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ABSTRACT: Sleep has repeatedly been connected to processes of memory consolidation. While extensive research indeed documents beneficial effects of sleep on memory, little is yet known about the role of sleep for interference effects in episodic memory. Although two prior studies reported sleep to reduce retroactive interference, no sleep effect has previously been found for proactive interference. Here we applied a study format differing from that employed by the prior studies to induce a high degree of proactive interference, and asked participants to encode a single list or two interfering lists of paired associates via pure study cycles. Testing occurred after 12 hours of diurnal wakefulness or nocturnal sleep. Consistent with the prior work, we found sleep in comparison to wake did not affect memory for the single list, but reduced retroactive interference. In addition we found sleep reduced proactive interference, and reduced retroactive and proactive interference to the same extent. The finding is consistent with the view that arising benefits of sleep are caused by the reactivation of memory contents during sleep, which has been suggested to strengthen and stabilise memories. Such stabilisation may make memories less susceptible to competition from interfering memories at test and thus reduce interference effects.
Memory 04/2013; · 2.09 Impact Factor
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ABSTRACT: Objective: Recent work in cognitive psychology suggests that testing can increase memory for both previously and subsequently studied information. Here we examined whether these beneficial (backward and forward) effects of testing generalize to individuals with severe traumatic brain injury (TBI). Method: Twenty-four persons with severe TBI, 12.7 years postinjury, and 12 healthy controls participated in the study. Participants studied three lists of items in anticipation of a final cumulative recall test. They were tested immediately between the study of lists or not. Results: Immediate testing of Lists 1 and 2 enhanced recall of both the previously studied information (Lists 1 and 2) and the subsequently studied information (List 3). The enhancement for the three lists arose for individuals with severe TBI and healthy controls, and did not differ in size between subject groups. Conclusion: The findings indicate that TBI persons show a very general benefit from testing, including both backward and forward effects of retrieval practice. Testing thus might be a powerful technique to improve learning and memory in persons with severe TBI. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
Neuropsychology 03/2013; 27(2):280-5. · 3.82 Impact Factor
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ABSTRACT: People can exert control over the contents of their memory and can intentionally forget information when cued to do so. The present study examined such intentional forgetting in older adults using the listwise directed forgetting (DF) task. We replicated prior work by finding intact forgetting in young-old adults (up to 75 years). Extending the prior work, we additionally found forgetting to decline gradually with individuals' age and to be inefficient in old-old adults (above 75 years). The results indicate that listwise DF is a late-declining capability, suggesting a deficit in very old adults' episodic memory control. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
Psychology and Aging 02/2013; · 2.73 Impact Factor
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ABSTRACT: When people are cued to forget previously studied irrelevant information and study new information instead, such cuing typically leads to forgetting of the precue information. But what do people forget if, before the forget cue is provided, both irrelevant and relevant information have been encoded? Using relatively short item lists, we examined in a series of three experiments whether participants are able to selectively forget the irrelevant precue information, when relevant and irrelevant precue items were presented subsequently in two separate lists (3-list task) and when the two types of items were presented alternatingly within a single list (2-list task). Selective forgetting of the irrelevant precue items arose in the 3-list task, independent of modality of item presentation and level of discriminability of the precue lists, and it arose in the 2-list task. The findings suggest that, at least with relatively short precue lists, participants may well be able to selectively forget irrelevant precue information when cued to do so. Implications of the results for theoretical accounts of list-method directed forgetting are discussed.
Memory & Cognition 01/2013; · 1.92 Impact Factor
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ABSTRACT: People's moods can influence moral judgment. Such influences may arise because moods affect moral emotion, or because moods affect moral thought. The present study provides evidence that, at least in the footbridge dilemma, moods affect moral thought. The results of two experiments are reported in which, after induction of positive, negative, or neutral moods and presentation of the footbridge scenario, participants were asked one of two differentially framed closing questions. In the active frame, participants were asked whether they would be active and push the man, making thoughts about pushing accessible; in the passive frame, they were asked whether they would be passive and not push the man, making thoughts about not pushing accessible. The results show that affective influences on moral judgment depended on participants' decision frame. Compared to neutral moods, positive moods induced utilitarian responding - i.e., deciding to push - in the active decision frame, but induced nonutilitarian responding - i.e., deciding to not push - in the passive decision frame; in negative moods, exactly the opposite picture arose. The results suggest that people's moods affect moral judgment by conferring value on moral thought. Positive moods promote and negative moods inhibit accessible thoughts.
