Short-term Store Research Articles

The role of articulation in the parsing and retention of letter strings in tachistoscopic free recall.

In Mewhort and Campbell's (1981) model of visual word recognition, a scan-parse mechanism transfer information from a character buffer to a short-term store and is largely responsible for the familiarity effects observed in tachistoscopic free recall. Although Mewhort and Campbell do not elaborate on the role of articulation in this task, they do suggest that the scan-parse mechanism acts prior to any involvement of articulatory processes (see Mewhort & Campbell, 1980). However, proponents of working memory (see Baddeley, 1986) are clear that articulation is necessary for the transfer of visual information to a phonological short-term store. In order to clarify the role of articulation in the parsing and retention of letter string, we asked subjects to undertake a tachistoscopic free-recall task, involving first- and fourth-order letter strings, with and without articulatory suppression and/or unattended speech. Unattended speech was observed to interfere with recall, but only when subjects were free to articulate the strings. This implies that subjects were retrieving information from the phonological store and that articulation is necessary for the registration of visual information in this store. The lack of interaction between order-of-approximation and suppression supports the view that the scan-parse mechanism acts independently of articulation. It appears, therefore, that letter strings are parsed at a stage preceding their transfer of the pharmacological store. Finally, the results indicate that subjects are able to draw directly on a representation of the parsed components of a letter string and may do so when phonological storage is difficult.(ABSTRACT TRUNCATED AT 250 WORDS)

Echoic memory in the rat: Effects of inspection time, retention interval, and the spectral composition of masking noise.

Memory for tones (1100 vs. 2330 Hz) was studied in 4 rats (Rattus norvegicus), as affected by the durations of both target tones (30 to 620 ms) and noise-filled retention intervals (0 to 480 ms). With a 0-ms delay, performance was near asymptotic with the 30-ms tone, but the memory of this brief tone suffered a massive decrement at retention intervals as brief as 60 ms; in contrast, memory for the 340-ms tone was stable for at least 240 ms. If the retention interval was filled by band-stop noise (with targets presented in the spectral gap), then the rat's memory for brief tones was superior to that obtained with the standard broad-band noise filler, and band-stop noise was better than a band-pass noise that had the tones embedded in the region of its spectral energy. These findings are consistent with the hypotheses that auditory memory in the rat consists of a transient sensorylike echoic store and a short-term store more resistant to the effects of retroactive interference.

Relationship between maternal thyroxine levels during pregnancy and memory function in childhood

Two investigations are reported into the memory functions of a group of subjects for whom information on maternal thyroxine (T 4) levels during pregnancy is available. The first study made when the subjects were aged 14–15 years examined forward and backward memory span. No relationship between maternal T 4 levels and capacity of the short-term store, measured as length of forward memory span, was found. Backward memory span, which involves performing a mental operation on the material held in store, was found to be associated with maternal T 4 level. The second study, made when the subjects were aged 16–17 years, found a relationship between maternal T 4 levels during pregnancy and memory for serial position. Findings are discussed in terms of the role of maternal thyroxine in fetal brain development.

Free recall of lists of word and sign labels by severely handicapped children

Two experiments are reported which tested short-term recall of lists of four sign or four word labels by severely handicapped children. The findings suggest that the subjects were more efficient at processing words than signs in short-term memory, and that their organization of sign and word lists were affected by the length of time the material had to be held in short-term store. Both of these effects were influenced by whether or not the subjects had to use the stimuli as labels when making a response.

Association Brain Systems as Apparatus of Behavior Control Involving Dominanta and Conditioning

The author's major conception concerning the associative brain systems (thalamoparietal and thalamofrontal) as the behavior control system are presented. The participation of association systems in performance of higher brain functions, due to the entrance of the whole information spectrum of biological and signal significance and the presence of neuronal plastic mechanisms, ensures the mechanism for retrieving the whole behavior programs from long-term memory, the ability of short-term storing of behavior programs, and estimation of their adequacy on the ground of dominanta and conditioning mechanisms.

Recency and the modality effect in immediate ordered recall.

