The terms ‘psychedelic’ can be applied not only to a class of chemical, but to a whole style of visual art, inspired by the visions that these chemicals produce. Why do these substances produce similar visual experiences across different individuals and where do these experiences come from? From breathing walls to melting hands, from symbolic imagery to entity encounters, psychedelic visions can tell us something about who and what we are.
During everyday waking consciousness we typically perceive a stable world of objects. This feels like a completely passive process–just open your eyes and there’s the world, no effort required. In reality, the felt simplicity of this experience masks the highly complex processing going on in your brain that allows you to see. Your retina is not a clear window through which your soul looks out onto the world. Instead it is a fleshly surface similar to the rest of your body, a piece of meat that blocks the light from the outside world, rather than letting it in.
What actually happens when we see is that the patterns of light are transformed into electrochemical signals that are sent down the optic nerve to the brain. The brain, sitting in your pitch-black skull, learns to actively build models of the objects out there in the world that these electrochemical clues relate to. Your normal perception can be understood as a controlled hallucination, kept in check by the data coming in through your senses and by your expectations of the world around you. However, this balance between the internal creativity of the models in your brain and the extent to which they are kept in check can be altered.
Psychedelics interact with brain cells to alter their activity in ways that disrupt the normal process of perception. At low doses of a psychedelic, the visual world becomes distorted in reliable ways. Perhaps you experience trails of light following your hands as you move them, or you perceive the walls to be breathing. This can be understood as the result of a temporary impairment in the Default Mode Network (DMN).
The DMN is a group of brain areas that builds up expectations about the world and uses them to keep our perception in check. When its ability to do this is reduced, our internal models of the visual world are free to make guesses about what we’re seeing. We may overestimate the distance of the wall then correct for our error based on the sensory data. Give the newfound flexibility offered to the brain areas involved in this process, they may underestimate, then overestimate. This process can continue on and on, resulting in a pendulating interpretation of the wall’s distance and the perception of the walls breathing. The same goes for the precise position of one’s hand in space over time.
Hallucinations of Interpretation
We’ve all seen shapes in the clouds or perhaps faces in the bark of a tree. Here we are using ambiguous sensory input and are finding internal models in our brains that roughly match the pattern. When on a psychedelic this process goes into overdrive and can result in us mistaking a flower for a lizard or a bowl of spaghetti for a bowl of worms. Why do we tend to see natural shapes like animals and not artificial ones? Why lizards and worms and not buildings and airplanes?
Our visual system evolved to recognize the patterns of the natural world that are relevant to survival and so, when given to opportunity to play, our visual systems show us these natural forms that we were built to detect. We have templates for snakes and spiders deeply programmed into us for example, something that simply isn’t the case for modern dangerous objects like cars and guns.
Our hallucinations can be thought of as what our brains expect to see, something that may also account for why we perceive colors to be highly saturated in the psychedelic state, as we’re experiencing the more pure template of the color than we typically experience in daily life. Understanding the basis of hallucination in our evolutionarily programmed expectation of the visual world also offers a way of understanding why eyes, serpents, and insects are so common in higher-dose psychedelic experiences, as these are highly biologically relevant patterns for us as a species.
The models in our brain that underlie perception are constructed by networks of brain cells. The vast computational power of such networks has resulted in their being imitated in modern Artificial Intelligence systems. Artificial Neural Networks such as Google’s Deep Dream can be trained to recognize different images, resulting in the construction of models in the neworks in a way that approximates learning in the brain. When we dream or hallucinate, the contents of these models become active with no sensory input to keep them in check. The same can be done with the artificial Neural Networks. When it is tasked with generating rather than recognizing images, they produce distinctly psychedelic visuals. The fact that this is the case provides striking evidence that certain psychedelic visuals are generated by the models in your brain being pushed into “create” mode.
