Does Articulatory Suppression Remove the Irrelevant Speech Effect?

Salamé and Baddeley (1982) reported that the effect of irrelevant speech on the serial recall of visually presented sequences was abolished when subjects performed articulatory suppression during presentation and recall of the target items. They argued that this is because suppression isolates visually presented material from the phonological store, which they consider to be the locus of the irrelevant speech effect. In the present experiment, an alternative interpretation of Salamé and Baddeley's findings was investigated. Salamé and Baddeley used nine-item sequences, and observed very low levels of recall when articulation was suppressed. It is therefore possible that Salamé and Baddeley's failure to observe any additional effect of irrelevant speech reflects either a floor effect or else a strategic choice by subjects to abandon the use of a phonological memory code because of task difficulty. In the experiment reported here, this issue was investigated by using both six- and nine-item sequences. Results revealed no effect of irrelevant speech under articulatory suppression even at the shorter sequence length. The results therefore replicate and extend the findings of Salamé and Baddeley (1982), and provide support for their view that visually presented material must be articulated before it becomes susceptible to interference from irrelevant speech.     

Irrelevant speech effects and statistical learning

Immediate serial recall of visually presented verbal stimuli is impaired by the presence of irrelevant auditory background speech, the so-called irrelevant speech effect. Two of the three main accounts of this effect place restrictions on when it will be observed, limiting its occurrence either to items processed by the phonological loop (the phonological loop hypothesis) or to items that are not too dissimilar from the irrelevant speech (the feature model). A third, the object-oriented episodic record (O-OER) model, requires only that the memory task involves seriation. The present studies test these three accounts by examining whether irrelevant auditory speech will interfere with a task that does not involve the phonological loop, does not use stimuli that are compatible with those to be remembered, but does require seriation. Two experiments found that irrelevant speech led to lower levels of performance in a visual statistical learning task, offering more support for the O-OER model and posing a challenge for the other two accounts.     

Irrelevant Speech,Phonological Similarity,and Presentation Modality

The phonological similarity effect refers to the finding that a list of similarsounding items is recalled less well than a list of dissimilar-sounding items. A strong prediction of the phonological store hypothesis, based on Baddeley's (1986, 1992) working memory framework, is that irrelevant speech should interact with the phonological similarity effect. We report three experiments that demonstrate that irrelevant speech eliminates the phonological similarity effect for visual but not for auditory items. In this respect, irrelevant speech functions much like articulatory suppression. Implications for the phonological store and changing state hypotheses are discussed.     

The phonological loop model of working memory: An ERP study of irrelevant speech and phonological similarity effects

The phonological loop model for retention of auditory verbal material in working memory, developed by Baddeley, assumes that irrelevant speech and phonological similarity influence only one and the same element of the system—that is, the phonological short-term store. We tested this idea by recording eventrelated potentials (ERPs) to auditorily presented letters that were phonologically similar or dissimilar and were to be memorized in the presence of more or less disturbing irrelevant speech. Irrelevant speech and phonological similarity caused ERP effects with clearly different scalp topographies, indicating that these factors influence different brain systems and hence probably different cognitive elements. Moreover, ERPs indicated that the phonological similarity effect might involve processes at the level of phonological analysis. Our data also support recent suggestions that the irrelevant speech effect is not based on the phonological similarity between relevant and irrelevant material, but on the phonological variability within the irrelevant stream.     

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.     

On the Irrelevance of Phonological Similarity to the Irrelevant Speech Effect

Irrelevant background speech disrupts immediate recall of visually presented items. Salame and Baddeley (1982) found that increasing the phonological similarity between the irrelevant speech and the visual items greatly increased this disruption. In contrast, Jones and Macken (1995) found little evidence for such an increase. The present experiments directly manipulated the phonological similarity of the irrelevant speech background and the to-be-remembered visual items. Experiments 1-4 compared background speech that shared virtually no phonemes with the visual stimuli with background speech that shared all of the phonemes of the visual stimuli. No effectof phonological similarity was found.Experiment5 replicatedthe method of Salame and Baddeley's critical experimentbut nottheir results. With regard to the two primary explanations ofthe irrelevant speech effect, these data present a strong challenge to the phonological store hypothesis while offering some support to the changing state hypothesis.     

