Optimal scoring of amnesia on the harvard group scale of hypnotic susceptibility, form A

Response to the suggestion for posthypnotic amnesia on the Harvard Group Scale of Hypnotic Susceptibility, Form A (Shor & E. Orne, 1962) was studied in a sample of 1351 Ss. Reversibility proved to be a somewhat better criterion of response than initial amnesia, as indexed by both item difficulty and item-to-total correlations. Continuous scoring of recall, however, was no better than dichotomous scoring. A joint dichotomous criterion, consisting of recall = s 3 on the initial amnesia test followed by recall 2 2 additional items on the reversibility test, is offered as both empirically defensible and conceptually preferable.