Speech-processing capacity in young and older adults: a dual-task study

Adult age differences in processing speech were examined with a dual-task paradigm. Subjects listened to spoken passages for later recall while performing a concurrent reaction time task intended to index cognitive capacity usage on the speech memory task. Age differences in secondary task decision latencies were eliminated when subgroups of young and older subjects were matched on working memory span. These findings are interpreted as showing that an age-related reduction in working memory efficiency contributes to age differences in processing discourse for memory.     

The Swedish Hayling task,and its relation to working memory,verbal ability,and speech‐recognition‐in‐noise

Cognitive functions and speech‐recognition‐in‐noise were evaluated with a cognitive test battery, assessing response inhibition using the Hayling task, working memory capacity (WMC) and verbal information processing, and an auditory test of speech recognition. The cognitive tests were performed in silence whereas the speech recognition task was presented in noise. Thirty young normally‐hearing individuals participated in the study. The aim of the study was to investigate one executive function, response inhibition, and whether it is related to individual working memory capacity (WMC), and how speech‐recognition‐in‐noise relates to WMC and inhibitory control. The results showed a significant difference between initiation and response inhibition, suggesting that the Hayling task taps cognitive activity responsible for executive control. Our findings also suggest that high verbal ability was associated with better performance in the Hayling task. We also present findings suggesting that individuals who perform well on tasks involving response inhibition, and WMC, also perform well on a speech‐in‐noise task. Our findings indicate that capacity to resist semantic interference can be used to predict performance on speech‐in‐noise tasks.     

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。     

Impact of anticipatory processing versus distraction on multiple indices of anxiety in socially anxious individuals

In models of social phobia, anticipatory processing before a social-evaluative event is a key maintaining factor for the disorder. This study investigated the impact of anticipatory processing versus distraction before a social-evaluative task on affective (self-reported anxiety), psychophysiological (skin conductance), cognitive (self-reported maladaptive self-beliefs) and behavioural (in-situation performance) responses of participants. High and low socially anxious undergraduates were randomly allocated to either an anticipatory processing or distraction condition, and then completed an impromptu speech task. Relative to distraction, anticipatory processing increased self-reported anxiety in all participants, and increased skin conductance and the strength of conditional and high standard beliefs in the high (but not low) socially anxious participants. Unconditional beliefs were not affected. For high socially anxious individuals, anticipatory processing was also indirectly associated with poorer speech performance by increasing self-reported anxiety. Anticipatory processing appears to have multiple adverse effects in socially anxious individuals.     

Disruption of comprehension by the meaning of irrelevant sound

This study investigates the claim that the disruption of comprehension by irrelevant sound is qualitatively different from that of short-term memory for order. Both meaningful and meaningless speech disrupted the comprehensive aspect of the task, but the effect of meaningful speech was significantly greater. Both rehearsal and semantic processing, which are involved in reading comprehension, seem to be susceptible to disruption by irrelevant meaningful speech. The study provides some evidence to suggest that the presence of meaning in the irrelevant sound in creases disruption of performance in cognitive tasks that also call upon processing of meaning.     

Disruption of comprehension by the meaning of irrelevant sound

This study investigates the claim that the disruption of comprehension by irrelevant sound is qualitatively different from that of short-term memory for order. Both meaningful and meaningless speech disrupted the comprehensive aspect of the task, but the effect of meaningful speech was significantly greater. Both rehearsal and semantic processing, which are involved in reading comprehension, seem to be susceptible to disruption by irrelevant meaningful speech. The study provides some evidence to suggest that the presence of meaning in the irrelevant sound in creases disruption of performance in cognitive tasks that also call upon processing of meaning.     

Improved segregation of simultaneous talkers differentially affects perceptual and cognitive capacity demands for recognizing speech in competing speech

Perception of speech in competing speech is facilitated by spatial separation of the target and distracting speech, but this benefit may arise at either a perceptual or a cognitive level of processing. Load theory predicts different effects of perceptual and cognitive (working memory) load on selective attention in flanker task contexts, suggesting that this paradigm may be used to distinguish levels of interference. Two experiments examined interference from competing speech during a word recognition task under different perceptual and working memory loads in a dual-task paradigm. Listeners identified words produced by a talker of one gender while ignoring a talker of the other gender. Perceptual load was manipulated using a nonspeech response cue, with response conditional upon either one or two acoustic features (pitch and modulation). Memory load was manipulated with a secondary task consisting of one or six visually presented digits. In the first experiment, the target and distractor were presented at different virtual locations (0° and 90°, respectively), whereas in the second, all the stimuli were presented from the same apparent location. Results suggest that spatial cues improve resistance to distraction in part by reducing working memory demand.     

