Directed remembering: subliminal cues alter nonconscious memory strategies

Much research on memory function has focused on changes in recognition performance brought about by differences in the processes engaged during encoding. In most of this work, participants either receive explicit instructions to remember particular items or they perform orienting (i.e., encoding) tasks that support different levels of memory performance. In daily life, however, the retention or dismissal of information often occurs without conscious intent, thereby suggesting an alternative, nonconscious route through which purposive remembering and forgetting can occur. Based on this line of reasoning, we speculated that recognition performance in a standard item-based forgetting paradigm may be moderated by subliminal cues that trigger the automatic activation of different mnemonic strategies. We report the results of two experiments that supported this prediction. In each experiment, the basic item-based forgetting effect was replicated, but via the subliminal presentation of "remember" and "forget" cues. In addition, cue-dependent differences in memory performance were traced to the operation of a covert rehearsal mechanism during encoding. We consider the implications of these findings for the non-conscious#10; operation of memory processes in everyday life.     

Directed remembering: Subliminal cues alter nonconscious memory strategies

Much research on memory function has focused on changes in recognition performance brought about by differences in the processes engaged during encoding. In most of this work, participants either receive explicit instructions to remember particular items or they perform orienting (i.e., encoding) tasks that support different levels of memory performance. In daily life, however, the retention or dismissal of information often occurs without conscious intent, thereby suggesting an alternative, nonconscious route through which purposive remembering and forgetting can occur. Based on this line of reasoning, we speculated that recognition performance in a standard item-based forgetting paradigm may be moderated by subliminal cues that trigger the automatic activation of different mnemonic strategies. We report the results of two experiments that supported this prediction. In each experiment, the basic item-based forgetting effect was replicated, but via the subliminal presentation of “remember” and “forget” cues. In addition, cue-dependent differences in memory performance were traced to the operation of a covert rehearsal mechanism during encoding. We consider the implications of these findings for the non-conscious operation of memory processes in everyday life.     

Not all information in visual working memory is forgotten equally

To improve maintenance of task-relevant information in visual working memory (VWM), previously encoded, but no longer relevant, information can be suppressed or forgotten. However, it is unclear whether a cue directing attention to a subset of stimuli leads to complete forgetting for non-cued stimuli. The current study utilized a novel method of testing to-be forgotten information to determine if the effectiveness of forgetting differs depending on the type of encoded stimuli. Participants performed a directed forgetting change detection task, and importantly, the changed stimulus could be a novel stimulus or a to-be-forgotten stimulus. Stimulus type (colors, objects, or shapes) was manipulated across two experiments. Results suggest that a cue benefits memory for to-be-remembered information, but performance is not equivalent to never encoding to-be-forgotten information. Furthermore, the type of encoded information impacts the extent of forgetting.     

内容与自我关联性对负性情绪记忆定向遗忘的影响

本研究使用消极情绪视频片段作为实验材料,采用词表法定向遗忘范式,用2个实验分别考察了内容与自我关联性对负性情绪要义和细节记忆的定向遗忘及其权衡的影响。研究结果表明：(1)内容关联性对定向遗忘几乎没有影响,在内容关联条件下,遗忘提示只增加了要义记忆没有增加细节记忆;(2)自我关联性对定向遗忘产生了影响,自我关联条件下出现了定向遗忘,而自我无关条件下定向遗忘消失;(3) 关联性对细节和要义记忆有不同的影响,表现出明显的要义-细节权衡。     

Constructing visual representations of natural scenes: the roles of short- and long-term visual memory

A "follow-the-dot" method was used to investigate the visual memory systems supporting accumulation of object information in natural scenes. Participants fixated a series of objects in each scene, following a dot cue from object to object. Memory for the visual form of a target object was then tested. Object memory was consistently superior for the two most recently fixated objects, a recency advantage indicating a visual short-term memory component to scene representation. In addition, objects examined earlier were remembered at rates well above chance, with no evidence of further forgetting when 10 objects intervened between target examination and test and only modest forgetting with 402 intervening objects. This robust prerecency performance indicates a visual long-term memory component to scene representation.     

