The Pointing-Vocal Coupling Progression in the First Half of the Second Year of Life

This study investigated the development of the pointing-vocal coupling system. We were interested in the infants' behavior to attune prosody with pointing intentions. Twenty-five children were involved at 12, 15, and 18 months of age in an experimental procedure devised to elicit imperative and declarative pointing. Pointing, vocality associated with pointing, and the prosody of that vocality were analyzed. A significant increase in the coupling of pointing and vocality was observed from 12 to 15 months, and in the ability to differentiate prosody with respect to the intention of the gesture from 15 to 18 months. Also, the infants who pointed declaratively at 12 months were likely to couple declarative pointing with vocality at 15 months, and the infants who coupled at 15 months were likely to differentiate prosody by the pointing intention at 18 months. Results suggest that the match between prosody and pointing intentions emerges gradually during the first half of the second year of life. They also show a relationship between earlier and later pointing-vocal coupling, and a role for declarative communication in promoting that progression. Overall, our study supports the view of intentional communication as a time-based and context-based developmental process.