Short-term memory for repeated and non-repeated items

Digit sequences containing repeated items are retained differently in short-term memory from sequences containing no repeated items. The repeated items are remembered better or worse than items in the corresponding positions of “all-different” sequences depending on the number of times the item is repeated, the number of items repeated, the number of items intervening between the occurences of a repeated item, and the position of the repeated items in relation to the beginning and end of the sequence. In every type of repetition studied, except one, memory for the non-repeated items in sequences with repeated items is better than for the corresponding items of all-different sequences. This is true in some cases despite significant specific interference between the (non-repeated) items following the separated occurrences of repeated items. The negative effects in memory for repeated items and the positive effects in memory for non-repeated items are greater when the items are presented at the rate of five per sec. than at one per sec., contrary to the hypothesis that differential rehearsal is responsible for these effects. The results are interpreted as supporting an “associative,” as opposed to a “non-associative,” theory of short-term memory, as this distinction is defined in the paper.     

重复刺激的末位优势效应

探讨在RSVP任务中重复刺激的呈现位置和报告方式对重复知盲效应的影响, 检验该研究提出的注意资源最优化假设和末位优势效应。实验1操作了刺激性质和重复刺激位置, 得出了刺激性质和重复刺激位置的交互效应; 实验2操作了刺激性质和情景信息, 结果是交互效应不显著; 实验3操作了刺激性质和报告方式, 出现了刺激性质和报告方式的交互效应。该结果表明: (1)由于注意资源分配的优化, 重复刺激有末位优势效应。(2)重复知盲的产生不是发生在知觉阶段, 而是发生在报告阶段。(3)注意资源分配最优化理论比建构/归因理论能更合理地解释重复知盲的发生。     

Time of day and the representation of text

This article reports an experiment to investigate the idea that time-of-day differences in memory for text are related to type of text processing that is carried out at different times of day. In particular, it was hypothesized that subjects tested in the morning tend to retain more of the exact wording of the text, whereas those tested in the afternoon are more likely to produce a meaning-based representation. The results of a recognition test showed that, in agreement with other studies, immediate text memory is better in the morning than in the afternoon. As predicted, the subjects tested in the morning better remembered the exact wording of the original passages. However, the idea that memory for meaning is better in the afternoon than the morning was not supported by the data. The results suggest that subjects at both times of day produce a meaning-based representation of the text but, in the morning, this representation is supported by good verbatim memory, enabling accurate recall of the text at that time.     

Time of day and the representation of text

This article reports an experiment to investigate the idea that time-of-day differences in memory for text are related to type of text processing that is carried out at different times of day. In particular, it was hypothesized that subjects tested in the morning tend to retain more of the exact wording of the text, whereas those tested in the afternoon are more likely to produce a meaning-based representation. The results of a recognition test showed that, in agreement with other studies, immediate text memory is better in the morning than in the afternoon. As predicted, the subjects tested in the morning better remembered the exact wording of the original passages. However, the idea that memory for meaning is better in the afternoon than the morning was not supported by the data. The results suggest that subjects at both times of day produce a meaning-based representation of the text but, in the morning, this representation is supported by good verbatim memory, enabling accurate recall of the text at that time.     

Daily Time-Place Learning in Young Children

Abstract

Pre-school children find it difficult to correctly report if it is morning or afternoon. The present study tested whether children could learn a non-verbal Time-Place Learning (TPL) task that depended on time of day. Twenty-five 4-year-olds were repeatedly asked to find a toy in one of two boxes. Children in the Cued condition were told the toy was in one box in the morning and in another box in the afternoon. Children in the Not Cued condition were told the toy was sometimes in one box and sometimes in the other box. After 80 trials, children were asked if it was morning or afternoon. About 65% of the children learned the TPL task, and about three-quarters of the children verbally identified if it was morning or afternoon. However, the children who learned the TPL task were not necessarily the children who correctly answered whether it was morning or afternoon, and those in the Cued condition were no more likely to solve the task than those in the Not Cued condition. The implication is that children have a sense of time that can be used to solve spatio-temporal contingencies, but does not depend on the verbal understanding of time of day.     

Short-term memory in autism spectrum disorder

Three experiments examined verbal short-term memory in comparison and autism spectrum disorder (ASD) participants. Experiment 1 involved forward and backward digit recall. Experiment 2 used a standard immediate serial recall task where, contrary to the digit-span task, items (words) were not repeated from list to list. Hence, this task called more heavily on item memory. Experiment 3 tested short-term order memory with an order recognition test: Each word list was repeated with or without the position of 2 adjacent items swapped. The ASD group showed poorer performance in all 3 experiments. Experiments 1 and 2 showed that group differences were due to memory for the order of the items, not to memory for the items themselves. Confirming these findings, the results of Experiment 3 showed that the ASD group had more difficulty detecting a change in the temporal sequence of the items.     

