'Stoned Ape' Theory & Human Evolution
Imagine Homo erectus,
a now-extinct species of hominids that stood upright and became the first of
our ancestors to move beyond a single continent. Around two million years ago,
these hominids, some of whom eventually evolved into Homo sapiens, began to expand their range beyond Africa, moving
into Asia and Europe. Along the way, they tracked animals, encountered dung,
and discovered new plants.
But that’s just the version of our origin story that happens
to be widely accepted by scientists.
A more radical interpretation of these events involves the
same animals, dung, and plants but also includes psychedelic drugs. In 1992,
ethnobotanist and psychedelics advocate Terence McKenna argued in the book Food
of the Gods that what enabled Homo erectus to evolve into Homo sapiens was its
encounter with magic mushrooms and psilocybin, the psychedelic compound within
them, on that evolutionary journey. He called this the Stoned Ape Hypothesis.
McKenna posited that psilocybin caused the primitive brain’s
information-processing capabilities to rapidly reorganize, which in turn
kick-started the rapid evolution of cognition that led to the early art,
language, and technology written in Homo sapiens’ archeological record. As
early humans, he said we “ate our way to higher consciousness” by consuming
these mushrooms, which, he hypothesized, grew out of animal manure. Psilocybin,
he said, brought us “out of the animal mind and into the world of articulated
speech and imagination.”
As human cultural evolution led to the domestication of wild
cattle, humans began to spend a lot more time around cattle dung, McKenna
explained. And, because psilocybin mushrooms commonly grow in cow droppings,
“the human-mushroom interspecies codependency was enhanced and deepened. It was
at this time that religious ritual, calendar making, and natural magic came
into their own."
McKenna, who died in 2000, passionately believed in his
hypothesis, but it was never seriously considered by the scientific community
during his lifetime. Dismissed as excessively speculative, McKenna’s hypothesis
now only pops up occasionally in online message boards and Reddit pages
dedicated to psychedelics.
However, a talk in April at Psychedelic Science 2017, a
scientific conference on psychedelics attended by researchers, therapists, and
artists who believe in the therapeutic potential of these drugs, renewed
interest in the theory. There, Paul Stamets, D.Sc., a noted psilocybin
mycologist, advocated for the Stoned Ape Hypothesis in his talk, “Psilocybin Mushrooms
and the Mycology of Consciousness.”
“I present this to you because I want to bring back the
concept of the Stoned Ape Hypothesis,” Stamets said to the crowd. “What is
really important for you to understand is that there was a sudden doubling of the
human brain 200,000 years ago. From an evolutionary point of view, that’s an
extraordinary expansion. And there is no explanation for this sudden increase
in the human brain.”
The “doubling” he talked about refers to the sudden growth
in the size of the human brain, and he’s right: The details are still up for
debate. Some anthropologists believe that the brain size of Homo erectus
doubled between 2 million and 700,000 years ago. Meanwhile, it’s estimated that
the brain volume in Homo sapiens grew three times larger between 500,000 and
100,000 years ago.
Laying out the tenets of the Stoned Ape hypothesis that
McKenna and his brother Dennis shaped, Stamets painted a portrait of primates
descending from African canopies, traveling across the savannahs, and coming
across “the largest psilocybin mushroom in the world growing bodaciously out of
dung of the animals.”
“I suggest to you that Dennis and Terence were right on,”
Stamets announced while acknowledging that the hypothesis was perhaps still
unprovable. “I want you or anyone listening, or seeing this, to suspend your
disbelief … I think this is a very, very plausible hypothesis for the sudden
evolution of Homo sapiens from our primate relatives.”
The crowd broke out into wild applause.
Terence McKenna (right) |
Is it finally time to take the Stoned Ape hypothesis seriously? Doing so requires integrating our advancements in scientific research on psilocybin, recent archeological discoveries, and our murky understanding of human consciousness and fitting these into our current understanding of human evolution. We can start with the common threads between McKenna’s view of the development of consciousness and other, more mainstream, theories, including the commonly accepted view that it emerged over thousands of years and that language played a central part in its evolution.
“I think that, like anything, there’s possibly some truth in
what he [McKenna] says,” paleontologist Martin Lockley, Ph.D., says.
Lockley, the author of a book called How Humanity Came Into Being, has one
major issue with McKenna’s reasoning: Believing in the Stoned Ape hypothesis,
which posits that our ancestors got high and consequently became conscious,
also means agreeing that there was a singular cause for the emergence of
consciousness. Most scientists, Lockley included, think it was much less
straightforward than that.
Consciousness, after all, is a very complex thing that we
are only beginning to understand. Anthropologists generally accept that it’s a
function of the human mind involved with receiving and processing information
that evolved over millennia of natural selection. A state of consciousness
comprises an awareness of multiple qualitative experiences: sensations and
feelings, the nuances of sensory qualities, and cognitive processes, like
evaluative thinking and memory. In 2016, scientists pinpointed where all of
this lives in the brain, discovering a physical link between the brain regions
associated with arousal and awareness.
McKenna’s theory chalks up the entirety of this complicated
phenomenon to a single spark; to him, psilocybin mushrooms were the
“evolutionary catalyst” that sparked consciousness by prompting early humans to
engage in experiences like sex, community bonding, and spirituality. Most
scientists would argue that McKenna’s explanation is excessively, and perhaps naively,
simplistic.
