Irrelevant Sound Disrupts Speech Production: Exploring the Relationship between Short-Term Memory and Experimentally Induced Slips of the Tongue

Understanding language and cognition after brain surgery - Tumour grade, fine-grained assessment tools and, most of all, individualized approach

Cognitive performance influences the quality of life and survival of people with glioma. Thus, a detailed neuropsychological and language evaluation is essential. In this work, we tested if an analysis of errors in naming can indicate semantic and/or phonological impairments in 87 awake brain surgery patients. Secondly, we explored how language and cognition change after brain tumour resection. Finally, we checked if low-tumour grade had a protective effect on cognition. Our results indicated that naming errors can be useful to monitor semantic and phonological processing, as their number correlated with scores on tasks developed by our team for testing these domains. Secondly, we showed that - although an analysis at a whole group level indicates a decline in language functions - significantly more individual patients improve or remain stable when compared to the ones who declined. Finally, we observed that having LGG, when compared with HGG, favours patients' outcome after surgery, most probably due to brain plasticity mechanisms. We provide new evidence of the importance of applying a broader neuropsychological assessment and an analysis of naming errors in patients with glioma. Our approach may potentially ensure better detection of cognitive deficits and contribute to better postoperative outcomes. Our study also shows that an individualized approach in post-surgical follow-ups can reveal reassuring results showing that significantly more patients remain stable or improve and can be a promising avenue for similar reports. Finally, the study captures that plasticity mechanisms may act as protective in LGG versus HGG after surgery.

Speech errors in consecutive interpreting: Effects of language proficiency, working memory, and anxiety

Interpreting can be seen as a form of language production, where interpreters extract conceptual information from the source language and express it in the target language. Hence, like language production, interpreting contains speech errors at various (e.g., conceptual, syntactic, lexical and phonological) levels. The current study delved into the impact of language proficiency, working memory, and anxiety on the occurrence of speech errors across these linguistic strata during consecutive interpreting from English (a second language) into Chinese (a first language) by student interpreters. We showed that speech errors in general decreased as a function of the interpreter's proficiency in the source (second) language and increased as a function of the interpreter's anxiety. Conceptual errors, which result from mistaken comprehension of the source language, decreased as a function of language proficiency and working memory. Lexical errors increased as a function of the interpreter's tendency of anxiety. Syntactic errors also decreased as a function of language proficiency and increased as a function of anxiety. Phonological errors were not sensitive to any of the three cognitive traits. We discussed implications for the cognitive processes underlying interpreting and for interpreting training.

Verbal Working Memory, Long-Term Knowledge, and Statistical Learning

Evidence supporting the idea that serial-order verbal working memory is underpinned by long-term knowledge has accumulated over more than half a century. Recent studies using natural-language statistics, artificial statistical-learning techniques, and the Hebb repetition paradigm have revealed multiple types of long-term knowledge underlying serial-order verbal working memory performance. These include (a) element-to-element association knowledge, which slowly accumulates through extensive exposure to an exemplar; (b) position–element knowledge, which is acquired through several encounters with an exemplar; and (c) whole-sequence knowledge, which is captured by the Hebb repetition paradigm and acquired rapidly with a few repetitions. Arguably, the first two are a basis for fluent and efficient language usage, and the third is a basis for vocabulary learning. Thus, statistical-learning mechanisms (and possibly episodic-learning mechanisms) may form the foundation of language acquisition and language processing, which characterize linguistic long-term knowledge for verbal working memory.

