Pii: S0163-6383(01)00061-3

This study investigated the associations of the quantity and quality of infant nondistress vocalization with maternal and infant social actions (smiling and gazing) during dyadic interaction. Thirteen infants and their mothers were observed weekly in a face-to-face interaction situation from 4 to 24 weeks. Results showed that the quantity (rate per minute) and quality (speech-likeness) of infant nondistress vocalization changed systematically with maternal smiling and gazing as well as with the infants’ own smiling and gazing. Infants produced more speech-like syllabic sounds when their mothers were smiling, when they were looking at their mothers’ faces, and when the infants themselves were smiling. Follow-up analysis revealed that the amount of infant speech-like syllabic sound was highest during Duchenne smiling (cheek-raise smiling), which is thought to be more emotionally positive than non-Duchenne smiling (smiling without cheek-raise). Sequential analysis further indicated that infants were more likely to produce speech-like syllabic sounds, following the onset of their smiling and gazing at mother and their mothers’ smiling as compared to nonspeech-like This research was supported by faculty research grants to Hui-Chin Hsu from the College of Family and Consumer Science, the University of Georgia, and the University of Georgia Research Foundation, and by grants to Alan Fogel from the National Institutes of Health (R01 HD21036), the National Institute of Mental Health (R01 MH48680 and MH57669), and the National Science Foundation (BN9006756). Portions of the data were presented at the International Conference on Infant Studies, April 1998, and the Human Development Conference, April 2000. The authors thank the mothers and infants who participated in the study, and the research assistants who helped with the project. * Corresponding author. Tel.: 1-706-542-2636; fax: 1-706-542-4489 E-mail address: [email protected] (H. Hsu). Infant Behavior & Development 24 (2001) 107–128 0163-6383/01/$ – see front matter © 2001 Elsevier Science Inc. All rights reserved. PII: S0163-6383(01)00061-3 vocalic sounds. These coordinative associations found within the child and between the dyad suggest that the speech quality of nondistress vocalization may be an index of positivity in dyadic face-to-face interactions during early infancy. © 2001 Elsevier Science Inc. All rights reserved.