陈述性记忆存储和巩固的神经机制

综述了陈述性记忆形成和巩固的神经机制,并对经典模型进行了修正和拓展。主要观点是：陈述性记忆的存储和巩固依赖于新皮层不同脑区之间建立新的联系,内侧颞叶在这一过程中起着重要作用;当陈述性记忆完全巩固后,信息的存储和提取完全依赖于新皮质;一个完整的陈述性记忆的信息被分别存储在解剖上分离的语义记忆与情节记忆存储系统内     

Retrieval processes in fifth graders and adults

This research was concerned with retrieval processes which underlie conceptual clustering. In a free recall task with categorized lists, fifth graders' and adults' retrieval was examined temporally by means of interword response times. List organization and retrieval cue factors were manipulated in order to assess the developmental relevance of an hypothesized three component retrieval model. The results indicated that both age groups used a qualitatively similar retrieval strategy, involving search for and decoding of higher-order memory units. Providing retrieval cues eliminated the category search component, but also increased the likelihood of exhaustive recall attempts under random presentation conditions. The results were discussed in terms of the inter-relationships between storage and retrieval strategies. Age-related differences in retrieval time were attributed to insufficient reorganization during input and failure to attempt to recall all of a category's members.     

Focused memory search in fact retrieval

Several studies of fact retrieval have shown that the more facts a person learns about a concept, the longer it takes him or her to retrieve any of these facts. This result has been interpreted to mean that retrieval of a fact about a concept involves a search of all facts stored in memory with that concept. In the present study, it is suggested that retrieval involves not an unfocused search of all facts stored with a concept, but rather a focused memory search that examines relevant stored facts and ignores irrelevant information. This argument is supported by three experiments in which subjects first learned simple facts (e.g., “The banker likes horses”) and then made speeded true-false decisions for test probes le.g., “The banker likes elephants”). Specifically, results suggest that facts stored with a concept may be organized into subsets. For example, a person’s knowledge about Richard Nixon might be organized into subsets concerning Nixon’s resignation, his trips to China, his family, and so on. The data further suggest that a person attempting to retrieve a fact about a concept (e.g., the name of Nixon’s wife) may simply decide which subset is most likely to contain the desired fact (e.g., the subset concerning Nixon’s family) and search that subset. If the sought-for fact is found in this subset, the search process terminates. If, however, the desired information is not located, other subsets of facts may be searched before the retrieval attempt is given up. The notion that memory search focuses on relevant stored facts and ignores irrelevant information may help to explain why experts (i.e., people who know a large number of facts about a topic) do not experience great difficulty in retrieving facts in their areas of expertise.     

Reconstructive memory: A computer model

This study presents a process model of very long-term episodic memory. The process presented is a reconstructive process. The process involves application of three kinds of reconstructive strategies—component-to-context instantiation strategies, component-instantiation strategies, and context-to-context instantiation strategies. The first is used to direct search to appropriate conceptual categories in memory. The other two are used to direct search within the chosen conceptual category. A fourth type of strategy, called executive search strategies, guide search for concepts related to the one targeted for retrieval. A conceptual memory organization implied by human reconstructive memory is presented along with examples which motivate it. A basic retrieval algorithm is presented for traversing that stucture. Retrieval strategies arise from failures in that algorithm. The memory organization and retrieval processes are implemented in a computer program called CYRUS which stores events in the lives of former Secretaries of State Cyrus Vance and Edmund Muskie and answers questions posed in English concerning that information. Examples which motivate the process model are drawn from protocols of human memory search. Examples of CYRUS's behavior demonstrate the implemented process model. Conclusions are drawn concerning retrieval failures and the relationship of episodic and semantic memory.     

