillon von Petzinger to record signs in 52 rarely visited caves. “We spent the equivalent of two weeks underground,” she says. In the process the pair discovered several previously unnoticed signs.

The resulting study was an eye-opener: She found just 32 types of signs in use across the entire continent during the Upper Paleolithic period. “For there to be this much continuity between sites, I realized that our ancient ancestors had to have a system in place,” she writes. Moreover, the early diversity of geometric signs she had discovered in France was repeated across Europe. This suggested that modern humans had invented these signs long before they arrived in Europe—mostly likely in their African homeland.

View Images Once strung on a necklace, these deer teeth were discovered in the grave of an Ice Age woman who lived nearly 16,000 years ago. The markings on the teeth may have been memory aids to help the owner recite an important tribal story. Photograph by D. von Petzinger

But what exactly was the point of the markings? At a decorated cave known as La Pasiega in Spain, early cave-art researchers discovered a rare sequence of Ice Age signs painted about 12 feet (3.6 meters) above the floor. Arranged in three groups separated by spaces, the markings in La Pasiega resembled a short written message, prompting speculation that the signs formed an early writing system.

Von Petzinger, however, found little evidence to support that idea. By definition, a writing system, she notes, “is the systematic representation of spoken language.” Any idea or thought that a speaker can express verbally can be jotted down or inscribed. But Europe’s cave artists did not have a sufficient number of geometric signs, or did not combine them in the right way, to represent all the words that would have occurred in their language. “We don’t seem to have all the complexities to write a paragraph or a sonnet,” von Petzinger says.

Even so, the Ice Age signs were far from meaningless, she says. Some markings, such as the meandering lines that von Petzinger spotted at a site in Portugal’s Côa Valley region, may have been maplike representations of a river or other landscape features. Other signs, such as the lines inscribed on the deer-tooth necklace, could have served as memory aids for ceremonialists presiding over important rituals or recounting a tribe’s origin stories. Such markings, says von Petzinger, seem to be a way of storing information externally—a form of graphic communication that eventually led to writing.

Paleoanthropologist Ian Tattersall, a curator emeritus at the American Museum of Natural History in New York, finds much value in the new study. “It’s really nice to see the abstract symbolism brought to the fore,” he says. “We have these wonderful animal images in caves like Chauvet and so forth, but that is just the tip of it. The symbolic stuff clearly had meaning.”

Other researchers think von Petzinger’s research will likely spur new interest in a neglected subject. “It will make people think about the signs all over again, and the extent of the record of signs will awaken people’s interest,” says Louise Leakey, a paleoanthropologist at the Turkana Basin Institute in Nairobi, Kenya.

Certainly von Petzinger would welcome more archaeologists in this field of research, as she’s convinced there is a lot to be learned.