Cognition 01/2013; 126(3):373-377. · 3.16 Impact Factor
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ABSTRACT: Results from numerous previous studies suggest that when subjects study items from different categories and then repeatedly retrieve, or restudy, some of the items from some of the categories, repeated retrieval, but not repeated study, induces forgetting of related unpracticed items. We investigated in two experiments whether such effects of pure retrieval and pure study practice generalize to mixed practice-that is, when retrieval and restudy trials are randomly interleaved within a single experimental block. Experiment 1 employed cued recall; Experiment 2 employed item recognition testing. In both experiments, pure repeated retrieval, but not pure repeated study, caused forgetting of related unpracticed items, which is consistent with the prior work. In contrast, with mixed practice, both retrieval and restudy induced forgetting. Thus, whereas retrieval caused forgetting regardless of practice mode, restudy caused forgetting with mixed practice, but not with pure practice. The finding provides first evidence for dynamic effects between retrieval and restudy trials when practice is mixed. It is consistent with the view that, with mixed practice, subjects engage in more retrieval during restudy trials, so that restudy trials may trigger similar processes as retrieval trials and, thus, induce forgetting of related, not restudied, items.
Memory & Cognition 01/2013; · 1.92 Impact Factor
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ABSTRACT: Recent work suggests a link between sleep and memory consolidation, indicating that sleep in comparison to wakefulness stabilizes memories. However, relatively little is known about how sleep affects forgetting. Here we examined whether sleep influences directed forgetting, the finding that people can intentionally forget obsolete memories when cued to do so. We applied the list-method directed forgetting task and assessed memory performance after 3 delay intervals. Directed forgetting was present after a short 20-min delay and after a 12-hr delay filled with diurnal wakefulness; in contrast, the forgetting was absent after a 12-hr delay that included regular nocturnal sleep. Successful directed forgetting after a delay thus can depend on whether sleep or wakefulness follows upon encoding: When wakefulness follows upon encoding, the forgetting can be successful; when sleep follows upon encoding, no forgetting may arise. Connections of the results to recent studies on the interplay between forgetting and sleep are discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved).
Journal of Experimental Psychology Learning Memory and Cognition 10/2012; · 2.85 Impact Factor
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ABSTRACT: Neural synchronization between distant cell assemblies is crucial for the formation of new memories. To date, however, it remains unclear whether higher-order brain regions can adaptively regulate neural synchrony to control memory processing in humans. We explored this question in two experiments using a voluntary forgetting task. In the first experiment, we simultaneously recorded electroencephalography along with fMRI. The results show that a reduction in neural synchrony goes hand-in-hand with a BOLD signal increase in the left dorsolateral prefrontal cortex (dlPFC) when participants are cued to forget previously studied information. In the second experiment, we directly stimulated the left dlPFC with repetitive transcranial magnetic stimulation during the same task, and show that such stimulation specifically boosts the behavioral forgetting effect and induces a reduction in neural synchrony. These results suggest that prefrontally driven downregulation of long-range neural synchronization mediates goal-directed forgetting of long-term memories.
Journal of Neuroscience 10/2012; 32(42):14742-51. · 7.11 Impact Factor
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ABSTRACT: Research in the past four decades has repeatedly shown that selective retrieval of some (non-target) memories can impair subsequent retrieval of other (target) information, a finding known as retrieval-induced forgetting. More recently, however, there is evidence that selective retrieval can both impair and enhance recall of related memories (K-H. T. Bäuml & Samenieh, 2010). To identify possible experimental dissociations between the detrimental and the beneficial effects of memory retrieval, we examined retrieval dynamics in listwise directed forgetting, varying the delay between preceding non-target and subsequent target recall. When target recall immediately followed non-target recall, we replicated the prior work and found detrimental effects of memory retrieval on to-be-remembered items but beneficial effects on to-be-forgotten items. In contrast, when a delay was introduced between non-target and target recall, the detrimental effects were present but the beneficial effects were absent. The results demonstrate a first experimental dissociation between the two effects of memory retrieval. They are consistent with a recent two-factor account of the two faces of selective memory retrieval.
