Disrupted retrieval in directed forgetting: a link with posthypnotic amnesia.

Certain reliable findings from research on directed forgetting seem difficult to accommodate in terms of the theoretical processes, such as selective rehearsal or storage differentiation, that have been put forward to account for directed-forgetting phenomena. Some kind of "missing mechanism" appears to be involved. In order to circumvent the methodological constraints that have limited the conclusions investigators could draw from past experiments, a new paradigm is introduced herein that includes a mixture of intentional and incidental learning. With this paradigm, a midlist instruction to forget the first half of a list was found to reduce later recall of the items learned incidentally as well as those learned intentionally. This result suggests that a cue to forget can lead to a disruption of retrieval processes as well as to the alteration of encoding processes postulated in prior theories. The results also provide a link between intentional forgetting and the literature on posthypnotic amnesia, in which disrupted retrieval has been implicated. With each of these procedures, the information that can be remembered is typically recalled out of order and often with limited recollection for when the information had been presented. It therefore was concluded here that retrieval inhibition plays a significant role in nonhypnotic as well as in hypnotic instances of directed forgetting. The usefulness of retrieval inhibition as a mechanism for memory updating was also discussed.