Binding and inhibition in working memory: individual and age differences in short-term recognition

Two studies investigated the relationship between working memory capacity (WMC), adult age, and the resolution of conflict between familiarity and recollection in short-term recognition tasks. Experiment 1 showed a specific deficit of young adults with low WMC in rejecting intrusion probes (i.e., highly familiar probes) in a modified Sternberg task, which was similar to the deficit found in old adults in a parallel experiment (K. Oberauer, 2001). Experiment 2 generalized these results to 3 recognition paradigms (modified Sternberg, local recognition, and n back tasks). Old adults showed disproportional performance deficits on intrusion probes only in terms of reaction times, whereas young adults with low WMC showed them only in terms of errors. The generality of the effect across paradigms is more compatible with a deficit in content-context bindings subserving recollection than with a deficit in inhibition of irrelevant information in working memory. Structural equation models showed that WMC is related to the efficiency of recollection but not of familiarity.     

Preserved spatial memory over brief intervals in older adults

Two studies compared young and older adults' memory for location information after brief intervals. Experiment 1 found that accuracy of intentional spatial memory for individual locations was similar in young and older participants for set sizes of 3 and 6. Both groups also encoded individual locations in relation to the larger configuration of locations. Experiment 2 showed that like young adults, older adults' latency to respond to a test probe in a letter working memory task was negatively influenced by spatial information that was irrelevant to the task. This interference effect indicated preserved incidental memory for spatial information in older adults. Together, these data suggest that initial encoding of spatial information for relatively small numbers of items is largely preserved in healthy older adults and that representations of spatial information persist over short intervals.     

Control of the contents of working memory--a comparison of two paradigms and two age groups

Two experiments investigated whether young and old adults can temporarily remove information from a capacity-limited central component of working memory (WM) into another component, the activated part of long-term memory (LTM). Experiment 1 used a modified Sternberg recognition task (S. Sternberg, 1969); Experiment 2 used an arithmetic memory-updating task. In both paradigms, participants memorized 2 lists, one of which was cued as temporarily irrelevant. Removal of the irrelevant list from capacity-limited WM was indexed by the disappearance of list-length effects of that list on latencies for concurrent processing tasks. Young adults could outsource the irrelevant list within 2-3 s and retrieve it back into the central part of WM later. Old adults showed the same flexibility in the arithmetic updating task but seemed somewhat less able or inclined to temporarily move information into the activated part of LTM in the modified Sternberg task.     

Decline in working memory updating through ageing: intrusion error analyses

The present research examines the decline in working memory updating through age. Two experiments compared groups of participants in different age ranges (young-old, 55-65 years, old, 66-75 years and old-old, more than 75 years and, in Experiment 2 only, young, 20-30 years). Memory updating tasks were administered, which required participants to remember the smallest items in each list. To perform the task correctly, participants had to update information efficiently, reducing interference from items no longer relevant. Intrusion errors were computed and in the first experiment these were described as "intrusions of irrelevant items" (immediate exclusion) and "intrusions of once relevant items" (delayed exclusion). The oldest adults performed worse in memory updating and made a greater number of intrusion errors of once relevant information. In the second experiment results showed that increases in memory load (number of items that had to be remembered) and updating demand (number of potentially relevant items) impaired performance. The oldest adults had greater difficulty when the task demand was increased. Furthermore, they produced a higher number of intrusion errors, particularly when the updating demand was increased. It therefore appears that elderly people have specific difficulty in updating information in working memory by excluding irrelevant information.     

Updating the contents of working memory in depression: interference from irrelevant negative material

This study was designed to assess the effects of irrelevant emotional material on the ability to update the contents of working memory in depression. For each trial, participants were required to memorize 2 lists of emotional words and subsequently to ignore 1 of the lists. The impact of irrelevant emotional material on the ability to update the contents of working memory was indexed by response latencies on a recognition task in which the participants decided whether or not a probe was a member of the relevant list. The authors compared response latencies to probes from the irrelevant list to response latencies to novel probes of the same valence (intrusion effect). The results indicate that, compared to control participants in both neutral and sad mood states, depressed participants showed greater intrusion effects when presented with negative words. In an important finding, intrusion effects for negative words were correlated with self-reported rumination. These findings indicate that depression is associated with difficulties removing irrelevant negative material from working memory. Results also indicate that the increased interference from irrelevant negative material is associated with rumination.     

