Dylan Marc Jones

Irrelevant tones produce an irrelevant speech effect: implications for phonological coding in working memory

A series of studies addresses the possibility that tones disrupt serial recall of visually presented material in the same way as speech. A stream of changing tones is as disruptive of visual serial recall as 4 syllables (Experiments 1 and 2). Similar effects were also shown with a repeated syllable that changed only in pitch (Experiment 3). Just as for speech, the effect of tones is not at encoding but during storage of the serial lists (Experiments 4 and 5). The results suggest that speech and tones are equipotent in their capacity to disrupt short-term memory. A «blackboard» model of working memory to account for the effects is outlined

Privileged access by irrelevant speech to short-term memory: the role of changing state

Memory for visually presented items is impaired by speech that is played as an irrelevant background. The paper presents the view that changing state of the auditory material is an important prerequisite for this disruption. Four experiments studied the effects of sounds varying in complexity in an attempt to establish which features of changing state in the auditory signal lead to diminished recall. Simple unvarying or repetitive speech sounds were not sufficient to induce the irrelevant speech effect (Experiment 1): in addition, simple analogues of speech, possessing regular or irregular envelopes and using a range of carriers, failed to imitate the action of speech (Experiment 2). Variability of between-utterance phonology in the irrelevant stream (Experiment 3) emerged as a crucial factor. Moreover, predictability of the syllable sequence did not reduce the degree of disruption (Experiment 4) suggesting that supra-syllabic characteristics of the speech are of little importance. The results broadly support the idea that disruption of short-term memory only occurs when the speech stream changes in state. It is argued that disruption occurs in memory when cues to serial order based on phonological representations of heard material interfere with the phonological codes of visual origin. It is suggested that cues to changing state of the speech input contaminate those associated with items of visual origin, which are already in a phonological store.

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.

Auditory distraction and short-term memory: phenomena and practical implications.

Irrelevant sound tends to break through selective attention and impair cognitive performance. This observation has been brought under systematic scrutiny by laboratory studies measuring interference with memory performance during exposure to irrelevant sound. These studies established that the degree of interference depends on the properties of the irrelevant sound as well as those of the cognitive task. The way in which this interference increases or diminishes as characteristics of the sound and of the cognitive task are changed reveals key functional characteristics of auditory distraction. A number of important practical implications that arise from these studies are discussed, including the finding that relatively quiet background sound will have a marked effect on efficiency in performing cognitive tasks.

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.

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.

Navigating Large-Scale Virtual Environments: What Differences Occur Between Helmet-Mounted and Desk-Top Displays?

Participants used a helmet-mounted display (HMD) and a desk-top (monitor) display to learn the layouts of two large-scale virtual environments (VEs) through repeated, direct navigational experience. Both VEs were virtual buildings containing more than seventy rooms. Participants using the HMD navigated the buildings significantly more quickly and developed a significantly more accurate sense of relative straight-line distance. There was no significant difference between the two types of display in terms of the distance that participants traveled or the mean accuracy of their direction estimates. Behavioral analyses showed that participants took advantage of the natural, head-tracked interface provided by the HMD in ways that included looking around more often while traveling through the VEs, and spending less time stationary in the VEs while choosing a direction in which to travel.

Interruption of the Tower of London Task: Support for a Goal-Activation Approach

Unexpected interruptions introduced during the execution phase of simple Tower of London problems incurred a time cost when the interrupted goal was retrieved, and this cost was exacerbated the longer the goal was suspended. Furthermore, time taken to retrieve goals was greater following a more complex interruption, indicating the processing limitations may be as important as time-based limitations in determining the ease of goal retrieval. Such findings cannot simply be attributed to task-switching costs and are evaluated in relation to current models of goal memory (E. M. Altmann & G. J. Trafton, 2002; J. R. Anderson & S. Douglass, 2001), which provide a useful basis for the investigation and interpretation of interruption effects.

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.

Disruption of visual short-term memory by changing-state auditory stimuli: The role of segmentation.

Typically, serial recall performance can be disrupted by the presence of an irrelevant stream of background auditory stimulation, but only if the background stream changes over time (the auditory changing-state effect). It was hypothesized that segmentation of the auditory stream is necessary for changing state to be signified. In Experiment 1, continuous random pitch glides failed to disrupt serial recall, but glides interrupted regularly by silence brought about the usual auditory changing-state effect. In Experiment 2, a physically continuous stream of synthesized vowel sounds was found to have disruptive effects. In Experiment 3, the technique of auditory induction showed that preattentive organization rather than critical features of the sound could account for the disruption by glides. With pitch glides, silence plays a preeminent role in the temporal segmentation of the sound stream, but speech contains corr-elated-time-varying changes in frequency and amplitude that make silent intervals superfluous.