What’s up with those 40,000-year-old cave paintings left behind by our earliest ancestors? The ancestors. They were high. On drugs.

So claims a group of Tokyo-based researchers, after discovering that patterns commonly found in cave paintings throughout the world are remarkably similar to those produced by modern-day test subjects under the influence of certain “mind-altering” hallucinogens.

These patterns, known as “Turing Instabilities,” actually resemble the structures of the human brain. While it’s fascinating how universal the neurological effects of psychedelics have been over the ages, this also means that cave drawings might not be as accurate a depiction of prehistoric reality as was once believed.

According to their article published in Adaptive Behavior, cavemen would deliberately seek out and eat hallucinogenic plants before engaging spiritual rituals, and would then paint all the swirly, trippy shit they “saw” onto whatever surfaces happened to be around.

“When these visual patterns are seen during altered states of consciousness they are directly experienced as highly charged with significance,” the research team writes. “In other words, the patterns are directly perceived as somehow meaningful and thereby offer themselves as salient motifs for use in rituals.”

Interested readers should check out Terence McKenna’s Food of the Gods: The Search for the Original Tree of Knowledge A Radical History of Plants, Drugs, and Human Evolution.

Republished with special permission from ANIMALNewYork.