Abstract: Instructing people to forget a list of items often leads to better recall of subsequently studied lists (known as the benefits of directed forgetting). The authors have proposed that changes in study strategy are a central cause of the benefits (L. Sahakyan & P. F. Delaney, 2003). The authors address 2 results from the literature that are inconsistent with their strategy-based explanation: (a) the presence of benefits under incidental learning conditions and (b) the absence of benefits in recognition testing. Experiment 1 showed that incidental learning attenuated the benefits compared with intentional learning, as expected if a change of study strategy causes the benefits. Experiment 2 demonstrated benefits using recognition testing, albeit only when longer lists were used. Memory for source in directed forgetting was also explored using multinomial modeling. Results are discussed in terms of a 2-factor account of directed forgetting.

Abstract: Explanations of directed forgetting—the poorer memory for information that we are instructed to forget (F items) than for information that we are instructed to remember (R items)—have featured two classes of accounts: rehearsal and retrieval. Under the rehearsal account, the argument has consistently been that R items are selectively rehearsed more than F items. Retrieval accounts have been more varied, but the concept of retrieval inhibition has become prevalent, the idea being that F items are suppressed following a forget instruction. For the last 10–15 years, these two explanations have been attached to the two most common procedures in directed forgetting studies: selective rehearsal to the item method, where individual items are randomly assigned instructions, and retrieval inhibition to the list method, where half the list is designated as to-be-forgotten. We report serial position and test warning effects that demonstrate clear selective rehearsal effects in the list procedure. We argue that a separate retrieval inhibition account of the list method is not parsimonious; rather, a selective rehearsal explanation can readily accommodate the principal results obtained under both procedures.

Abstract: Two diary experiments demonstrated directed forgetting (DF) of autobiographical events, previously observed only for less complex memory items. Using a 2-week diary paradigm, we compared recall between a group of participants who were directed to forget Week 1 memories (forget group) and a group who did not receive a forget instruction (remember group). In Experiment 1, the forget group remembered fewer items from Week 1 than did the remember group. The effect was observed for negative and positive valence events, as well as for high and low emotional intensity events. The effect was replicated in Experiment 2 despite a memorable holiday (Valentine's Day) that occurred during the manipulation week. Forget participants remembered fewer low emotional intensity items in Experiment 2. We conclude that intentional forgetting is a plausible explanation for the loss of some autobiographical memories.

Abstract: In three experiments, we investigated the effect of recall order on directed forgetting when the within-participants list method is used. Experiment 1 showed that participants tend to recall to-beremembered (R) items before to-be-forgotten (F) items when they can recall items in any order. In Experiment 2, recall order was manipulated (F-R or R-F). The results showed that only the R-F order led to directed forgetting. Finally, in Experiment 3, recall order was also manipulated, and half of the participants were explicitly instructed to use a relational strategy when both F and R items were presented. Again, only the R-F order led to directed forgetting. These results demonstrate that directed forgetting under the list method hinges on the output order in which participants recall the F and R information. Thus, output order should be taken into account by researchers investigating specific mechanisms that lead to directed forgetting.

Abstract: Acute stress disorder is characterized by dissociative responses that are theorized to result in deficient encoding and retrieval of trauma-related material. This study examined retrieval inhibition using the list method of the directed forgetting paradigm in traumatized individuals with acute stress disorder (ASD; n = 14), no ASD (n = 14), and a nontraumatized control group (n = 15). Participants were presented with a list of intermixed positive, neutral, and trauma-related words. Instructions to forget that list and instead remember a second list were then given, and a new list presented. ASD participants exhibited poorer recall of to-be-forgotten trauma words than the non-ASD and control groups. The ASD group also demonstrated deficient recognition of to-be-remembered and to-be-forgotten positive words. Severity of acute posttraumatic stress response was associated with retrieval impairments. The cumulative findings suggest that ASD is associated with impoverished memory for trauma-related and positive material.

Abstract: We hypothesized that patients with bipolar disorder would demonstrate verbal recognition performance deficits consistent with processing efficiency theory, a theory about how emotional states modulate performance by interfering with working memory resources or increasing cognitive arousal/effort. We predicted that (1) a manic group (n=26) would demonstrate slow reaction time (RT) and low accuracy, (2) a euthymic group (n=23) would demonstrate slow RT to maintain high accuracy; and (3) a healthy comparison group (n=25) would demonstrate fast RT and high accuracy. The groups were administered symptom-rating scales and compared on a computerized, trial-by-trial, directed forgetting in recognition task. This task requires participants to comply with an overt instruction to forget irrelevant studied words, and it places a relatively high demand on working memory. The manic group was impaired on directed-forgetting sensitivity; however, when RT was statistically controlled, the groups demonstrated similar directed-forgetting effects. These findings are consistent with processing efficiency theory. They suggest that bipolar patients perform directed forgetting in recognition by increasing effortful control at encoding at the expense of processing efficiency, although acute mania reduces the capacity for control, thereby impairing recognition performance. Problems with processing efficiency are viewed as trait characteristics of bipolar disorder that may be overlooked by traditional error-based assessments.

Abstract: Directed forgetting may reduce the ORM false memory illusion by interfering with meaning processing. Participants were presented with a list composed of six 10-word semantically associated sub-list...

Abstract: The repeated recall of items from lists that participants were earlier instructed to either remember or to forget was examined in two experiments. RR participants (those instructed to remember both lists they were presented) tended to recall more List 1 items than FR participants (those instructed to forget the first list and to remember the second list). FR participants recalled more List 2 items than did RR participants, but only when directed to report those items (Experiment 1), not when directed to report items from both lists (Experiment 2). Participants experienced difficulty correctly reporting the list source of items they recalled and incorrect source recall increased across tests, showing hypermnesia. This later result underscores the need for caution when assessing the accuracy of information retrieved from multiple sources across repeated tests. Together, the data patterns provide support for the retrieval dynamics account of hypermnesia, the context-change account of directed forgetting, and limited support for the retrieval inhibition view of directed forgetting.

Abstract: Directed forgetting is shown as impaired performance on a memory test following an instruction that the presented items will not be tested. Experiments utilizing the delayed matching-to-sample (DMTS) task have demonstrated that this ability to actively control memory is present in animals; however, no study has yet confirmed that cues to forget established in one DMTS discrimination will successfully transfer to other discriminations. Lacking such evidence, it is not clear whether forgetting cues act as “higher level” task instructions or are represented more simply, perhaps as part of a sample-specific sequence of events. The present study revealed good transfer of the forget cue function in pigeons after prior training with the forget cues in a separate discrimination. This finding is discussed in relation to analogous experiments on occasion setting, in which training within more than one discriminative context has been shown to be critical to the transfer of a conditional relation.

Abstract: The current study examined the influence of directed forgetting instructions on children's memory for an event. Children between the ages of five and seven years learned a magic trick containing eight critical details. The play session leader instructed the children to forget four details and to remember the remaining details. Either one week or six weeks after the play session children were misinformed about half of the details and an interviewer later asked children to recall their play experiences. In cued recall, children generated more correct responses for remember-cued details than forget-cued details after a one-week delay but not after a six-week delay. There was also a trend toward children providing more false suggested responses for forget-cued details than remember-cued details. Relevance and implications of these results for child witnesses are discussed, as well as directions for future research.