The paper reviews methods of investigation into the structure and functional role of working memory (WM). The methodology of WM studies are comprehensively analyzed from the perspective of two main theoretical approaches. Firstly, Alan Baddeley's multiple-systems model of WM serves as a ground for the review and analysis of different methodologies aimed at determining the capacity and functions of two slave subsystems (phonological loop and visual sketchpad) dedicated to storing and processing verbal and visual information, respectively. The advantages and limits of these are concerned as well. Secondly, Cowan's single-system model of WM based on activation mechanism is analyzed. The authors also present methods aimed at investigating control and executive functions of the WM system.
The authors investigated whether capacity for short term information storage influences the complexity of the choice process. To this end a study was conducted where participants 1) had to memorize a string of digits and then recognize a target digit which was either present or absent in the string (working memory (WM) task) and 2) had to choose one of four alternatives described on six dimensions (multi-attribute choice task). Subjects who decided longer and acquired more information before the decision were also more correct on the WM task, especially in the more demanding condition of exhaustive search. Additionally, for those subjects with the higher tendency to search pre-decisional information selectively the performance on WM task deteriorated more slowly with increasing memory load. These results point to the inverse relationship between the capacity to store information for a short time and the complexity of the process of decision making.
Decision making, as a complex mental process, consists of sequences of rudimentary cognitive operations. Therefore, various alternative strategies of information processing can be applied during decision making. The choice of a given strategy depends on situational factors, as well as on the personal characteristics of a decision maker. These characteristics refer mostly to efficiency of attention and working memory processes. Elementary cognitive operations occur in working memory, so its efficiency must be vital for the process of decision making. In spite of these obviously clear assumptions, attempts to investigate the relationships between elementary cognitive operations and the processes of decision making are relatively scarce. In this chapter, the authors discuss such relationships. Particular stress is put on the problem of strategies of decision making and their dependency on the attention and working memory functioning.
Current studies on cognitive processes focused also on specificity and neurobiology of working memory. Working memory is mostly connected with the activity of prefrontal cortex, and their disturbances are an important element in the etiopathogenesis of mental illnesses. Activity of different neurotransmitters and also neurotrophic systems, especially brain derived neurotrophic factors (BDNF) play an important role in memory processes. It is also important in brain developmental processes and the polymorphism of BDNF gene now is in the center of genetic-molecular studies on working memory processes. The aim of this study was to evaluate a relation between polymorphisms Val66Met and C-270T of BDNF gene and the efficiency of working memory measured by neuropsychological tools: Wisconsin Card Sorting Test (WCST), Stroop test and Trail Making Test A&B in healthy subjects. The study was performed on 90 healthy volunteers (33 women, 57 men) aged 18-58 years. The results obtained have demonstrated the relation between performance on some of neuropsychological tests and polymorphism C-270T of BDNF gene, and the relationship was different in male and female group. However no association between the performance of the neuropsychological tests and polymorphism of Val66Met of BDNF gene was found. The results indicate different influence of the BDNF gene polymorphisms in working memory processes.
Aim of the paper is to develop model of autobiographical memory. Conway and Pleydell-Pearce (2000) distinguished two parts of autobiographical memory: autobiographical knowledge base and processes of autobiographical memories construction. This model should be completed with ideas concerning relations between above mentioned parts of autobiographical memory. It is proposed that working memory is responsible for communication between autobiographical knowledge base and autobiographical memories construction. Two models of working memory - those of Baddeley's and Cowan's - were used to demonstrate specificity of information coding and retrieval in autobiographical memory. Crucial point for these two approaches is a problem of usefulness of episodic buffer. This buffer may be distinct element in autobiographical memory system, but it is also possible that its function may be fulfilled by central executive. Empirical studies are required to establish a status of episodic buffer proposed recently by Baddeley.
This article presents the neuropsychological contribution to origin and development of the working memory model. A matter for current investigation and discussion was a model established originally by Baddeley and Hitch. Within a large working memory system, they proposed three subcomponents: the central executive, the phonological loop, and the visuospatial sketchpad. Later, a fourth component was proposed, the episodic buffer, which is assumed to be purely mnemonic in character. The goal of this paper is to clarify the neural and cognitive determinants of these systems, as well as to show explanatory value and limitations of the working memory model. Current interest focuses most strongly both on the link between subcomponents of memory, and between working memory and other cognitive processes. Neuroanatomical correlates were taken into account as well. It was emphasized that working memory has a rather widespread representation in the brain, which involves both prefrontal and non-frontal structures. The original concept of working memory seems controversial and simplified, mostly because it underestimates the role of complex language processes in memory functioning, and a close relationship between memory and posterior parts of the brain.