Memory search following valid and invalid abrupt-onset cues

The impact of abrupt-onset cues on memory search was investigated, where the abrupt-onset cue was a valid (Experiment 1), random (Experiment 2), or irrelevant (Experiment 3) predictor of the location containing the test probe. In Experiment 4, the abrupt-onset cue either preceded or followed the test probe. Sternberg-like functions were obtained in Experiments 1 and 2, with the effects of the abrupt-onset cue localized primarily in the intercept rather than the slope. Experiment 3 demonstrated that a spatially separated and irrelevant abrupt-onset cue increased latency even when all memory probes occurred at the fixation point. In Experiment 4, the robust impact of an abrupt-onset cue vanished, regardless of stimulus onset asynchrony, when it followed the target. We concluded that abrupt-onset cues captured attention regardless of their predictability, manifested as a delaying of search. However, once attention was captured by the target, a subsequent abrupt-onset stimulus had no effect. These results were discussed in terms of diffuse attention and contingent capture models of attention.     

空间工作记忆负载对中央注视线索返回抑制的影响

通过两个实验,探讨空间工作记忆负载对中央注视线索引发返回抑制（inhibition of return,IOR）的影响。实验一通过再认面孔的相似度来控制与中央注视线索相关的空间工作记忆任务负载,结果发现,高任务负载条件下出现IOR,低任务负载条件下中央注视线索促进搜索;实验二在实验一高任务负载的基础上加入与注视线索无关的空间工作记忆任务,结果发现,仅在与注视线索无关的空间工作记忆负载低的条件下出现IOR。结果表明,中央注视线索引发的IOR受到空间工作记忆资源的限制,中央注视线索只有在获得足够的资源时才能引发IOR。注视线索获得空间工作记忆资源多少决定中央注视线索能否引发IOR。     

Decline in working memory updating through ageing: Intrusion error analyses

The present research examines the decline in working memory updating through age. Two experiments compared groups of participants in different age ranges (young‐old, 55–65 years, old, 66–75 years and old‐old, more than 75 years and, in Experiment 2 only, young, 20–30 years). Memory updating tasks were administered, which required participants to remember the smallest items in each list. To perform the task correctly, participants had to update information efficiently, reducing interference from items no longer relevant. Intrusion errors were computed and in the first experiment these were described as “intrusions of irrelevant items” (immediate exclusion) and “intrusions of once relevant items” (delayed exclusion). The oldest adults performed worse in memory updating and made a greater number of intrusion errors of once relevant information. In the second experiment results showed that increases in memory load (number of items that had to be remembered) and updating demand (number of potentially relevant items) impaired performance. The oldest adults had greater difficulty when the task demand was increased. Furthermore, they produced a higher number of intrusion errors, particularly when the updating demand was increased. It therefore appears that elderly people have specific difficulty in updating information in working memory by excluding irrelevant information.     

Recognition and frequency judgments in young and elderly adults

Three experiments examined frequency judgments and recognition memory in young and elderly adults. Subjects were presented a long list of words at either a 5-s rate (Experiments 1 & 3) or a 1-s rate (Experiment 2), after which frequency-judgment and recognition memory tasks were administered. Either an absolute (Experiments 1 & 2) or a relative (Experiment 3) frequency-judgment task was used. The recognition test, which involved repeated tests of some items, involved either one incorrect item paired with each correct item (Experiments 1 & 2), or four incorrect items (Experiment 3). Age-related differences in frequency judgments, for the more frequently presented items, were found in all three experiments. For the recognition scores, the predicted interaction between age and successive tests was found only in Experiment 3. The results were interpreted within the framework of age-related differences in elaborative encoding and in distractibility to irrelevant stimuli.     

