Computational spirits: a neuroscientific account of psychedelic entity encounters.

Under the influence of psychedelics, people often report encountering "entities" who seem to have their own autonomous agency. Depending on the cultural milieu, these entities are reported to take a variety of forms, including spirits, elves, ancestors, or fragments of the self. Encounters with such beings hold a central place in many traditions of psychedelic practice around the world. And yet, mechanistic accounts of these experiences are scarce in the neuroscientific literature. Here, we propose a neurocomputational model to account for experiences of entities, focusing primarily on those occasioned by the serotonergic psychedelic N,N-dimethyltryptamine. Our model builds on earlier theoretical accounts, including the entropic brain model of psychedelics, computational accounts of the felt presence of other minds, and theories of self-other discrimination based on sensory attenuation. We synthesize and expand on these perspectives through an overarching physics-based approach to cognition and brain function-the active inference framework. We propose that the general effects of psychedelics on large-scale neural dynamics may shape the way the brain comes to infer and interpret agentic presences. In particular, the reduction in the predictability of sensory perceptions during the psychedelic state may incline the brain to interpret perceptions, both internal and external, as resulting from non-self-agentic sources. In specifying the neurocomputational mechanisms, our model aims to explain how the brain supports entity encounters while also accounting for the diversity (and similarity) of these experiences across cultural contexts.