Electronic Theses and Dissertations



Document Type


Degree Name

Doctor of Philosophy


Communication Sciences & Disorders

Committee Chair

Eugene Buder

Committee Member

Naomi Eichorn

Committee Member

Philip Pavlik

Committee Member

D. Kimbrough Oller


This dissertation investigates the development of pitch coordination between infants and mothers during the first year. The study contributes a longitudinal aspect to the small literature on this topic and introduces a new approach to understanding parent-infant interaction through the use of fine-grained acoustic analysis. Focusing exclusively on mutually-coordinated segments of interaction, acoustic measures examined pitch matching and other harmonic relationships between temporally contiguous utterances of the primary caregiver and infant. Fundamental frequency (fo) measurements were taken at turn exchanges, both at response boundaries and within overlapping vocalizations. Data was collected from 12 mother-infant dyads across two ages 3 months and 12 months. Additional measurements were taken from non-contiguous vocalizations, referred to as pseudo-interactions, to assess random baseline matching rates. Hypotheses predicted more frequent pitch matching in real interactions compared to pseudo-interactions, and greater pitch matching at 12 months compared to 3 months of age. It was also hypothesized that the direction of response (i.e. mother to infant or infant to mother) would play a role in the occurrence of pitch matching at 3 months but not at 12 months of age. Pitch matching occurred significantly more in real interactions than in pseudo-interactions and significantly more when the infant was 12 months. The direction of the response was not a significant factor. However, an interaction effect between age and direction of response could not be ruled out due to the limited power of the analysis. Secondary explorations examined the occurrence of overlap between ages and the role of harmonic tension (i.e. dissonance or consonance) between measured pitches. Overlap occurred more frequently at 3 months than at 12 months, which fits theoretical expectations for age effects in parent-infant turn exchanges. The secondary research questions related to harmonic tension did not yield significant differences.Findings are interpreted in terms of age-related changes in infant vocal control as well as the choice to measure only in mutually-coordinated interactions. Future directions include a study using closer age intervals as well as later ages, and a comparison study of pitch matching in coordinated and uncoordinated segments.


Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest