Collaborative memory and part-set cueing impairments: the role of executive depletion in modulating retrieval disruption

When people are exposed to a subset of previously studied list items they recall fewer of the remaining items compared to a condition where none of the studied items is provided during recall. This occurs both when the subset of items is provided by the experimenter (i.e., the part-set cueing deficit in individual recall) and when they are provided during the course of a collaborative discussion (i.e., the collaborative inhibition effect in group recall). Previous research has identified retrieval disruption as a common mechanism underlying both effects; however, less is known about the factors that may make individuals susceptible to such retrieval disruption. In the current studies we tested one candidate factor: executive control. Using an executive depletion paradigm we directly manipulated an individual's level of executive control during retrieval. Results revealed no direct role of executive depletion in modulating retrieval disruption. In contrast, executive control abilities were indirectly related to retrieval disruption through their influence at encoding. Together these results suggest that executive control des not directly affect retrieval disruption at the retrieval stage, and that the role of this putative mechanism may be limited to the encoding stage.     

The joint influence of collaboration and part-set cueing

The present study was designed to examine the effects of retrieval cues on memory performance for both individuals and collaborating pairs. Participants worked either alone or together in the presence or absence of part-set cues to recall list items in Experiments 1 and 2 and to reconstruct the order of a list items in Experiment 3. The detrimental effects of collaborative inhibition were observed across all three experiments. In contrast, part-set cueing inhibition was found following free recall, whereas part-set cueing facilitation was observed on reconstruction tasks. Taken together, the results of the present experiments suggest that the effects of collaborative inhibition and part-set cueing may operate independently of one another.     

Part-set cueing and the generation effect: An evaluation of a two-mechanism account of part-set cueing

The part-set cueing effect refers to paradoxical memory impairment often observed when elements from a set of items appear as ostensibly helpful retrieval cues during testing of memory for the set. We tested predictions of a two-mechanism account of part-set cueing—that, without enhanced relational processing, standard encoding leaves items susceptible to cueing-induced inhibition that persists after cues are removed; and that increasing item-specific encoding increases this persisting inhibition. Experiment 1 used antonym generation during study to increase item-specific encoding relative to standard encoding. Tests using item-specific probes revealed greater cueing-induced impairment for the generation condition, as predicted. However, when part-set cues were later removed, this impairment abated significantly in the generation condition and even disappeared in the standard-encoding condition—effects not predicted by the two-mechanism account, challenging its completeness. In Experiment 2, we ruled out an artifactual explanation of these results by replicating previously reported persisting impairment on free recall tests.     

Suppression in retrieval practice,part-set cueing,and negative priming memory: The hydrogen model

A number of phenomena in memory have been explained using appeals to active suppression processes, including retrieval practice, part-set cueing, and the negative priming that is observed with associative interference. However, more formal attempts to capture such processes have been absent. This paper outlines the hydrogen model of memory retrieval, which aims to be a simple model with the modest goal of trying to explore what influence suppression would have on memory retrieval. This model contains a single activation component and a single suppression component in which suppression comes into play only after retrieval interference has been detected. This model was created to explore the plausibility and viability of ideas about the operation of suppression during memory retrieval. For hydrogen, the degree of suppression recruited is proportional to the amount of interference experienced. Overall, the pattern of human data was captured by the suppression model.     

Exploring the relationship between retrieval disruption from collaboration and recall

When people recall together in a collaborative group they recall less than their potential. This phenomenon of collaborative inhibition is explained in terms of retrieval disruption. However, collaborative recall also re-exposes individuals to items recalled by others that they themselves might otherwise have forgotten. This re-exposure produces post-collaborative benefits in individual recall. The current study examined whether reduced retrieval disruption during group recall is related not only to less collaborative inhibition, but also to greater post-collaborative recall benefits. To test this we devised a paradigm to calculate the extent to which each individual experienced retrieval disruption during group recall. We also included two types of collaborative groups, one of which was expected to experience greater retrieval disruption than the other. Results suggest that the relationship between retrieval disruption and recall performance depends on the level at which retrieval disruption is measured. When retrieval disruption was assessed at the individual level, then minimising retrieval disruption was associated with higher recall (i.e., less collaborative inhibition and greater post-collaborative individual recall). However, when retrieval disruption was assessed at the group level there was no relationship with recall. Furthermore, the findings from this design suggest a role of cross-cueing in modulating group recall levels.     

