Proceedings of the Annual Meeting of the Cognitive Science Society

Controlled clinical trials using LSD, psilocybin, ayahuasca to treat major mood disorders and addictions have recentlyachieved significant results. Psychedelic drugs cause acute alterations in visual object perception, where object borderswithin the visual scene exhibit illusory rhythmic movements. What is the relationship between the perceptual effectsand the clinical efficacy of psychedelic drugs? Here, I sketch a novel hypothesis to link the perceptual phenomenologyof psychedelic drugs with their clinical efficacy. I propose that psychedelics temporarily suspend statistical regulari-ties (Bayesian priors) accumulated through past experience across perceptual, affective, and cognitive domains of neuralinformation processing. This temporary unlearning of established priors can explain both the destabilization of visualperception and the potential for psychedelics to disrupt unwanted patterns of thinking and emotion associated with mooddisorders and addictions. I support these hypotheses with plausible neurobiological mechanisms and empirical data fromneurophysiological and clinical studies with psychedelic drugs in humans.