Some of the oldest human art in Europe is completely hidden from view, hidden in the narrow crawl spaces of deep, dark and winding caves.
To see the walls, let alone to decorate them, artists from the Stone Age would have to crawl around with various torches, and archaeologists now suspect that all the smoke is causing an altered state of consciousness.
Hallucinatory plants have long been associated with other world cave art, but this new hypothesis suggests that ancient humans consciously pursued a similar transformative experience in the depths of the underworld, long before they began using other psychoactive substances.
The further they crawl out of fresh air, experts suggest, the greater the spiritual journey and the more artistic they become.
“A few years ago, when I visited some ornate caves in France, I noticed that most of the images are deep in very narrow caves,” said archaeologist Yafit Kedar of Tel Aviv University in Israel. The Jerusalem Post.
“I began to wonder why they preferred to work this way, as opposed to paint at the entrance of wider caves, where they could also enjoy natural light.”
Kedar and her colleagues modeled the effect of torches and lamps on the airflow of a cave. The narrower the entrance to a cave, the faster one will starve for oxygen.
In a deep cave with only one entrance, simulations show that oxygen levels can drop to below 18 percent in just fifteen minutes, which can potentially cause a state of hypoxia if the concentrations drop low enough.
In humans, oxygen deficiency can naturally release dopamine into the brain, which can sometimes result in drowsiness, euphoria, hallucinations or out-of-body experiences. In fact, scientists studying caves have reported experiencing similar effects, even without a burning torch in hand.
The additional use of fire makes such a condition much more likely.
In a large cave mouth with open access to the outside world, a burning flame tends to create two different layers of air: the lower layer consists of air from outside, and the upper layer consists of exhaust gas that flows out again .
Air flow in an open cave. (Kedar et al., The Journal of Archeology, Consciousness and Culture, 2021)
When fire burns in a narrow aisle, on the other hand, the upper and lower layers partially mix, which means that air everywhere carries significantly less oxygen than the 21 percent we normally inhale.
What’s more, because oxygen atoms are lighter than carbon dioxide, they tend to float upwards, descending from the tunnels of the cave to the entrance. The deeper someone moves in a cave system with a burning flame, the greater the chance that they starve themselves of oxygen.
In various simulations, when ventilation was particularly limited, researchers found that oxygen levels could drop to 9 percent, which is about the point where someone may lose consciousness.
It may sound like a great deterrent, and yet hundreds of ancient cave paintings from the Upper Paleolithic, between 14,000 and 40,000 years ago, are located at the same depth. In fact, some cave art has been found as far from the mouth of a cave as an artist could find feasible.
In the French Rouffignac cave, most ancient statues, for example, were painted on the walls of extremely narrow corridors, about 730 meters from the only entrance.
Map of Rouffignac Cave with red dots representing cave art. (Dachary, Plassard and Valladas, 2016)
So it seems possible that some old people have crept deep into Europe’s dark caves to deliberately go into a changed state of consciousness. The effects of sensory deprivation, coupled with the lack of oxygen, could have even been the cause of the surrealistic nature of their cave art.
“The images depicted in such a hallucinatory state float on the cave surfaces (walls, floors and ceilings) as if it were a membrane connecting the upper and lower worlds,” the authors explain. Kedar now hopes to test oxygen levels in real caves to compare it to the simulations.
Although psychoactive plants are certainly available in Europe, evidence for their use appears much later in the archaeological report than these cave paintings.
Hypoxia would thus have been an easier and more natural way for early people to consciously change their state of mind, making a person feel more connected to the world around him and more expressive in his work.
It has even been found that the Lascaux caves in France – home to some of the most famous paintings from the Upper Paleolithic – leach out natural gases, which could have caused a similar hallucinatory condition in ancient humans.
“The cave environment was seen as a liminal space and as an ontological arena, allowing early humans to maintain their connection to the cosmos,” the authors suggest.
“It was not the decoration that made the caves significant; the significance of the chosen caves was rather the reason for its decoration.”
The study was published in The Journal of Archeology, Consciousness and Culture.