Role of serial order in the irrelevant speech effect: Tests of the changing-state hypothesis.

The effects of irrelevant speech were examined on a range of memory tasks. A missing-item task, which relied on a nonserial strategy for recall, proved less sensitive to the effects of irrelevant speech than one calling on memory for serial order. The finding that the effect of irrelevant speech both on a recognition task and on a paired-associates task was modified significantly by articulatory suppression further suggested that memory for serial order is the dominant feature of these tasks and that it renders them vulnerable to disruption by irrelevant speech. Taken together, the results of the experimental series support the notion that tasks involving memory for serial order are particularly susceptible to disruption by irrelevant speech. These and other findings converge on the notion that interference with information processing by irrelevant sound is based on similarity of process rather than similarity of content. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Phonological Store of Working Memory: Is It Phonological and Is It a Store?

The phonological store construct of the working memory model is critically evaluated. Three experiments test the prediction that the effect of irrelevant sound and the effect of phonological similarity each survive the action of articulatory suppression but only when presentation of to-be-remembered lists is auditory, not visual. No evidence was found to support the interaction predicted among irrelevant speech, modality, and articulatory suppression. Although evidence for an interaction among modality, phonological similarity, and articulatory suppression was found, its presence could be diminished by a suffix, which is an acoustic, not a phonological factor. Coupled with other evidence-from the irrelevant sound effect and errors in natural speech-the action attributed to the phonological store seems better described in terms of a combination of auditory-perceptual and output planning mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evolution on a volcanic conveyor belt: using phylogeographic reconstructions and K-Ar-based ages of the Hawaiian Islands to estimate molecular evolutionary rates

This article reports dissociations between verbal span and the recency portion of the serial position curve in immediate free recall, in 2 neuropsychological case studies and in 3 experiments with normal participants. Patient A. N. presented with an impaired serial verbal span while showing an intact recency effect. The opposite pattern was observed in patient G. C., who despite a poor recency showed normal span in verbal serial recall tasks. Experiments 1 and 2 showed a recency effect with visually and auditory presented lists and written recall was resistant to the effects of articulatory suppression and of irrelevant speech, but was disrupted by the suffix effect. Experiment 3 showed that in contrast with recency, memory span was affected by articulatory suppression and irrelevant speech during presentation but not by a suffix. These findings are not consistent with the idea that span and recency measure aspects of the same memory system. Moreover, in clinical practice, they should not be used as equivalent alternatives.     

Dissociation between recency and span: Neuropsychological and experimental evidence.

This article reports dissociations between verbal span and the recency portion of the serial position curve in immediate free recall, in 2 neuropsychological case studies and in 3 experiments with normal participants. Patient A. N. presented with an impaired serial verbal span while showing an intact recency effect. The opposite pattern was observed in patient G. C., who despite a poor recency showed normal span in verbal serial recall tasks. Experiments 1 and 2 showed a recency effect with visually and auditory presented lists and written recall was resistant to the effects of articulatory suppression and of irrelevant speech, but was disrupted by the suffix effect. Experiment 3 showed that in contrast with recency, memory span was affected by articulatory suppression and irrelevant speech during presentation but not by a suffix. These findings are not consistent with the idea that span and recency measure aspects of the same memory system. Moreover, in clinical practice, they should not be used as equivalent alternatives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual word recognition during reading is followed by subvocal articulation.

Three experiments examined whether the identification of a visual word is followed by its subvocal articulation during reading. An irrelevant spoken word (ISW) that was identical, phonologically similar, or dissimilar to a visual target word was presented when the eyes moved to the target in the course of sentence reading. Sentence reading was further accompanied by either a sequential finger tapping task (Experiment 1) or an articulatory suppression task (Experiment 2). Experiment 1 revealed sound-specific interference from a phonologically similar ISW during posttarget viewing. This interference was absent in Experiment 2, where similar and dissimilar ISWs impeded target and posttarget reading equally. Experiment 3 showed that articulatory suppression left the lexical processing of visual words intact and that it did not diminish the influence of visual word recognition on eye guidance. The presence of sound-specific interference during posttarget reading in Experiment 1 is attributed to deleterious effects of a phonologically similar ISW on the subvocal articulation of a target. Its absence in Experiment 2 is attributed to the suppression of a target’s subvocal articulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spectra of spontaneous frameshift mutations at the hisD3052 allele of Salmonella typhimurium in four DNA repair backgrounds