And yet, they’re equally stumped when asked to answer the
question at the root of the debate over the Stoned Ape hypothesis and
consciousness research in general: How did consciousness evolve? If it wasn’t
psychedelic mushrooms that started the process, then what did? Michael
Graziano, Ph.D., a professor of psychology and neuroscience at Princeton
University who studies consciousness, had not heard of the Stoned Ape theory
but concurs that the evolution of human consciousness is somehow linked to the
formation of communities. In his own theory, he argues that brains had to
develop the ability to understand subjective experiences to serve social needs.
Since it was evolutionarily beneficial to be socially intelligent, he says,
it’s reasonable to believe that consciousness evolved as a survival tactic.
“It is possible that consciousness emerged partly to
monitor, understand, and predict other creatures, and then we turned the same
skill inward, monitoring and modeling ourselves,” Graziano says. “Or
it could be that consciousness emerged much earlier, when basic attentional
focus first emerged, and that it is related to the ability to focus the brain’s
resources on a limited number of signals. That would put it very early in
evolution, perhaps half a billion years ago.”
Likewise, the theories of anthropologist Ian Tattersall,
Ph.D., have nothing to do with psychedelic drugs but share the Stoned Ape’s
emphasis on socialization. In his 2004 paper “What happened in the origin of
human consciousness?” Tattersall, a researcher at the American Museum of
Natural History, argued that self-awareness — and thus consciousness — was born
as early man learned to consider itself apart from nature and grew capable of
evaluating and expressing the thoughts within its mind. Language developed
shortly after, followed by modern human cognition.
Where Tattersall remains stumped — and where McKenna’s
theory offers some explanation — is in trying to figure out when that crucial
transition took place.
“Where did modern human cognition emerge?” Tattersall
writes. “Almost certainly in Africa, like modern human anatomy. For it is in
this continent that we find the first glimmerings of ‘modern behaviors’ … But
the moment of transformation still eludes us and may well do so almost
indefinitely.”
McKenna might have argued that psilocybin-containing
mushrooms caused this “moment of transformation.” But even experts on ancient
drug users think it’s unlikely that a single factor caused such a radical
change, despite it being entirely reasonable to think that early hominids munched
on magic mushrooms as they made their way through Africa.
“Human evolution is a tremendously intricate process in
which several factors have played their part,” archaeologist Elisa Guerra-Doce,
Ph.D., says. Guerra-Doce’s research on the use of drug plants in
prehistoric times has detailed how early humans used mind-altering drugs for
ritual and spiritual purposes. But despite the fact that she’s encountered
remnants of opium poppy in the teeth of Neolithic specimens, ancient charred
cannabis seeds, and even abstract drawings of the use of hallucinogenic
mushrooms on cave walls in the Italian Alps, she is not on board with the
Stoned Ape hypothesis.
“From my point of view, McKenna’s hypothesis is too
simplistic and lacks direct evidence to support it — that is, any evidence of
consumption of hallucinogenic mushrooms by the earliest Homo sapiens,” she
says, pointing out that he got some of his basic facts wrong. “He points to the
Algerian paintings of Tassili-n-Ajjer, which include some depictions of
mushrooms, but we must bear in mind that these paintings date back to the
Neolithic.”
If the science behind McKenna’s hypothesis is unstable, what
worth does it have in the search for the origin of human consciousness?
At its best, the Stoned Ape hypothesis is, as Stamets
described it, an “unprovable hypothesis” that fits some – but not nearly all –
of the knowledge we have about the evolution of consciousness. At its worst,
it’s a gross oversimplification of the multitude of factors that may have
jump-started modern human cognition and consciousness. However, McKenna
deserves credit for sparking an idea in the 1990's that scientists have only
recently been able to prove: Psilocybin does alter consciousness and can
trigger physical changes in the brain.
In recent years, drug researchers have determined that
psilocybin induces a state of “unconstrained cognition,” triggering a
pronounced surge in activity in the primitive brain network, the region
associated with emotional reactions. On psilocybin, the parts of the brain
linked to emotions and memory become more coordinated, creating brain activity
patterns resembling those of people who are asleep and dreaming. At the same
time, the region that controls higher-level thinking and is linked to a sense
of self becomes disorganized, which is why some people who take psilocybin feel
a loss of “ego,” leading them to feel more a part of the world than they do
their own bodies.
Regardless of the holes that have been pointed out in
McKenna’s scientific logic, Amanda Feilding, founder and director of the
Beckley Foundation, a leading psychedelic research think tank, says that we must see past McKenna’s errors and consider his greatest insight: that
the story of humankind is inseparable from our fascination with psychedelic
drugs. Even if early man encountered psychoactive substances closer to the
Neolithic period, she says, the experience of entering an altered state of
consciousness likely changed human society for the better.
“The imagery that comes with the psychedelic experience is a
theme that runs through ancient art, so I’m sure that psychedelic experience
and other techniques, like dancing and music, were used by our early ancestors
to enhance consciousness, which then facilitated spirituality, art, and
medicine,” she says.
The Stoned Ape hypothesis may now be lost to the annals of
fringe science, but some remnant of its legacy remains. Now that scientists
better understand the way psilocybin physically affects the brain, they can
seriously investigate its potential to treat disorders like substance abuse,
anxiety, and depression. If that happens — and it looks like it will —
psilocybin will become a part of mainstream culture as an agent of positive
change. And isn’t that ultimately what McKenna was advocating for?
Maybe we’ll never know how magic mushrooms helped early
humans. But there’s no doubt they’ll be contributing to the wellness of modern
humans as we continue down our strange evolutionary path.
See you all tomorrow.
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