Effects of repeated collaborative retrieval on individual memory vary as a function of recall versus recognition tasks

Our research examines how prior group collaboration modulates later individual memory. We recently showed that repeated collaborative recall sessions benefit later individual recall more than a single collaborative recall session (Blumen & Rajaram, 2008). Current research compared the effects of repeated collaborative recall and repeated collaborative recognition on later individual recall and later individual recognition. A total of 192 participants studied a list of nouns and then completed three successive retrieval sessions in one of four conditions. While two collaborative recall sessions and two collaborative recognition sessions generated comparable levels of individual recall (CRecall-CRecall-I Recall ～ CRecognition-CRecognition-I Recall , Experiment 1a), two collaborative recognition sessions generated greater levels of individual recognition than two collaborative recall sessions (CRecognition-CRecognition- IRecognition > CRecall-CRecall- I Recognition , Experiment 1b). These findings are discussed in terms of two opposing mechanisms that operate during collaborative retrieval—re-exposure and retrieval disruption—and in terms of transfer-appropriate processing across collaborative and individual retrieval sessions.     

No effects of executive control depletion on prospective memory retrieval processes

Research has suggested that prospective memory retrieval is reliant on executive control processes, and the degree to which these processes are necessary for intention fulfillment is dependent on a host of variables related to the prospective memory task. Based on results suggesting that aspects of the prospective memory task vary in their need for executive control, the current study examined the possibility that executive control depletion from the Stroop task would negatively transfer to prospective memory performance. Depletion of executive control, measured objectively in a Stroop task, did not impair prospective memory performance in either low or high cue-target association conditions. However, participants’ subjective assessments of their own cognitive fatigue correlated significantly with their prospective memory performance, regardless of the association between cues and target responses.     

The role of item similarity in part-list cueing impairment

The presentation of a subset of studied items as retrieval cues can have detrimental effects on recall of the remaining (target) items. In three experiments we examined whether such part-list cueing impairment depends on the similarity between cue and target items. Item similarity was manipulated by making use of pre-experimental semantic similarities between cue and target items (Experiments 1 and 2), or was episodically induced through a similarity-encoding task, in which participants were asked to interrelate cue and target items in a meaningful way (Experiment 3). In all three experiments reliable part-list cueing impairment arose when the similarity between cues and targets was low, but no impairment was found when the similarity between cues and targets was high. Inhibitory as well as non-inhibitory explanations of the findings are discussed.     

部分线索对记忆提取的影响:认知抑制能力的作用

在回忆时,以刚刚学过的部分项目作为提取线索,被试的回忆成绩反而比没有任何线索时的回忆成绩差,这一现象被称为部分线索效应。该效应通常被认为是抑制执行控制过程对非线索项目记忆表征强度抑制的结果。本研究以Stroop效应量(实验1)和工作记忆容量(实验2)为指标,从个体差异角度考察了认知抑制能力对部分线索效应的影响。结果发现,Stroop效应量与部分线索效应各指标呈显著负相关,Stroop效应量越小,部分线索效应各指标的值越大;工作记忆容量与部分线索效应各指标呈显著正相关,高工作记忆容量个体的部分线索效应各指标的值也更大。结果表明,认知抑制能力越强,部分线索对回忆的破坏作用越大,研究结果支持部分线索效应的提取抑制假说。     

Aging and strategic retrieval in a cued-recall test: the role of executive functions and fluid intelligence

Cued-recall in episodic memory was investigated in relation to low and high cognitive support at retrieval, executive function level and fluid intelligence level in 81 healthy adults divided first into two age groups (young and elderly adults). The first analyses showed that age-related differences were greater when a low cognitive support was provided to recall the words. An individual index of loss of performance when the number of cues was decreased was then calculated. Hierarchical regression analysis revealed that the executive functions measure (perseverative errors on the Wisconsin Card Sorting Test) was a better candidate than the fluid intelligence measure (Cattell's culture fair test) to account for the age-related variance of the size of performance loss. These findings suggest that age differences in implementing strategic retrieval may be mainly due to a decline in executive functions.     

