About sixty years ago the scientist C.H.W. Horne wrote that "it is remarkable that one characteristic which seems to separate man from the allegedly lower animals is a recurring desire to escape from reality." He was referring to the widespread use of
hallucinogens by young people during the middle of the last century. What is even more remarkable, in my opinion, is how long humans have been documenting their interest in the use of hallucinogens. Cultural and
religious rituals developed around the use of these hallucinogens probably as soon as they were discovered in the various plants and fungi that were present in their environment.
Imagine that the year is 2000 BCE (before the current era) and as you are foraging for something safe to eat you discover a small yellowish mushroom that would one day be called Psilocybe mexicana. We now realize that this mushroom contains a hallucinogen called psilocybin. Indeed, psilocybin would ultimately be discovered in at least 75 different species of mushrooms, so there was a good chance that someone, one day would have stumbled onto a mushroom containing it. Regardless, today is your lucky day - you discovered it first.
After eating this mushroom you rather quickly developed a stomach ache that lasted for about thirty minutes and then something truly mystical started to happen. You began seeing things that you had never seen before, images that could only be due to the intervention of a god (or goddess, depending upon your local traditions). You began sharing your collection of mushrooms with others and everyone marveled at their amazing and quite mystical visual experiences. Ultimately, the use of psilocybin-containing mushrooms in the Central and South America became an integral part of many religious rituals. The mushroom was worshiped and was given the name Teonanacatl, which is thought to mean "god's flesh" or "sacred mushroom." Using this sacred mushroom became an important milestone in every person's religious path to the spirit world. Mushroom art and sculptures as well as numerous images on stones clearly designate the important role played by this mushroom in the local religions. When the Spaniard Francisco Hernandez invaded in the 1570s he documented the use of these mushrooms and eventually added them to their own list of medicinal herbs.
The stone carvings provide some insight into the effects that the mushrooms produced in the minds of these primitive peoples. Some of these carvings are shown above. You can imagine the challenge facing someone 4000 years ago who wished to represent to others what they experienced while visiting their mushroom-inspired spirit world. What if your only tools for representing this experience were stones and bones?
Even today people find it difficult to describe their personal experiences with hallucinogens. Consider this interesting question: Did hallucinogens produced qualitatively different experiences in people living 4000 years ago as compared to people alive today? In 1928 the scientist Heinrich Kluver attempted to answer this question. He interviewed people who had used hallucinogenic mushrooms as well as many other naturally-occurring hallucinogens. He discovered that these drugs all produce a surprisingly similar consensus of experiences that consistently included seeing geometric images that were accompanied by highly altered emotions. Although the specific colors reported varied, participants consistently reported brightness intensification. Moreover, the apparent size and design of the geometrical shapes, as well as their degree of symmetry, were strikingly similar from participant to participant.
More recently, a study asked a similar question of 500 participants who reported using LSD or mescaline. Once again these subjects reported seeing vivid swirling colors, sounds that seemed to be associated with specific colors and an intensification of visual imagery, often refered to as Cs & Ps (Hickman et al., 1969) for colors and patterns. Often the images tended to pulsate and move toward a center tunnel or away from a bright center. Anyone who's experienced a migraine aura knows exactly what this looks like.
What neuroscientists have discovered by examining ancient carvings and drawings, and by interviewing people today who use LSD, psilocybin, mescaline, ibogaine and a host of other hallucinogens, is that basic visual experience has been highly consistent across the last four millennia! These investigations reveal a great deal about how our brain responds to hallucinogens. Overall, the human visual system responds with a very limited number of form constants. The four most consistent geometric forms reported following use of these drugs include 1) a latticework, grating or honeycomb; 2) a cobweb structure; 3) a tunnel or funnel alley; or 4) a spiral image. Now take a look again at the stone carvings and you can appreciate what our South American ancestors were attempting to tell us.
Why have these hallucinogenic images remained so consistent across time? Most likely it is because the human brain has not changed in the past 4000 years. The architecture and neuronal circuitry of the visual cortex was same 4000 years ago as it is today. The similarity of the hallucinations is due to the pattern of connections between neurons within the visual processing regions of the cortex.
These drugs uniformly and consistently produce abnormal activation of cortical neurons leading to spontaneous pattern formation within visual cortex. Under normal circumstances this condition is associated with experiencing a visual image. Thus, hallucinogens alter how our neurons communicate with each other to process visual information in our brain; the result is something that is both familiar (such as an object of worship) and quite unusual (such as a distortion of the objects color).
These investigations teach us a lot about how our brain functions and provide insight into the religious world of our ancient ancestors. How truly fantastic!
© Gary L. Wenk, Ph.D. author of Your Brain on Food (Oxford, 2010); the blue mushroom image was created by Ryan Bliss.
