Evolution is a rock-solid scientific theory, as strong as theories come. It explains the extreme diversity of the organisms present on this world. It is supported by mountains of scientific data, most importantly molecular biology and the fossil record. However, now and again, apparent anomalies appear in the fossil record which baffle even those most familiar with biology and evolution.
From the evolution of the first Homo species, Homo habilis, to Homo sapien, the human brain size doubled more than doubled (from 612cc to 1000-1900cc*), in a period of almost 2 million years (an incredibly small amount of time on the evolutionary timeline). There is much debate on how this managed to happen, considering that this is the fastest, largest growth of any organ in the entire fossil record. The late Terence Mckenna provides an intriguing answer to this biological phenomenon. He offers the Stoned Ape Theory, which I would like to familiarize you with.
Mushrooms and Human Evolution
As our ape ancestors were driven from rainforests to grassy plains due to climatic change and our incapability to safely use fire, their diets changed. While foraging for food on these newly inhabited grasslands, they began to encounter psilocybin containing mushrooms, and this symbiosis made its mark on human evolution in several ways.
“Psilocybin is a naturally occurring psychedelic compound produced by more than 200 species of mushrooms . . . As a prodrug, psilocybin is quickly converted by the body to psilocin, which has mind-altering effects similar to those of LSD and mescaline . . . The effects generally include euphoria, visual and mental hallucinations, changes in perception, a distorted sense of time, and spiritual experiences, and can include possible adverse reactions such as nausea and panic attacks.”*
Psilocybin had three immediate effects on grazing Homo habilis.
- Visual Acuity: Visual acuity and edge-detection are, as Mckenna states, the “first level” of psilocybin effects. Visual acuity was a remarkable advantage for the hunter-gatherer communities.
- Sexual Arousal: Psilocybin acts as a nervous system stimulant, and thus instances of copulation naturally increase din our restless ancestors. This helped to naturally select individuals who consumed psilocybin-containing mushrooms.
- Spiritual Enlightenment: Mckenna’s third level of psilocybin effects is full shamanic ecstasy. He proposed that high doses of psilocybin caused some spiritual enlightenment in tribal groups, promoting social responsibility and oneness.
Mckenna also noted psilocybin’s tendency to facilitate linguistic thinking and communication. Primates under the effects of psilocybin would have been inclined to begin vocalization, which would produce vibrations that cleanse the brain of impurities and cause genetic diversity.* Once speciated into Homo sapiens, the species began to migrate from Africa to colonize the rest of the world.
The Stoned Ape theory is interesting but not foolproof, and this post only scratches the surface when it comes to human evolution. You can find more information on the Stoned Ape Theory for yourself by reading Terence Mckenna’s book, Food of the Gods.