The Effects of List-Method Directed Forgetting on Recognition Memory

Article excerpt

It is an almost universally accepted claim that the list-method procedure of inducing directed forgetting does not affect recognition. However, previous studies have omitted a critical comparison in reaching this conclusion. This article reports evidence that recognition of material learned after cue presentation is superior for conditions in which the material that preceded cue presentation was designated as to-be-forgotten. Because the absence of an effect of directed-forgetting instructions on recognition is the linchpin of the theoretical claim that retrieval inhibition and not selective rehearsal underlies that effect, the present results call into question the need to postulate a role for inhibition in directed forgetting.

The directed-forgetting methodology, in which the effects of experimental instructions to forget a subset of studied material are examined, has undergone somewhat of a renaissance in the recent literature. This renewed interest probably derives in part from an influential and fascinating recently edited volume by Golding and MacLeod (1998), in which parallels are drawn between the basic experimental procedure and widely ranging phenomena of clinical, legal, and social interest. In the 7 years prior to the publication of that book, PsycINFO reports there were 37 entries that used the term directed forgetting; in the 7 years following its publication, there were 109. Some of the attention probably owes to the claim that directed forgetting involves memory inhibition, a claim that invites comparison with arguments about memory repression (Freud, 1915).

The central empirical finding that has been used to support the claim of memory inhibition in directed forgetting is that the list-method procedure-in which a cue to remember or forget the preceding material is placed in the middle of a list of studied items-appears to affect recall (see, e.g., R. A. Bjork, LaBerge, & Legrand, 1968) but not recognition (Block, 1971 ; Elmes, Adams, & Roediger, 1970) performance. This apparent dissociation contrasts with results from experiments that have used the itemmethod procedure, in which individual items are cued as to-be-remembered or to-be-forgotten immediately following their presentation. In that paradigm, to-be-forgotten items have been more poorly recalled and recognized (see, e.g., Davis & Okada, 1971; MacLeod, 1975). For recall, it has generally been accepted that selective rehearsal accounts well for the pattern of results (B. H. Basden, D. R. Basden, & Gargano, 1993).

In a comprehensive review of the work on directed forgetting, MacLeod (1998) listed the finding that listmethod directed forgetting leads to a null effect on recognition as one of the 12 most important findings in the field to date. However, there have actually been very few studies that directly assessed recognition memory using the list-method procedure, and they all shared an odd characteristic: They failed to report performance for all of the conditions relevant to the basic directed-forgetting effect. Early studies (Block, 1971; Elmes etal., 1970) reported recognition performance only for precue items, for which hit rates did not differ between cue conditions. B. H. Basden et al. (1993) tested both pre- and postcue items, but only for a group that received a forget cue: They did not include a control condition in which subjects received a remember cue between list halves. Performance did not differ between conditions in that experiment. Instead, a null effect was evident between pre- and postcue items in the group that received the forget instruction.

The purpose of the present study is to examine the full set of conditions relevant to the assessment of the directedforgetting effect. Two canonical findings are a sine qua non of that effect: (1)A forget instruction leads to poorer memory for the targeted material than does a remember instruction, and (2) a forget instruction leads to superior memory for materials learned following that instruction. …