Visual imagery in autobiographical memory: The role of repeated retrieval in shifting perspective

Recent memories are generally recalled from a first-person perspective whereas older memories are often recalled from a third-person perspective. We investigated how repeated retrieval affects the availability of visual information, and whether it could explain the observed shift in perspective with time. In Experiment 1, participants performed mini-events and nominated memories of recent autobiographical events in response to cue words. Next, they described their memory for each event and rated its phenomenological characteristics. Over the following three weeks, they repeatedly retrieved half of the mini-event and cue-word memories. No instructions were given about how to retrieve the memories. In Experiment 2, participants were asked to adopt either a first- or third-person perspective during retrieval. One month later, participants retrieved all of the memories and again provided phenomenology ratings. When first-person visual details from the event were repeatedly retrieved, this information was retained better and the shift in perspective was slowed.     

The role of the executive system in visuo-spatial memory functioning

Participants were presented with a spatial sequence in which between 4 and 10 cells were highlighted. On each trial list length was unknown to the participant who was required to serially recall the last four cells. Processing of longer lists is assumed to call upon the executive system, which is thought to be involved in updating the contents of the short-term visuo-spatial store. Study 1 revealed that loading the executive system with concurrent random letter generation impaired performance on the spatial task especially recall of the early serial positions. However, contrary to expectation the degree of impairment was no greater on the longer lists, where it had been assumed that updating would be occurring. Study 2 confirmed this finding and demonstrated that relative to sequences of known length, under conditions of uncertainty when the list length was unknown, spatial recall was impaired even on short sequences. The present results support the growing consensus, which is suggestive of closer links between visuo-spatial and executive processes. However, it remains unclear whether or not updating is actually occurring on the longer sequences, and if it is, what specific executive processes are involved.     

Aging and self-reported internal and external memory strategy uses: The role of executive functioning

The aim of this study was to investigate the effect of advanced age on self-reported internal and external memory strategy uses, and whether this effect can be predicted by executive functioning. A sample of 194 participants aged 21 to 80 divided into three age groups (21-40, 41-60, 61-80) completed the two strategy scales of the Metamemory in Adulthood (MIA) questionnaire, differentiating between internal and external everyday memory strategy uses, and three tests of executive functioning. The results showed that: (1) the use of external memory strategies increased with age, whereas use of internal memory strategy decreased; (2) executive functioning appeared to be related only to internal strategies, the participants who reported the greatest use of internal strategies having the highest executive level; and (3) executive functioning accounted for a sizeable proportion of the age-related variance in internal strategy use. These findings suggest that older adults preferentially use external memory strategies to cope with everyday memory impairment due to aging. They also support the view that the age-related decrease in the implementation of internal memory strategies can be explained by the executive hypothesis of cognitive aging. This result parallels those observed using objective laboratory memory strategy measures and then supports the validity of self-reported memory strategy questionnaire.     

The role of meaning in contextual cueing: Evidence from chess expertise

In contextual cueing, the position of a search target is learned over repeated exposures to a visual display. The strength of this effect varies across stimulus types. For example, real-world scene contexts give rise to larger search benefits than contexts composed of letters or shapes. We investigated whether such differences in learning can be at least partially explained by the degree of semantic meaning associated with a context independently of the nature of the visual information available (which also varies across stimulus types). Chess boards served as the learning context as their meaningfulness depends on the observer's knowledge of the game. In Experiment 1, boards depicted actual game play, and search benefits for repeated boards were 4 times greater for experts than for novices. In Experiment 2, search benefits among experts were halved when less meaningful randomly generated boards were used. Thus, stimulus meaningfulness independently contributes to learning context–target associations.     

The applied value of collaborative memory research in aging: Behavioral and neural considerations

Our aim in this paper is to bring attention to the applied value of collaborative memory research in aging. At this time, much collaborative memory research focuses on the negative effects of collaboration in younger adults, and is primarily basic in nature. Here, we highlight the positive effects of collaboration that have received less attention, with a particular emphasis on the applied value of these effects in older adults. We first review studies to show that recalling in a group improves later individual recall and reduces memory errors in older adults. We then outline a four-step approach towards bridging laboratory and applied collaborative memory research, which involves: (1) complementing traditional paradigms with more ecologically valid paradigms, (2) evaluating these paradigms in applied settings, (3) adapting these paradigms for use with cognitively intact and cognitively impaired populations, and (4) modifying these paradigms to examine the neural systems that operate during collaborative recall.     

