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Yoo H, Su PL, Ramsay G, Long HL, Bene ER, Oller DK. Infant vocal category exploration as a foundation for speech development. PLoS One 2024; 19:e0299140. [PMID: 38809807 PMCID: PMC11135693 DOI: 10.1371/journal.pone.0299140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 02/06/2024] [Indexed: 05/31/2024] Open
Abstract
Non-random exploration of infant speech-like vocalizations (e.g., squeals, growls, and vowel-like sounds or "vocants") is pivotal in speech development. This type of vocal exploration, often noticed when infants produce particular vocal types in clusters, serves two crucial purposes: it establishes a foundation for speech because speech requires formation of new vocal categories, and it serves as a basis for vocal signaling of wellness and interaction with caregivers. Despite the significance of clustering, existing research has largely relied on subjective descriptions and anecdotal observations regarding early vocal category formation. In this study, we aim to address this gap by presenting the first large-scale empirical evidence of vocal category exploration and clustering throughout the first year of life. We observed infant vocalizations longitudinally using all-day home recordings from 130 typically developing infants across the entire first year of life. To identify clustering patterns, we conducted Fisher's exact tests to compare the occurrence of squeals versus vocants, as well as growls versus vocants. We found that across the first year, infants demonstrated clear clustering patterns of squeals and growls, indicating that these categories were not randomly produced, but rather, it seemed, infants actively engaged in practice of these specific categories. The findings lend support to the concept of infants as manifesting active vocal exploration and category formation, a key foundation for vocal language.
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Affiliation(s)
- Hyunjoo Yoo
- Department of Communicative Disorders, College of Arts & Sciences, The University of Alabama, Tuscaloosa, Alabama, United States of America
| | - Pumpki Lei Su
- Department of Speech, Language and Hearing, School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, Texas, United States of America
| | - Gordon Ramsay
- Spoken Communication Laboratory, Marcus Autism Center, Children’s Healthcare of Atlanta, Atlanta, Georgia, United States of America
- Department of Pediatrics, Emory School of Medicine, Atlanta, Georgia, United States of America
| | - Helen L. Long
- Waisman Center, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Edina R. Bene
- Origins of Language Laboratory, School of Communication Sciences and Disorders, University of Memphis, Memphis, Tennessee, United States of America
| | - D. Kimbrough Oller
- Origins of Language Laboratory, School of Communication Sciences and Disorders, University of Memphis, Memphis, Tennessee, United States of America
- Institute for Intelligent Systems, University of Memphis, Memphis, Tennessee, United States of America
- Konrad Lorenz Institute for Evolution and Cognition Research, Klosterneuburg, Austria
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Yoo H, Su PL, Ramsay G, Long HL, Bene ER, Kimbrough Oller D. Infant vocal category exploration as a foundation for speech development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.17.576142. [PMID: 38293228 PMCID: PMC10827196 DOI: 10.1101/2024.01.17.576142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Non-random exploration of infant speech-like vocalizations (e.g., squeals, growls, and vowel- like sounds or "vocants") is pivotal in speech development. This type of vocal exploration, often noticed when infants produce particular vocal types in clusters, serves two crucial purposes: it establishes a foundation for speech because speech requires formation of new vocal categories, and it serves as a basis for vocal signaling of wellness and interaction with caregivers. Despite the significance of clustering, existing research has largely relied on subjective descriptions and anecdotal observations regarding early vocal category formation. In this study, we aim to address this gap by presenting the first large-scale empirical evidence of vocal category exploration and clustering throughout the first year of life. We observed infant vocalizations longitudinally using all-day home recordings from 130 typically developing infants across the entire first year of life. To identify clustering patterns, we conducted Fisher's exact tests to compare the occurrence of squeals versus vocants, as well as growls versus vocants. We found that across the first year, infants demonstrated clear clustering patterns of squeals and growls, indicating that these categories were not randomly produced, but rather, it seemed, infants actively engaged in practice of these specific categories. The findings lend support to the concept of infants as manifesting active vocal exploration and category formation, a key foundation for vocal language.
