Pre-linguistic infants employ complex communicative loops to engage mothers in social exchanges and repair interaction ruptures

Language has long been identified as a powerful communicative tool among humans. Yet, pre-linguistic communication, which is common in many species, is also used by human infants prior to the acquisition of language. The potential communicational value of prelinguistic vocal interactions between human infants and mothers has been studied in the past decades. With 120 dyads (mothers and 3 or 6-month-old infants), we used the classical Still-Face Paradigm (SFP) in which mothers interact freely with their infants, then refrain from communication (Still Face, SF), and finally resume play. We employed innovative automated techniques to measure infant and maternal vocalization and pause, and dyadic parameters (infant response to mother, joint silence and overlap) and the emotional component of Infant Directed Speech (e-IDS) throughout the interaction. We showed that : (1) during the initial free play mothers use longer vocalizations and more e-IDS when they interact with older infants and (2...