Distinct neural systems recruited when speech production is modulated by different masking sounds

When talkers speak in masking sounds, their speech undergoes a variety of acoustic and phonetic changes. These changes are known collectively as the Lombard effect. Most behavioural research and neuroimaging research in this area has concentrated on the effect of energetic maskers such as white noise on Lombard speech. Previous fMRI studies have argued that neural responses to speaking in noise are driven by the quality of auditory feedback-that is, the audibility of the speaker's voice over the masker. However, we also frequently produce speech in the presence of informational maskers such as another talker. Here, speakers read sentences over a range of maskers varying in their informational and energetic content: speech, rotated speech, speech modulated noise, and white noise. Subjects also spoke in quiet and listened to the maskers without speaking. When subjects spoke in masking sounds, their vocal intensity increased in line with the energetic content of the masker. However, the opposite pattern was found neurally. In the superior temporal gyrus, activation was most strongly associated with increases in informational, rather than energetic, masking. This suggests that the neural activations associated with speaking in noise are more complex than a simple feedback response.

The dynamics of variation in individuals

This paper examines the factors conditioning the production of linguistic variables in real time by individual speakers: the study of what we term the dynamics of variation in individuals. We propose a framework that recognizes three types of factors conditioning variation: sociostylistic (s-), internal linguistic (i-), and psychophysiological (p-). We develop two main points against this background. The first is that sequences of variants produced by individuals display systematic patterns that can be understood in terms of s-conditioning and p-conditioning (with a focus on the latter). The second main point is that p-conditioning and i-conditioning are distinct in their mental implementations; this claim has implications for understanding the locality of the factors conditioning alternations, for the universality and language-specificity of variation, and for the general question of whether grammar and language use are distinct. Throughout the paper, questions about the dynamics of variation in individuals are set against the typical community-centered variationist perspective, with an eye towards showing how findings in the two domains, though differing in explanatory focus, can ultimately be mutually informative.

Distinguishing Target From Distractor in Stroop, Picture-Word, and Word-Word Interference Tasks

Lexical selection-both during reading aloud and speech production-involves selecting an intended word, while ignoring irrelevant lexical activation. This process has been studied by the use of interference tasks. Examples are the Stroop task, where participants ignore the written color word and name the color of the ink, picture-word interference tasks, where participants name a picture while ignoring a super-imposed written word, or word-word interference (WWI) tasks, where two words are presented and the participants need to respond to only one, based on an pre-determined visual feature (e.g., color, position). Here, we focus on the WWI task: it is theoretically impossible for existing models to explain how the cognitive system can respond to one stimulus and block the other, when they are presented by the same modality (i.e., they are both words). We describe a solution that can explain performance on the WWI task: drawing on the literature on visual attention, we propose that the system creates an object file for each perceived object, which is continuously updated with increasingly complete information about the stimulus, such as the task-relevant visual feature. Such a model can account for performance on all three tasks.

[Investigating phonological planning processes in speech production through a speech-error induction technique]

The present study investigated principles of phonological planning, a common serial ordering mechanism for speech production and phonological short-term memory. Nakayama and Saito (2014) have investigated the principles by using a speech-error induction technique, in which participants were exposed to an auditory distracIor word immediately before an utterance of a target word. They demonstrated within-word adjacent mora exchanges and serial position effects on error rates. These findings support, respectively, the temporal distance and the edge principles at a within-word level. As this previous study induced errors using word distractors created by exchanging adjacent morae in the target words, it is possible that the speech errors are expressions of lexical intrusions reflecting interactive activation of phonological and lexical/semantic representations. To eliminate this possibility, the present study used nonword distractors that had no lexical or semantic representations. This approach successfully replicated the error patterns identified in the abovementioned study, further confirming that the temporal distance and edge principles are organizing precepts in phonological planning.

