Instructed forgetting: hypnotic and nonhypnotic.

In a commentary on an article by Geiselman, Bjork, and Fishman (1983), directed forgetting observed in the normal waking state is compared with amnesia as induced by hypnotic suggestion. The two paradigms typically differ with respect to the role of incidental or intentional learning, the amount of study devoted to the items, the temporal location of the cue to forget, the retention interval involved, and the measure of memory that is of interest. Depending on the directed-forgetting paradigm used, they also differ with respect to the actual inaccessibility of the to-be-forgotten items, the reversibility of the forgetting, and the extent of interference of the items targeted by the forget cue on other items. However, these comparisons are vitiated somewhat by the methodological differences between the two paradigms. Theoretically, the three mechanisms typically used to account for directed forgetting--selective rehearsal, list segregation, and selective search--do not appear to account for the amnesia observed in hypnosis. However, the two phenomena do appear to share a fourth mechanism, retrieval inhibition. Final acceptance of this conclusion, however, awaits comparison of the two types of instructed forgetting within a common experimental paradigm.