Post-training and pretest effects of adrenocorticotropin on retention: the influence of the hour of the day, the training-test interval, and pretest naloxone administration

Rats received an ip injection of 0.2 microgram/kg of ACTH-(1-39) 1 min after step-down inhibitory avoidance training and/or 5 min prior to retention testing. Experiments were carried out either in the morning or in the afternoon using either a 3- or a 24-h training-test interval. Post-training ACTH induced memory facilitation in the morning and amnesia in the afternoon at both training-test intervals. Pretest ACTH reversed the afternoon amnesic effect, also at both training-test intervals. In addition, pretest ACTH induced a naloxone-reversible memory enhancement, both on its own and in animals treated with a facilitatory post-training dose of ACTH in the morning; this effect was seen only at the 24-h training-test interval. Naloxone had no effect of its own and did not influence the reversal of ACTH-induced amnesia caused by pretest ACTH in the afternoon. The results point to the variety of memory modulatory influences of ACTH, and to some of the factors involved in the elicitation of one or other effect, namely, the presumable basal rate of secretion of endogenous ACTH, and the previous pharmacological history of the animal.     

Domain-specific and domain-general constraints on word and sequence learning

The relative influences of language-related and memory-related constraints on the learning of novel words and sequences were examined by comparing individual differences in performance of children with and without specific deficits in either language or working memory. Children recalled lists of words in a Hebbian learning protocol in which occasional lists repeated, yielding improved recall over the course of the task on the repeated lists. The task involved presentation of pictures of common nouns followed immediately by equivalent presentations of the spoken names. The same participants also completed a paired-associate learning task involving word–picture and nonword–picture pairs. Hebbian learning was observed for all groups. Domain-general working memory constrained immediate recall, whereas language abilities impacted recall in the auditory modality only. In addition, working memory constrained paired-associate learning generally, whereas language abilities disproportionately impacted novel word learning. Overall, all of the learning tasks were highly correlated with domain-general working memory. The learning of nonwords was additionally related to general intelligence, phonological short-term memory, language abilities, and implicit learning. The results suggest that distinct associations between language- and memory-related mechanisms support learning of familiar and unfamiliar phonological forms and sequences.     

After-effects of responding and of withholding responses in C.RT tasks

The effects of response repetition on choice RT were compared in b-reaction and in c-reaction tasks [Experiments I(a) and I(b)]. The difference in RTs for repeated and for non-repeated responses was found to be less for c-reaction than for b-reaction tasks. This seemed to be because in c-reaction tasks subjects can prepare themselves to make the same response on every trial, so that there is little further RT reduction consequent on immediate response repetition. In b-reaction tasks subjects cannot always prepare to make the same response, so that the difference between response repetition RT and responce alteration RT is greater. Experiment II examined transitions between events in a serial, self-paced C.RT task in which subjects made a different response to each of two signals but withheld any response to the onset of a third. In this task responses were faster when they followed other, different responses than when they followed “no go” trials. The results of these experiments allow us to reject, even for very elementary tasks, a simple “S--R connection network” model for the processes involved in the identification of signals and the production of responses to them.     

重复知盲效应产生的机制——来自汉语叠词加工的证据

以汉语中的叠词为实验材料,对重复知盲产生机制的类型标记个体化理论和建构理论进行检验。采用RSVP研究范式,在两个实验中让178名被试口头报告列表中出现的所有汉字（全部报告）或列表中最后两个字（部分报告）。结果发现：（1）在呈现速率为128ms和198ms时,完全重复的汉字在全部报告和部分报告任务中均存在RB效应,但在部分报告任务下出现的RB相比全部报告任务的减少了,符合建构理论的假设。（2）在全部报告条件下,不仅重复刺激的正确报告率会降低,而且与重复刺激相关的非重复刺激的正确报告率也会降低。研究表明建构理论比类型标记个体化理论更能解释RB效应的产生机制。     

When people’s judgments of learning (JOLs) are extremely accurate at predicting subsequent recall: the “Displaced-JOL effect”