Effects of concurrent cognitive processing on the fluency of word repetition: comparison between persons who do and do not stutter

This study investigated how silent reading and word memorization may affect the fluency of concurrently repeated words. The words silently read or memorized were phonologically similar or dissimilar to the words of the repetition task. Fourteen adults who stutter and 16 who do not participated in the experiment. The two groups were matched for age, education, sex, forward and backward memory span and vocabulary. It was found that the disfluencies of persons who stutter significantly increased during word repetition when similar words were read or memorized concurrently. In contrast, the disfluencies of persons who do not stutter were not significantly affected by either secondary task. These results indicate that the speech of persons who stutter is more sensitive to interference from concurrently performed cognitive processing than that of nonstuttering persons. It is proposed that the phonological and articulatory systems of persons who stutter are protected less efficiently from interference by attention-demanding processing within the central executive system. Alternative interpretations are also discussed. EDUCATIONAL OBJECTIVES: Readers will learn how modern speech production theories and the concept of modularity can account for stuttering, and will be able to explain the greater vulnerability of stutterer's speech fluency to concurrent cognitive processing.     

The development of cognitive inhibition in streams-of-consciousness and directed speech

This research examined the development of the ability to inhibit thoughts within free speech by manipulating the content requirements of overt streams-of-consciousness. A picture-naming task with procedural manipulations similar to the stream-of-consciousness task was created as an additional method of investigating the development of the inhibition of speech. Comparison of adults' performance in the two tasks indicated that mature performance reflected inhibitory processing rather than selective attention. The children's performance in the stream-of-consciousness task suggested a developmental change in their ability to produce a stream-of-consciousness overtly. An investigation of inhibition in the picture-naming task with kindergartners, second graders, fifth graders and adults revealed a developmental improvement in inhibitory ability over the middle childhood years. These results are consistent with the interpretation that developmental improvements in cognitive inhibition contribute to developmental improvements in cognitive function on a variety of tasks.     

Easier Said Than Done? Task Difficulty's Influence on Temporal Alignment,Semantic Similarity,and Complexity Matching Between Gestures and Speech

Gestures and speech are clearly synchronized in many ways. However, previous studies have shown that the semantic similarity between gestures and speech breaks down as people approach transitions in understanding. Explanations for these gesture–speech mismatches, which focus on gestures and speech expressing different cognitive strategies, have been criticized for disregarding gestures’ and speech's integration and synchronization. In the current study, we applied three different perspectives to investigate gesture–speech synchronization in an easy and a difficult task: temporal alignment, semantic similarity, and complexity matching. Participants engaged in a simple cognitive task and were assigned to either an easy or a difficult condition. We automatically measured pointing gestures, and we coded participant's speech, to determine the temporal alignment and semantic similarity between gestures and speech. Multifractal detrended fluctuation analysis was used to determine the extent of complexity matching between gestures and speech. We found that task difficulty indeed influenced gesture–speech synchronization in all three domains. We thereby extended the phenomenon of gesture–speech mismatches to difficult tasks in general. Furthermore, we investigated how temporal alignment, semantic similarity, and complexity matching were related in each condition, and how they predicted participants’ task performance. Our study illustrates how combining multiple perspectives, originating from different research areas (i.e., coordination dynamics, complexity science, cognitive psychology), provides novel understanding about cognitive concepts in general and about gesture–speech synchronization and task difficulty in particular.     