How to say no: single- and dual-process theories of short-term recognition tested on negative probes

Three experiments with short-term recognition tasks are reported. In Experiments 1 and 2, participants decided whether a probe matched a list item specified by its spatial location. Items presented at study in a different location (intrusion probes) had to be rejected. Serial position curves of positive, new, and intrusion probes over the probed location's position were mostly parallel. Serial position curves of intrusion probes over their position of origin were again parallel to those of positive probes. Experiment 3 showed largely parallel serial position effects for positive probes and for intrusion probes plotted over positions in a relevant and an irrelevant list, respectively. The results support a dual-process theory in which recognition is based on familiarity and recollection, and recollection uses 2 retrieval routes, from context to item and from item to context.     

Recognition memory across the adult life span: The role of prior knowledge

Two experiments were performed to investigate the effects of prior knowledge on recognition memory in young adults, younger old adults, 76-year-olds, and 85-year-olds. In Experiment 1, we examined episodic recognition of dated and contemporary famous persons presented as faces, names, and faces plus names. In Experiment 2, four types of faces were presented for later recognition: dated familiar, contemporary familiar, old unfamiliar, and young unfamiliar. The results of both experiments showed that young adults performed better with contemporary than with dated famous persons, whereas the reverse was true for all groups of older adults. In addition, the data of Experiment 2 indicated that (1) young adults showed better recognition for young than for old unfamiliar faces, (2) younger old adults performed better with old than with young unfamiliar faces, and (3) the two oldest age groups showed no effect of age of face. These results suggest that the ability to utilize rich semantic knowledge to improve episodic memory is preserved in very old age, although the aging process may be associated with deficits in the ability to utilize prior knowledge to support memory when the underlying representation lacks semantic and contextual features. The overall data pattern was discussed in relation to the notion that, with increasing adult age, there is an increase in the level of cognitive support required to enhance episodic remembering.     

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.     

What happens to information to be suppressed in working-memory tasks? Short and long term effects

The study explored, from an individual differences point of view, what happens to information to be suppressed in a working-memory task at short and long term. In particular, it was examined whether control mechanisms of irrelevant information in working memory imply their complete elimination from working memory or just the modulation of their activation. To this end, we compared the fate of irrelevant information in groups of subjects with high and low reading comprehension (Experiments 1 and 2) and subjects with high and low working memory (Experiments 1, 2, 3, and 4). All the experiments presented a working-memory task devised by De Beni, Palladino, Pazzaglia, and Cornoldi (1998), which required participants to process lists of words, to tap when a word from a particular category was presented, and then to recall only the last items in each list. Results confirmed that participants with high reading comprehension also have higher working memory and make less intrusion errors due to irrelevant items that have to be processed but then discarded. Furthermore, it was found that participants with low working memory have slightly better implicit (Experiment 1) and explicit memory (Experiments 3 and 4) of highly activated irrelevant information. Nevertheless, in a long-term recognition test, participants with high and low reading comprehension/working memory presented a similar pattern of memory for different types of irrelevant information (Experiment 2), whereas in a short-term memory recognition test, low-span participants presented a facilitation effect in the time required for the recognition of highly activated irrelevant information (Experiment 4). It was concluded that efficient working-memory performance is related to the temporary reduction of activation of irrelevant information but does not imply its elimination from memory.     

Working memory binding of visual object features in older adults

Accurate mental representation of visual stimuli requires retaining not only the individual features but also the correct relationship between them. This associative process of binding is mediated by working memory (WM) mechanisms. The present study re-examined reports of WM-related binding deficits with aging. In Experiment 1, 31 older and 31 younger adults completed a visual change detection task with feature–location relations presented either simultaneously or sequentially; the paradigm was also designed specifically to minimize the impact of lengthy retention intervals, elaborative rehearsal, and processing demands of multi-stimulus probes. In Experiment 2, 38 older and 42 younger adults completed a modified task containing both feature–location relations and feature–feature conjunctions. In Experiment 1 although feature–location binding was more difficult with sequential compared with simultaneous presentation, the effect was independent of age. In Experiment 2 while older adults were overall slower and less accurate than young adults, there were no age-specific deficits in WM binding. Overall, after controlling for methodological factors, there was no evidence of an age-related visual WM binding deficit for surface or location features. However, unlike younger adults, older adults appeared less able to restrict processing of irrelevant features, consistent with reported declines with age in strategic capacities of WM.     