Memory 05/2012; 20(5):478-86. · 2.09 Impact Factor
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ABSTRACT: Retrieval-induced forgetting (RIF) refers to the finding that retrieval of a subset of previously studied material can cause forgetting of related unpractised material. Prior work on the role of delay between practice and test for RIF reported mixed results. Whereas some studies found RIF to be a relatively transient phenomenon, others found RIF to persist over time. We examined whether the persistence of RIF can depend on whether wakefulness or sleep follows retrieval practice. We employed a variant of the retrieval-practice paradigm with short (20 minutes) and long (12 hours) delay conditions. In all conditions participants studied a perceptually categorised list followed by retrieval practice on some of the items from some of the categories. Participants studied and practised the material in the morning or the evening. RIF was present in the short-delay conditions, and it was present in the long-delay condition if the delay included nocturnal sleep; if the long delay was filled with diurnal wakefulness, RIF was absent. Results show that whether delay eliminates RIF or not can depend on whether sleep or wake follows retrieval practice. Connections of the results to recent findings about the role of delay and sleep for RIF are discussed.
Memory 05/2012; 20(5):420-8. · 2.09 Impact Factor
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ABSTRACT: In list-method directed forgetting, people are cued to forget a previously studied item list and to learn a new list instead. Such cuing typically leads to forgetting of the first list and to memory enhancement of the second, referred to as list 1 forgetting and list 2 enhancement. In the present study, two experiments are reported that examined influences of items' serial learning position in a list and the two lists' output order on list-method directed forgetting. The results show that list output order influences list 2 enhancement but not list 1 forgetting. The enhancement was higher when list 2 was recalled first than when list 1 was recalled first and, in both cases, was higher for early list 2 items than for middle and late list 2 items. In contrast, the forgetting was equally present for all list 1 items and did not depend on the two lists' output order. The findings suggest that two separate factors can contribute to list 2 enhancement: one (encoding) factor that is restricted to early list 2 items and does not depend on list output order, and another (retrieval) factor that pertains to all list 2 items and varies with the two lists' output order. A new two-mechanism account of directed forgetting is suggested that reconciles previous (encoding or retrieval) views on list 2 enhancement.
Memory & Cognition 05/2012; 40(6):861-73. · 1.92 Impact Factor
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ABSTRACT: Selectively retrieving a subset of previously studied information can cause forgetting of related, nonretrieved information. Such retrieval-induced forgetting (RIF) has typically been attributed to inhibitory control processes. Examining participants with a mean age of about 70 years, previous work reported intact RIF in older adults, suggesting efficient inhibition in older adults' episodic memory. We replicated the prior work by finding reliable RIF in young-old participants (60-75 years), but additionally found RIF to decline with increasing age and to be inefficient in old-old participants (above 75 years). The results support the proposal of an inhibitory deficit in (very) old age. (PsycINFO Database Record (c) 2012 APA, all rights reserved).
Psychology and Aging 05/2012; · 2.73 Impact Factor
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ABSTRACT: In making decisions, people have to balance between the competing demands of speed and accuracy, a balance generally referred to as the speed-accuracy tradeoff (SAT). In this study, we investigated the role of controlled SAT in a two-choice task in which manual responses were either validly or invalidly cued. Examining electrophysiological measurements of oscillatory brain activity, theta power in the anterior cingulate cortex (ACC), alpha power in the occipital cortex, and beta power in the motor cortex were found to be related to SAT. Because oscillatory effects of SAT were found to emanate from the SAT baseline interval preceding the two-choice task, the results indicate that SAT is modulated by a change of visuo-motor baseline activities rather than a change of response threshold. Moreover, in the two-choice task, conflict-induced theta power in the ACC was found to be more pronounced in speed than in accuracy trials, whereas priming-related beta power dynamics in the motor cortex were unaffected by SAT. These results indicate that conflict processing, but not response priming, depends on SAT.
