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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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Long HL, Bowman DD, Yoo H, Burkhardt-Reed MM, Bene ER, Oller DK. Social and endogenous infant vocalizations. PLoS One 2020; 15:e0224956. [PMID: 32756591 PMCID: PMC7406057 DOI: 10.1371/journal.pone.0224956] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 07/20/2020] [Indexed: 12/04/2022] Open
Abstract
Research on infant vocal development has provided notable insights into vocal interaction with caregivers, elucidating growth in foundations for language through parental elicitation and reaction to vocalizations. A role for infant vocalizations produced endogenously, potentially providing raw material for interaction and a basis for growth in the vocal capacity itself, has received less attention. We report that in laboratory recordings of infants and their parents, the bulk of infant speech-like vocalizations, or "protophones", were directed toward no one and instead appeared to be generated endogenously, mostly in exploration of vocal abilities. The tendency to predominantly produce protophones without directing them to others occurred both during periods when parents were instructed to interact with their infants and during periods when parents were occupied with an interviewer, with the infants in the room. The results emphasize the infant as an agent in vocal learning, even when not interacting socially and suggest an enhanced perspective on foundations for vocal language.
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Affiliation(s)
- Helen L. Long
- Origins of Language Laboratory, School of Communication Sciences and Disorders, University of Memphis, Memphis, Tennessee, United States of America
| | - Dale D. Bowman
- Department of Mathematics, University of Memphis, Memphis, Tennessee, United States of America
| | - Hyunjoo Yoo
- Department of Communicative Disorders, College of Arts & Sciences, The University of Alabama, Tuscaloosa, Alabama, United States of America
| | - Megan M. Burkhardt-Reed
- Origins of Language Laboratory, School of Communication Sciences and Disorders, University of Memphis, Memphis, Tennessee, 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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Long HL, Oller DK, Bowman DA. Reliability of Listener Judgments of Infant Vocal Imitation. Front Psychol 2019; 10:1340. [PMID: 31244735 PMCID: PMC6579846 DOI: 10.3389/fpsyg.2019.01340] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 05/23/2019] [Indexed: 12/14/2022] Open
Abstract
There are many theories surrounding infant imitation; however, there is no research to our knowledge evaluating the reliability of listener perception of vocal imitation in prelinguistic infants. This paper evaluates intra- and inter-rater judgments on the degree of "imitativeness" in utterances of infants below 12 months of age. 18 listeners were presented audio segments selected from naturalistic recordings to represent in each case a parent vocal model followed by an infant utterance ranging from low to high degrees of imitativeness. The naturalistic data suggested vocal imitation occurred rarely across the first year, but strong intra- and inter-rater correlations were found for judgments of imitativeness. Our results suggest salience of the infant's vocal imitation despite its rare occurrence as well as active perception by listeners of the imitative signal. We discuss infant vocal imitation as a potential signal of well-being as perceived by caregivers.
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Affiliation(s)
- Helen L. Long
- Infant Vocalizations Laboratory, School of Communication Sciences and Disorders, University of Memphis, Memphis, TN, United States
| | - D. Kimbrough Oller
- Infant Vocalizations Laboratory, School of Communication Sciences and Disorders, University of Memphis, Memphis, TN, United States
- Konrad Lorenz Institute for Evolution and Cognition Research, Klosterneuburg, Austria
- Institute for Intelligent Systems, University of Memphis, Memphis, TN, United States
| | - Dale A. Bowman
- Department of Mathematical Sciences HL, University of Memphis, Memphis, TN, United States
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Yoo H, Buder EH, Bowman DD, Bidelman GM, Oller DK. Acoustic Correlates and Adult Perceptions of Distress in Infant Speech-Like Vocalizations and Cries. Front Psychol 2019; 10:1154. [PMID: 31191389 PMCID: PMC6548812 DOI: 10.3389/fpsyg.2019.01154] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 05/02/2019] [Indexed: 11/13/2022] Open
Abstract
Prior research has not evaluated acoustic features contributing to perception of human infant vocal distress or lack thereof on a continuum. The present research evaluates perception of infant vocalizations along a continuum ranging from the most prototypical intensely distressful cry sounds ("wails") to the most prototypical of infant sounds that typically express no distress (non-distress "vocants"). Wails are deemed little if at all related to speech while vocants are taken to be clear precursors to speech. We selected prototypical exemplars of utterances representing the whole continuum from 0 and 1 month-olds. In this initial study of the continuum, our goals are to determine (1) listener agreement on level of vocal distress across the continuum, (2) acoustic parameters predicting ratings of distress, (3) the extent to which individual listeners maintain or change their acoustic criteria for distress judgments across the study, (4) the extent to which different listeners use similar or different acoustic criteria to make judgments, and (5) the role of short-term experience among the listeners in judgments of infant vocalization distress. Results indicated that (1) both inter-rater and intra-rater listener agreement on degree of vocal distress was high, (2) the best predictors of vocal distress were number of vibratory regimes within utterances, utterance duration, spectral ratio (spectral concentration) in vibratory regimes within utterances, and mean pitch, (3) individual listeners significantly modified their acoustic criteria for distress judgments across the 10 trial blocks, (4) different listeners, while showing overall similarities in ratings of the 42 stimuli, also showed significant differences in acoustic criteria used in assigning the ratings of vocal distress, and (5) listeners who were both experienced and inexperienced in infant vocalizations coding showed high agreement in rating level of distress, but differed in the extent to which they relied on the different acoustic cues in making the ratings. The study provides clearer characterization of vocal distress expression in infants based on acoustic parameters and a new perspective on active adult perception of infant vocalizations. The results also highlight the importance of vibratory regime segmentation and analysis in acoustically based research on infant vocalizations and their perception.
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Affiliation(s)
- Hyunjoo Yoo
- Department of Communicative Disorders, The University of Alabama, Tuscaloosa, AL, United States
| | - Eugene H. Buder
- School of Communication Sciences and Disorders, The University of Memphis, Memphis, TN, United States
- Institute for Intelligent Systems, The University of Memphis, Memphis, TN, United States
| | - Dale D. Bowman
- Institute for Intelligent Systems, The University of Memphis, Memphis, TN, United States
- Department of Mathematical Sciences, The University of Memphis, Memphis, TN, United States
| | - Gavin M. Bidelman
- School of Communication Sciences and Disorders, The University of Memphis, Memphis, TN, United States
- Institute for Intelligent Systems, The University of Memphis, Memphis, TN, United States
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, United States
| | - D. Kimbrough Oller
- School of Communication Sciences and Disorders, The University of Memphis, Memphis, TN, United States
- Institute for Intelligent Systems, The University of Memphis, Memphis, TN, United States
- Konrad Lorenz Institute for Evolution and Cognition Research, Klosterneuburg, Austria
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