What prehistoric art tells us about the evolution of the human brain.
Everyone answers the question “What makes humans human?” in her own way, but if you were ever a liberal arts student, you might have to resist the urge to roll your eyes and reply, “The humanities.” Maybe you’d get more specific, quoting the critic Haldane McFall: "That man who is without the arts is little above the beasts of the field."
OK, so you’d be pretty pretentious, but would you be wrong? Not really. Paleontologists tend to link the development of modern human cognition to the rise of our ability to express ourselves as artists and historians through cave painting, sculptures, and other prehistoric art. Representing the world in symbols may have heralded the beginnings of language. Creating paint from charcoal, iron-rich ochre, crumbled animal bones, and urine meant understanding how materials could combine to form substances with new properties. Storing the paint—perhaps in an abalone shell that would be discovered 100,000 years later in a cavern on the South African coast—required innovation and planning ahead.
Since at least the 1970s, the question of when we first acquired our humanness has been tangled up in discoveries about when we began making art. Richard Klein at Stanford used carvings such as the 30,000-year-old Lion Man of Hohlenstein Stadel to substantiate his theory that a genetic mutation caused a sudden mental flowering in our ancestors 40,000 years ago. (Homo sapiens have been around for 200,000 years, but apparently they spent much of that time twiddling their opposable thumbs.) Yet in 1991, the excavation of 77,000-year-old beads and engraved shards of red ochre in South Africa upended Klein’s hypothesis. It suggested that symbolic thinking had emerged much earlier than anyone had thought—maybe even at the same time that our modern bodies evolved. The notion of a game-changing genetic mutation fell out of fashion as older and older artifacts were uncovered. By 2012, Curtis Marean, a paleoanthropologist at Arizona State University, was voicing conventional wisdom when he told Smithsonian’s Erin Wayman: “It always made sense that the origins of modern human behavior, the full assembly of modern uniqueness, had to occur at the origin point of the lineage.”
It seems likely that our brains have been equipped for abstraction for as long as we have been human. But how does prehistoric art help us understand this capacity—which today asserts itself everywhere from the walls of MoMA to the icons on our smartphones? The images in the Lascaux, Nerja, and Chauvet caverns look far from hyperrealistic. One simple explanation holds that our ancestors didn’t have the time or skill to render horses and cattle exactly as they appeared. Yet researchers in neuroaesthetics are beginning to wonder whether the abstraction in Paleolithic art actually mirrors the way our minds process the world.
A leading proponent of this theory is V.S. Ramachandran, director of the Center for Brain and Cognition at UC-San Diego and author of The Tell-Tale Brain: A Neuroscientist’s Quest for What Makes Us Human. Ramachandran outlined 10 aesthetic principles that interest or delight the neurons in our visual cortex. One of them, peak shift, describes the way “we find deliberate distortions of a stimulus even more exciting than the stimulus itself.” Peak shift was first discovered by the scientist Niko Tinbergen in the 1950s. Noting that seagull chicks tapped at the beaks of their mothers in order to be fed regurgitated fish, Tinbergen sought to isolate what it was about the beaks that provoked this response. He presented baby herring gulls with fake beaks—painted wooden sticks with single red dots at the ends, like the red dot at the end of an adult gull’s beak. The chicks pecked eagerly. Next, he showed the chicks the same sticks, except with three red dots instead of one. The chicks pecked even faster. The experiment revealed that the baby gulls had an exaggerated response to stimuli that were also exaggerated. Tinbergen named this effect “peak shift” (because all the peak pecking happened after the stimulus was shifted).
Ramachandran’s insight lay in connecting the chicks’ feverish tapping to the way early humans portrayed the world around them. If our ancestors were also hardwired to respond more intensely to magnified stimuli, then it would make sense for that preference to find its way into their art. Sure enough, cave paintings from Spain to Australia emphasize the most salient parts of the animals they represent: Bison are blooms of meat on tiny legs, rhinoceroses sprout enormous horns, bears are fat but powerfully jawed. And human forms received the same essentializing treatment. Take the Venus of Willendorf, an 11-cm-high carving discovered in Austria in 1908. Her pendulous breasts, swollen stomach, and prominent genitalia capture what it meant to be female 25,000 years ago. She has no arms or facial features, but she doesn’t need them to convey fertility. An even more ancient statue, the Venus of Hohle Fels, barely has limbs or a head: Her message—sex, procreation, and abundance—comes across in broad hips and a carefully carved pelvic girdle.
