How Level is the 'Cognitive Playing Field'?


Set and Setting

How to Cite

Martin, J. M., & Sterzer, P. (2022). How Level is the ’Cognitive Playing Field’? Context Shapes Alterations in Self-Conception During the Psychedelic Experience. Philosophy and the Mind Sciences, 3.


In Philosophy of Psychedelics, Letheby provides a convincing basis for the idea that psychedelics primarily derive their therapeutic potential through mediating favourable changes to self-related belief systems. In this commentary, we take a closer look at the role that contextual factors (‘set’ and ‘setting’) play in Letheby’s two-factor account of psychedelic therapy. While Letheby acknowledges that psychedelic effects are highly context-dependent, the exact role that context plays in self-modelling during the acute experience is not entirely clear. We argue that context plays an essential role in shaping the ‘discovery’ of alternate self-conceptions during the acute experience. Specifically, users are more likely to experience alterations in self-conception that are consistent with context-dependent features, such as one’s prior mindset (‘set’) and aspects of the external environment (‘setting’). This is consistent with a REBUS model of psychedelic effects, where a corollary effect of relaxing high-level prior beliefs is that the system becomes increasingly sensitised to bottom-up information (‘prediction errors’) from lower-level intrinsic sources and the sensory periphery. Furthermore, it may explain why a positive well-intentioned state of mind and a supportive therapeutic environment are more likely to result in positive acute experiences and long-term improvements in mental wellbeing. We see this position as being largely compatible with Letheby’s proposal, but may shift some aspects of its emphasis and framing. In particular, it may conflict with Letheby’s notion that psychedelics lead to a ‘level cognitive playing field’, where self-related hypotheses are thought to be assigned more or less equal probability.


Beliveau, V., Ganz, M., Feng, L., Ozenne, B., Højgaard, L., Fisher, 355 P. M., Svarer, C., Greve, D. N., & Knudsen, G. M. (2017). A high-resolution in vivo atlas of the human brain’s serotonin system. Journal of Neuroscience, 37(1), 120–128.

Carbonaro, T. M., Bradstreet, M. P., Barrett, F. S., MacLean, K. A., Jesse, R., Johnson, M. W., & Griffiths, R. R. (2016). Survey study of challenging experiences after ingesting psilocybin mushrooms: Acute and enduring positive and negative consequences. Journal of Psychopharmacology, 30(12), 1268–1278.

Carhart-Harris, R. L., & Friston, K. (2019). REBUS and the anarchic brain: Toward a unified model of the brain action of psychedelics. Pharmacological Reviews, 71(3), 316–344.

Carhart-Harris, R. L., & Nutt, D. J. (2017). Serotonin and brain function: A tale of two receptors. Journal of Psychopharmacology, 31(9), 1091–1120.

Carhart-Harris, R. L., Roseman, L., Haijen, E., Erritzoe, D., Watts, R., Branchi, I., & Kaelen, M. (2018). Psychedelics and the essential importance of context. Journal of Psychopharmacology, 32(7), 725–731.

Clark, A. (2015). Surfing Uncertainty: Prediction, Action, and the Embodied Mind. Oxford University Press. Corlett, P. R., Honey, G. D., & Fletcher, P. C. (2016). Prediction error, ketamine and psychosis: An updated model. Journal of Psychopharmacology, 30(11), 1145–1155.

Corlett, P. R., Horga, G., Fletcher, P. C., Alderson-Day, B., Schmack, K., & Powers III, A. R. (2019). Hallucinations and strong priors. Trends in Cognitive Sciences, 23(2), 114–127.

Gashi, L., Sandberg, S., & Pedersen, W. (2021). Making “bad trips” good: How users of psychedelics narratively transform challenging trips into valuable experiences. International Journal of Drug Policy, 87, 102997.

Griffiths, R. R., Johnson,M.W., Carducci,M. A., Umbricht, A., Richards,W. A., Richards, B. D., Cosimano,M. P., & Klinedinst, M. A. (2016). Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial. Journal of Psychopharmacology, 30(12), 1181–1197.

Grof, S. (1994). Crisis intervention in situations related to unsupervised use of psychedelics. In LSD Psychotherapy. Hunter House Publishers.

Gukasyan, N., & Nayak, S. M. (2021). Psychedelics, placebo effects, and set and setting: Insights from common factors theory of psychotherapy. Transcult Psychiatry. https://doi:10.1177/1363461520983684

Haijen, E. C., Kaelen, M., Roseman, L., Timmermann, C., Kettner, H., Russ, S., Nutt, D., Daws, R. E., Hampshire, A. D., & Lorenz, R. (2018). Predicting responses to psychedelics: A prospective study. Frontiers in Pharmacology, 897.