In immediate ordered recall, recency is the improved recall of the last item of a presentation, and the modality effect is the advantage for an acoustic presentation over a subvocalized visual presentation, primarily occurring at the last serial position. Experiment 1 tested grouped presentations. There was a modality effect for the first item of the last group, even though that item was at the third-to-last or fourth-to-last serial position. In Experiment 2, for vocalized presentations of syllables ending in a, recency was larger for staccato speech than legato speech; for subvocalized presentations, there was a substantial recency for the legato style. In Experiment 3, recency was larger for a set of syllables ending in ATE than for a set of syllables ending in AME. These results suggest that recency cannot be explained by the existence of a fixed-capacity store, auxiliary to the auditory short-term store, that retains only some types of presentations. It is suggested instead that recency might reflect an auxiliary method of using the information in the auditory short-term store.

Explanations of grouping in immediate ordered recall.

This article is about grouping in immediate ordered recall. The following findings are reported: (1) grouping a presentation improves recall, even when steps are taken to prevent rehearsal; (2) grouping primarily improves recall of the items adjoining the grouping, creating primacy and recency within groups; and (3) this primacy and recency are found even when single, isolated errors in recall are considered. These results suggest that the effects of grouping cannot be fully explained by rehearsal, chunking, or the number of directions in which an item can be transposed. It is suggested instead that (1) the auditory short-term store contains an unparsed and uncategorized representation that must be parsed and categorized just prior to recall, in a process of recovery; (2) items adjoining the boundary of a presentation are more easily recovered; and (3) grouping creates a boundary within the presentation. To support this explanation, a final experiment demonstrates an interaction between type of stimuli and serial position, with grouping most improving recall of adjoining phonemes.

Effects of Background Music on Phonological Short-Term Memory

Immediate memory for visually presented verbal material is disrupted by concurrent speech, even when the speech is unattended and in a foreign language. Unattended noise does not produce a reliable decrement. These results have been interpreted in terms of a phonological short-term store that excludes non-speechlike sounds. The characteristics of this exclusion process were explored by studying the effects of music on the serial recall of sequences of nine digits presented visually. Experiment 1 compared the effects of unattended vocal or instrumental music with quiet and showed that both types of music disrupted STM performance, with vocal music being more disruptive than instrumental music. Experiment 2 attempted to replicate this result using more highly trained subjects. Vocal music caused significantly more disruption than instrumental music, which was not significantly worse than the silent control condition. Experiment 3 compared instrumental music with unattended speech and with noise modulated in amplitude, the degree of modulation being the same as in speech. The results showed that the noise condition did not differ from silence; both of these proved less disruptive than instrumental music, which was in turn less disruptive than the unattended speech condition. Theoretical interpretation of these results and their potential practical implications for the disruption of cognitive performance by background music are discussed.

Verbal memory function after subarachnoid haemorrhage determined by the localisation of the ruptured aneurysm.

A total of 219 patients who had suffered from subarachnoid haemorrhage (SAH) were given a set of memory tests. The tests comprised immediate free recall (indexing long-term memory, LTM, and short-term memory, STM), final free recall (LTM) and final cued recall (LTM) of words as well as a digit-span test (an index of working memory, WM). STM was highly sensitive to brain damage caused by SAH whereas WM was not. Localisation of the ruptured aneurysm, angiographic vasospasm or mass effect did not have any selective influence on the SAH group's STM or WM. The final free recall test was the most sensitive measure of LTM whereas the LTM part of the immediate free recall test was the least sensitive. LTM impairment was most pronounced for patients with ruptured left anterior communicating artery aneurysms or for patients with angiographic vasospasm or mass effect. It is suggested that, in the SAH patients, a passive phonological short-term store is impaired, but the active maintenance rehearsal mechanism is intact. For patients with LTM dysfunction, deeper, more elaborate, active processing is disrupted, hindering efficient long-term storage.

When long-term learning depends on short-term storage

Since the 1960s, there has been controversy as to whether long-term learning might depend on some form of temporary short-term storage. Evidence that patients with grossly impaired memory span might show normal learning was, however, particularly problematic for such views. We reexamine the question by studying the learning capacity of a patient, P.V., with a very pure deficit in short-term memory. A series of experiments compare her learning capacity with that of matched controls. The first experiment shows that her capacity to learn pairs of meaningful words is within the normal range. A second experiment examines her capacity to learn to associate a familiar word with an unfamiliar item from another language. With auditory presentation she is completely unable to perform this task. Further studies show that when visual presentation is used she shows evidence of learning, but is clearly impaired. It is suggested that short-term phonological storage is important for learning unfamiliar verbal material, but is not essential for forming associations between meaningful items that are already known. Implications for the possible role of a phonological short-term store in the acquisition of vocabulary by children are discussed.

