Measuring agency change across the domain of hypnosis


Building on Hilgard’s (1965) classic work, the domain of hypnosis has been conceptualized by Barnier, Dienes, and Mitchell (2008) as comprising 3 levels that represent distinct aspects of hypnotic phenomena: a) responses to different types of hypnotic suggestions, b) varying patterns of response over the phases of a suggestion, and c) the impact of state and trait influences. The current experiment investigates sense of agency across each of these three levels. Forty-six high hypnotizable participants completed an ideomotor (arm levitation), a challenge (arm rigidity), and a cognitive (anosmia) item, with or without a hypnotic induction. In a postexperimental inquiry, participants rated their feelings of control at three time points for each item: during the suggestion, test, and cancellation phases. They also completed the Sense of Agency Rating Scale (Polito, Barnier, & Woody, 2013) for each item. Pass rates and control ratings fluctuated across the different types of items and the three phases of each item; control ratings and agency scores also differed between participants who passed and failed each item. In addition, whereas a hypnotic induction influenced the likelihood of passing items, it had no direct effect on agentive experiences. These results suggest that altered sense of agency is not a unidimensional or static quality ‘switched on’ by hypnotic induction, but a dynamic multidimensional construct that varies across items, over time, and according to whether individuals pass or fail suggestions.

Psychology of Consciousness: Theory, Research, and Practice, (1), 1, pp. 3–19,