Experimental procedure
The experimental sessions took place in the afternoon, between 3 and 5 p.m., at least 3 hours after the last meal and caffeine containing beverages intake, in a sound and light attenuated, temperature controlled (22°C) room. Alcohol consumption was prohibited during the preceding 24 hours. On the day of the experimental session, all participants completed the Tellegen Absorption Scale (TAS, Tellegen & Atkinson, 1974; Tellegen, 1981) whose score indicates the proneness to be deeply absorbed in mental activities (range: 1-34). They were also interviewed about the last night sleep satisfaction (range: 0-10) and were invited to sit in an armchair with their head, legs and arms supported, and prepared for EEG recording. Finally, they were informed that every instruction will be given to them by the same experimenter sitting nearby and that at a certain point they will have to listen to a pre-recorded voice (SHSS, A induction modified owing to the direct request to close eyes in R). The experimental session consisted of open eyes baseline (B, 3 min), closed eyes relaxation (R, 3 min), hypnotic induction modified from the SHSS, A (IND, divided into IND1 and IND2, 3 min each), neutral hypnosis (NH, 3 min), Post (post hypnosis, 3 min). At the end of the session participants were invited to score the degree of change in the state of consciousness experienced during the session (range: 0-10). None of the participants showed EEG sleep episodes.