Human Brain Mapping 01/2012; 33(8):1834-49. · 5.88 Impact Factor
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ABSTRACT: Evolutionary psychologists propose that human cognition evolved through natural selection to solve adaptive problems related to survival and reproduction, with its ultimate function being the enhancement of reproductive fitness. Following this proposal and the evolutionary-developmental view that ancestral selection pressures operated not only on reproductive adults, but also on pre-reproductive children, the present study examined whether young children show superior memory for information that is processed in terms of its survival value. In two experiments, we found such survival processing to enhance retention in 4- to 10-year-old children, relative to various control conditions that also required deep, meaningful processing but were not related to survival. These results suggest that, already in very young children, survival processing is a special and extraordinarily effective form of memory encoding. The results support the functional-evolutionary proposal that young children's memory is "tuned" to process and retain fitness-related information.
Cognition 01/2012; 122(1):118-22. · 3.16 Impact Factor
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ABSTRACT: Previous studies demonstrated that increases in the theta frequency band with concomitant decreases in the alpha/beta frequency band indicate successful memory formation. However, little is known about the brain regions and the cognitive processes that underlie these encoding-related oscillatory memory effects. We investigated this relationship using simultaneous EEG-fMRI recordings in humans during long-term memory encoding. In line with prior studies, we demonstrate that a decrease in beta power and an increase in theta power positively predict subsequent recall. In fMRI, stronger activity in the left inferior prefrontal cortex and the right parahippocampal gyrus correlated with successful memory formation. EEG source localization revealed that the subsequent memory effect in the beta band was localized in the left inferior prefrontal cortex, whereas the effect in the theta band was localized in medial temporal lobe regions. Trial-by-trial correlations between EEG and BOLD activity showed that beta power correlated negatively with left inferior prefrontal cortex activity. This correlation was more pronounced for items that could later be successfully recalled compared to items later forgotten. Based on these findings, we suggest that beta oscillations in the left inferior prefrontal cortex indicate semantic encoding processes, whereas theta oscillations in the medial temporal lobe reflect the binding of an item to its spatiotemporal context.
Journal of Neuroscience 11/2011; 31(44):15674-80. · 7.11 Impact Factor
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ABSTRACT: Research from the past decades has shown that retrieval of a specific memory (e.g., retrieving part of a previous vacation) typically attenuates retrieval of other memories (e.g., memories for other details of the event), causing retrieval-induced forgetting. More recently, however, it has been shown that retrieval can both attenuate and aid recall of other memories (K.-H. T. Bäuml & A. Samenieh, 2010). To identify the circumstances under which retrieval aids recall, the authors examined retrieval dynamics in listwise directed forgetting, context-dependent forgetting, proactive interference, and in the absence of any induced memory impairment. They found beneficial effects of selective retrieval in listwise directed forgetting and context-dependent forgetting but detrimental effects in all the other conditions. Because context-dependent forgetting and listwise directed forgetting arguably reflect impaired context access, the results suggest that memory retrieval aids recall of memories that are subject to impaired context access but attenuates recall in the absence of such circumstances. The findings are consistent with a 2-factor account of memory retrieval and suggest the existence of 2 faces of memory retrieval.
Journal of Experimental Psychology Learning Memory and Cognition 09/2011; 38(2):488-94. · 2.85 Impact Factor
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ABSTRACT: Across 3 experiments, we examined the interplay of part-list cuing and forgetting, employing 3 different methods to induce episodic forgetting-list--method directed forgetting, context-dependent forgetting, and proactive interference. For each form of forgetting, participants were asked at test to recall the target items of a previously studied list in the presence or the absence of the list's remaining items serving as retrieval cues. We found such part-list cuing to amplify the forgetting in proactive interference but to diminish the forgetting in list-method directed forgetting and context-dependent forgetting. These results show that the effects of part-list cuing on forgotten memories depend critically on the circumstances surrounding the forgetting. If the forgetting reflects impaired access to the original encoding context, as has been suggested in list-method directed forgetting and context-dependent forgetting (but not in proactive interference), part-list cues improve access to forgotten memories; if the forgetting does not reflect such a contextual effect, no such beneficial effects emerge, and access to forgotten memories may even be impaired.