Issues of representation and limited capacity in the visuospatial sketchpad.

This article is about a visual short-term store called the visuospatial sketchpad (VSSP), which is tested by immediate ordered recall. Several claims are made: first, even for categorizable stimuli such as digits and letters, the representation in VSSP is uncategorized and unparsed. Second, the representation in VSSP is parsed and categorized just prior to recall in a process called recovery. The probability of recovering an item depends upon the fidelity of that item's representation. Third, VSSP has a fixed amount of representational medium which is allocated proportionally to the items in the presentation. When too many items are presented for recall, not all of the items are represented with sufficient fidelity to be recovered, producing the phenomenon of limited capacity.

Issues of representation and limited capacity in the auditory short-term store.

This article makes several related claims about the auditory short-term store (ASTS) tested by immediate ordered recall. The first claim is that the representation in ASTS is uncategorical and unparsed. The second claim is that there is a stage of recovery just prior to recall, in which the information in ASTS is parsed and categorized. Finally, it is proposed that the amount of representational medium in ASTS is fixed and allocated proportionally to each item in the presentation. When too many items are presented, the items are not represented with sufficient fidelity to be recovered, leading to the phenomenon of limited capacity. These claims are contrasted to the predictions of a slot model, in which ASTS is hypothesized to store a fixed number of categorical and parsed items. Novel explanations are given for several phenomena in immediate ordered recall, including the Hebb effect, the correlation between perceptibility and capacity, and serial position curves.

Mixed transcortical aphsia. On relative sparing of phonological short-term store in a case

A case of Mixed Transcortical Aphasia is reported. The patient showed completely impaired verbal comprehension and speech production, with preservation of automatic speaking and singing; repetition was relatively spared. A detailed study of word and nonword repetition is reported, in order to demonstrate that the patient's residual repetition ability is based on relative sparing of short-term phonological store.

Models of memory: information processing.

A complete understanding of human memory will necessarily involve consideration of the active processes involved at the time of learning and of the organization and nature of representation of information in long-term memory. In addition to process and structure, it is important for theory to indicate the ways in which stimulus-driven and conceptually driven processes interact with each other in the learning situation. Not surprisingly, no existent theory provides a detailed specification of all of these factors. However, there are a number of more specific theories which are successful in illuminating some of the component structures and processes. The working memory model proposed by Baddeley and Hitch (1974) and modified subsequently has shown how the earlier theoretical construct of the short-term store should be replaced with the notion of working memory. In essence, working memory is a system which is used both to process information and to permit the transient storage of information. It comprises a number of conceptually distinct, but functionally interdependent components. So far as long-term memory is concerned, there is evidence of a number of different kinds of representation. Of particular importance is the distinction between declarative knowledge and procedural knowledge, a distinction which has received support from the study of amnesic patients. Kosslyn has argued for a distinction between literal representation and propositional representation, whereas Tulving has distinguished between episodic and semantic memories. While Tulving's distinction is perhaps the best known, there is increasing evidence that episodic and semantic memory differ primarily in content rather than in process, and so the distinction may be of less theoretical value than was originally believed.(ABSTRACT TRUNCATED AT 250 WORDS)

Phonological short-term store and sentence processing

Abstract The grammatical and semantic processing of auditorily presented sentences and passages of prose was investigated in a left brain-damaged patient (PV), who has a reduced auditory memory span, interpreted in terms of a selective deficit of the phonological short-term store component of working memory. In the case of short sentences the patient's performance is well within the normal range, whether tested by sentence-picture matching or by the detection of syntactic or semantic anomalies. She retains an intact capacity to detect semantic anomalies whether tested using short sentences, long sentences, or prose passages. She retains some capacity for detecting syntactic anomalies even in long sentences, provided these are tested under conditions where such mismatches are very frequent; when they are embedded in more varied material, however, her performance deteriorates. Finally, when the syntactic anomaly involves an anaphoric mismatch across sentences, her performance drops to chance level. These re...

