Then one day in 2011, a Griffith University archaeologist named Adam Brumm noticed that some of the artwork was covered with calcite growths colloquially known as cave popcorn. That meant they could be dated by measuring radioisotopes using new techniques mastered by Brumm’s colleague at Griffith, Maxime Aubert.
Aubert cut samples of the cave popcorn, shaving the calcite into ultrathin layers in a process he calls micro-excavating. For each sample, he measured the ratio of uranium to thorium, a byproduct of radioactive decay. The proportions gave him the minimum age of the underlying art. A drawing of a local beast known as a pig-deer was at least 35,400 years old, and one of the hand stencils was created at least 39,900 years ago — older than animal paintings in France’s Chauvet cave, the earliest known example in Europe.
These artworks pose a serious challenge to conventional wisdom about the development of our species. Ever since 1880, when the first prehistoric paintings were discovered in Spain’s Altamira Cave, most paleontologists have assumed that humans became fully modern in Europe about 35,000 years ago. European cave paintings were seen as evidence of a “creative explosion” sometimes attributed to a brain mutation, a theory reinforced by the apparent age discrepancy between figurative art in Europe and other, more recent art elsewhere.
“There was a long time when people thought Africans had nothing to do with the rest of the world after the first human ancestors left Africa 2 [million] to 1.8 million years ago,” Brooks explains. The fact that Europe is not uniquely the seat of the earliest art “argues very strongly that the humans who left Africa had the capacity to make images and to make symbols,” she says, “and they probably had it for a while.”
Anthropologist Paul Taçon — a Griffith University colleague of Aubert and Brumm who was not involved in their study — concurs, connecting the Sulawesi paintings to the Javanese shell engraving. “We don’t give our ancestors enough credit,” he quips. “A lot of what we thought was invented by modern humans probably goes back much further in time.” The age-old process of migration and adapting to unfamiliar circumstances may have spurred artistic expression through countless small, creative explosions. “Abstract design was probably something that archaic humans engaged in for hundreds of thousands of years,” Taçon says.
The search for the origins of art is going global. Taçon is currently studying rock art in Australia, China and Malaysia. Brooks is scrutinizing cave paintings in Namibia. Aubert is looking at rock shelters in Borneo. And Joordens is returning to the site first dug up by Dubois, in search
of the masterpieces Java Man may still be hiding.
[This article originally appeared in print as "Making a Mark."]