Irrelevant speech,articulatory suppression,and phonological similarity: A test of the phonological loop model and the feature model

Two experiments tested competing predictions about the nature of the irrelevant speech effect that were derived from Neath's (2000) feature model and from Salamé and Baddeley's (1982) phonological loop model. The first experiment examined the combined effects of irrelevant speech and articulatory suppression when target items were presented auditorily. Contrary to the suggestions of Neath, but consistent with the phonological loop model, the effects of articulatory suppression and irrelevant speech were additive even when the irrelevant speech was presented during the retention interval The second experiment examined the combined effects of irrelevant speech and phonological similarity when target items were presented visually. Consistent with the phonological loop model, the effects of phonological similarity and irrelevant speech were additive when participants were specifically instructed to use articulatory/phonological rehearsal to remember the list items. The results therefore contradicted Neath's claim that irrelevant speech abolishes the phonological similarity effect when list items are presented visually. However, the effect of phonological similarity was abolished in the irrelevant speech conditions when no instructions were given concerning rehearsal. It is argued that the phonological similarity effect disappears in some experiments because participants sometimes employ a semantic rehearsal strategy, consistent with the views of Salamé and Baddeley (1986).     

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.     

Modeling the effects of irrelevant speech on memory

The feature model (Nairne, 1990) is extended to account for the effects of irrelevant speech and concomitant interactions in immediate serial recall. In the feature model, both articulatory suppression and irrelevant speech are seen as adding noise to the memory representation, the difference being that articulatory suppression diverts more resources than does irrelevant speech. The addition of noise impairs recall because it reduces the probability of successful redintegration. When a competitor is incorrectly recalled, rather than the correct item, this competitor is recalled out of order, producing an increase in order errors. Six simulations are reported that show that the model accounts for (1) the impairment by both irrelevant speech and articulatory suppression, (2) the irrelevance of the phonological and semantic composition of the irrelevant speech, (3) greater disruption when the irrelevant speech tokens vary, (4) the abolition of the phonological similarity effect for visual, but not for auditory, items, (5) the abolition of the word length effect for both visual and auditory items, and (6) the abolition of the irrelevant speech effect under articulatory suppression for both visual and auditory items. The feature model is compared with the two other major views of irrelevant speech, the phonological store hypothesis and the changing state hypothesis.     

Irrelevant speech eliminates the word length effect

Theword length effect refers to the observation that memory is better for short than for long words. Theirrelevant speech effect refers to the finding that memory is better when items are presented against a quiet background than against one with irrelevant speech. According to Baddeley’s (1986, 1994) working memory, these variables should not interact: The word length effect arises from rehearsal by the articulatory control process, whereas irrelevant speech reduces recall through interference in the phonological store. Four experiments demonstrate that, like articulatory suppression, irrelevant speech eliminates the word length effect for both visual and auditory items. These results (1) provide further evidence against the ability of working memory to explain the word length and irrelevant speech effects and (2) confirm a specific prediction of Nairne’s (1990) feature model.     

Irrelevant speech and serial recall: Implications for theories of attention and working memory

Irrelevant speech markedly impairs serial recall of visually presented lists, even though the person is asked to ignore the speech. In this, the first major review of the phenomenon, we conclude that (i) the effect occurs in memory rather than at encoding; (ii) within memory, the disruption occurs as a result of a confluence of information at the phonological rather than at the articulatory stage of coding; (iii) speech does not have privileged access to memory, since its disruptive effects may be attenuated by habituation; and (iv) disruption occurs as a result of the changing state of the auditory channel, not as had previously been thought the phonological similarity of visual and auditory streams, and is particularly sensitive to pitch changes in both speech and non-speech stimuli. These conclusions are discussed in the light of two complementary theoretical constructs: a cascading filter system responsible for the access of speech to memory and a system of coding within memory sensitive to changing state of the stream responsible for disruption of serial order. Recommendations are made also for empirical work to refine these constructs.     

