Multimodal coordination of vocal and gaze behavior in mother-infant dyads across the first year of life.

Research examining mother-infant interactions indicates a close connection between vocal and gaze behavior. The present longitudinal study examined the development of both intraindividual and dyadic coordination of vocal and gaze behavior in mother-infant dyads at 3, 6, 9, and 12 months. Mother and infant vocalization and gaze behavior during in-home toy play interactions were coded on a moment-by-moment basis and coordinations (i.e., co-occurrences and sequences of behavior) were compared to randomized baselines in order to determine whether coordinate exceeded chance levels. Infants timed their own vocalizations with gaze to partner's face and inhibited vocalizations during gaze to objects at greater than chance levels across the first year. Mother's displayed above-chance intraindividual coordination of vocalizations and gaze to partner's face and objects. Mothers and infants demonstrated dyadic coordination of vocalizations and gaze at above-chance levels, but developmental change and leading-following dynamics varied based on gaze location (i.e., face vs. object). Results emphasize the importance of examining coordination across communication modalities and of considering bidirectional influences on mother and infant vocal and gaze behavior.