Showing papers by "Alan D. Baddeley published in 2000"

Working memory and the vividness of imagery.

Abstract: The working memory framework was used to investigate the factors determining the phenomenological vividness of images. Participants rated the vividness of visual or auditory images under control conditions or while performing tasks that differentially disrupted the visuospatial sketchpad and phonological loop subsystems of working memory. In Experiments 1, 2, and 6, participants imaged recently presented novel visual patterns and sequences of tones; ratings of vividness showed the predicted interaction between stimulus modality and concurrent task. The images in experiments 3, 4, 5, and 6 were based on long-term memory (LTM). They also showed an image modality by task interaction, with a clear effect of LTM variables (meaningfulness, activity, bizarreness, and stimulus familiarity), implicating both working memory and LTM in the experience of vividness.

A Comparison of ''Errorless'' and ''Trial-and-error'' Learning Methods for Teaching Individuals with Acquired Memory Deficits

Abstract: We present nine experiments, in three study phases, which test the hypothesis that learning methods which prevent the making of errors (“errorless learning”) will lead to greater learning than “trial-and-error” learning methods amongst individuals who are memory impaired as a result of acquired brain injury. Results suggest that tasks and situations which facilitate retrieval of implicit memory for the learned material (such as learning names with a first letter cue) will benefit from errorless learning methods, whilst those that require the explicit recall of novel associations (such as learning routes or programming an electronic organiser) will not benefit from errorless learning. The more severely amnesic patients benefit to a greater extent from errorless learning methods than those who are less severely memory impaired, but this may only apply when the interval between learning and recall is relatively short.

Verbal short-term memory deficits in Down syndrome: a consequence of problems in rehearsal?

Abstract: Individuals with Down syndrome suffer from relatively poor verbal short-term memory. Previous explanations of this deficit have been framed in terms of inefficient or absent rehearsal of verbal material in Down syndrome within the phonological loop component of Baddeley and Hitch's (1974) working memory model. Two experiments are presented which test this explanation by looking for the markers of rehearsal in children with Down syndrome and verbal mental age matched controls. Both experiments confirm that individuals with Down syndrome show poorer verbal short-term memory performance than controls. However, they rule out rehearsal as an explanation of these deficits because the evidence suggests that neither individuals with Down syndrome nor matched controls are engaging in spontaneous subvocal rehearsal. Other explanations of poor verbal short-term memory performance in Down syndrome, in terms of impairments both within and outside of the phonological loop system, are discussed. Practical implications for intervention strategies aimed at improving verbal short-term memory skills in Down syndrome are also outlined.

Visual similarity effects in immediate verbal serial recall

Abstract: The role of visual working memory in temporary serial retention of verbal information was examined in four experiments on immediate serial recall of words that varied in visual similarity and lette...

Improvement or simply practice? The effects of twenty repeated assessments on people with and without brain injury.

Abstract: Measuring recovery of function may mean testing the same individual many times, a procedure that is inevitably open to improvement due to learning on the specific tests rather than recovery per se. This is particularly likely to be an issue with measures of memory performance. We therefore studied the performance of normal and brain-injured people across 20 successive test sessions on measures of orientation, simple reaction time, forward and backward digit span, visual and verbal recognition, word list learning and forgetting, and on three semantic memory measures, namely, letter and category fluency and speed of semantic processing. Differences in overall performances between the two groups occurred for all tests other than orientation, digit span forward, and simple reaction time, although the tests differed in their degree of sensitivity. The tests varied in the presence or absence of practice effects and in the extent to which these differed between the two groups. Data are presented that should allow investigators to select measures that are likely to optimize sensitivity while minimizing possible confounding due to practice effects. (JINS, 2000, 6, 469–479.)

The phonological loop and the irrelevant speech effect: Some comments on Neath (2000)

Abstract: Neath (2000) presents a useful overview of the evidence to be explained by any model of the effects of irrelevant speech on immediate serial memory and proposes a model accompanied by computational simulation. While his review is in general accurate, it is limited in its explanation of the crucial characteristics of the disrupting sounds. It also neglects strategic issues, particularly the tendency for subjects to switch strategy as list length increases. As a result, his model fails to account for the absence of an interaction between irrelevant speech and acoustic similarity for lists of span length. Points of issue between Neath’s feature hypothesis and the phonological loop interpretation are outlined, and the contribution of his computational simulation is discussed.

Phonological similarity and the irrelevant speech effect: implications for models of short-term verbal memory.

