Ordinary Interactions Challenge Proposals That Maternal Verbal Responses Shape Infant Vocal Development Purpose This study tested proposals that maternal verbal responses shape infant vocal development, proposals based in part on evidence that infants modified their vocalizations to match mothers' experimentally manipulated vowel or consonant–vowel responses to most (i.e., 70%–80%) infant vocalizations. We tested the proposal in ordinary rather than experimentally manipulated interactions. ... Research Article
Research Article  |   October 17, 2017
Ordinary Interactions Challenge Proposals That Maternal Verbal Responses Shape Infant Vocal Development
 
Author Affiliations & Notes
  • Mary K. Fagan
    Department of Communication Sciences and Disorders, Chapman University, Irvine, CA
  • Kate N. Doveikis
    Department of Communication Science and Disorders, University of Missouri, Columbia
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication. ×
  • Correspondence to Mary K. Fagan: mfagan@chapman.edu
  • Editor: Julie Liss
    Editor: Julie Liss×
  • Associate Editor: Maria Grigos
    Associate Editor: Maria Grigos×
Article Information
Development / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   October 17, 2017
Ordinary Interactions Challenge Proposals That Maternal Verbal Responses Shape Infant Vocal Development
Journal of Speech, Language, and Hearing Research, October 2017, Vol. 60, 2819-2827. doi:10.1044/2017_JSLHR-S-16-0005
History: Received January 5, 2016 , Revised July 20, 2016 , Accepted May 27, 2017
 
Journal of Speech, Language, and Hearing Research, October 2017, Vol. 60, 2819-2827. doi:10.1044/2017_JSLHR-S-16-0005
History: Received January 5, 2016; Revised July 20, 2016; Accepted May 27, 2017

Purpose This study tested proposals that maternal verbal responses shape infant vocal development, proposals based in part on evidence that infants modified their vocalizations to match mothers' experimentally manipulated vowel or consonant–vowel responses to most (i.e., 70%–80%) infant vocalizations. We tested the proposal in ordinary rather than experimentally manipulated interactions.

Method Response-based proposals were tested in a cross-sectional study of 35 infants, ages 4 to 14 months, engaged in everyday interactions in their homes with their mothers using a standard set of toys and picture books.

Results Mothers responded to 30% of infant vocalizations with vocal behaviors of their own, far fewer than experimentally manipulated response rates. Moreover, mothers produced comparatively few vowel and consonant–vowel models and responded to infants' vowel and consonant–vowel vocalizations in similar numbers. Infants showed little evidence of systematically modifying their vocal forms to match maternal responses in these interactions. Instead, consonant–vowel vocalizations increased significantly with infant age.

Conclusions Results obtained in ordinary interactions, rather than response manipulation, did not provide substantial support for response-based mechanisms of infant vocal development. Consistent with other research, however, consonant–vowel productions increased with infant age.

Acknowledgments
We thank Kerry Beasley, Amanda Garner, Lauren Martin, Renae Mattson, Kate McDevitt, Leah Miener, Courtney Nachtsheim, and Margaret Hill, for assistance in data coding, and Amanda Millett, whose work on the project also contributed to her master's thesis project. We also thank the families for their participation.
A portion of the data was presented at the 2015 meeting of the Missouri Speech-Language-Hearing Association.
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