Stone age individuals might have intentionally ventured into oxygen-depleted caves to color whereas having out-of-body experiences and hallucinations, in response to a brand new examine.
Within the nineteenth century, researchers found a sequence of embellished caves that date again between 40,000 and 14,000 years — to the Higher Paleolithic period or late Stone Age — throughout Western Europe. The caves, discovered primarily in Spain and France, had been full of wall work, a lot of them in areas that may very well be accessed solely by slim passageways. The depictions had been painted in black and pink and primarily confirmed animals with some hand stencils, handprints and geometric summary indicators.
However why would individuals undergo the difficulty of strolling by slim cave passages to make artwork? To reply this query, a gaggle of researchers at Tel Aviv College targeted on a attribute of such deep, slim caves, particularly people who require synthetic mild to navigate: low ranges of oxygen.
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The researchers ran pc simulations of mannequin caves with totally different passageway lengths that result in barely bigger “corridor” areas the place work could also be discovered and analyzed the modifications in oxygen concentrations if an individual was to face within the totally different components of the cave burning a torch. Hearth, reminiscent of that from torches, is considered one of a number of elements that depletes oxygen inside caves.
They discovered that oxygen focus relied on the peak of the passageways, with the shorter passageways having much less oxygen. In a lot of the simulations, oxygen concentrations dropped from the pure ambiance degree of 21% to 18% after being contained in the caves for less than about quarter-hour.
Such low ranges of oxygen can induce hypoxia within the physique, a situation that may trigger headache, shortness of breath, confusion and restlessness; however hypoxia additionally will increase the hormone dopamine within the mind, which might generally result in hallucinations and out-of-body experiences, in response to the examine. For caves with low ceilings or small halls, the oxygen focus dipped as little as 11%, which might trigger the extra extreme signs of hypoxia.
The researchers hypothesize that historic individuals crawled into these deep, darkish areas to induce altered states of consciousness.
“Hypoxia may properly be a believable rationalization for lots of the depiction places, that are removed from the cave mouth and require passing by low, slim passages,” the authors wrote. “We contend that getting into these deep, darkish caves was a acutely aware selection, motivated by an understanding of the transformative nature of an underground, oxygen-depleted house.”
Caves had a particular significance for these historic civilizations. They had been seen as “portals that hook up with the underworld,” lead creator Yafit Kedar, a doctoral candidate within the Division of Archaeology and Close to Jap Cultures at Tel Aviv College, advised Reside Science in an electronic mail. The findings recommend that the traditional individuals sought altered states of consciousness and created cave depictions as “a solution to preserve their reference to the entities” of the underworld.
There are some components of the caves that had been extra ventilated that additionally contained these depictions. Nevertheless, altered states of consciousness “may very well be achieved in these contexts through different companies than hypoxia,” the authors wrote. What’s extra, the authors solely simulated the impact that torches have on oxygen within the caves, however different parameters reminiscent of human respiration or pure chemical reactions that happen in caves may even additional lower oxygen focus, they wrote.
The researchers now hope to investigate how many individuals may very well be collectively on the similar time in these caves with restricted quantities of oxygen and for the way lengthy.
The findings had been printed on March 31 in The Journal of Archaeology, Consciousness and Tradition.
Initially printed on Reside Science.