Involuntariness of Response on the Harvard Group Scale of Hypnotic Susceptibility

Following a tape-recorded administration of the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) of Shor and E. Orne (1962), some 272 Ss recorded their objective responses in the standard scoring booklet and then rated the voluntariness-involuntari-ness of their responses to each HGSHS:A item. The ratings indicated that in about 75% of the instances where HCSHS:A items were objectively passed, Ss experienced their response as completely or mostly involuntary, and this percentage did not differ between ideomotor items and the more difficult challenge items. For a subset of 35 Ss tested on the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) of Weitz-enhoffer and Hilgard (1962), SHSS:C score was predicted reliably by HGSHS:A objective score. Thus, HGSHS:A is an adequate predictor of hypnotic susceptibility according to a criterion measure (SHSS:C), in spite of the fact that individual HGSHS:A items are not perfect measures of the classical suggestion effect according to the criterion of involuntar-iness. Ss with higher HCSHS:A scores had significantly higher mean involuntariness ratings for passed items than did lower scoring Ss.