Should abstract engravings dating back more than half a million years – even before our species evolved – be considered art? If they are, they would represent the oldest example of this quintessentially human activity, and tell us something important about human evolution. However, some anthropologists have remained skeptical.

Professor Francesco d'Errico of the University of Bordeaux found an original way to test this question. By studying people's brain patterns when they first saw images of the engravings, d'Errico assessed whether the responses resembled those we have to photographs or drawings, or to scrambled versions of images lacking in meaning.

D'Errico used fMRI machines to map the activation of blood oxygen in 27 volunteers when shown original and scrambled images of cave engravings between 540,000 and 30,000 years old respectively. The same subjects also looked at control images of objects and landscapes, compared to scrambled versions of these photographs.

Looking at the engravings activated regions of the brain “in a pattern similar to that activated by the perception of objects,” d'Errico and coauthors write in Royal Society Open Science, but this was not replicated for the scrambled versions. This, the authors argue, indicates that while the lines may not look like anything they “are processed as organized visual representations in the brain."

"These results support the hypothesis that these engravings have the visual properties of meaningful representations in present-day humans,” they add.

Sadly we can't test the effect these images had on the people who made them. Perhaps half a million years of being surrounded by scratched objects changed the way our brains processed sights like these. Nevertheless, the most straightforward interpretation of d'Errico's findings is that these lines had a symbolic meaning to those who made them, and when we look at them we are seeing the first stirrings of art.

We have no trouble recognizing cave paintings of people and animals made in Europe, Borneo, and Australia around 40,000 years ago as art, some of it breathtakingly beautiful. These were predated, however, by abstract painting, such as the 70,000-year-old “hashtag” of six crossed lines found in South Africa last year.

This has created a debate about whether these lines could be considered art, or if they were random scratchings that only appear to have meaning in retrospect. The same questions apply to scratches found on bone, ivory, and, in the most ancient case we know, mussel shells.

Until recently it was thought that all the symbolic cave paintings were made by our ancestors, but recent studies suggest some of them may have been the work of Neanderthals prior to the arrival of humans in Europe. If so, it would prove the making of art is not exclusive to Homo Sapiens, making it more credible that the abstract engravings that predate our appearance might also qualify.