Judgments of learning (JOL) made after a delay more accurately predict subsequent recall than JOLs made immediately after learning. One explanation is that delayed JOLs involve retrieving information about the target item from secondary memory, whereas immediate JOLs involve retrieval from primary memory. One view of working memory claims that information in primary memory is displaced to secondary memory when attention is shifted to a secondary task. Thus, immediate JOLs might be as accurate as delayed JOLs if an intervening task displaces the target item from primary memory, requiring retrieval from secondary memory, prior to making the JOL. In four experiments, participants saw related word-pairs and made JOLs predicting later recall of the item. In Experiment 1, delayed JOLs were more accurate than JOLs made shortly after learning, regardless of whether a secondary task intervened between learning and JOL. In Experiments 2–4, the secondary task demands increased and JOLs made shortly after learning with an intervening task were just as accurate as delayed JOLs, and both were more accurate than immediate JOLs with no intervening task (Experiment 4). These results are consistent with a retrieval-based account of JOLs, and demonstrate that the “delayed-JOL effect” can be obtained without a long delay.     

图形项目记忆与位置来源提取的ERP研究

采用事件相关电位（ERP）方法研究大学生图形项目记忆与位置来源提取新/旧效应的时、空分布特征。学习屏幕左侧（或右侧）呈现的图形后在屏幕中央呈现某一测验项目（已学图形或新图形）,对受试者进行两类测验：其一是判断该项目是否已学过;其二是将从某侧学过的测验项目判断为目标,而将其它测验项目判断为非目标的来源测验（排除任务）。实验结果表明：图形位置来源提取比项目再认新/旧效应的头皮分布更广,持续时程更长;与前人相同实验范式的研究结果相比,本研究位置来源提取效应的头皮分布范围较广;非目标-旧图形与目标图形新/旧效应的头皮激活程度不同。上述结果说明：图形位置来源提取比项目再认激活的大脑区域更多,这与双重加工模型的观点一致;实验范式和来源知觉的特性共同调节来源记忆新/旧效应的时、空分布特征;意识水平对来源信息提取的新/旧效应存在一定的影响     

The effect of repetition on search through active memory

Short lists of digits, some of which contained repeated items, were searched in memory. Repeated items were recognized faster than non-repeated items. Search times for non-repeated items in lists with a repeat were slightly faster than those for lists of the same length in which no items were repeated. A serial position effect was found such that items at either the beginning or end of the memory list were responded to faster than items in the middle of the list. Neither the repeated digit effect nor the serial position effect support serial exhaustive search. An empirical equation was found by which response time is predicted by the log proportion of items in a memory list that match the test stimulus. These results are compatible with the notions of neural pathway activation and trace strength.     

Hebb repetition effects for non-verbal visual sequences: determinants of sequence acquisition

We report four experiments premised upon the work of Horton et al. [(2008). Hebb repetition effects in visual memory: The roles of verbal rehearsal and distinctiveness. Quarterly Journal of Experimental Psychology, 61(12), 1769–1777] and Page et al. [(2013). Repetition-spacing and item-overlap effects in the Hebb repetition task. Journal of Memory and Language, 69(4), 506–526], and explore conditions under which the visual Hebb repetition effect is observed. Experiment 1 showed that repetition learning is evident when the items comprising the non-repeated (filler) sequences and the repeated (Hebb) sequences are different (no-overlap). However, learning is abolished when the filler and Hebb sequences comprise the same items (full-overlap). Learning of the repeated sequence persisted when repetition spacing was increased to six trials (Experiment 2), consistent with that shown for verbal stimuli (Page et al., 2013). In Experiment 3, it was shown that learning for the repeated sequence is accentuated when the output motor response at test is also repeated for the Hebb sequence, but only under conditions of no-overlap. In Experiment 4, repetition spacing was re-examined with a repeated motor output response (a closer methodological analogue to Page et al., 2013). Under these conditions, the gradient of Hebb repetition learning for six trial repetition intervals was markedly similar to that for three trial intervals. These findings further support the universality of the Hebb repetition effect across memory and are discussed in terms of evidence for amodality within-sequence memory.     

Task probability and report of feature information: What you know about what you ‘see’ depends on what you expect to need

We investigated the influence of dimensional set on report of object feature information using an immediate memory probe task. Participants viewed displays containing up to 36 coloured geometric shapes which were presented for several hundred milliseconds before one item was abruptly occluded by a probe. A cue presented simultaneously with the probe instructed participants to report either about the colour or shape of the probe item. A dimensional set towards the colour or shape of the presented items was induced by manipulating task probability — the relative probability with which the two feature dimensions required report. This was done across two participant groups: One group was given trials where there was a higher report probability of colour, the other a higher report probability of shape. Two experiments showed that features were reported most accurately when they were of high task probability, though in both cases the effect was largely driven by the colour dimension. Importantly the task probability effect did not interact with display set size. This is interpreted as tentative evidence that this manipulation influences feature processing in a global manner and at a stage prior to visual short term memory.     