Episodic storage and retrieval in visuo-spatial tasks: evidence of indirect retrieval

Episodic storage contends that the relevant target and irrelevant distractor features of a display are processed and then stored together within the boundaries of an episode, and are linked in this way. Accordingly, the selective and “direct” retrieval of either a stored target or distractor should result in the “indirect” and unintended retrieval of the other stimulus. In the present investigation, interest focused upon spatial tasks and the “indirect” retrieval of prime distractor processing. The novel findings obtained supported the existence of the “indirect” retrieval of prime distractor processing in visuo-spatial tasks and, to a lesser extent, of the stored prime target event, consistent with identity tasks (i.e. bi-directional episodically-based retrieval). Clearly, more is retrieved than is presented (Hintzman, D. L. (1984). MINERVA 2: A simulation model of human memory. Behavior Research Methods, Instruments, & Computers, 16, 96–101. doi:10.3758/BF03202365), as an episodic storage structure would predict.     

Memory for common and bizarre stimuli: A storage-retrieval analysis

We tested the hypothesis that common stimuli are stored in memory better than bizarre stimuli are. Subjects memorized a series of noun pairs embedded within 20 common or bizarre sentences. By using a between-list design, free and cued recall, and intentional-learning instructions, we were able to obtain a commonness effect (i.e., a recall advantage for the common sentences). Riefer and Rouder’s (1992) multinomial processing-tree model for measuring storage and retrieval was applied to the data, which revealed that the recall advantage for common sentences was due to storage and not retrieval processes. We propose a two-factor theory: that common items are stored better in memory, but that bizarre items are retrieved better from memory. This storage-retrieval explanation does a good job of accounting for a number of findings associated with the bizarreness effect.     

Memory metaphors in cognitive psychology

In describing memory phenomena in natural language, a spatial metaphor is typically employed. Memories are considered to be objects that are stored in a mind space, and the process of retrieval is conceived as a search for these objects. It is argued that this metaphor has been carried over into many of the popular theories of memory in cognitive psychology and that seemingly diverse theories employ the same underlying set of assumptions. A survey of the analogies that have been used to explain memory is presented and alternatives to the dominant spatial storage and search assumptions are discussed. The spatial metaphor is evaluated, and the role of analogical explanation in psychology is briefly considered. One result of the increasing number of analogical models is the proliferation of hypothetical mental constructs that are only loosely connected to behavioral measures. nt|mis|A number of members of Ebbinghaus Empire at the University of Toronto contributed analogies that are listed in Table 1 and commented on the views expressed here.     

编码与提取干扰对内隐和外显记忆的非对称性影响

以往研究表明在外显记忆中,编码与提取加工存在着非对称性,但在内隐记忆中,二者的关系并不明确,因此实验采用“学习-再认”范式,考察在编码或提取中分别附加的干扰任务对词汇判断或再认产生的影响。结果证实编码与提取干扰对内隐或外显记忆都具有非对称性的影响,但又存在着差异,即编码干扰会导致随后外显记忆成绩显著减少,而提取干扰对其影响较小,相反,编码干扰对随后内隐测验中启动效应的影响较小,但提取干扰会破坏启动效应,从而为内隐记忆和外显记忆的分离提供了进一步的证据     

Variation in working memory capacity and temporal-contextual retrieval from episodic memory

Unsworth and Engle (2007) recently proposed a model of working memory capacity characterized by, among other things, the ability to conduct a strategic, cue-dependent search of long-term memory. Although this ability has been found to mediate individual variation in a number of higher order cognitive tasks, the component processes involved remain unclear. The current study was designed to investigate individual variation in successfully retrieving information from episodic memory by examining various aspects of the retrieval process. Both high- and low-working memory capacity participants were found to initiate recall in a similar fashion; however, low-working memory capacity participants did not show the classic asymmetry in their conditional-response probabilities that is typically observed. Overall, the retrieval deficits observed in low-working memory capacity individuals appear to be rooted in their inability to use the products of retrieval to further aid their search.     