Irrelevant speech does not interfere with serial recall in early blind listeners

Phonological working memory is known be (a) inversely related to the duration of the items to be learned (word-length effect), and (b) impaired by the presence of irrelevant speech-like sounds (irrelevant-speech effect). As it is discussed controversially whether these memory disruptions are subject to attentional control, both effects were studied in sighted participants and in a sample of early blind individuals who are expected to be superior in selectively attending to auditory stimuli. Results show that, while performance depended on word length in both groups, irrelevant speech interfered with recall only in the sighted group, but not in blind participants. This suggests that blind listeners may be able to effectively prevent irrelevant sound from being encoded in the phonological store, presumably due to superior auditory processing. The occurrence of a word-length effect, however, implies that blind and sighted listeners are utilizing the same phonological rehearsal mechanism in order to maintain information in the phonological store.     

Cross-modal, auditory-visual Stroop interference: a reply to Cowan and Barron (1987)

This series of experiments was performed to verify Cowan and Barron's (1987) reported effect of auditory color-word interference on a visual Stroop task. Extant theory predicts effects of irrelevant speech on visual memory tasks involving immediate, ordered recall of the items. Interference between the two sources of information (visual and auditory) is assumed to be located at the phonological store component of the articulatory loop. Perceptual tasks such as the Stroop task, which do not require use of the articulatory loop for rehearsal purposes, should not be similarly susceptible. The present data fail to replicate Cowan and Barron's findings, and are thus consistent with contemporary theory.     

工作记忆中的语音回路对汉语阅读理解的影响

语音回路是工作记忆中一个重要的组成部分,主要负责加工和存储语音信息。采用混合实验设计,以正确数和反应时 为指标,汉语语篇为阅读材料,探讨工作记忆中的语音回路对汉语阅读理解的影响。本研究包括两个实验,实验一采用发音抑制的范式,结合错误干扰考察了语音回路中的发音复述装置对汉语阅读理解的影响;实验二采用无关言语的范式,结合错误干扰考察了语音回路中的语音存储装置对汉语阅读理解的影响。结果表明：(1)通过发音抑制和无关言语的方法证明,语音回路中的发音复述装置和语音存储装置在汉语阅读理解中起着重要作用。(2) 字音和字形都影响汉语的阅读理解,但字形比字音起着更大的作用,而且它们的作用机制也不相同,字音直接进入语音存储装置,而字形要经过字音的转换进入语音存储装置。(3) 词频与语音回路有密切关系,语音回路中的发音复述装置的作用在高频词上有明显的表现。(4) 词频与字形、字音也有密切关系,在低频词的条件下,字形的作用大于字音的作用     

Directly assessing the relationship between irrelevant speech and articulatory suppression

Larsen and Baddeley (2003) examine whether the disruption caused by articulatory suppression on immediate memory tasks is similar to or different from the disruption caused by irrelevant speech. Based on experiments in which they test whether the phonological similarity effect is present or absent, they conclude that articulatory suppression and irrelevant speech are different. We assessed whether articulatory suppression and irrelevant speech are similar or different by correlating the disruption each causes. A significant correlation obtained, indicating a relation between the two. These apparently different conclusions can be readily resolved by adopting the view that articulatory suppression, irrelevant speech, and many other factors vary in the degree to which they are likely to cause subjects to abandon reliance on phonological/acoustic cues in particular tasks.     

不相关言语对视觉觉察的影响

前人多在记忆层面探讨不相关言语效应(the Irrelevant Speech Effect, ISE), 而本文选择在意识觉察(conscious awareness)阶段观察这一现象。所有实验均采用视觉掩蔽及听觉输入不相关声音的视听交互方式。实验1在安静、纯音及不相关言语3种听觉背景下让被试对简单图片做视觉觉察判断, 结果发现不相关言语干扰了视觉觉察, 而纯音则未产生干扰。实验2在相同的3种听觉背景下要求被试对复杂图片做视觉觉察判断, 结果同实验1。实验3采用事件相关电位技术, 在同样的3种听觉背景下观察被试对简单图片做视觉觉察判断时的脑电变化, 结果发现不相关言语干扰了视觉觉察负波的形成, 验证了行为学研究的结果。本文结果表明不相干言语在视觉意识觉察阶段就对被试的行为产生了干扰。     