RSVP任务下双刺激重复的优势与劣势

本研究探讨重复知盲发生在知觉阶段还是在记忆阶段。采用快速视觉系列呈现(rapid serial visual representation, 简称RSVP)任务, 让被试即时回忆80个词表中呈现的词。操作了词表中目标词的重复数, 分为无重复、单刺激重复(重复一对)和双刺激重复(重复两对)三种, 和目标词的情绪效价, 分为中性词和情绪词两种。结果发现, 对目标词回忆的正确率是：当目标词和非目标词都是中性词汇, 即二者的情绪效价强度相当时(实验1), 在无重复条件与双刺激重复条件下无差异, 二者均大于单刺激重复条件; 当目标词是消极词汇, 非目标词是中性词汇, 即目标刺激的情绪效价强度大于非目标刺激时(实验2), 无重复条件与单刺激重复条件无差异, 二者均大于双刺激重复条件。结果表明：(1)RSVP 任务下词表中有双刺激重复时, 如果刺激的效价强度相当, 出现重复优势; 如果目标刺激的效价强度高于非目标刺激, 出现重复劣势; (2)人们会主动分配更多的注意资源给效价高的刺激, 重复知盲产生在记忆阶段, 支持注意资源分配最优化假设。     

The effect of an extraneous added memory set on item recognition: A test of parallel-dependent vs. serial-comparison models

The linear increase in response time (RT) in item recognition as a function of memory set size may be attributed either to increased memory search, as in Sternberg’s serial-comparison model, or to increased interference and competition for a limited processing capacity, as in a parallel-dependent model. An additional memory load was imposed on the normal item recognition task. If the normal task involved letters, the additional task involved digits, or vice versa. The added set was presented before and tested after the normal core set was presented and tested. Across the four trial blocks, the subjects did come to dissociate the two memory sets, but this could be due as much to directed rehearsal as to directed search when other results, including the subjects’ postsession reports, are considered. Other findings, such as the higher error rate and shorter RT for positive than negative trials, seem to reflect differences in effective trace strength, and thus are consistent with the parallel-dependent model.     

Auditory pattern recognition by untrained listeners

Earlier work with unpracticed Ss has indicated that identification (naming) of the temporal order of components within repeated sequences consisting of three or four unrelated sounds cannot be accomplished when the item durations are 200 msec or less. In the present experiment, separate groups of 30 unpracticed Ss were required to teil whether alternated sequences, each consisting of reiterated presentations of the same three or four successive items, were in identical or permuted order. Naming of the order within the sequences was not required. Accuracy of same/different judgments was significantly better than chance when all items lasted 200 msec. Changing the duration of each item in one of the two sequences above or below 200 msec made the task more difficult. These results, together with other evidence, suggest that: (1) identification of order and recognition of auditory temporal patterns may represent fundamentally different processes, and (2) recognition may involve matching of “temporal templates.”     

Dorsolateral prefrontal cortex mediates working memory processes in motor skill learning

Neuroimaging studies have shown that the dorsolateral prefrontal cortex (DLPFC) is recruited during motor skill learning, which suggests the involvement of the DLPFC in working memory (WM) processes, such as selection and integration of motor representations temporarily stored in WM. However, direct evidence linking activation of the DLPFC to WM storage and manipulation during motor skill learning in real-time is rare. In this study, we conducted two experiments to investigate the causal role of DLPFC activity in WM storage and manipulation during motor skill learning under low and high WM-demand conditions. Participants received continuous theta burst stimulation (cTBS) and sham stimulation (crossover design) over the left DLPFC (experiment 1) or right DLPFC (experiment 2). Before and after stimulation, participants in both experiments performed a sequential finger-tapping (SFT) task containing repeated sequence (low-WM demand) and non-repeated sequence (high-WM demand) conditions which are used to study WM processes. The number of correct sequences (NoCS) and reproduction error rate were analyzed. Learning gains in NoCS improved significantly with the practice for both sequence types in the presence of either stimulation type. Compared to sham stimulation, cTBS over the left DLPFC resulted in significantly reduced learning gains in NoCS for non-repeated sequences. These results suggest that the left DLPFC contributes to WM manipulation during motor skill learning.