Rates of forgetting in attention deficit hyperactivity disorder

The present study evaluated rates of forgetting on verbal and nonverbal memory tests in children diagnosed with Attention Deficit Hyperactivity Disorder (ADHD). Although children with ADHD are known to have poor organizational and attentional problems that may impair memory performance, we hypothesized that savings scores would remain intact, because poor recall reflects difficulty with initial learning versus memory per se. Fifty-seven children diagnosed with ADHD were administered tests of nonverbal memory (Rey-Osterreith Complex Figure) and verbal memory (Story Memory, Wide Range Assessment of Memory and Learning) as part of a comprehensive neuropsychological evaluation. Subjects showed no evidence of rapid forgetting of information across the delay on either nonverbal memory (mean savings score=93%) or verbal memory (mean savings score=88%) tests. Cognitive remediation for children with ADHD should address ways to initiate and execute organizational strategies so that more information is learned upon immediate presentation.     

On the course of forgetting in very long-term memory

For practical reasons, little information is available about memory across very long learning-retention intervals. To determine the time course of forgetting in very long-term memory, a memory test was constructed that sampled events (former one-season television programs) that had occurred during a single year from 1 to 15 years ago. Updated versions of the test were administered each year for 9 consecutive years, and a forgetting curve was then calculated by superimposing the results from the nine tests. The best fitting function to the curve was monotonic and nonlinear. The findings show that forgetting in very long-term memory can be gradual and continuous for many years after learning.     

Directed forgetting for categorised pictures: recognition memory for perceptual details versus gist

ABSTRACT

Item-based directed forgetting (DF) was tested using 2-alternative forced-choice recognition to examine the effects of forgetting instructions on memory for perceptual detail and gist of categorised pictures of scenes and objects in three experiments. When the distractor is from the same category as the target (exemplar test condition), discrimination must be based on memory for perceptual details, whereas recognition can be based on gist or general category information when the distractor is from a novel category (novel test condition). Recognition accuracy was greater for Remember-cued than Forget-cued pictures when discrimination must be based on perceptual details in the exemplar test condition but not when discrimination could be based on gist in the novel test condition. Accuracy in scene and object recognition is greater for gist than for perceptual details, and DF instructions serve to reduce recognition memory based on perceptual details.     

Examining the life story account of the reminiscence bump: Why we remember more from young adulthood

The reminiscence bump is a robust finding demonstrated mostly with the cue-word method in Western cultures. The first aim of the study was to replicate the reminiscence bump using a life history timeline method and to extend reminiscence bump research to a Turkish sample. The second aim was to empirically examine the recently proposed life story account (Glück & Bluck, 2007) for the reminiscence bump. The sample consisted of 40 women and 32 men aged 52 to 66 years. Participants’ lives were divided into 5-year intervals and they verbally reported as many memories as possible in a standard timeframe from each interval (in random order) and provided ratings of several memory characteristics. As expected, the lifespan distribution of the resulting 6373 memories demonstrated a reminiscence bump. In support of the life story account, bump memories were found to be more novel, more important for identity development, more distinct, and more likely to involve developmental transitions than memories from other age periods. Findings are discussed in terms of the life story account, which synthesises lifespan developmental theory and life story theory.     

The impact of different directed forgetting instructions on implicit and explicit memory: New evidence from a modified process dissociation procedure

In contrast to previous research on directed forgetting, the present studies adopted a recent modification of the process dissociation procedure (Jacoby, 1991; Richardson-Klavehn & Gardiner, 1995) to accommodate the cross-contamination of memory test performance by implicit and explicit memorial factors. In Experiment 1, 120 subjects were compared in global directed forgetting, item-by-item directed forgetting, and control conditions on estimates of voluntary conscious memory, involuntary conscious memory, and involuntary unconscious memory performance. In Experiment 2, 80 subjects were compared in specific directed forgetting and control conditions on estimates of voluntary conscious memory, involuntary conscious memory, and involuntary unconscious memory performance. Subjects showed significant decrements in voluntary and involuntary conscious memory performance following instructions for directed forgetting in all conditions. None of the directed forgetting conditions showed a decrement in involuntary unconscious memory performance. Results suggest that, regardless of instruction type, directed forgetting prevents the conscious expression of memorial information (both voluntary and involuntary) while leaving unconscious memory intact.     

Faster forgetting contributes to impaired spatial memory in the PDAPP mouse: Deficit in memory retrieval associated with increased sensitivity to interference?