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Ruan Y, Byers-Heinlein K, Orena AJ, Polka L. Mixed-Language Input and Infant Volubility: Friend or Foe? BILINGUALISM (CAMBRIDGE, ENGLAND) 2023; 26:1051-1066. [PMID: 38187471 PMCID: PMC10769107 DOI: 10.1017/s1366728923000287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Language mixing is a common feature of many bilingually-raised children's input. Yet how it is related to their language development remains an open question. The current study investigated mixed-language input indexed by observed (30-second segment) counts and proportions in day-long recordings as well as parent-reported scores, in relation to infant vocal activeness (i.e., volubility) when infants were 10 and 18 months old. Results suggested infants who received a higher score or proportion of mixed input in one-on-one social contexts were less voluble. However, within contexts involving language mixing, infants who heard more words were also the ones who produced more vocalizations. These divergent associations between mixed input and infant vocal development point for a need to better understand the causal factors that drive these associations.
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Affiliation(s)
- Yufang Ruan
- School of Communication Sciences and Disorders, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada
- Centre for Research on Brain, Language and Music, Montréal, Québec, Canada
| | - Krista Byers-Heinlein
- Centre for Research on Brain, Language and Music, Montréal, Québec, Canada
- Department of Psychology, Concordia University, Montréal, Québec, Canada
- Centre for Research in Human Development, Concordia University, Montréal, Québec, Canada
| | - Adriel John Orena
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Linda Polka
- School of Communication Sciences and Disorders, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada
- Centre for Research on Brain, Language and Music, Montréal, Québec, Canada
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Nguyen T, Zimmer L, Hoehl S. Your turn, my turn. Neural synchrony in mother-infant proto-conversation. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210488. [PMID: 36871582 PMCID: PMC9985967 DOI: 10.1098/rstb.2021.0488] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023] Open
Abstract
Even before infants utter their first words, they engage in highly coordinated vocal exchanges with their caregivers. During these so-called proto-conversations, caregiver-infant dyads use a presumably universal communication structure-turn-taking, which has been linked to favourable developmental outcomes. However, little is known about potential mechanisms involved in early turn-taking. Previous research pointed to interpersonal synchronization of brain activity between adults and preschool-aged children during turn-taking. Here, we assessed caregivers and infants at 4-6 months of age (N = 55) during a face-to-face interaction. We used functional-near infrared spectroscopy hyperscanning to measure dyads' brain activity and microcoded their turn-taking. We also measured infants' inter-hemispheric connectivity as an index for brain maturity and later vocabulary size and attachment security as developmental outcomes potentially linked to turn-taking. The results showed that more frequent turn-taking was related to interpersonal neural synchrony, but the strength of the relation decreased over the course of the proto-conversation. Importantly, turn-taking was positively associated with infant brain maturity and later vocabulary size, but not with later attachment security. Taken together, these findings shed light on mechanisms facilitating preverbal turn-taking and stress the importance of emerging turn-taking for child brain and language development. This article is part of a discussion meeting issue 'Face2face: advancing the science of social interaction'.
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Affiliation(s)
- Trinh Nguyen
- Department of Developmental and Educational Psychology, University of Vienna, Liebiggasse 5, 1010 Vienna, Austria.,Neuroscience of Perception and Action Lab, Italian Institute of Technology (IIT), Center for Life Nano and Neuro Science, Viale Regina Elena 291, 00161 Rome, Italy
| | - Lucie Zimmer
- Department of Psychology, Ludwig-Maximilians University Munich, Leopoldstrasse 13, 80802 Munich, Germany
| | - Stefanie Hoehl
- Department of Developmental and Educational Psychology, University of Vienna, Liebiggasse 5, 1010 Vienna, Austria
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Michon M, Zamorano-Abramson J, Aboitiz F. Faces and Voices Processing in Human and Primate Brains: Rhythmic and Multimodal Mechanisms Underlying the Evolution and Development of Speech. Front Psychol 2022; 13:829083. [PMID: 35432052 PMCID: PMC9007199 DOI: 10.3389/fpsyg.2022.829083] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 03/07/2022] [Indexed: 11/24/2022] Open
Abstract
While influential works since the 1970s have widely assumed that imitation is an innate skill in both human and non-human primate neonates, recent empirical studies and meta-analyses have challenged this view, indicating other forms of reward-based learning as relevant factors in the development of social behavior. The visual input translation into matching motor output that underlies imitation abilities instead seems to develop along with social interactions and sensorimotor experience during infancy and childhood. Recently, a new visual stream has been identified in both human and non-human primate brains, updating the dual visual stream model. This third pathway is thought to be specialized for dynamics aspects of social perceptions such as eye-gaze, facial expression and crucially for audio-visual integration of speech. Here, we review empirical studies addressing an understudied but crucial aspect of speech and communication, namely the processing of visual orofacial cues (i.e., the perception of a speaker's lips and tongue movements) and its integration with vocal auditory cues. Along this review, we offer new insights from our understanding of speech as the product of evolution and development of a rhythmic and multimodal organization of sensorimotor brain networks, supporting volitional motor control of the upper vocal tract and audio-visual voices-faces integration.