Abstract: Three experiments studied the interaction between irrelevant speech and phonological similarity within both the remembered and the irrelevant auditory material. Phonological similarity within the remembered list impaired performance in both baseline and irrelevant speech conditions, whereas phonological similarity between the remembered and ignored irrelevant items did not influence performance. Although there was a tendency for similarity within the irrelevant items to reduce interference, this proved to be a less robust finding. Implications for the theoretical interpretation of the irrelevant speech effect are discussed.

Word fluency in Williams syndrome : Evidence for unusual semantic organisation?

Abstract: Introduction : Tests of semantic fluency require participants to produce as many examples as possible of a category in a limited time. It has been suggested that individuals with Williams syndrome perform relatively well on such tasks, and in addition produce particularly unusual category exemplars. This may reflect an abnormal organisation of semantic information. Methods : A study is reported which tests these claims, by comparing the semantic fluency of a group of individuals with Williams syndrome with that of controls matched for level of vocabulary. Individuals' responses are analysed in terms of absolute number of items produced, frequency and typicality of these items as category exemplars, and the ordering of semantically related items. Results : The results show that individuals with Williams syndrome produce as many items as controls, and that the items produced are not particularly unusual or atypical. However, the ordering of items provides evidence that individuals with Williams syndrome may...

Selective Attention and Performance in Dangerous Environments

Abstract: Evidence on human performance in dangerous environments is reviewed and suggests that danger reduces efficiency, except in the case of experienced subjects. Perceptual narrowing is shown to be one source of decrement. It is suggested that danger increases the subject's arousal level which influences performance by producing a narrowing of attention. The nature of the performance decrement and of adaptation to danger are discussed in this context.

The brain decade in debate: I. Neurobiology of learning and memory

Abstract: This article is a transcription of an electronic symposium in which some active researchers were invited by the Brazilian Society for Neuroscience and Behavior (SBNeC) to discuss the last decade's advances in neurobiology of learning and memory. The way different parts of the brain are recruited during the storage of different kinds of memory (e.g., short-term vs long-term memory, declarative vs procedural memory) and even the property of these divisions were discussed. It was pointed out that the brain does not really store memories, but stores traces of information that are later used to create memories, not always expressing a completely veridical picture of the past experienced reality. To perform this process different parts of the brain act as important nodes of the neural network that encode, store and retrieve the information that will be used to create memories. Some of the brain regions are recognizably active during the activation of short-term working memory (e.g., prefrontal cortex), or the storage of information retrieved as long-term explicit memories (e.g., hippocampus and related cortical areas) or the modulation of the storage of memories related to emotional events (e.g., amygdala). This does not mean that there is a separate neural structure completely supporting the storage of each kind of memory but means that these memories critically depend on the functioning of these neural structures. The current view is that there is no sense in talking about hippocampus-based or amygdala-based memory since this implies that there is a one-to-one correspondence. The present question to be solved is how systems interact in memory. The pertinence of attributing a critical role to cellular processes like synaptic tagging and protein kinase A activation to explain the memory storage processes at the cellular level was also discussed.

Do two separate speech measures constrain verbal short-term memory in children?

Abstract: Previous research has indicated that 2 processing rates may constrain verbal short-term memory performance. These have been linked to individual differences in (a) the time taken to articulate spoken words and (b) the duration of pauses that occur between words in the output responses to memory tasks. Two experiments examined whether evidence for these effects on memory can be obtained for measures taken from a single speech sample. Children articulated pairs of words as rapidly as possible. In both experiments, the spoken duration of words and the length of the pauses between them predicted significant variance in verbal short-term memory performance. It is argued that the duration of words is linked to memory performance through the processes underlying time-based forgetting in short-term memory. In contrast, the duration of pauses in speeded articulation may index individual differences in speech planning processes.

The development of reading tests for use in a regularly spelled language

Abstract: Data are presented on the development of tests of reading skill in rural Tanzanian primary school pupils. Instruction in these schools is in Kiswahili, a regularly spelt language. Using a translation of a standard reading test, children could read aloud all words once they had learnt sound-letter correspondences, regardless of comprehension. In addition, children can appear to pass traditional comprehension tasks by decoding only some of the words. Three graded tests were developed which allow testing of children who either have only some letter knowledge, can read single words, or are proficient readers. The tests require children to both decode and understand the reading material in order to achieve high scores. The tests correlated well with scores on other educational achievement tests, and showed age and school grade differences. It is suggested that these tests are useful measures of reading development in a regularly spelt language. Adaptation to English and validation against standardised instruments is planned.