Deborah L. Fishman

Bio: Deborah L. Fishman is an academic researcher. The author has contributed to research in topics: Recall & Amnesia. The author has an hindex of 2, co-authored 2 publications receiving 328 citations.

Disrupted Retrieval in Directed Forgetting: A Link With Posthypnotic Amnesia

Abstract: 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.

Mechanisms of hypnotic and nonhypnotic forgetting.

Abstract: Subjects participated in two experimental sessions designed to study laboratory-induced amnesia, one using a standard hypnosis paradigm and one using a non-hypnotic directed-forgetting paradigm. Two independent sources of variation were derived from the hypnotic amnesia data: retrieval inhibition and inhibition release. In the nonhypnotic directed-forgetting procedure, some items were cued to be forgotten shortly after presentation and some were cued to be remembered. At test, the subjects were asked to recall both the to-be-remembered and the to-be-forgotten items. Over 39% of the variance in the recall of the to-be-forgotten items could be accounted for by the inhibition and release constructs obtained with hypnosis. These relations between the two procedures were not mediated by verbal ability or cognitive style (field independence). We concluded that the mechanisms of forgetting involved in laboratory demonstrations of hypnotic and nonhypnotic amnesia are related, and the implication is that some of them are the same, namely, retrieval inhibition and inhibition release. We also argued that the possible demand characteristics that accompany the hypnosis procedure are not apparent with the nonhypnotic procedure. Therefore, the relationships observed in the present results were taken as evidence that hypnotically induced amnesia is not entirely the result of subjects' reactions to demand characteristics. Language: en

Paradoxical Effects of Thought Suppression

Abstract: In a first experiment, subjects verbalizing the stream of consciousness for a 5-min period were asked to try not to think of a white bear, but to ring a bell in case they did. As indicated both by mentions and by bell rings, they were unable to suppress the thought as instructed. On being asked after this suppression task to think about the white bear for a 5-min period, these subjects showed significantly more tokens of thought about the bear than did subjects who were asked to think about a white bear from the outset. These observations suggest that attempted thought suppression has paradoxical effects as a self-control strategy, perhaps even producing the very obsession or preoccupation that it is directed against. A second experiment replicated these findings and showed that subjects given a specific thought to use as a distracter during suppression were less likely to exhibit later preoccupation with the thought to be suppressed.

Suppressing unwanted memories by executive control

Abstract: Freud proposed that unwanted memories can be forgotten by pushing them into the unconscious, a process called repression1. The existence of repression has remained controversial for more than a century, in part because of its strong coupling with trauma, and the ethical and practical difficulties of studying such processes in controlled experiments. However, behavioural and neurobiological research on memory and attention shows that people have executive control processes directed at minimizing perceptual distraction2,3, overcoming interference during short and long-term memory tasks3,4,5,6,7 and stopping strong habitual responses to stimuli8,9,10,11,12,13. Here we show that these mechanisms can be recruited to prevent unwanted declarative memories from entering awareness, and that this cognitive act has enduring consequences for the rejected memories. When people encounter cues that remind them of an unwanted memory and they consistently try to prevent awareness of it, the later recall of the rejected memory becomes more difficult. The forgetting increases with the number of times the memory is avoided, resists incentives for accurate recall and is caused by processes that suppress the memory itself. These results show that executive control processes not uniquely tied to trauma may provide a viable model for repression.

Working-memory capacity, proactive interference, and divided attention: limits on long-term memory retrieval.

Abstract: Two experiments examined how individual differences in working-memory capacity (WM) relate to proactive interference (PI) susceptibility We tested high and low WM-span participants in a PI-buildup task under single-task or dual-task ("load") conditions In Experiment 1, a finger-tapping task was imposed during encoding and retrieval of each list; in Experiment 2, tapping was required during encoding or retrieval In both experiments, low spans showed greater PI than did high spans under no load, but groups showed equivalent PI under divided attention Load increased PI only for high spans, suggesting they use attention at encoding and retrieval to combat PI In Experiment 2, only low spans showed a dual-task cost on List 1 memory, before PI built up Results indicate a role for attentional processing, perhaps inhibitory in nature, at encoding and retrieval, and are discussed with respect to theories of WM and prefrontal cortex function

A context maintenance and retrieval model of organizational processes in free recall

Abstract: The authors present the context maintenance and retrieval (CMR) model of memory search, a generalized version of the temporal context model of M. W. Howard and M. J. Kahana (2002a), which proposes that memory search is driven by an internally maintained context representation composed of stimulus-related and source-related features. In the CMR model, organizational effects (the tendency for related items to cluster during the recall sequence) arise as a consequence of associations between active context elements and features of the studied material. Semantic clustering is due to longstanding context-to-item associations, whereas temporal clustering and source clustering are both due to associations formed during the study episode. A behavioral investigation of the three forms of organization provides data to constrain the CMR model, revealing interactions between the organizational factors. Finally, the authors discuss the implications of CMR for their understanding of a broad class of episodic memory phenomena and suggest ways in which this theory may guide exploration of the neural correlates of memory search.