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Affiliation(s)
- Maëva Michon
- Laboratory for Cognitive and Evolutionary Neuroscience, Department of Psychiatry, Faculty of Medicine, Interdisciplinary Center for Neuroscience, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Estudios en Neurociencia Humana y Neuropsicología, Facultad de Psicología, Universidad Diego Portales, Santiago, Chile
| | - José Zamorano-Abramson
- Centro de Investigación en Complejidad Social, Facultad de Gobierno, Universidad del Desarrollo, Santiago, Chile
| | - Francisco Aboitiz
- Laboratory for Cognitive and Evolutionary Neuroscience, Department of Psychiatry, Faculty of Medicine, Interdisciplinary Center for Neuroscience, Pontificia Universidad Católica de Chile, Santiago, Chile
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Long HL, Ramsay G, Griebel U, Bene ER, Bowman DD, Burkhardt-Reed MM, Oller DK. Perspectives on the origin of language: Infants vocalize most during independent vocal play but produce their most speech-like vocalizations during turn taking. PLoS One 2022; 17:e0279395. [PMID: 36584126 PMCID: PMC9803194 DOI: 10.1371/journal.pone.0279395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 12/07/2022] [Indexed: 12/31/2022] Open
Abstract
A growing body of research emphasizes both endogenous and social motivations in human vocal development. Our own efforts seek to establish an evolutionary and developmental perspective on the existence and usage of speech-like vocalizations ("protophones") in the first year of life. We evaluated the relative occurrence of protophones in 40 typically developing infants across the second-half year based on longitudinal all-day recordings. Infants showed strong endogenous motivation to vocalize, producing vastly more protophones during independent vocal exploration and play than during vocal turn taking. Both periods of vocal play and periods of turn-taking corresponded to elevated levels of the most advanced protophones (canonical babbling) relative to periods without vocal play or without turn-taking. Notably, periods of turn taking showed even more canonical babbling than periods of vocal play. We conclude that endogenous motivation drives infants' tendencies to explore and display a great number of speech-like vocalizations, but that social interaction drives the production of the most speech-like forms. The results inform our previously published proposal that the human infant has been naturally selected to explore protophone production and that the exploratory inclination in our hominin ancestors formed a foundation for language.
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Affiliation(s)
- Helen L. Long
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
| | - Gordon Ramsay
- Marcus Autism Center, Children’s Healthcare of Atlanta, Atlanta, Georgia, United States of America
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, United States of America
- Center for Translational Social Neuroscience, Emory University, Atlanta, Georgia, United States of America
| | - Ulrike Griebel
- Institute for Intelligent Systems, University of Memphis, Memphis, Tennessee, United States of America
- School of Communication Sciences and Disorders, University of Memphis, Memphis, Tennessee, United States of America
- Konrad Lorenz Institute for Evolution and Cognition Research, Klosterneuburg, Austria
| | - Edina R. Bene
- School of Communication Sciences and Disorders, University of Memphis, Memphis, Tennessee, United States of America
| | - Dale D. Bowman
- Institute for Intelligent Systems, University of Memphis, Memphis, Tennessee, United States of America
- Department of Mathematics, University of Memphis, Memphis, Tennessee, United States of America
| | - Megan M. Burkhardt-Reed
- School of Communication Sciences and Disorders, University of Memphis, Memphis, Tennessee, United States of America
| | - D. Kimbrough Oller
- Institute for Intelligent Systems, University of Memphis, Memphis, Tennessee, United States of America
- School of Communication Sciences and Disorders, University of Memphis, Memphis, Tennessee, United States of America
- Konrad Lorenz Institute for Evolution and Cognition Research, Klosterneuburg, Austria
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