Similarities between the irrelevant sound effect and the suffix effect

Although articulatory suppression abolishes the effect of irrelevant sound (ISE) on serial recall when sequences are presented visually, the effect persists with auditory presentation of list items. Two experiments were designed to test the claim that, when articulation is suppressed, the effect of irrelevant sound on the retention of auditory lists resembles a suffix effect. A suffix is a spoken word that immediately follows the final item in a list. Even though participants are told to ignore it, the suffix impairs serial recall of auditory lists. In Experiment 1, the irrelevant sound consisted of instrumental music. The music generated a significant ISE that was abolished by articulatory suppression. It therefore appears that, when articulation is suppressed, irrelevant sound must contain speech for it to have any effect on recall. This is consistent with what is known about the suffix effect. In Experiment 2, the effect of irrelevant sound under articulatory suppression was greater when the irrelevant sound was spoken by the same voice that presented the list items. This outcome is again consistent with the known characteristics of the suffix effect. It therefore appears that, when rehearsal is suppressed, irrelevant sound disrupts the acoustic-perceptual encoding of auditorily presented list items. There is no evidence that the persistence of the ISE under suppression is a result of interference to the representation of list items in a postcategorical phonological store.     

Word Dose in the Disruption of Serial Recall by Irrelevant Speech: Phonological Confusions or Changing State?

Irrelevant background speech disrupts serial recall of visually presented lists of verbal material. Three experiments tested the hypothesis that the degree of disruption is dependent on the number of words heard (i.e. word dose) whilst the task was undertaken. Experiments 1 and 2 showed that more disruption is produced if the word dose is increased, thereby providing evidence to support the experimental hypothesis. It was concluded from the first two experiments that the word-dose effect might be the result of increasing the amount of changing-state information in the speech. The results of Experiment 3 supported this conclusion by showing an interaction between word dose and changing-state information. It was noted however that the results might be explained within the working memory account of the disruptive action of irrelevant speech. A further two experiments cast doubt on this possibility by failing to replicate the finding that the phonological similarity between heard and seen material affects the degree of interference (Salame & Baddeley, 1982). The findings are discussed in relation to the changing state hypothesis of the irrelevant speech effect (e.g. Jones, Madden, & Miles, 1992).     

无关言语对阅读的干扰基于内容还是过程？——来自眼动研究的证据

采用眼动追踪技术,考察无关言语对句子材料相同的自然阅读和校对阅读的影响,探讨无关言语对阅读的干扰机制是基于内容还是过程。结果发现,有意义言语显著干扰了正常的阅读行为,而无意义言语与无背景音条件不存在显著差异。并且背景言语类型与任务类型的交互作用显著,表现为言语的语义成分只干扰了自然阅读,而对校对阅读没有影响。实验结果支持过程干扰假说。     

Overlap of phonetic features as a determinant of the between-stream phonological similarity effect

Serial recall from working memory is known to be impaired by the presence of irrelevant background speech, but several prior studies have concluded that the magnitude of the impairment is independent of the phonological relationship between to-be-remembered (TBR) and to-be-ignored (TBI) sources of information. In the present study, we examined the influence of between-stream phonological similarity in serial recall while attending to a heretofore uncontrolled variable, the phonetic feature. We found that TBI items sharing many phonetic features with TBR items produced significantly stronger working-memory impairments than TBI items with minimal phonetic feature overlap. In addition, participants were more likely to report remembering incorrect items that incorporated phonological characteristics of the TBI stream in the high-overlap condition. These findings provide evidence for subphonemic between-stream interactions and suggest that multiple parallel processes contribute to the irrelevant speech effect. We propose that a 2-component model, which combines the assumptions of process- and content-based accounts for the irrelevant speech effect, offers the best explanation for these findings.