Selection of objects and tasks in working memory

When people hold several objects (such as digits or words) in working memory and select one for processing, switching to a new object takes longer than selecting the same object as that on the preceding processing step. Similarly, selecting a new task incurs task- switching costs. This work investigates the selection of objects and of tasks in working memory using a combination of object-switching and task-switching paradigms. Participants used spatial cues to select one digit held in working memory and colour cues to select one task (addition or subtraction) to apply to it. Across four experiments the mapping between objects and their cues and the mapping between tasks and their cues were varied orthogonally. When mappings varied from trial to trial for both objects and tasks, switch costs for objects and tasks were additive, as predicted by sequential selection or resource sharing. When at least one mapping was constant across trials, allowing learning of long-term associations, switch costs were underadditive, as predicted by partially parallel selection. The number of objects in working memory affected object-switch costs but not task-switch costs, counter to the notion of a general resource of executive attention.     

Transfer of old ‘reactivated’ memory retrieval cues in rats

The present studies examined whether the retrieval of an old ‘reactivated’ memory could be brought under the control of new contextual cues. In Experiment 1 rats trained in one context were exposed to different contextual cues either immediately, 60 or 120 min after a cued reactivation of the training memory. When tested in the shifted context, subjects exposed shortly after reactivation treated the shifted context as the original context. This transfer diminished with longer post-reactivation delays. Experiment 2 replicated the basic finding and demonstrated that the transfer of the old retrieval cues was specific to the contextual cues present during exposure. These findings are consistent with previous research [i.e., Briggs, J. F., Fitz, K. I., & Riccio, D. C. (in press). Transfer of memory retrieval cues in rats. Psychonomic Bulletin & Review] showing the transfer of retrieval cues for a new memory, and demonstrating a similarity (in this case) between newly acquired and old reactivated memories.     

The role of semantically related distractors during encoding and retrieval of words in long-term memory

We examined the influence of divided attention (DA) on recognition of words when the concurrent task was semantically related or unrelated to the to-be-recognised target words. Participants were asked to either study or retrieve a target list of semantically related words while simultaneously making semantic decisions (i.e., size judgements) to another set of related or unrelated words heard concurrently. We manipulated semantic relatedness of distractor to target words, and whether DA occurred during the encoding or retrieval phase of memory. Recognition accuracy was significantly diminished relative to full attention, following DA conditions at encoding, regardless of relatedness of distractors to study words. However, response times (RTs) were slower with related compared to unrelated distractors. Similarly, under DA at retrieval, recognition RTs were slower when distractors were semantically related than unrelated to target words. Unlike the effect from DA at encoding, recognition accuracy was worse under DA at retrieval when the distractors were related compared to unrelated to the target words. Results suggest that availability of general attentional resources is critical for successful encoding, whereas successful retrieval is particularly reliant on access to a semantic code, making it sensitive to related distractors under DA conditions.     

Working memory capacity and retrieval limitations from long-term memory: An examination of differences in accessibility

In two experiments, the locus of individual differences in working memory capacity and long-term memory recall was examined. Participants performed categorical cued and free recall tasks, and individual differences in the dynamics of recall were interpreted in terms of a hierarchical-search framework. The results from this study are in accordance with recent theorizing suggesting a strong relation between working memory capacity and retrieval from long-term memory. Furthermore, the results also indicate that individual differences in categorical recall are partially due to differences in accessibility. In terms of accessibility of target information, two important factors drive the difference between high- and low-working-memory-capacity participants. Low-working-memory-capacity participants fail to utilize appropriate retrieval strategies to access cues, and they also have difficulty resolving cue overload. Thus, when low-working-memory-capacity participants were given specific cues that activated a smaller set of potential targets, their recall performance was the same as that of high-working-memory-capacity participants.     

协作抑制的作用机制：来自编码阶段的证据

协作抑制是指当人们在一个记忆小组中一起提取信息的时候,小组提取的信息总量比等量个体提取的信息总量要少。本研究采用经典的协作抑制研究范式和两次提取任务,考察编码方式和学习次数对协作提取任务的影响,进一步将考察协作抑制的产生机制作为总研究目的。结果表明,编码方式相同条件下出现协作抑制,而编码方式不同条件下协作抑制消失,显示协作抑制的出现与否依赖于认知条件的改变;无论是学习一次还是学习两次,在第一次小组提取中出现协作抑制,而在第二次个人提取中协作抑制消失,在使用困难学习材料时也得到同样的研究结果。研究结果支持协作抑制的提取策略破坏假说。