Some of Europe’s oldest human artists are completely hidden from view, hidden in the narrow crawling spaces of deep, dark, winding caves.
Even to see the walls, let alone decorate them, Stone Age artists would have had to crawl with various torches and now archaeologists suspect that all the smoke induced an altered state of consciousness.
Hallucinating plants had been connected to the extraterrestrial nature of rock art, but this new hypothesis suggests that ancient humans consciously pursued a transformative experience similar to the depths of the underworld, long before they began using other substances. psychoactive.
The farther away from the fresh air they crawl, experts propose, the greater the mental journey and the more artistic they will become.
“A few years ago, while visiting some decorated caves in France, I began to notice that most of the images are in very narrow caves,” said archaeologist Yafit Kedar of Tel Aviv University in Israel. The Jerusalem Post.
“I began to wonder why they chose to work this way, instead of painting at the entrance to wider caves, where they might as well have enjoyed natural light.”
Modeling the effect of torches and lamps on the airflow of a cave, Kedar and colleagues have found that the narrower the entrance to a cave, the faster a human will die d ‘oxygen.
In a deep cavern with only one inlet, simulations show that oxygen levels can drop by 18% in as little as fifteen minutes, possibly causing a state of hypoxia if concentrations are reduced low enough.
In humans, oxygen deprivation can naturally release dopamine into the brain, sometimes resulting in drowsiness, euphoria, hallucinations, or experiences outside the body. In fact, scientists studying the caves have reported that they have experienced similar effects even without a burning torch in their hand.
The added use of fire makes this state 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 outside air and the upper layer consists of exhaust gases that come 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 passage, by contrast, both the upper and lower layers are partially mixed, meaning that air everywhere carries significantly less oxygen than the 21% we usually breathe.
Also, because oxygen atoms are lighter than carbon dioxide, they tend to float upward, descending from the tunnels of a cave to the entrance. The further you go into a cave system someone travels with a burning flame, the more likely they are to die of oxygen.
In several simulations, when ventilation was particularly restricted, the researchers found that oxygen levels can drop as low as 9%, roughly the point at which a person can lose consciousness.
It might seem like an important deterrent, and yet hundreds of ancient Upper Paleolithic cave paintings, between 14,000 and 40,000 years ago, are found at very similar depths. In fact, some rock art has been found as far from the mouth of a cave as an artist could achieve.
In the French cave of Rouffignac, for example, most ancient images have been painted on the walls of extremely narrow passages, 730 meters (approximately 2,400 feet) from the only entrance.
Map of the cave of Rouffignac with red dots representing rock art. (Dachary, Plassard and Valladas, 2016)
It therefore seems possible that some ancient humans were crawling deep into the dark caves of Europe to purposely enter an altered state of consciousness. The effects of sensory deprivation, combined with a lack of oxygen, could have even been the trigger for the surreal nature of his rock art.
“The images projected in this hallucinatory state appear to float on the surfaces of caves (walls, floors, and ceilings) as if they constituted a membrane connecting the upper and lower worlds,” the authors explain. Kedar now hopes to test oxygen levels in real caves to compare them to the simulations.
Although psychoactive plants are definitely available in Europe, evidence of their use appears much later in the archaeological record than these cave paintings.
Therefore, hypoxia could have been an easier and more natural way for early humans to consciously alter their mood, making a person feel more connected to the world around them and more expressive in their work.
Lascaux caves in France, home to some of the most famous Upper Paleolithic paintings, have even been found to leach natural gases, which could have induced a similar hallucinatory state in ancient humans.
“The atmosphere of the caves was conceived as both a liminal space and an ontological arena, allowing early humans to maintain their connection to the cosmos,” the authors propose.
“It was not the decoration that made the caves significant; rather, the importance of the caves chosen was the reason for their decoration.”
The study was published in The Journal of Archeology, Awareness and Culture.