Hartogsohn, I. (2016). Set and setting, psychedelics and the placebo response: An extra-pharmacological perspective on psychopharmacology. Journal of Psychopharmacology, 30(12), 1259–1267.

Hartogsohn, I. (2018). The meaning-enhancing properties of psychedelics and their mediator role in psychedelic therapy, spirituality, and creativity. Frontiers in Neuroscience, 12, 129.

Hohwy, J. (2013). The Predictive Mind. Oxford University Press.

James, E., Robertshaw, T. L., Hoskins, M., & Sessa, B. (2020). Psilocybin occasioned mystical-type experiences. Human Psychopharmacology: Clinical and Experimental, 35(5), e2742.

Kaertner, L. S., Steinborn, M. B., Kettner, H., Spriggs, M. J., Roseman, L., Buchborn, T., Balaet, M., Timmermann, C., Erritzoe, D., & Carhart-Harris, R. L. (2021). Positive expectations predict improved mental-health outcomes linked to psychedelic microdosing. Scientific Reports, 11(1), 1–11.

Lavazza, A. (2017). Ways of being well: Realistic and unrealistic well-being. In L. Tadio (Ed.), New Perspectives on Realism, 237–252. Mimesis International.

Leary, T., Litwin, G. H., & Metzner, R. (1963). Reactions to psilocybin administered in a supportive environment. Journal of Nervous and Mental Disease, 137(6), 561–573.

Leary, T., Metzner, R., & Alpert, R. (1964). The Psychedelic Experience: A Manual Based on the Tibetan Book of the Dead. New York: University Press Books.

Letheby, C. (2021). Philosophy of Psychedelics. Oxford University Press.

Masters, R., & Houston, J. (2000). The Varieties of Psychedelic Experience: The Classic Guide to the Effects of LSD on the Human Psyche. Simon and Schuster.

McGovern, H. T., Leptourgos, P., Hutchinson, B., & Corlett, P. R. (2021). Do psychedelics change beliefs? PsyArXiv Preprints. https://10.31234/

Metzner, R., Litwin, G., & Weil, G. (1965). The relation of expectation and mood to psilocybin reactions: A questionnaire study. Psychedelic Review, 5, 3–39.

Noorani, T., & Alderson-Day, B. (2020). Spotlight commentary: REBUS and the anarchic brain. Neuroscience of Consciousness, 2020(1), niaa007.

Noorani, T., Garcia-Romeu, A., Swift, T. C., Griffiths, R. R., & Johnson, M. W. (2018). Psychedelic therapy for smoking cessation: Qualitative analysis of participant accounts. Journal of Psychopharmacology, 32(7), 756–769.

Roseman, L., Nutt, D. J., & Carhart-Harris, R. L. (2018). Quality of acute psychedelic experience predicts therapeutic efficacy of psilocybin for treatment-resistant depression. Frontiers in Pharmacology, 8, 974.

Ross, S. (2018). Therapeutic use of classic psychedelics to treat cancer-related psychiatric distress. International Review of Psychiatry, 30(4), 317–330.

Ross, S., Bossis, A., Guss, J., Agin-Liebes, G., Malone, T., Cohen, B., Mennenga, S. E., Belser, A., Kalliontzi, K., Babb, J., Su, Z., Corby, P., & Schmidt, B. L. (2016). Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: A randomized controlled trial. Journal of Psychopharmacology, 30(12), 1165–1180.

Safron, A. (2020). On the varieties of conscious experiences: Altered beliefs under psychedelics (ALBUS). PsyArXiv Preprints. https://10.31234/

Sterzer, P., Adams, R. A., Fletcher, P., Frith, C., Lawrie, S. M., Muckli, L., Petrovic, P., Uhlhaas, P., Voss, M., & Corlett, P.R. (2018). The predictive coding account of psychosis. Biological Psychiatry, 84(9), 634–643.

Studerus, E., Gamma, A., Kometer, M., & Vollenweider, F. X. (2012). Prediction of psilocybin response in healthy volunteers. PloS One, 7(2), e30800.

Timmermann, C., Kettner, H., Letheby, C., Roseman, L., Rosas, F. E., & Carhart-Harris, R. L. (2021). Psychedelics alter metaphysical beliefs. Scientific Reports, 11(1), 1–13.

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Copyright (c) 2022 Joshua M. Martin, Philipp Sterzer