Can hypnosis make you ticklish? Using suggestion to modulate agency.

Agency is the subjective sense of control we have over our actions. According to an influential model, this arises when the predicted sensory effects of movements match actual sensory feedback. Consistent with this, previous research found that mechanically manipulating the sensory consequences of actions creates the illusion that they are externally-produced. Across three experiments, we aimed to develop a hypnotic analogue and clarify specific components of hypnosis that contribute to alterations in agency. We compared different suggestions based on clinical impairments whist varying the hypnotisability of subjects and the presence of a hypnotic induction. We found that suggestions designed to model self-monitoring deficits increased perceived involuntariness of actions; these effects were stronger in high hypnotisable participants and after an induction; and could not be explained by demand characteristics alone. These results highlight the capacity of hypnosis to alter sense of agency and model deficits associated with clinical conditions using hypnosis.