Within-word serial order control: Adjacent mora exchange and serial position effects in repeated single-word production

An essential function of language processing is serial order control. Computational models of serial ordering and empirical data suggest that plan representations for ordered output of sound are governed by principles related to similarity. Among these principles, the temporal distance and edge principles at a within-word level have not been empirically demonstrated separately from other principles. Specifically, the temporal distance principle assumes that phonemes that are in the same word and thus temporally close are represented similarly. This principle would manifest as phoneme movement errors within the same word. However, such errors are rarely observed in English, likely reflecting stronger effects of syllabic constraints (i.e., phonemes in different positions within the syllable are distinctly represented). The edge principle assumes that the edges of a sequence are represented distinctly from other elements/positions. This principle has been repeatedly observed as a serial position effect in the context of phonological short-term memory. However, it has not been demonstrated in single-word production. This study provides direct evidence for the two abovementioned principles by using a speech-error induction technique to show the exchange of adjacent morae and serial position effects in Japanese four-mora words. Participants repeatedly produced a target word or nonword, immediately after hearing an aurally presented distractor word. The phonologically similar distractor words, which were created by exchanging adjacent morae in the target, induced adjacent-mora-exchange errors, demonstrating the within-word temporal distance principle. There was also a serial position effect in error rates, such that errors were mostly induced at the middle positions within a word. The results provide empirical evidence for the temporal distance and edge principles in within-word serial order control.

Twisting tongues and memories: Explorations of the relationship between language production and verbal working memory

Many accounts of working memory posit specialized storage mechanisms for the maintenance of serial order. We explore an alternative, that maintenance is achieved through temporary activation in the language production architecture. Four experiments examined the extent to which the phonological similarity effect can be explained as a sublexical speech error. Phonologically similar nonword stimuli were ordered to create tongue twister or control materials used in four tasks: reading aloud, immediate spoken recall, immediate typed recall, and serial recognition. Dependent measures from working memory (recall accuracy) and language production (speech errors) fields were used. Even though lists were identical except for item order, robust effects of tongue twisters were observed. Speech error analyses showed that errors were better described as phoneme rather than item ordering errors. The distribution of speech errors was comparable across all experiments and exhibited syllable-position effects, suggesting an important role for production processes. Implications for working memory and language production are discussed.

Visual word recognition is accompanied by covert articulation: evidence for a speech-like phonological representation

Two lexical decision task (LDT) experiments examined whether visual word recognition involves the use of a speech-like phonological code that may be generated via covert articulation. In Experiment 1, each visual item was presented with an irrelevant spoken word (ISW) that was either phonologically identical, similar, or dissimilar to it. An ISW delayed classification of a visual word when the two were phonologically similar, and it delayed the classification of a pseudoword when it was identical to the base word from which the pseudoword was derived. In Experiment 2, a LDT was performed with and without articulatory suppression, and pseudowords consisted of regular pseudowords and pseudohomophones. Articulatory suppression decreased sound-specific ISW effects for words and regular pseudowords but not for pseudohomophones. These findings indicate that the processing of an orthographically legal letter sequence generally involves the specification of more than one sound code, one of which involves covert articulation.

Can children with (central) auditory processing disorders ignore irrelevant sounds?

This study investigated the effects of irrelevant sounds on the serial recall performance of visually presented digits in a sample of children diagnosed with (central) auditory processing disorders [(C)APD] and age- and span-matched control groups. The irrelevant sounds used were samples of tones and speech. Memory performance was significantly disrupted in the presence of irrelevant sounds in all three groups of children. While irrelevant speech was more disruptive than irrelevant tones in the two control groups, children diagnosed with (C)APD did not show larger disruption from irrelevant speech compared to irrelevant tones. Children diagnosed with (C)APD appear to process speech differently from their typically developing peers, and this may be remediated with auditory training procedures and the placement of these children in smaller classes.

What is the relationship between phonological short-term memory and speech processing?

Traditionally, models of speech comprehension and production do not depend on concepts and processes from the phonological short-term memory (pSTM) literature. Likewise, in working memory research, pSTM is considered to be a language-independent system that facilitates language acquisition rather than speech processing per se. We discuss couplings between pSTM, speech perception and speech production, and we propose that pSTM arises from the cycling of information between two phonological buffers, one involved in speech perception and one in speech production. We discuss the specific role of these processes in speech processing, and argue that models of speech perception and production, and our understanding of their neural bases, will benefit from incorporating them.