Retrieval experience in prospective memory: strategic monitoring and spontaneous retrieval

According to the multi-process model of prospective memory (McDaniel & Einstein, 2000), performance in a prospective memory task may be due to spontaneous retrieval processes or due to strategic monitoring. Spontaneous retrieval is typically accompanied by a pop up experience and strategic monitoring by a search experience. In this study we report two experiments with young adults in which we systematically investigated whether retrieval experience differed across experimental conditions. In Experiment 1 some prospective memory targets were preceded by associated primes. We expected that presenting primes would enhance performance by an automatic activation of the intention and hence lead to an increase in pop up experiences. In Experiment 2 half of the participants received instructions containing information about the specific context in which the prospective memory task would occur, whereas the other half of the participants received no such information. We expected that specific context instructions would enhance performance by legitimate anticipation of the prospective memory task and hence would lead to an increase in search experiences. The results confirmed these expectations. They indicate that the assessment of retrieval experience can provide valuable insights into the processes underlying prospective memory performance. They also suggest that retrieval experience can vary systematically across experimental situations as predicted by the multi-process model.     

Working memory and counterexample retrieval for causal conditionals

The present study is part of recent attempts to specify the characteristics of the counterexample retrieval process during causal conditional reasoning. The study tried to pinpoint whether the retrieval of stored counterexamples (alternative causes and disabling conditions) for a causal conditional is completely automatic in nature or whether the search process also demands executive working memory (WM) resources. In Experiment 1, participants were presented with a counterexample generation task and a measure of WM capacity. We found a positive relation between search efficiency, as measured by the number of generated counterexamples in limited time, and WM capacity. Experiment 2 examined the effects of a secondary WM load on the retrieval performance. As predicted, burdening WM with an attention-demanding secondary task decreased the retrieval efficiency. Both low and high spans were affected by the WM load but load effects were less pronounced for the most strongly associated counterexamples. Findings established that in addition to an automatic search component, the counterexample retrieval draws on WM resources.     

Cognitive psychometrics: assessing storage and retrieval deficits in special populations with multinomial processing tree models

This article demonstrates how multinomial processing tree models can be used as assessment tools to measure cognitive deficits in clinical populations. This is illustrated with a model developed by W. H. Batchelder and D. M. Riefer (1980) that separately measures storage and retrieval processes in memory. The validity of the model is tested in 2 experiments, which show that presentation rate affects the storage of items (Experiment 1) and part-list cuing hurts item retrieval (Experiment 2). Experiments 3 and 4 examine 2 clinical populations: schizophrenics and alcoholics with organic brain damage. The model reveals that each group exhibits deficits in storage and retrieval, with the retrieval deficits being stronger and occurring more consistently over trials. Also, the alcoholics with organic brain damage show no improvement in retrieval over trials, although their storage improves at the same rate as a control group.     

Declarative working memory: A bio-inspired cognitive architecture proposal

Memory is considered one of the most important functions since it allows us to code, store and retrieve knowledge. These qualities make it an indispensable function for a virtual creature. In general, memory can be classified based on the durability of the stored data in working memory and long-term memory. Working memory refers to the capacity to maintain temporarily a limited amount of information in mind, which can then be used to support various abilities, including learning, reasoning, planning and decision-making. Unlike short-term memory, working memory is not only a storage site, but it is also a framework of interacting processes that involve the temporary storage and manipulation of information in the service of performing complex cognitive activities. Declarative memory is a type of long-term memory related with the storage of facts and events. This research focuses on the development of a cognitive architecture for the type of working memory that maintains and manipulates declarative information. The construction of the model was grounded in theoretical evidence taken from cognitive sciences such as neuroscience and psychology, which gave us the components and their processes. The model was evaluated through a case study that covers the encoding, storing, and retrieval stages. Our hypothesis is that a virtual creature endowed with our working memory model will provide faster access to the information needed for the ongoing task. Therefore, it improves the planning and decision-making processes.     

Development of organization in recall: A stages-of-learning analysis

An experiment is reported in which the effects of taxonomic organization on 7-year-old and 11-year-old children's free and cued recall of two- and four-category lists were examined. The data were analyzed using a stages-of-learning model that simultaneously delivers estimates of the impact of these manipulations on storage and retrieval components of recall. The results indicated that for the Grade 2 children providing a category label at the time of recall primarily enhanced storage whereas increasing the number of categories primarily enhanced retrieval. For Grade 6 children, on the other hand, the use of category labels to cue recall primarily enhanced retrieval, whereas increasing the number of categories affected both storage and retrieval in free recall, but only retrieval in cued recall. In addition, while older children were superior to younger children at both storing and retrieving information, age differences at retrieval were generally larger than those at storage.     