In the model of Baddeley (Working Memory, Oxford University Press, Oxford, 1986), one function of the visuospatial sketchpad (VSSP) component of working memory is to allow the processing of mental images. Properties of the VSSP were investigated by means of the usual dual-task paradigm (to search for interference from the other components of working memory, i.e., the articulatory loop and the central executive), applied to three distinct subprocesses of mental imagery (Kosslyn, 1994 Image and Brain. MIT Press, Cambridge, MA): image generation (Experiment 1), image maintenance (Experiment 2), and image rotation (Experiment 3). First, in the control condition (no interference task) of each experiment, we replicated the effects of stimulus or task complexity already reported. Second, no interference from the articulatory loop was observed. Third, maintenance of images appeared free from any interference. And fourth, generation and rotation tasks were interfered to a greater extent by the central executive than by the involvement of the VSSP in a secondary task. These observations (a) support the dissociation between the articulatory loop and the VSSP, (b) suggest an important use of central attentional resources in the generation and rotation of mental images, (c) would support the distinction between visual and spatial components in the structure of working memory, and (d) suggest the dissociation of the VSSP into two subcomponents: a passive visuospatial store and an active device for recapitulating visuospatial information.     

Functional equivalence of verbal and spatial information in serial short-term memory.

Performance on a test of serial memory for the spatial position of a sequence of dots showed similarities to typical results from the serial recall of verbal material: a marked increase in error with increasing list length, a modest rise in error as retention interval increased, and bow-shaped serial position curves. This task was susceptible to interference from both a spatial task (rote tapping) and a verbal task (mouthed articulatory suppression) and also from the presence of irrelevant speech. Effects were comparable to those found with a serial verbal task that was generally similar in demand characteristics to the spatial task. As a generalization, disruption of the serial recall of visuospatial material was more marked if the interference conditions involved a changing sequence of actions or materials, but not if a single event (tap, mouthed utterance, or sound) was repeated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional characteristics of the inner voice and the inner ear: Single or double agency?

Double agency theories of short-term memory posit the functional independence of a phonological store (inner ear) and articulatory process (inner voice). A series of 5 experiments challenges this view. Articulatory suppression during retention of 9-item lists gives rise to a changing-state effect similar to that shown for irrelevant speech. Also, vocalized suppression is more disruptive than silently mouthed suppression, but this difference arises from vocalization itself rather than from any auditory feedback to which it gives rise. Class similarity between the to-be-remembered items and the articulatory material is not a critical determinant, but the effect occurs only with tests of serial order. For mouthed suppression, the irrelevant speech effect is only attenuated with changing-state suppression. Also, the presence of changing-state irrelevant speech abolishes the changing-state effect of articulatory suppression. Functional equivalence of codes from auditory, visual, and articulatory sources is claimed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Event-based prospective memory and executive control of working memory

In 5 experiments, the character of concurrent cognitive processing was manipulated during an event-based prospective memory task. High- and low-load conditions that differed only in the difficulty of the concurrent task were tested in each experiment. In Experiments 1 and 2, attention-demanding tasks from the literature on executive control produced decrements in prospective memory. In Experiment 3, attention was divided by different loads of articulatory suppression that did not ultimately lead to decrements in prospective memory. A high-load manipulation of a visuospatial task requiring performance monitoring resulted in worse prospective memory in Experiment 4, whereas in Experiment 5 a visuospatial task with little monitoring did not. Results are discussed in terms of executive functions, such as planning and monitoring, that appear to be critical to successful event-based prospective memory.     