Anthropologists still debate the purpose of these figurines. Were they religious talismans, art objects, children’s toys, or even prehistoric porn? A team of researchers at Victoria University of Wellington, New Zealand suggests that voluptuous statues “symbolized the hope for a well-nourished community.” Translating this into neuroscientific terms, Ramachandran speculates that our early ancestors were primed to respond to signs of health and successful reproduction. They lived toward the end of the last Ice Age, facing grim winters and a scarce food supply. It’s not surprising that the sight of a corpulent or pregnant woman would have caused their brains to light up with pleasure and attention.
In an article on peak shift in Psychology Today, Jonah Lehrer describes a study in which subjects could more readily identify famous figures like Richard Nixon by cartoon caricatures than by photographs. The part of the brain recruited for facial recognition, called the fusiform gyrus, excels at interpreting the qualities that distinguish one object from another, to the point where it favors slightly warped representations of reality. Lehrer linked the Nixon experiment to the visionary distortions of Picasso, whose portrait of Gertrude Stein “intensifies reality” through a process of careful abstraction. “Art is the lie that reveals the truth,” Lehrer wrote, quoting the cubist master.
(Of course, while the 2009 article described above passed a review for accuracy this March, Lehrer himself was a master at distorting facts to achieve a more pleasing, orderly story. For this reason alone, he belongs in a discussion of falsehoods that charm the brain.)
Cave art illuminates some of the truths of the prehistoric world: that buffalo meat made a great dinner; that women seemed magically procreative; that the parts of the lion to watch out for were its head and mouth. (It also reminds us that our ancestors were relentless hunters—some of the most haunting cave art depicts animals that we may have driven to extinction, including the cave bear, auroch, Irish elk, and woolly rhinoceros.)
But peak shift doesn’t quite explain the strange patterns overlying some of the animal images in Altamira and Lascaux—a drifting scrim of dots, lines, and grids with no discernible reference points. We could consult the perceptual grammar that governs human sight, its syntax of basic shapes and colors. Maybe our ancestors found these stimuli aesthetically pleasing because neurons are programmed to fire at the sight of them. But researchers into trance states have another theory. They argue that the patterns are not abstract at all. Instead, they are literal representations of hallucinations that the artists experienced deep in the caves.
In 2007, the London psychiatrist Dominic H. Fftche began running experiments with a new toy he had invented. The apparatus used light-emitting diodes attached to goggles to bathe the eyes in flashes of light that created a sort of “white noise” and prevented people from seeing anything meaningful. In the absence of visual cues from the optic nerve, the brain amplified the neural noise in the brain, creating signals where none existed and giving rise to hallucinations. Even with their eyes closed, people saw shimmering spots, lines, and cross hatchings—just like the ones hovering over the painted creatures in the European caverns.
Interviews with members of the San tribe in South Africa conducted in the 19th century corroborate this connection. Just 200 years ago, San bushmen decorated the walls of the Drakensburg mountains with abstract patterns eerily similar to the ones in France and Spain. The tribespeople explained to interviewers that they entered a trance before capturing their visions in paint. Their stories launched speculation that all the dots, grids, and streaks from the Paleolithic caves were snapshots of what our cave-dwelling, light-starved ancestors saw under similar conditions. Ironically, the most abstract designs of the prehistoric era may have required the least symbolic thinking.
So is it art or just an artifact of neuroscience? Should their achievement be less impressive if ancient men and women adorned cave walls with forms that provoked an enhanced brain response? Only a Neanderthal would say yes (and possibly out of artistic envy). That our early ancestors intuited the rules of visual perception and creatively applied them should augment our admiration for their work, not diminish it. Somehow Picasso knew that bringing out the severe lines in Gertrude Stein’s face, her long nose and misshapen eyes, would mesmerize us. Likewise, whatever their intent, prehistoric artists ended up creating beauty in the context of the shared laws of seeing.
Almost every place with cave art around the world includes one last symbol: outlines of hands, belonging to men, women and children. Again, time has blurred their meaning. Are they signatures? Part of a ritual in which shamans or painters communed with the rock wall? Perhaps the five-fingered designs are simply marks that say, “I was here.” Today, because of the paintings, we know that our ancestors were here, and that their minds were much like ours.
Katy Waldman is a Slate assistant editor.