Journal of Experimental Psychology Learning Memory and Cognition 09/2011; 38(2):366-75. · 2.85 Impact Factor
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ABSTRACT: A number of neuropsychological models implicate disinhibition and a lack of response confidence in the pathogenesis of obsessive-compulsive disorder (OCD). To provide a fair test of the inhibition and confidence account, a variant of the directed forgetting (DF) paradigm with OCD-related and unrelated conditions was administered in 30 OCD patients and 20 healthy controls. First, 16 words were presented which the participant was subsequently instructed to forget. Then, 16 words were presented that should be memorized. After a short interval, patients were shown the to-be-forgotten and the to-be-remembered items along with new items in random order. The subjects were instructed to recollect both the to-be-remembered and the to-be-forgotten items. The subject was asked to grade responses according to confidence. In accordance with prior findings from our group, patients did not differ from controls on overall recollection, response confidence, and the recollection of to-be-forgotten (allegedly inhibited) information. Our study cannot refute the claim that disinhibition plays a role in OCD in view of the vast array of paradigms tapping different aspects of inhibition. Still, we deem a psychological understanding more fruitful that looks at dysfunctional coping strategies and false beliefs as mechanisms for the persistence and pervasiveness of obsessive thoughts.
Psychiatry Research 08/2011; 189(2):265-9. · 2.52 Impact Factor
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ABSTRACT: In multiple-list learning, retrieval during learning has been suggested to improve recall of the single lists by enhancing list discrimination and, at test, reducing interference. Using electrophysiological, oscillatory measures of brain activity, we examined to what extent retrieval during learning facilitates list encoding. Subjects studied 5 lists of items in anticipation of a final cumulative recall test and did either a retrieval or a no-retrieval task between study of the lists. Retrieval was from episodic memory (recall of the previous list), semantic memory (generation of exemplars from an unrelated category), or short-term memory (2-back task). Behaviorally, all 3 forms of retrieval enhanced recall of both previously and subsequently studied lists. Physiologically, the results showed an increase of alpha power (8-14 Hz) from List 1 to List 5 encoding when no retrieval activities were interpolated but no such increase when any of the 3 retrieval activities occurred. Brain-behavior correlations showed that alpha-power dynamics from List 1 to List 5 encoding predicted subsequent recall performance. The results suggest that, without intermittent retrieval, encoding becomes ineffective across lists. In contrast, with intermittent retrieval, there is a reset of the encoding process for each single list that makes encoding of later lists as effective as encoding of early lists.
Journal of Experimental Psychology Learning Memory and Cognition 03/2011; 37(2):287-97. · 2.85 Impact Factor
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ABSTRACT: When people are cued to forget a previously studied list of items and to learn a new list instead, such cuing typically leads to forgetting of the first list and to memory enhancement of the second. In two experiments, we examined such listwise directed forgetting in children (and adults), using a forget cue that placed either high emphasis or low emphasis on the need to forget. In the low-emphasis condition, (adult-like) List 1 forgetting was present in fourth graders, but not in first graders (and kindergartners); in contrast, in the high-emphasis condition, (adult-like) List 1 forgetting was present from first grade on. Only fourth graders showed (adult-like) List 2 enhancement, regardless of task instruction. The finding that first graders showed List 1 forgetting only in the high-emphasis condition points to a production deficiency in first graders' directed forgetting, suggesting that the children are capable of intentional forgetting but fail to do so spontaneously. The finding that first graders showed List 1 forgetting without List 2 enhancement suggests that the two directed-forgetting effects are mediated by different processes with different developmental trajectories.
Psychonomic Bulletin & Review 12/2010; 17(6):784-9. · 2.61 Impact Factor
