What prehistoric art tells us about the evolution of the human brain.
(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.