Access to information in working memory: exploring the focus of attention

Participants memorized briefly presented sets of digits, a subset of which had to be accessed as input for arithmetic tasks (the active set), whereas another subset had to be remembered independently of the concurrent task (the passive set). Latencies for arithmetic operations were a function of the setsize of active but not passive sets. Object-switch costs were observed when successive operations were applied to different digits within an active set. Participants took 2 s to encode a passive set so that it did not affect processing latencies (Experiment 2). The results support a model distinguishing 3 states of representations in working memory: the activated part of long-term memory, a capacity limited region of direct access, and a focus of attention.     

Aging and interference in verbal working memory.

According to inhibitory views of working memory, old adults should have particular problems deleting irrelevant information from working memory, leading to greater interference effects compared with young adults. The authors investigated this hypothesis by using variations of an A-B, C-D retroactive interference paradigm in working memory with young and old adults. They used a recognition measure of memory, assessing both accuracy and reaction time. The primary finding was that senior adults consistently exhibited proportionally greater retroactive interference effects compared with young adults when interfering word pairs that had been read aloud had to be rejected. Patterns of recognition and reaction time data suggested that old adults' activation of target material is similar to young adults, but they experience sustained activation of irrelevant material that has entered working memory. Theoretical implications of these findings for inhibitory deficit (R. T. Zacks & L. Hasher, 1998) and source memory deficit accounts of cognitive aging are discussed.     

无关负性信息对复发性抑郁缓解者工作记忆内容更新的影响

摘 要 采用改编后的Sternberg 任务考查无关负性信息对复发性抑郁缓解个体工作记忆内容更新的影响。与正常组相比,缓解期个体在无关负性条件下对探测图片的反应时要长于有关负性条件下的反应时,而正常个体在无关正性探测图片的反应时明显长于有关正性条件下的反应时。同时缓解期个体在无关负性条件下对探测图片的反应时明显长于新图条件下的反应时,出现明显的干扰效应。结果表明反复发作的抑郁缓解者在摒弃工作记忆中无关负性内容时存在障碍。     

Age differences in response selection for pure and mixed stimulus-response mappings and tasks

Two experiments examined effects of mixed stimulus-response mappings and tasks for older and younger adults. In Experiment 1, participants performed two-choice spatial reaction tasks with blocks of pure and mixed compatible and incompatible mappings. In Experiment 2, a compatible or incompatible mapping was mixed with a Simon task for which the mapping of stimulus color to location was relevant and stimulus location was irrelevant. In both experiments, older adults showed larger mixing costs than younger adults and larger compatibility effects, with the differences particularly pronounced in Experiment 1 when location mappings were mixed. In mixed conditions, when stimulus location was relevant, older adults benefited more than younger adults from complete repetition of the task and stimulus from the preceding trial. When stimulus location was irrelevant, the benefit of complete repetition did not differ reliably between age groups. The results suggest that the age-related deficit associated with mixing mappings and tasks is primarily due to older adults having more difficulty separating task sets that activate conflicting response codes.     

Distinguishing age differences in knowledge, strategy use, and confidence during strategic skill acquisition

The authors examined how age differences in strategy selection are related to associative learning deficits and metacognitive variables, including memory ability confidence. In Experiment 1, increases in memory reliance for performance of the noun-pair lookup task were compared with increases in noun-pair memory ability. In Experiment 2, memory reliance was assessed for noun pairs memorized prior to the task. In each experiment, older adults manifested a substantial delay in transition to a retrieval-based strategy despite comparable noun-pair knowledge. In Experiment 3, young and older adults reported comparable confidence ratings for the accuracy of each memory probe response. However, older adults reported lower confidence in their general ability to use the memory retrieval strategy, which correlated with avoidance of the retrieval strategy.