At higher doses geometric patterns can be observed, especially when one closes one’s eyes, thereby excluding the sensory data that would otherwise keep one’s models in check. The patterns of the natural word are geometric in essence, all patterns are. Geometric hallucinations can reveal certain common patterns that are fundamental to our experience of the world. Psychedelics are not the only way to shift the visual brain into a mode where it displays their core patterns. When one “sees stars” after being hit on the head, the visuals being perceived are called phosphenes. Phosphenes can also be seen when pressure is placed on the eyeball. These geometric patterns are routinely experienced in the psychedelic state and have been observed in ancient cave art, leading to the suggestion that early cave art represents the earliest attempts of our species to carry back the experiences of the psychedelic state.
At high doses of classical psychedelics, people routinely experience ancient imagery exemplified in the art of cultures as found in ancient Egypt and Mesoamerica. Mesoamerican cultures are known to have ingested psychedelic mushrooms and it has been suggested that religion in ancient Egypt for a time revolved around the consumption of such mushroom, based on the similarity of depictions of Egyptian crowns to different stages of the development of this type of mushroom . The psychoactive blue lotus is also believed to have been consumed ritually in ancient Egypt. From our contemporary perspective, the styles depicted in the artworks feel as if they originated in these cultures. In reality the imagery of the psychedelic experience may have come first and the art later.
Another experience that can be had at high doses, especially with DMT, is the experience of visiting another “dimension”. In such an experience the person typically feels as if they have left their body behind and have been transported to another world. Understanding that our perception of the world around us is not the passive experience of a true picture of the world but instead is a controlled hallucination generated by our minds allows us to explain such experiences. As in a dream, the brain is pushed into a creative mode where it is especially decoupled from the sensory data coming from the world around. Certain contents, such as snakes and eyes, can be readily explained by the idea that they reflect deeply programmed visual patterns that are relevant to survival.
Not all of the contents fit neatly into this interpretation however, with visions of technology being particularly difficult to account for. One speculative explanation for such visions is that they reflect geometric hallucinations varying in three dimensions of space and in time.
When having the experience of moving to another dimension it is common to experience passage down a tunnel. It has been suggested by “the Godfather of LSD”, Stan Grof, that the tunnel experience is a memory of the experience of birth, although the fact that those born by cesarean section can still experience tunnels seems to rule this explanation out. Neurobiologist Jack Cowan has argued that spontaneous activity moving across the visual cortex might translate into the experience of concentric rings, as a result of the way that the retina maps onto the surface of the cortex .
Dramatic psychedelic experiences can feel like they reflect actual experiences of pre-existing phenomena that exist outside oneself, rather than being generated from within. This shouldn’t be a surprise as our perception always presents us with the feeling of an objective reality outside of ourselves, even though it is a controlled hallucination created inside us.
The nature of these experiences has led some scientists and philosophers to suggest that the material world is secondary to another reality that we interact with in these states, this ultimate reality varying from a spiritual realm, other dimensions, baseline reality in which our current world is merely a simulation, or a universal consciousness that underpins reality itself. The challenge of these perspectives, other than overturning the current prevailing paradigm, is to explain why low doses produce effects that are so readily explained by our understanding of how normal perception functions in the brain, and at high doses why these other worlds are show patterns that are biologically relevant to us, such as human eyes and natural imagery.
Seeing Under the Hood
Psychedelic experiences can allow us to delve into our deepest personal programming and beyond into our deepest evolutionary programming, bequeathed to us by countless ancestors. Understanding the origin of psychedelic visions as coming from within does not reduce their meaning. We get the opportunity to explore ancient patterns on which our sense of meaning itself is scaffolded, we may confront aspects of Jung’s collective unconscious or realize how our visions connect us in time to our unimaginably long past as an evolved creature. Understanding how such experiences are generated, while interesting, is not necessary to derive pleasure and benefit from them. The value really is in the experience itself, whatever is going on behind the scenes.
 Cowan, J. D. 1982. Spontaneous symmetry breaking in large-scale nervous activity International Journal of Quantum Chemistry, 22:1059-1082.