Structure of communication and reports of involuntariness by hypnotic and nonhypnotic subjects

We hypothesized that phrasing a communication to move the arm as either a suggestion, a directive, or an instruction would differentially affect subjects' interpretations of the movement. 45 hypnotic and 45 nonhypnotic subjects who responded positively to a suggestion tended to describe the movement as involuntary both on open-ended questionnaires and later on an explicit involuntariness scale. Subjects given a directive to move the arm, or an instruction to reach for a pencil, rarely described their experience as involuntary on the open-ended questionnaires but sometimes rated it as involuntary on the scale. The ratings of involuntariness by subjects given suggestions seem likely to reflect interpretations made concurrently with the movement suggested. However, such ratings by subjects given directives or instructions are likely to reflect retrospective interpretations cued by the instrument used to assess subjects' experiences.