Working memory constraints on linear reasoning with spatial and temporal contents

The present article reports two experiments testing the use of working memory components during reasoning with temporal and spatial relations in four-term series problems. In the first experiment four groups of subjects performed reasoning tasks with temporal and with spatial contents either without (control) or with a secondary task (articulatory suppression, visuo-spatial suppression or central executive suppression). The second experiment tested the secondary task effects in a within-subjects design either on problems with a spatial content or on problems with a temporal content, and within each content domain either under conditions of self-paced or of fixed presentation of the premises. Both experiments found effects of all three secondary tasks on reasoning accuracy. This supports the hypothesis that the subjects construct spatial representations of the premise information with the support of visuo-spatial resources of working memory. The second experiment also showed that during premise intake, only visuo-spatial and central executive secondary tasks had an effect. The implications of the data for the working memory requirements of reasoning and for theories of linear reasoning are discussed.     

Developments in the concept of working memory.

The authors summarize developments in the concept of working memory as a multicomponent system, beginning by contrasting this approach with alternative uses of the term working memory. According to a 3-component model, working memory comprises a phonological loop for manipulating and storing speech-based information and a visuospatial sketchpad that performs a similar function for visual and spatial information. Both are supervised by a central executive, which functions as an attentional control system. A simple trace-decay model of the phonological loop provides a coherent account of the effects of word length, phonemic similarity, irrelevant speech, and articulatory suppression in verbal short-term memory tasks. This model of the loop has also proved useful in the analysis of neuropsychological, developmental and, cross-cultural data. The notion of the sketchpad is supported by selective interference with imagery in normal adults and by specific neuropsychological impairment. Analysis of the central executive is illustrated by work on deficits in the ability to coordinate subproccesses in Alzheimer's disease (AD). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working-memory-triggered dynamic adjustments in cognitive control.

Dynamic adjustments in cognitive control are well documented in conflict tasks, wherein competition from irrelevant stimulus attributes intensifies selection demands and leads to subsequent performance benefits. The current study investigated whether mnemonic demands, in a working memory (WM) task, can drive similar online control modifications. Demand levels (high vs. low) of WM maintenance (memory load of 2 items vs. 1 item) and delay-spanning distractor interference (confusable vs. not confusable with memoranda) were manipulated using a factorial design during a WM delayed-recognition task. Performance was best subsequent to trials in which both maintenance and distractor interference demands were high, followed by trials with high demand in either of these 2 control domains, and worst following trials with low demand in both domains. These results suggest that dynamic adjustments in cognitive control are not triggered exclusively by conflict-specific contexts but are also triggered by WM demands, revealing a putative mechanism by which this system configures itself for successful task performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phonological loop and intermittent activity: A whistle task as articulatory suppression.

Examined whether the effect of articulatory suppression is due to the activation of an irrelevant phonology or to intermittent articulatory movements. In Exp 1, 24 undergraduates were tested for serial recall of visually presented letter sequences that were either phonologically similar or dissimilar, and had to remember each of the letter sequences under a no-suppression control or a suppression condition. In the suppression condition, half of the Ss were engaged in an intermittent speech suppression and the other half were in an intermittent whistle suppression task. The phonological similarity effects appeared in the control condition, but not in the suppression condition, irrespective of the type of suppression. In Exp 2, the phonological similarity effect again disappeared in the intermittent whistling condition, but not in the condition in which the 15 undergraduates required to engage a continuous whistling task. The results suggest that the effect of articulatory suppression was due to intermittent articulatory activity rather than the activation of an irrelevant phonology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory and the control of action: Evidence from task switching.

A series of 7 experiments used dual-task methodology to investigate the role of working memory in the operation of a simple action-control plan or program involving regular switching between addition and subtraction. Lists requiring switching were slower than blocked lists and showed 2 concurrent task effects. Demanding executive tasks impaired performance on both blocked and switched lists, whereas articulatory suppression impaired principally the switched condition. Implications for models of task switching and working memory and for the Vygotskian concept of verbal control of action are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Control of interference during working memory updating.

The current study examined the nature of the processes underlying working memory updating. In 4 experiments using the n-back paradigm, the authors demonstrate that continuous updating of items in working memory prevents strong binding of those items to their contexts in working memory, and hence leads to an increased susceptibility to proactive interference. Results of Experiments 1 and 2 show that this interference reflects a competition between a process that reveals the degree of familiarity of an item and a context-sensitive recollection process that depends on the strength of bindings in working memory. Experiment 3 further clarifies the origins of interference during updating by demonstrating that even items that are semantically related to the updated working memory contents but that have not been maintained in working memory before cause proactive interference. Finally, the results of Experiment 4 indicate that the occurrence of interference leads to top-down behavioral adjustments that prioritize recollection over familiarity assessment. The implications of these findings for the construct validity of the n-back task, for the control processes involved in working memory updating, and for the concept of executive control more generally are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The irrelevant sound effect: Does speech play a special role?