Two experiments were conducted to investigate the possibility of faster forgetting by PDAPP mice (a well-established model of Alzheimer's disease as reported by Games and colleagues in an earlier paper). Experiment 1, using mice aged 13-16 mo, confirmed the presence of a deficit in a spatial reference memory task in the water maze by hemizygous PDAPP mice relative to littermate controls. However, after overtraining to a criterion of equivalent navigational performance, a series of memory retention tests revealed faster forgetting in the PDAPP group. Very limited retraining was sufficient to reinstate good memory in both groups, indicating that their faster forgetting may be due to retrieval failure rather than trace decay. In Experiment 2, 6-mo-old PDAPP and controls were required to learn each of a series of spatial locations to criterion with their memory assessed 10 min after learning each location. No memory deficit was apparent in the PDAPP mice initially, but a deficit built up through the series of locations suggestive of increased sensitivity to interference. Faster forgetting and increased interference may each reflect a difficulty in accessing memory traces. This interpretation of one aspect of the cognitive deficit in human mutant APP mice has parallels to deficits observed in patients with Alzheimer's disease, further supporting the validity of transgenic models of the disease.     

短时记忆定向遗忘的负荷效应:来自ERP的证据

采用事件相关电位(ERPs)技术,通过一个短时记忆测试,考察记忆/遗忘线索在不同的工作记忆负荷条件下诱发的脑电差异。实验以字母和数字为刺激,要求被试记忆或遗忘不同数量的视觉信息。ERP结果发现:在线索呈现230~430ms的时间窗口,高负荷条件的遗忘线索比低负荷条件的遗忘线索诱发了更正的ERPs。这一结果表明,抑制机制在定向遗忘中有重要作用,抑制不同数量的信息需要不同数量的认知资源。     

情绪对连续事件定向遗忘的影响

本研究采用项目法定向遗忘范式以中性和负性连续事件的视频为实验材料, 通过2个实验考察了情绪对连续事件定向遗忘的影响, 并进一步探讨了情绪对细节记忆和要义记忆的定向遗忘的影响。结果发现, 情绪可以消除细节记忆的定向遗忘效应, 而仅有要义记忆的定向遗忘效应则主要受到事件连续性而非情绪的影响。     

Monitoring one's own forgetting in younger and older adults

The present study examined whether there are age-related differences in the ability to accurately monitor forgetting. Young and older adults studied a mixed list of categorized words, and later recalled items when cued with each category. They then estimated the number of additional items that they did not recall-a form of monitoring one's forgetting. Older adults exhibited impaired memory performance compared with young adults, but also accurately estimated they forgot more information than young adults. Both age groups were fairly accurate in predicting forgetting in terms of resolution, indicating that aging does not impair the ability to monitor forgetting.     

Recent Innovative Studies of Memory in Temporal Lobe Epilepsy

Investigations of patients with temporal lobe epilepsy continue to result in significant advancements in the neuroscience of human memory, as they have for over 50 years. Recent reviews describing the state of the art in the clinical neuropsychology of TLE generally have emphasized (1) lateralization of cognitive deficits and the material-specific model of memory and/or (2) the relationships among pre- and post-surgery performance on standardized measures of anterograde memory, demographic and epilepsy variables and neuroimaging, neuropathology, and neurosurgery data. As information continues to accumulate about the pattern of performance on standard laboratory memory tests and the implications of these data before and after anterior temporal lobectomy for the treatment of TLE, innovative assessment techniques also are increasingly being applied. This review focuses on English language publications that addressed selected novel topics in adult TLE memory research. These topics are: (1) remote memory; (2) accelerated forgetting or long term amnesia; and (3) lateral versus mesial temporal lobe contributions to memory.     

Memory strategies used by young normal and retarded children in a directed forgetting paradigm

Two experiments were reported investigating the possibility that normal children (6- to 7-years old) and retarded children (9- to 10-years old) equated for immediate memory performance may not use effective strategies to eliminate interference from irrelevant information in memory. In both experiments a directed forgetting paradigm was used in which the children were presented with two sets of four pictures, and recalled only one set on each trial. On some trials, there was a cue to forget the first four and to remember only the last four pictures. In the first experiment both groups adopted a passive-active strategy in which the to-be-remembered items were processed actively only after a forget cue. Experiment 2 replicated this pattern of results. The use of sophisticated directed forgetting strategies seemed to be beyond the immediate abilities of these children. Two possible interpretations of the passive-active strategy were offered: (a) The strategy was an attempt to cope with the presence of occasionally irrelevant information and (b) The strategy was an attempt to cope with memory overload.