The aim of the studies was to assess the possibility and consequences of marking elements stored in working memory by affective stimuli. Two experiments in the memory search paradigm were conducted. In both studies one of the elements was suboptimally visually primed either by affective or neutral stimulus. It was hypothesized that such manipulation would result in higher activation of the primed element. The activation should result in higher accuracy in affective vs. neutral priming condition. The obtained results showed that the affective priming influenced task performance. Nevertheless, depending on a neutral stimulus type (mask vs. neutral face), the performance accuracy increased or decreased. The results of the studies suggest that such an effect could depend on the automatic activation of primed stimuli representation, and also on the conscious focusing of attention on the important, from evolutionary perspective, affective stimulus. Such focusing could impair memory search task performance.
The main aim of presented study was to investigate the influence of distraction on working memory functioning (mainly articulatory loop). It was expected that the results of the experiment would allow us to resolve between two competing models of articulatory loop ('storage' model and 'tape' model). Working memory search task based on Sternberg paradigm was used. Subjects were asked to memorize sets of three-letter words or trigrams that did not have any meaning. In the experimental conditions distractor (either a song or a melody) was introduced. Distraction was effective only in the most difficult conditions of the memory task. There were no differences between two kinds of distraction. Results suggest that both 'storage' and 'tape' models of articulatory loop could be hold, depending on type of material to be memorized.
The aim of presented studies was to determine which of the two alternative models of working memory (Baddeley's multiple-system model vs Cowan's single-system model) explains performance in various types of memory search task better. In two experiments the authors deal with the peculiar issue of working memory structure and possible role of activation mechanism in searching working memory contents. Both of them applied modified Sternberg's task in which after memorizing a sequence of elements participants had to judge whether the probe element was, or was not, present in the sequence. In Experiment I participants had to memorize stimuli in either one (verbal or visual) or multiple (verbal and visual) modality. In Experiment II subliminal visual priming was used to manipulate the activation of working memory content.The results of Experiment I suggest single-system coding of stimuli in working memory, whereas Experiment II results support the notion of activation as a working memory search mechanism.
The article in the first part investigates the different coding strategies used by deaf signers in short term memory. The deaf signers lack the use of the phonetical-acoustical coding but they are capable sometimes to use the articulatory code. It becomes also clear that it is possible to use the signs efficiently as a code if the presentation of the items is in the same modality. The use of the signs in short term memory tasks depends on the abilities and linguistic competencies of the deaf signers. Despite the difference in short term memory span, hearing speakers and deaf signers have comparable working memory resources during language use, indicating similar abilities to maintain and manipulate linguistic information online. The auditory system is known to be highly efficient in retaining the order of occurrence of sounds. It is possible that speakers and signers may encode order information in quite different manners, speakers relay predominantly on temporal encoding and signers predominantly on spatial encoding. The sign language is a natural language and thus presents an opportunity to examine the neural organisation of language. In the second part of this article the author analyses the way the different sensorial modality can influence the neural representation of language. In his view there is a strong similarity between the regions activated within the left hemisphere by sign language in deaf individuals, compared with those activated by spoken language in hearing individuals. This may suggest that the cortical neural organisation of language processing does not depend on the different sensorial inputs but it is determined by the inner structure of the natural language.
This paper presents the analyses of limitations in working memory functions among older adults in comparison to depressed students and to appropriate control participants. The first part reviews the newest findings from the neuroimaging studies on working memory among depressed and older adults. These studies showed some interesting similarities in activation of brain regions involved in working memory functioning and its specific pattern in either depressed or elder persons. The next part presents the reanalysis of the performance of more or less complex working memory tasks by depressed and older adults. In these reanalyses the authors applied the Brinley plots for comparing results from different populations and from tasks of varied difficulty. After reviewing research findings they suggest that both old age and depression may limit the working memory functioning, but the mechanisms of these limitations are different in each group.
Language aptitude and working memory are considered to be the most important cognitive variables that affect success in language learning. The authoresses' research investigated the relationship of verbal working memory, language aptitude and proficiency among 64 first-year students of a bilingual secondary school in Budapest, who participated in a year-long intensive English course. Among the components of language aptitude, inductive language learning ability was found to show the highest correlation with competence in a foreign language. Verbal working memory span was moderately correlated with vocabulary, grammar skills and fluency in English. On the basis of their results, they argued that verbal working memory does not only play an important role in learning foreign language words and sequences, but also in how efficiently the learners can retrieve their acquired knowledge in these fields and how well they can divide their attention between planning the content of their message and linguistic processing. In their research they found no relationship between verbal working memory span and language aptitude, which seems to indicate that these two cognitive variables contribute separately to the success of language learning.
A meta-analysis was carried out to demonstrate the existence of publication bias in research on the relationship between measures of fluid intelligence and working memory. Reanalysis of data collected in Ackerman, Beier, & Boyle, 2005 was conducted. A heterogeneous distribution of correlation coefficients in the absence of asymmetry in the distribution of coefficients was observed. According to the author of the analysis, there are no arguments for the presence of publication bias in this particular set of results drawn from research on intelligence and working memory.