Constraints on retrieval search for episodic information in children and adults

The hypothesis that a lack of structural constraint limits children's ability to use context and category cues to search associative memory for episodic information is examined in this study. Second and fifth graders and college adults were shown word triplets at acquisition and asked to recall the final target member of each triplet in a cued recall task. The manipulations concerned sources of associative structure that could constrain retrieval search. The degree to which the members of the triplets were associated was varied, as well as the kind of association, and the kind and amount of retrieval support provided in the cue, and encoding was constrained by orienting questions or was unconstrained. The results showed that children's effective use of retrieval cues was more dependent on episodic associative structure, retrieval support, and the constrained encoding of associative information than was adults'. Differences in the associative structure of information in permanent memory seemed to contribute to the results.     

Memory for verbal and nonverbal stimuli in learning disability subgroups: analysis by selective reminding

Memory for verbal and nonverbal stimuli was evaluated using selective reminding procedures in normal achieving children and four groups of disabled learners: (1) reading-spelling disabled (R-S); (2) reading-spelling-arithmetic disabled (R-S-A); (3) spelling-arithmetic disabled (S-A); and (4) arithmetic disabled (A). Each child received two analogous free-list memory tasks, one for verbal material (animal names) and the other for nonverbal material (random dot patterns). These tasks were administered using selective reminding procedures that permit separation of storage and retrieval aspects of memory by reminding children only of those words not recalled on previous trials. Results revealed that relative to controls, the A and S-A children had significantly lower storage and retrieval scores on the nonverbal task, but did not differ on the verbal task; the R-S children differed only on retrieval scores from the verbal task; and the R-S-A children on retrieval scores on the verbal task and storage and retrieval scores on the nonverbal task. Thus, results indicate that the memory performance of disabled learners varies according to (1) the type of learning problem (arithmetic vs reading), (2) the nature of the stimuli (verbal vs nonverbal), and (3) the aspect of memory being assessed (storage vs retrieval). This study provides external validation for the classification of disabled learners according to patterns of academic achievement, demonstrating a useful procedure for dealing with the intrasubject variability characteristic of disabled learners.     

The interaction of semantic memory with storage and retrieval processes

A procedure for separating storage from retrieval (R. Chechile & D. L. Meyer, Journal of Mathematical Psychology, 1976, 14, 430–437) lead to the conclusion that memory development involves changes in both storage and retrieval. Nevertheless, these changes resulted from the interaction of storage and retrieval mechanisms with the age-related elaboration of the semantic memory system. This study shows that the memory improvement with age, between kindergarten and second grade, vanished when the meaningfulness of the materials were equated. The most plausible interpretation of the results is the hardware invariance hypothesis. According to that hypothesis, the memory apparatus for information processing is constant across ages, but the hardware is used more effectively if there is a better-developed semantic memory system.     

Alcohol-induced state-dependent learning: Differentiating stimulus and storage hypotheses

State-dependent effects of alcohol have been demonstrated in animals and man. Most studies have used tasks for which accurate performance typically requires that stimulus input was adequately stored initially and that the items were retrieved at the time of testing. Thus an alcohol-induced decrement in performance could be due to impaired storage, impaired retrieval, or both. The purpose of this experiment was to distinguish between stimulus and storage hypotheses of state-dependent learning (SDL). Sixteen subjects were used in a 2×2 design in which the task involved the learning and recall of a 19-item ‘route’ map. During initial learning, all subjects were sober. Immediately after learning, half the subjects were given a moderate dose of alcohol. Twenty-four hours later, all subjects were tested for recall under the same or different conditions. Greater retention was found for those subjects whose drug states were the same in memory storage/consolidation and retrieval. Thus an alcohol state effective during the memory consolidation interval following acquisition appears to be a sufficient condition for producing SDL. In this context, SDL might be better termed state-dependent memory storage and retrieval. The implications of these results for the aetiology and treatment of alcohol dependence are discussed.