Beyond Bayesian integration: how meaning shapes placebo effects.

Placebo effects illustrate how strongly expectations can shape symptom perception and treatment outcomes. Contemporary Bayesian accounts have provided valuable insights by formalising how expectations are integrated with sensory information. However, such accounts can struggle to explain why treatment expectations persist despite disconfirming evidence and why placebo responses vary widely across individuals. We argue that placebo effects arise from richer inferential processes in which the individual aims to make sense of their observations through inferred explanatory states that are shaped by their motivational preferences and guide the interpretation of treatment effects. Combining Bayesian principles with latent-state inference and higher-level beliefs provides a more comprehensive account of placebo effects and highlights new opportunities for neuroscience and clinical practice.