Updating can be considered as a basic control process responsible for efficient use of working memory (WM) capacity. It provides dynamic control of the contents of WM. For instance, it is suggested that updating controls the meaning of the information and its relevance to the ongoing task/activity. If so, it is plausible to hypothesize that updating requires both attentional and memory processes. Therefore, updating is characterized as coordinated control of the contents of meta-record (record of the task relevant meaning of remembered pieces of information) and direct record (record of items themselves) in WM. The distinction between contents of these two classes of representation may help to understand and account for ambiguous effects of load in WM tasks. Conducted experiment aims at testing the following broad hypotheses: (1) Updating requires attentional processes and (2) Updating requires interaction of attentional and memory processes. The authors used a complex memory task (MATTE) with auditory noise as a additional factor. They argue that attentional selection is far more important for effective updating than availability of resources or small (few elements) changes in memory load.
Theoretical study aimed at comparison functions of working memory and consciousness. The paper presents comparative analysis of working memory and consciouness functions. Consciousness is analyzed from the point of view of metaphorical and high context approach of Bernard Baars. Two distinct approaches to functions of working memory were taken into account. The first approach assumes that working memory consists of various structures and processes (Baddeley approach), while the second one is based on assumption of homogeneity of memory processes. Working memory in considered as activated part of long term memory. Fundamental difference between consciousness and both approaches to working memory refers to temporal range of regulation. Working memory is capable to regulate behavior during short period of time - not longer than few seconds. Consciousness may be very effective for a very long time. The two considered systems, i.e. working memory and consciousness may related to different kinds of emotional processes. These processes may be termed as phasic and tonic emotions. Phasic emotions occur as fast and short response to external stimuli; on the other hand tonis emotions may be considered as a result on interaction between distant goals (motivational system) and current situational demands. Consequences of such approach to working memory and consciousness for many psychological theories are discussed.
The authors research group adapted the well-known English Listening Span task to the Hungarian language to test working memory capacity in Hungarian. The English version of the task has been widely used to test age related changes and to map pathological variations of working memory. One of the great advantages of this task is that it can be used with a much larger target group than the previous tests, because reading or writing skills are not requisites for testing. Furthermore, it can be a useful diagnostic tool in assessing learning disabilities and other cognitive impairments. The Hungarian Listening Span task and data is presented for the first time.
The main purpose of this research is to study the relationship between verbal working memory an morphological complexity of words. Hungarian as an agglutinative language is of special interest for psycholinguistic inquiries in morphology. The authors present three word-recall experiments. The recall of words was measured by the classical span design. The item lists consisted of 2 syllable stems and 2 syllable morphologically complex words (stem + suffix). Within one list the words were of the same length, the same phonological structure (CVCVC), the same fluency and the same concreteness. The experimental design was the same with 3 syllable words as well. The capacity of the phonological loop was measured by digit span and non-word repetition. Results indicated that morphological complexity has a significant effect on word span. Partial correlation analysis suggests that the effect of the phonological loop on morphologically complex words is mediated by stems rather than suffixes.
Understanding of visual perception requires explanation of the interactive functioning of working memory and visual selection system, especially problem of common attentional resources involved in both of them (Mitchell et al. 2002). The review of theories of saccade generation and working memory supplied a hypotheses concerning existence of common resources, and rules of its distribution. In experiments, saccadic reaction times (SRT) were investigated as a function of increasing verbal and spatial working memory workload. In first experiment linear decreasing of SRTs has been demonstrated, in second investigation increasing SRTs as an effect of growing memory workload has been observed. The data has been interpreted in terms of automation and control of eye movements. When verbal memory workload biased central executive eye movements became more automated and faster. In second experiment both tasks used common structure- spatial sketch pad- what explains prolongation of SRTs.
This paper reports on the experiment measuring the effect of foreign language sound segments on phonological short-term memory. The capacity of the phonological store and the accuracy of the representations is measured through a nonword repetition task in which participants reproduce two kinds of stimuli: L1-sounding nonwords, comprising first language phones exclusively and L2-sounding nonwords containing both native and foreign language phones. Responses were assessed according to a set of criteria which was devised to control for various production factors , in particular that of accent. The results show a significant difference between the recall of the two types of stimuli, which suggests that the presence of unfamiliar sound segments in the verbal input impairs the maintenance of short-term phonological representations and thus affects the whole process of second language acquisition. The study, at the same time, offers a novel methodological framework for further research on the role of working memory in vocabulary acquisition.
Numerous studies have identified and explored the factors that affect order information processing in verbal working memory (WM), whereas little is known about order maintenance in visual WM. To gain better insight into the possible mechanisms of the representing order in visual WM, we assessed the extent of serial position and item distance effects on visual WM. 20 students performed a visual WM task. They were asked to encode and maintain either the identity or temporal order of four visual stimuli. The results revealed recency and distance effects congruent with previous studies of verbal WM however no primacy effect in accuracy results was detected. Distance was revealed to be closely intertwined with recency, making it difficult to estimate their separate effects on order recognition. These results suggest that order coding in visual WM involves the use of a magnitude of codes similar to those employed in number processing and verbal WM.