Human Evolution – a Psychedelic Trip

Published by on November 18, 2023

When did humans branch off from our humanoid common ancestors and evolve into the distinct species we are today? Why and how did humans develop differently from our ape and chimpanzee relatives (Choi and LiveScience, 2023)?

The Stoned Ape hypothesis believes that humans developed our complex cognitive abilities from a diet consisting of psychedelic mushrooms (Rodríguez Arce and Winkelman, 2021). Further, this theory believes that approximately 2 million years ago, human ancestors began eating fungi that grew on animal dung. This type of mushroom had the compound psilocybin, which is believed to have increased neuroplasticity and led to the development of unique cognitive abilities (Micu, 2023). There is evidence to support the idea that humanoid ancestors began to utilize the forest floor for nutritional resources in the Pliocene era, where is geographic evidence suggests that a significant portion of the food being gathered was likely fungal species, including those with psychedelic properties. The ingestion of fungal species is presently demonstrated in primate diets (Hanson, Hodge and Porter, 2003). There are currently 200 known species of fungi that naturally produce psilocybin (Barron, 2023), an example of one of these species is Psilocybe cubenis, which can be seen in Figure 1. Further, there is insufficient evidence to answer the question of why mushrooms produce psilocybin. Currently, a popular hypothesis is that psilocybin repels insects and the psychoactive properties discourage large consumptions of the fruiting bodies (Meyer and Slot, 2023).

Figure 1: A photo of the psychedelic mushroom Psilocybe cubensis (Peter, 2023).

Psychedelics, specifically psilocybin, target vital receptors in the brain and alter the brain’s function. Psilocybin and the other psychedelics being ingested would have primarily targeted the serotonin 2A receptor subtype, which stimulates the brain’s capacity for adaptive cognitive changes. These changes could have developed in the form of enhanced linguistic, rationalization, cooperative communication, social learning abilities (Figure 2), and the development of religion and rituals. Furthermore, these abilities could have led to increased adaptability to an ever-changing environment and thereby increased fitness (Rodríguez Arce and Winkelman, 2021).

Figure 2: A model demonstrating the correlation between the ingestion of psychedelic plants and mushrooms the effects on cognition, sociality, communication and social learning (Rodríguez Arce and Winkelman, 2021).


The Stoned Ape hypothesis can be seen in current human behaviours and more recent historical human behaviours. For a historical example, we can look to ancient Rome, where there were seasonal rituals involving the ingestion of ergot (a fungus with psychedelic properties) and other psychedelics (George, et al., 2022).

However, the use of psychedelics in religion and rituals seemed to fall out of practice between ancient religions and the present day. It is in recent decades that Western medicine has begun to study psychedelics and their connection to mental health. Currently, numerous studies are seeking to determine treatment methods that use psilocybin to improve mental health. The focus of current research surrounds using psilocybin for the treatment of obsessive-compulsive disorders, eating disorders, depression, Alzheimer’s, as well as substance use disorders (Barron, 2023).

Ultimately, It will be interesting to see where this research continues and what is found in the years to come surrounding psychedelic treatment and psychedelic history, as so much is still unknown.



References:

Barron, M., 2023. Psilocybin and Mental Health: The Magic in the Mushrooms. [online] ASM.org. Available at: <https://asm.org:443/Articles/2023/February/Psilocybin-and-Mental-Health-The-Magic-in-the-Mush> [Accessed 30 January 2024].

Choi, C.Q., and LiveScience, 2023. Fossil Reveals What Last Common Ancestor of Humans and Apes Looked Like. [online] Scientific American. Available at: <https://www.scientificamerican.com/article/fossil-reveals-what-last-common-ancestor-of-humans-and-apes-looked-liked/> [Accessed 30 January 2024]

George, D.R., Hanson, R., Wilkinson, D. and Garcia-Romeu, A., 2022. Ancient Roots of Today’s Emerging Renaissance in Psychedelic Medicine. Culture, Medicine and Psychiatry, 46(4), pp.890–903. https://doi.org/10.1007/s11013-021-09749-y.

Hanson, A.M., Hodge, K.T. and Porter, L.M., 2003. Mycophagy among Primates. Mycologist, 17(1), pp.6–10. https://doi.org/10.1017/S0269915X0300106X.

Meyer, M. and Slot, J., 2023. The evolution and ecology of psilocybin in nature. Fungal Genetics and Biology, 167, p.103812. https://doi.org/10.1016/j.fgb.2023.103812.

Micu, A., 2023. The Stoned Ape Theory: The wild idea that psychedelics shaped the evolution of humans. [online] ZME Science. Available at: <https://www.zmescience.com/feature-post/history-and-humanities/anthropology-articles/stoned-ape-theory-feature/> [Accessed 30 January 2024]

Peter, J., 2023. Where Do Psilocybin Mushrooms Grow | sanctuarywellnessinstitute.com. [online] Available at: <https://sanctuarywellnessinstitute.com/blog/where-do-psilocybin-mushrooms-grow/> [Accessed 30 January 2024]

Rodríguez Arce, J.M. and Winkelman, M.J., 2021. Psychedelics, Sociality, and Human Evolution. Frontiers in Psychology, 12, p.729425. https://doi.org/10.3389/fpsyg.2021.729425.