Significance of pauses for speech perception

Pauses can be used to facilitate certain operations involved in the production and in the perception of speech. In the case of speech perception, pauses have been found to improve the accuracy of detection and the recall of lists of digits and letters. The aim of the present experiments was to examine the effects of pause time on the perception of sentences. In experiment I, a semantic categorization task was used and in experiment II a sentence recall task. The results indicated that in sentences containing pauses between clauses, words were categorized more rapidly (experiment I) and propositions were recalled more accurately (experiment II) than in sentences containing pauses, within the clause. The results are interpreted in the context of existing models of speech processing, and the significane of pause time for cognitive activity is discussed.     

Developmental shifts in children's sensitivity to visual speech: a new multimodal picture-word task

This research developed a multimodal picture-word task for assessing the influence of visual speech on phonological processing by 100 children between 4 and 14 years of age. We assessed how manipulation of seemingly to-be-ignored auditory (A) and audiovisual (AV) phonological distractors affected picture naming without participants consciously trying to respond to the manipulation. Results varied in complex ways as a function of age and type and modality of distractors. Results for congruent AV distractors yielded an inverted U-shaped function with a significant influence of visual speech in 4-year-olds and 10- to 14-year-olds but not in 5- to 9-year-olds. In concert with dynamic systems theory, we proposed that the temporary loss of sensitivity to visual speech was reflecting reorganization of relevant knowledge and processing subsystems, particularly phonology. We speculated that reorganization may be associated with (a) formal literacy instruction and (b) developmental changes in multimodal processing and auditory perceptual, linguistic, and cognitive skills.     

Levels of processing in speech perception

Four experiments are reported investigating previous findings that speech perception interferes with concurrent verbal memory but difficult nonverbal perceptual tasks do not, to any great degree. The forgetting produced by processing noisy speech could not be attributed to task difficulty, since equally difficult nonspeech tasks did not produce forgetting, and the extent of forgetting produced by speech could be manipulated independently of task difficulty. The forgetting could not be attributed to similarity between memory material and speech stimuli, since clear speech, analyzed in a simple and probably acoustically mediated discrimination task, produced little forgetting. The forgetting could not be attributed to a combination of similarity and difficutly since a very easy speech task involving clear speech produced as much forgetting as noisy speech tasks, as long as overt reproduction of the stimuli was required. By assuming that noisy speech and overtly reproduced speech are processed at a phonetic level but that clear, repetitive speech can be processed at a purely acoustic level, the forgetting produced by speech perception could be entirely attributed to the level at which the speech was processed. In a final experiment, results were obtained which suggest that if prior set induces processing of noisy and clear speech at comparable levels, the difference between the effects of noisy speech processing and clear speech processing on concurrent memory is completely eliminated.     

What phonological deficit?

We review a series of experiments aimed at understanding the nature of the phonological deficit in developmental dyslexia. These experiments investigate input and output phonological representations, phonological grammar, foreign speech perception and production, and unconscious speech processing and lexical access. Our results converge on the observation that the phonological representations of people with dyslexia may be intact, and that the phonological deficit surfaces only as a function of certain task requirements, notably short-term memory, conscious awareness, and time constraints. In an attempt to reformulate those task requirements more economically, we propose that individuals with dyslexia have a deficit in access to phonological representations. We discuss the explanatory power of this concept and we speculate that a similar notion might also adequately describe the nature of other associated cognitive deficits when present.     

Inhibitory control and the speech patterns of second language users

Inhibitory control (IC), an ability to suppress irrelevant and/or conflicting information, has been found to underlie performance on a variety of cognitive tasks, including bilingual language processing. This study examines the relationship between IC and the speech patterns of second language (L2) users from the perspective of individual differences. While the majority of studies have supported the role of IC in bilingual language processing using single‐word production paradigms, this work looks at inhibitory processes in the context of extended speech, with a particular emphasis on disfluencies. We hypothesized that the speech of individuals with poorer IC would be characterized by reduced fluency. A series of regression analyses, in which we controlled for age and L2 proficiency, revealed that IC (in terms of accuracy on the Stroop task) could reliably predict the occurrence of reformulations and the frequency and duration of silent pauses in L2 speech. No statistically significant relationship was found between IC and other L2 spoken output measures, such as repetitions, filled pauses, and performance errors. Conclusions focus on IC as one out of a number of cognitive functions in the service of spoken language production. A more qualitative approach towards the question of whether L2 speakers rely on IC is advocated.     