Memory for order is markedly impaired by the presence of irrelevant sound, even though participants are instructed to ignore the sound. Although a great deal of research has disclosed some features of the task and of the sound that augment or reduce the degree of interference, one important issue of the irrelevant sound effect not yet resolved is whether speech has a special status. This study revealed, within a design of adequate power, that the same physical stimulus (sine wave speech), whether perceived as speech or as nonspeech sound, produces similar degrees of disruption and is less disruptive of serial recall than natural speech. This outcome suggests that the acoustic constituents of sound rather than its source are most influential in determining the impact of irrelevant material. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Disruption of short-term memory by changing and deviant sounds: Support for a duplex-mechanism account of auditory distraction.

The disruption of short-term memory by to-be-ignored auditory sequences (the changing-state effect) has often been characterized as attentional capture by deviant events (deviation effect). However, the present study demonstrates that changing-state and deviation effects are functionally distinct forms of auditory distraction: The disruption of visual-verbal serial recall by changing-state speech was independent of the effect of a single deviant voice embedded within the speech (Experiment 1); a voice-deviation effect, but not a changing-state effect, was found on a missing-item task (Experiment 2); and a deviant voice repetition within the context of an alternating-voice irrelevant speech sequence disrupted serial recall (Experiment 3). The authors conclude that the changing-state effect is the result of a conflict between 2 seriation processes being applied concurrently to relevant and irrelevant material, whereas the deviation effect reflects a more general attention-capture process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An electromyographical study of subvocal speech and recall in preschool children.

Investigated the relationship of subvocal speech to recall for 46 4- and 5-yr-olds. The electromyographical activity on 5 memory trials, consisting of nonlabel pictures' names, was used as a control for nonspeech artifactual activity for 5 labial trials. Electromyographical activity was recorded from 3 muscle sites: lip, chin, and a nonspeech control. A more sensitive measurement procedure than is commonly employed was used to quantify electromyographical activity. Results indicate that (a) significant amounts of subvocalization occurred both during picture presentation and a prerecall delay; (b) amount of subvocalization was significantly related to recall; and (c) younger, less bright Ss subvocalized less than older, brighter Ss during a prerecall delay period. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive processes in counting.

Five experiments investigated the effects of articulatory suppression and unattended speech on performance in simple counting tasks. Results were consistent in showing substantial disruption of counting performance by concurrent articulatory suppression. However, when response errors occurred, they tended to be numerically close to the correct figure, suggesting that performance was not totally disrupted by suppression. A small effect of unattended speech on counting was obtained when the unattended speech was phonologically similar to numbers used in counting. A larger effect on counting was observed when the unattended speech consisted of random number sequences; however, this effect was much less than that found with suppression. These results are tentatively interpreted in terms of two separate components of the counting task: subvocalization of a running total and priming of the most recently accessed numbers in an input register or long-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intentional inhibition in memory and hallucinations: Directed forgetting and updating.

Hallucinations have been recently associated with inhibitory deficits in memory. In this study, the authors investigated whether hallucinations were related to difficulties to inhibit irrelevant information from episodic memory (Experiment 1) and working memory (Experiment 2). In Experiment 1, a directed forgetting task was used. This task measures participants' ability to intentionally forget some recently learned material, when instructions indicate that it is no longer relevant. In Experiment 2, an updating task was used. This task requires participants to intentionally suppress irrelevant information from working memory. Results showed that patients with schizophrenia with hallucinations presented inhibitory deficits in the directed forgetting task and an increase in the number of intrusions in the updating task, compared to patients without hallucinations and healthy controls. No correlations were found between indices of inhibition and other general, negative or positive symptoms. These findings support the existence of an association between intentional inhibition in memory and hallucinations, and they suggest that problems to suppress memory representations can underlie hallucinations in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)