Consciousness Modulations in Hypnosis: the Case of the Sense of Agency

The present work proposes an explanation of agency modulations in the context of hypnotic suggestions referred to as “motor suggestions”. During motor suggestions, individuals are asked to imagine that a specific movement (e.g. raising the arm) will execute by itself. A feeling of passivity usually accompanies these suggested movements. The explanation we are proposing postulates two things. First, it assumes that motor suggestions generate a prior of passivity in the subject, which, in turn, produces specific sensory predictions. In particular, it predicts that sensory feedback (e.g. proprioceptive feedback) linked to the suggested movement should be associated with high precision (the inverse of variance), as in the case of a truly passive action. Second, it hypothesises that actual sensory feedback is associated with high precision owing to attentional modulations. Therefore, the matching between predicted and actual sensory signals leads to the feeling of passivity accompanying suggested movements.