Disruption of verbal-spatial serial memory by extraneous air-traffic speech

The disruptive impact of task-extraneous air-traffic radio speech on a task involving the serial-recall of combined verbal and spatial stimuli (7 letters and their locations) that were broadly analogous to information about aircraft callsigns and movements was examined. Regardless of the dimension to be recalled (identity or spatial location), accuracy was significantly disrupted by the air-traffic speech. Prior knowledge as to which dimension to recall did not affect accuracy and did not interact with the disruptive effect of air-traffic speech, but did extend the time to initiate a response to the first item. The results are discussed with reference to theories of the irrelevant sound effect and stimulus-dimension binding in short-term memory. The vulnerability of cognitive processing related to air-traffic management and similar work environments is also discussed.     

Dissociable patterns of brain activity during comprehension of rapid and syntactically complex speech: evidence from fMRI

Sentence comprehension is a complex task that involves both language-specific processing components and general cognitive resources. Comprehension can be made more difficult by increasing the syntactic complexity or the presentation rate of a sentence, but it is unclear whether the same neural mechanism underlies both of these effects. In the current study, we used event-related functional magnetic resonance imaging (fMRI) to monitor neural activity while participants heard sentences containing a subject-relative or object-relative center-embedded clause presented at three different speech rates. Syntactically complex object-relative sentences activated left inferior frontal cortex across presentation rates, whereas sentences presented at a rapid rate recruited frontal brain regions such as anterior cingulate and premotor cortex, regardless of syntactic complexity. These results suggest that dissociable components of a large-scale neural network support the processing of syntactic complexity and speech presented at a rapid rate during auditory sentence processing.     

Where do dialectal effects on speech processing come from? Evidence from a cross-dialect investigation

Accented speech has been seen as an additional impediment for speech processing; it usually adds linguistic and cognitive load to the listener's task. In the current study we analyse where the processing costs of regional dialects come from, a question that has not been answered yet. We quantify the proficiency of Basque–Spanish bilinguals who have different native dialects of Basque on many dimensions and test for costs at each of three levels of processing–phonemic discrimination, word recognition, and semantic processing. The ability to discriminate a dialect-specific contrast is affected by a bilingual's linguistic background less than lexical access is, and an individual's difficulty in lexical access is correlated with basic discrimination problems. Once lexical access is achieved, dialectal variation has little impact on semantic processing. The results are discussed in terms of the presence or absence of correlations between different processing levels. The implications of the results are considered for how models of spoken word recognition handle dialectal variation.     

Imageability and semantic association in the representation and processing of event verbs

This study examined the relative salience of imageability (the degree to which a word evokes mental imagery) versus semantic association (the density of semantic network in which a word is embedded) in the representation and processing of four types of event verbs: sensory, cognitive, speech, and motor verbs. ERP responses were recorded, while 34 university students performed on a lexical decision task. Analysis focused primarily on amplitude differences across verb conditions within the N400 time window where activities are considered representing meaning activation. Variation in N400 amplitude across four types of verbs was found significantly associated with the level of imageability, but not the level of semantic association. The findings suggest imageability as a more salient factor relative to semantic association in the processing of these verbs. The role of semantic association and the representation of speech verbs are also discussed.     

Aging and the vulnerability of speech to dual task demands

Tracking a digital pursuit rotor task was used to measure dual task costs of language production by young and older adults. Tracking performance by both groups was affected by dual task demands: time on target declined and tracking error increased as dual task demands increased from the baseline condition to a moderately demanding dual task condition to a more demanding dual task condition. When dual task demands were moderate, older adults' speech rate declined but their fluency, grammatical complexity, and content were unaffected. When the dual task was more demanding, older adults' speech, like young adults' speech, became highly fragmented, ungrammatical, and incoherent. Vocabulary, working memory, processing speed, and inhibition affected vulnerability to dual task costs: vocabulary provided some protection for sentence length and grammaticality, working memory conferred some protection for grammatical complexity, and processing speed provided some protection for speech rate, propositional density, coherence, and lexical diversity. Further, vocabulary and working memory capacity provided more protection for older adults than for young adults although the protective effect of processing speed was somewhat reduced for older adults as compared to the young adults.