Articulation and verbal short-term memory: Evidence from anarthria

Abstract The role of articulation in verbal short-term memory was investigated in two patients suffering from a selective and total impairment of overt articulation. Case GF was totally speechless due to a ventral pontine lesion and case MDC due to bilateral anterior opercular softenings. Both patients had normal auditory comprehension, a digit span performance within the normal range, and displayed the standard effect of phonological similarity in immediate memory performance with auditory material. This pattern of results suggests that a total impairment of overt articulation, occurring in adult age, does not disrupt the function of the phonological short-term store component of working memory. These conclusions are consistent with the view that a phonological nonarticulatory input short-term storage system is a main functional component involved in auditory span performance. Finally, while GF's phonological processing of visual material was unaffected, in MDC's case a defective phonological recoding of...

Phonological short-term store and the nature of the recency effect: Evidence from neuropsychology

The recency effect in immediate recall of lists of unrelated words was investigated in P.V., a left hemisphere-damaged patient, who had a grossly reduced auditory verbal span, attributed to a selective impairment of a phonological short-term store. No recency effect was evident in free recall of auditorily presented material. When the patient was instructed to recall the final items of the list first, the recency performance remained defective, even though P.V. was able to adopt a recall from end order. In the case of visual presentation P.V.'s free recall performance was within the normal range and a clear recency occurred in the recall from end condition. These results are consistent with the view that the standard recency effect in immediate free recall of auditorily presented material represents the output of a phonological short-term store to which ordinal retrieval strategies, in P.V.'s case unimpaired, are applied. Finally, the contributions of the phonological short-term store and the process of rehearsal to the recency effect and to immediate memory span performance are discussed.

Associations across time: The hippocampus as a temporary memory store

AbstractAll recent memory theories of hippocampal function have incorporated the idea that the hippocampus is required to process items only of some qualitatively specifiahle kind, and is not required to process items of some complementary set. In contrast, it is now proposed that the hippocampus is needed to process stimuli of all kinds, but only when there is a need to associate those stimuli with other events that are temporally discontiguous. In order to form or use temporally discontiguous associations, it is essential to maintain some memory of the first component until the second component has occurred. When the temporal gap to he spanned is small, and the number of items to be temporarily retained is low, a limited-capacity, short-term store is sufficient to allow associations to be formed. Such a store is presumed to operate in parallel with the hippocampus in normal animals. Hippocampal damage disrupts a much higher-capacity store that has a slower decay rate, and so leaves animals with only a very limited ability to form temporally discontiguous associations. Hippocampal damage, however, is not held to affect the long-term storage of associations of any kind, if they can be formed. Analyses of both new and existing data are presented to show that by classifying tasks in terms of the need to use a temporary memory store to retain temporally discontiguous information one can cut right across existing classifications as well as achieve a better fit to the data. The hippocampus thus seems best described as a high-capacity, intermediate-term memory store.

The short-term storage as a buffer memory between long-term storage and the motor system: A simultaneous-processing model

It is assumed that in a free-recall task the short-term store serves as a memory buffer between the long-term store and a final motor stage of word production. Because of this the retrieval process in long-term store is not hindered by the final motor stage of word production since continued output from the long-term store queues in the buffer for motoric processing. Otherwise a time consuming communication between the two processes would be necessary. A stochastic model of this conceptualization is provided to predict the temporal course of free recall as well as a paradigm in which the contribution of the short-term store in free recall can be studied. The experimental results from this paradigm were used to test the model and to estimate short-term storage capacity on the basis of the time course of free recall. The model predictions were in good agreement with the data and the capacity estimate coincides well with estimates found by totally different methods reported in the literature.

Testing visual short-term memory: simultaneous versus sequential presentations.

Two experiments testing immediate ordered recall are presented; in these experiments, subjects engaged in repetitive speech (“articulatory suppression”) during a visual presentation in order to prevent auditory recoding of the stimuli. In both experiments, a simultaneous presentation produced results that suggested the use of visual short-term memory, whereas a sequential presentation did not. In Experiment 1, visual confusion errors occurred more often than would be expected by chance for a simultaneous presentation but not for a sequential presentation. In Experiment 2, recall from visual short-term memory was expected to suffer more when subjects wrote a prefix than when they spoke a prefix; this effect occurred for a simultaneous presentation but not for a sequential presentation. These results suggest that existence of a visual short term store that retains a simultaneous presentation but not a sequential presentation.