Effects of Participant Engagement on Prosodic Prominence

Speakers are more cooperative and less individual when interacting in larger group sizes

Introduction

Cooperation, acoustically signaled through vocal convergence, is facilitated when group members are more similar. Excessive vocal convergence may, however, weaken individual recognizability. This study aimed to explore whether constraints to convergence can arise in circumstances where interlocutors need to enhance their vocal individuality. Therefore, we tested the effects of group size (3 and 5 interactants) on vocal convergence and individualization in a social communication scenario in which individual recognition by voice is at stake.

Methods

In an interactive game, players had to recognize each other through their voices while solving a cooperative task online. The vocal similarity was quantified through similarities in speaker i-vectors obtained through probabilistic linear discriminant analysis (PLDA). Speaker recognition performance was measured through the system Equal Error Rate (EER).

Results

Vocal similarity between-speakers increased with a larger group size which indicates a higher cooperative vocal behavior. At the same time, there was an increase in EER for the same speakers between the smaller and the larger group size, meaning a decrease in overall recognition performance.

Discussion

The decrease in vocal individualization in the larger group size suggests that ingroup cooperation and social cohesion conveyed through acoustic convergence have priority over individualization in larger groups of unacquainted speakers.

Adjustment of cue weighting in speech by speakers and listeners: Evidence from amplitude and duration modifications of Mandarin Chinese tone

Speech contrasts are signaled by multiple acoustic dimensions, but these dimensions are not equally diagnostic. Moreover, the relative diagnosticity, or weight, of acoustic dimensions in speech can shift in different communicative contexts for both speech perception and speech production. However, the literature remains unclear on whether, and if so how, talkers adjust speech to emphasize different acoustic dimensions in the context of changing communicative demands. Here, we examine the interplay of flexible cue weights in speech production and perception across amplitude and duration, secondary non-spectral acoustic dimensions for phonated Mandarin Chinese lexical tone, across natural speech and whispering, which eliminates fundamental frequency contour, the primary acoustic dimension. Phonated and whispered Mandarin productions from native talkers revealed enhancement of both duration and amplitude cues in whispered, compared to phonated speech. When nonspeech amplitude-modulated noises modeled these patterns of enhancement, identification of the noises as Mandarin lexical tone categories was more accurate than identification of noises modeling phonated speech amplitude and duration cues. Thus, speakers exaggerate secondary cues in whispered speech and listeners make use of this information. Yet, enhancement is not symmetric among the four Mandarin lexical tones, indicating possible constraints on the realization of this enhancement.

Prosody indexes both competence and performance

Prosody is an important feature of language that conveys a wide range of information. However, prosody is widely considered to be a difficult domain of study within the language sciences. One consequence of this is that existing grammatical theories of prosody fail to explain prosodic choices that seem to arise from nonlinguistic cognitive demands, such as communicative context, top-down expectations, and recent articulatory and acoustic experience. We provide an account of some of these phenomena and argue that linguistic theories that do not incorporate these factors into models of prosody are likely to mischaracterize its role in language. This article is categorized under: Linguistics > Language in Mind and Brain Psychology > Language Linguistics > Linguistic Theory.

Communicative Context Affects Use of Referential Prosody

The current study assessed the extent to which the use of referential prosody varies with communicative demand. Speaker-listener dyads completed a referential communication task during which speakers attempted to indicate one of two color swatches (one bright, one dark) to listeners. Speakers' bright sentences were reliably higher pitched than dark sentences for ambiguous (e.g., bright red versus dark red) but not unambiguous (e.g., bright red versus dark purple) trials, suggesting that speakers produced meaningful acoustic cues to brightness when the accompanying linguistic content was underspecified (e.g., "Can you get the red one?"). Listening partners reliably chose the correct corresponding swatch for ambiguous trials when lexical information was insufficient to identify the target, suggesting that listeners recruited prosody to resolve lexical ambiguity. Prosody can thus be conceptualized as a type of vocal gesture that can be recruited to resolve referential ambiguity when there is communicative demand to do so.

Protocol for a conversation-based analysis study: PREVENT-ED investigates dialogue features that may help predict dementia onset in later life

INTRODUCTION

Decreasing the incidence of Alzheimer's disease (AD) is a global public health priority. Early detection of AD is an important requisite for the implementation of prevention strategies towards this goal. While it is plausible that patients at the early stages of AD may exhibit subtle behavioural signs of neurodegeneration, neuropsychological testing seems unable to detect these signs in preclinical AD. Recent studies indicate that spontaneous speech data, which can be collected frequently and naturally, provide good predictors for AD detection in cohorts with a clinical diagnosis. The potential of models based on such data for detecting preclinical AD remains unknown.

METHODS AND ANALYSIS

The PREVENT-Elicitation of Dialogues (PREVENT-ED) study builds on the PREVENT Dementia project to investigate whether early behavioural signs of AD may be detected through dialogue interaction. Participants recruited through PREVENT, aged 40-59 at baseline, will be included in this study. We will use speech processing and machine learning methods to assess how well speech and visuospatial markers agree with neuropsychological, biomarker, clinical, lifestyle and genetic data from the PREVENT cohort.

ETHICS AND DISSEMINATION

There are no expected risks or burdens to participants. The procedures are not invasive and do not raise significant ethical issues. We only approach healthy consenting adults and all participants will be informed that this is an exploratory study and therefore has no diagnostic aim. Confidentiality aspects such as data encryption and storage comply with the General Data Protection Regulation and with the requirements from sponsoring bodies and ethical committees. This study has been granted ethical approval by the London-Surrey Research Ethics Committee (REC reference No: 18/LO/0860), and by Caldicott and Information Governance (reference No: CRD18048). PREVENT-ED results will be published in peer-reviewed journals.