Stoned Ape Theory Human Evolution

The Stoned Ape Theory of Human Evolution

Modern humans have evolved from apes, in fits and starts, over the last 5 million years, with modern humans appearing 200,000 – 300,000 years ago. While there have been many physical and intellectual enhancements that helped drive our species to flourish and proliferate all over the world, and while archaeologists and evolutionary biologists can point to these enhancements and why they have helped us succeed, it has never been entirely clear HOW these evolutions took place. Evolution, of course, occurs when DNA does not replicate perfectly, and in its mutations, accidentally creates improvements that help offspring outperform. But the pace with which our evolution from apes took place, particularly our brain capacity, is a process that is not well understood. Dr. Terence McKenna proposed a theory that, while by no means verified, continues to persist amongst evolutionary biologists to this day: The Stoned Ape Theory Of Human Evolution

Dr. McKenna was born in 1946 in Colorado. As he came of age in the 1970’s, the early advancements in the study of medical uses of psychedelic compounds was just coming to an end, as the U.S. first declared a ‘War on Drugs’ and classified psychedelics as Schedule 1 narcotics.

Early awakening

Dr. McKenna’s journey began at UC Berkeley where he was accepted into the Tussman Experimental College, a leading institution in the study of psychedelic effects. Through his education and from personal experiences dating back to his youth (when his personal experimentation with psychedelics and cannabis began), McKenna began to see the mind-expanding and enhancing power of the compounds.

McKenna paused his studies to travel the world, seeking out cultures that welcomed the use of psychedelic compounds as part of their transcendental aspirations. Through Central and Southeast Asia, and later through South America, McKenna was able to see, through first-hand experience, how cultures of monks, shamans and other believers ingested psychedelics of various shapes and sizes, and how this impacted their quest for enlightenment.

Deeply intrigued by the power of these compounds and their ability to transform the mind, McKenna returned to U.C. Berkeley to finish his degree in 1972, and by 1975 he had graduated with perhaps the most obscure triple major in history: ecology, conservation of natural resources, and shamanism. With his studies behind him, McKenna, alongside his brother Dennis, who had been the co-pilot on many of his world travels, wrote a book to reflect on their experiences through South America, called The Invisible Landscape: Mind, Hallucinogens and the I Ching. McKenna continued to write prodigiously, first in another recount of the South American trip in True Hallucinations, and then, perhaps most famously, in his tome, “Food of the Gods”. And it was in this work that McKenna laid out his most provocative thinking – the Stoned Ape Theory of Human Evolution.

The Stoned Ape Theory

In the Stoned Ape Theory Of Human Evolution, McKenna’s central thesis holds that humanity’s seismic evolution, over just a few million years, from our earliest ancestors within the Homo genus, to modern times (wherein he believed he had evolved beyond the Homo genus entirely), was supported by their adoption of magic mushrooms as a part of their diet.

McKenna’s thesis begins roughly 100,000 years ago hen our ancestors still lived predominantly in sub-saharan Africa. The earth was moving through a natural warming cycle, leading the African continent to heat up and dry out rather rapidly. This sudden desertification forced our ancestors out of what had been a lush tropical ecosystem and out through the continent in search of food. At this point, many evolutionary biologists have presumed that these wandering groups arrived at the continent’s coasts and started to eat fish, whose Omega-3 fats drove the rapid development of our brains. But for McKenna, the answer was underfoot. He believed that these wanderers were hot on the heels of herds of wild cattle, a robust and easily caught source of sustenance, and that in this chase, they would have noticed a peculiar and abundant mushroom growing out of the cattle dung – the Psilocybe cubensis.

As shroom consumption continued, the pace of evolution saw an inflection. Much science now exists that supports McKenna’s hypothesis that low doses of psilocybin can improve sight, peripheral vision and response time. Those hunters that ingested small amounts of mushrooms would develop natural advantages over those that didn’t, which would have led to their having more food and higher status. Of course, McKenna is taking an extraordinary leap of logic here, as he presumes that these psilocybin-inspired gifts could be passed down to subsequent generations. At slightly higher doses, the mushroom’s propensity to trigger a sexual response could have directly led to a greater number of children, while at even higher doses, McKenna (who presumably had a fantastic time on his South American trip) claimed that psilocybin helped to connect a community at a spiritual, and visceral, level, leading to polygamous relationships. The resulting mixing of the gene pool would have driven genetic diversity and a shared sense of responsibility for all the children in a community. As recent science appears to be supporting, McKenna also argued that higher doses of psilocybin would trigger the “language-forming region of the brain”, and may have driven the development and widespread use of language for the very first time (dating this important step in our evolution at roughly 100,000 years ago). So the Stoned Ape theory essentially states that, as a direct result of our early access to copious amounts of psilocybin, humanity’s evolutionary march dramatically accelerated. Psilocybin was the “evolutionary catalyst” that drove the formation of language, religion and philosophy, art, culture (and, I suppose, the orgy).

Criticism of the Stoned Ape Theory of Evolution

While a superficial read of McKenna’s theory seems compelling and comprehensive, the thesis doesn’t currently stand up to scientific rigour and investigation. From a methodological perspective, mainstream scientists are quick to point out that the work is not all that collaborative; McKenna constructed his theory in a bubble, and did not assign much effort to cross-referencing his assumptions (including dates, anthropological knowledge or the fossil record) to assess their validity. Perhaps even worse, when working to base his theory off of established research, his frequently misquoted or inappropriately cited the studies he referenced, a measure of sloppiness that is quite uncommon in academia. His assertion that psilocybin can drive sexual arousal is a central tenet of his position, but lacks evidence, and again, it isn’t entirely clear that just having more offspring would have driven this evolutionary event, because it’s not clear that prolonged psilocybin use creates genetic adaptations that can be passed down to the next generations. And there are plenty of more recent examples of humans that used psychedelics as a key part of their cultures but did not have the resulting communal spirit (many Mesoamerican civilizations used psychedelics prodigiously in religious ceremony, but there is no evidence of a communal ‘lovefest’). Ayahuasca-loving South American civilizations have been shown to be quite violent in their social interactions, further suggesting that the experience laid out in the research may have been specifically supported by McKenna’s own experiences, and nothing more.

So…is it true?

McKenna, who passed away in the year 2000 at just 54 years old, garnered much popular acclaim in his career, and became something akin to Timothy Leary as an architect of counter-culture, coming to be seen as a supporter of ‘90’s ‘rave culture’. And while he continued to speak to his ‘Stoned Ape Theory’ right up until he passed away, to date the Theory remains widely contested by the scientific community. Over time, we may find that future archaeologists find support for this theory by finding evidence of psilocybin consumption; for now, it makes for a fascinating, if contested, read.

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About the Author

Jon is the CEO of He is a passionate believer in the transformational power of plant medicines and believes that the science can not be ignored forever, no matter how well-financed the opposition! Having visited more than 40 countries across the globe, nothing makes Jon happier than traveling to far-flung jungle locales to meet the kind-hearted people who are driving the psychedelic renaissance. Next up, Peru!

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