Memorization-Based Training and Testing Paradigm for Robust Vocal Identity Recognition in Expressive Speech Using Event-Related Potentials Analysis

Summary

The study introduces a training-testing paradigm to investigate old/new effects of event-related potentials in confident and doubtful prosodic scenarios. Data reveals an enhanced late positive component between 400-850 ms at Pz and other electrodes. This pipeline can explore factors beyond speech prosody and their influence on cue-binding target identification.

Abstract

Recognizing familiar speakers from vocal streams is a fundamental aspect of human verbal communication. However, it remains unclear how listeners can still discern the speaker's identity in expressive speech. This study develops a memorization-based individual speaker identity recognition approach and an accompanying electroencephalogram (EEG) data analysis pipeline, which monitors how listeners recognize familiar speakers and tell unfamiliar ones apart. EEG data captures online cognitive processes during new versus old speaker distinction based on voice, offering a real-time measure of brain activity, overcoming limits of reaction times and accuracy measurements. The paradigm comprises three steps: listeners establish associations between three voices and their names (training); listeners indicate the name corresponding to a voice from three candidates (checking); listeners distinguish between three old and three new speaker voices in a two-alternative forced-choice task (testing). The speech prosody in testing was either confident or doubtful. EEG data were collected using a 64-channel EEG system, followed by preprocessing and imported into RStudio for ERP and statistical analysis and MATLAB for brain topography. Results showed an enlarged late positive component (LPC) was elicited in the old-talker compared to the new-talker condition in the 400-850 ms window in the Pz and other wider range of electrodes in both prosodies. Yet, the old/new effect was robust in central and posterior electrodes for doubtful prosody perception, whereas the anterior, central, and posterior electrodes are for confident prosody condition. This study proposes that this experiment design can serve as a reference for investigating speaker-specific cue-binding effects in various scenarios (e.g., anaphoric expression) and pathologies in patients like phonagnosia.

Introduction

Human vocal streams are rich in information, such as emotion^1,2, health status^3,4, biological sex⁵, age⁶, and, more importantly, the individual vocal identity^7,8. Studies have suggested that human listeners have a robust capacity to recognize and differentiate their peers' identities through voices, overcoming within-speaker variations around speaker identity's average-based representation in the acoustic space⁹. Such varia....

Protocol

The Ethics Committee of the Institute of Linguistics, Shanghai International Studies University, has approved the experiment design described below. Informed consent was obtained from all participants for this study.

1. Preparation and validation of the audio library

1. Audio recording and editing
   1. Create a Chinese vocal database following the standard procedure of making a previous English version while making adaptations where needed to fit into the conte.......

Discussion

The study presents a pipeline for EEG data collection and analysis, focusing on recognizing previously learned speaker identities. This study addresses variations between learning and recognition phases, including differences in speech content²² and prosody¹⁰. The design is adaptable to a range of research fields, including psycholinguistics, such as pronoun and anaphoric processing⁴¹.

The training-testing paradigm is a c.......

Materials

Name	Company	Catalog Number	Comments
64Ch Standard BrainCap for BrainAmp	Easycap GmbH	Steingrabenstrasse 14 DE-82211	https://shop.easycap.de/products/64ch-standard-braincap
Abrasive Electrolyte-Gel	Easycap GmbH	Abralyt 2000	https://shop.easycap.de/products/abralyt-2000
actiCHamp Plus	Brain Products GmbH	64 channels + 8 AUX	https://www.brainproducts.com/solutions/actichamp/
Audio Interface	Native Instruments GmbH	Komplete audio 6	https://www.native-instruments.com/en/products/komplete/audio-interfaces/komplete-audio-6/
Foam Eartips	Neuronix	ER3-14	https://neuronix.ca/products/er3-14-foam-eartips
Gel-based passive electrode system	Brain Products GmbH	BC 01453	https://www.brainproducts.com/solutions/braincap/
High-Viscosity Electrolyte Gel	Easycap GmbH	SuperVisc	https://shop.easycap.de/products/supervisc