The computer-assisted hypnosis scale : reliability and validity investigations of a computer-administered measure of hypnotic ability

This research investigates the reliability and validity of the Computer-Assisted Hypnosis Scale (CARS), a twelve-item computer-administered hypnotic ability scale. In a counterbalanced, within-subjects, repeated measures design, 130 subjects experienced both a computerized hypnosis (CARS) and a hetero-hypnosis (SRSSrC). For each hypnosis, responsiveness was assessed along three dimensions: behavioral (using the CARS and SRSS:C), subjective depth (using the Field Depth Inventory), and relational involvement (using the Archaic Involvement Measure). Subjects also completed a SRSS:C self-scoring measure and the Tellegen Absorption Scale. The CARS was shown to be a psychometrically sound instrument for measuring hypnotic ability. The various dimensions of CARS hypnotic responsiveness were highly positively related, and the CARS compared favorably with the SRSS:C across the three dimensions assessed. However, an unexpected interaction effect emerged: For the three dimensions of hypnotic responsiveness assessed, SRSS:C scores were lower when the SRSS:C was preceded by a CARS than when the SRSS:C administration was first. CARS scores for the three dimensions were not significantly affected regardless of whether or not a SRSS:C administration preceded the CARS administration. Results are discussed in terms of the theory and practice of hypnotic ability assessment, and directions for future research are noted.