Ancient cave art reveals origins of symbolic thought

© Christopher Brand

Three years ago, on an expedition to Sulawesi, one of the larger islands in the Indonesia archipelago, the archaeologist Adam Brumm visited a cave decorated with ancient art: mulberry-colored hand stencils and paintings of corpulent pig-deer and midget buffalo, complete with hairlike brush strokes. Squeezing past a giant block of limestone at the cave's entrance, Brumm made his way toward a narrow nook and crawled along it. There, on a section of ceiling less than a foot above his head, he saw ghostly silhouettes of human hands speckled with warty growths of calcite known as "cave popcorn."

A year later, Brumm returned with his colleague Maxime Aubert and a diamond-bladed saw. Aubert specializes in using calcite - which contains trace amounts of steadily decaying radioactive uranium - to determine precise dates for ancient rock art. Researchers had long assumed that Sulawesi's cave paintings were less than 10,000 years old; anything older, the thinking went, would have eroded in the island's humid climate. But Brumm and Aubert's analysis, published in October, revealed that one hand stencil is at least 39,900 years old - the oldest hand stencil on record. A nearby painting of a female pig-deer was estimated to be 35,400 years old, making it one of the most ancient examples of figurative art.

These findings are the latest in a series of discoveries urging researchers to rethink the origins of human creativity and symbolic thought. Homo sapiens began to emigrate from Africa between 60,000 and 125,000 years ago, but did not reach Europe until about 40,000 years ago. It was only there, concluded 20th-century archaeologists, that humans began to think symbolically, to make simple figurines and geometric designs and, eventually, paintings. How else to explain the abundance of Paleolithic art in Europe and the comparatively sparse Stone Age galleries of Africa and Asia?

"There has always been the belief that a light switched on in Europe, and there was this efflorescence of creativity," says Brumm, a research fellow at Griffith University. "That's not the case. On the other side of the world, the same thing was going on at the same time." Indeed, it might have happened earlier. Brumm and a growing number of archaeologists are ready to abandon longstanding Eurocentric views regarding the origin of human imagination. Like so much that makes us human, symbolism appears to have emerged early on in Africa and spread from there.

Different researchers have defined "symbol" in different ways, but at the most fundamental level a symbol is something that represents something else: a two-dimensional outline of a three-dimensional beast; a band of gold indicating matrimony. The use of symbols is an impressive mental feat. It requires the mind to escape the bonds of literality, to see in something more than is actually there.

Christopher Henshilwood of the University of Bergen has discovered some particularly compelling evidence of pre-European symbolism in South Africa's Blombos cave. When he first started excavating Blombos in 1991, few researchers believed that symbolism might have emerged before 50,000 years ago. But Henshilwood's subsequent discoveries - and those of other archaeologists working in Africa and the Levant - began to change minds. At Blombos, he and his team unearthed a 100,000-year-old animal-bone paintbrush and palettes: abalone shells in which prehistoric humans mixed pulverized red ocher with bone marrow, charcoal and water to form a colorful paste. The cave also contained an ocher slab with 75,000-year-old geometric engravings and 41 sea-snail shells drilled through with holes so they could be strung as beads.

"There is now a great deal of support for the notion that symbolic creativity was part of our cognitive repertoire as we began dispersing from Africa," says Paul Pettitt, an expert in Paleolithic art at Durham University. Henshilwood adds that what archaeologists have found so far may be a fraction of what existed; a lot of ancient art in Africa was most likely painted on exposed rocks and eroded by the elements over millenniums.

Humans are not the only animals that understand symbolism: Bonobos can form simple sentences using pictograms on a tablet computer, and researchers have trained capuchin monkeys to purchase grapes, apples and Jell-O with aluminum discs. As far as we know, however, only humans make symbols from scratch.

Before early hominins (our nearest primate ancestors) created symbols of their own, they recognized them in nature - in particular, uncanny semblances of the living in the inanimate. Three million years ago in South Africa, an ancient hominin stumbled onto a red jasperite pebble weathered in such a way as to resemble a face. He or she was mesmerized enough to make the stone a keepsake, carrying it back to a home base several miles away, where it was found by modern researchers. Paleolithic hominins also had a penchant for collecting fossilized coral, snails and shellfish.

This primal fascination with naturally occurring symbols coincided with a nascent appreciation for the aesthetics of tools. I recently visited a forthcoming exhibit at the Cooper Hewitt, Smithsonian Design Museum in New York, where a few prehistoric tools are on display. A 300,000-year-old hand ax was particularly gorgeous: a teardrop of russet flint marbled yellow and gray, tapered neatly to a point. I could see the many marks where one of our distant ancestors had struck the stone again and again to achieve its striking symmetry.

To make such hand axes - the oldest of which date to 1.76 million years ago - early hominins had to imagine a finished tool in a lump of rock and guide their hands to realize it. Chimpanzees use this same mental process when they strip twigs of leaves to make ant-fishing rods, but they never continue the process beyond the minimum required for a tool to work. But early humans became dissatisfied with the merely pragmatic. They spent a great deal of time and effort making their tools beautiful, sometimes struggling with unmalleable but attractive materials.

A few ancient hand axes are so handsome, large and heavy - to the point of being unwieldy - that some researchers have argued they were not intended for practical use, but were instead meant to attract mates by symbolizing skills or status in a group. Once early humans realized that their handicrafts could be both utilitarian and symbolic, both functional and beautiful, it would not have taken a great leap to start experimenting: to try recreating with stone and paint the icons they observed in weathered pebbles, fossils and their own handprints.

Even as they evolved, symbols never stopped being tools. The suggestion of a human hand on a cave wall, a nation's flag, even a Rothko - each is a powerful mental heuristic designed to conjure a particular emotion, a memory, an idea. Rather than directly changing the world around us, symbols change the way we perceive it. They extend not our bodies, but our minds.