The effect of rating scale descriptors on hypnotic depth reports

The effect of varying number of response descriptors on hypnotic depth ratings was assessed. Following hypnotic susceptibility testing, subjects in one group (n = 111) rated their hypnotic depth on a unidimensional four-point scale with alternatives ranging from "not hypnotized" to "highly hypnotized." A second group (n = 111) responded to a four-point scale that confounded the two descriptors, hypnotic depth and degree of absorption. The alternatives on this scale ranged from "neither hypnotized nor absorbed" to "highly hypnotized and absorbed." Finally, those in a third group (n = 111) were given a scale that included degree of hypnosis and degree of absorption as separate descriptors. Thus, these subjects could rate themselves either as hypnotized to some degree or as "absorbed to some degree but not hypnotized." Substantially fewer subjects at all susceptibility levels rated themselves as "hypnotized to some degree" when given the scale with alternative descriptors as opposed to a scale that did not permit choice of descriptors. These data challenge the validity of measures of hypnotic depth and suggest caution in their interpretation.