The distribution and factor structure of hypnosis scores following intervention

Abstract

An intervention procedure was found to produce significant gains in hypnotic performance in a sample of 90 SS. It was argued that the postintervention mres could be regarded as a measure of asymptotic rather than average hypnotizability. The distribution and factor structure of these scores were then consid ered to see whether these differed from what is generally found when average hypnotizability is measured. Using Orne and O'Connell's (1967) Diagnostic Rating Scales, a trimodd distribution was obtained with the modes falling at the top of the ideomotor passive range, the bottom of the cognitive range, and the middle of the classic somnambulist” range. Analysis of subscale scores based on this distribution indicated the presence of a trait of general hypnotic competence. A 3-factor solution gave a strong general hypnotic factor, best represented by challenge items, a second ideomotor passive factor, and a third factor which could represent either a diaculty or a dissociation dimension. A 4-factor solution reduced the generality of the first factor, gave it more the appearance of a challenge factor, and introduced a strong imagery factor along with a passive ideomotor and a posthypnotic suggestiodnegative hallucination factor. The size of the unrotated first factor was found to compare favorably with that obtained in other studies: this could be interpreted as meaning that the effect of training is to increase the size of the general factor in hypnotic performance. It is suggested that the 3 modes may represent 3 hierarchically arranged “ideal types” of hypnotic response, and that the effect of training has been to push members of the 3 classes closer towards their paradigm.