Project Summary/Abstract Severe-to-profound hearing loss during infancy is a risk factor for poor spoken language development, even after early cochlear implantation. A key to acquiring spoken language is developing the ability to learn associations between words and their referents (i.e., novel word learning). Many young children with cochlear implants (CIs) struggle to learn novel words and those who do tend to have poor language outcomes. We know that successful word learning in normal-hearing, typically developing children depends in large part on the real-time quantitative and qualitative properties of parent-child social interactions, such as the synchrony between when parents name objects and children’s attention to those objects. Our central hypothesis is that the atypical auditory experiences of CI users influence naming synchrony, affecting word-learning opportunities and language outcomes. This proposed project is built upon an already established collaboration between MPI Chen Yu, who has developed a multi-method, multi-modal approach involving high-resolution data of eye, head, and hand movements to characterize the micro-structure of social coordination, and MPI Derek Houston, who has investigated speech perception and novel word learning in children with cochlear implants for over 18 years. We will collect multiple streams of data from both parents and children as they play with each other and as parents spontaneously name novel objects, and investigate the role of congenital deafness and subsequent cochlear implantation on the quantity and quality of naming synchrony and explore potential micro- and macro- level mechanisms that may account for differences in naming synchrony between dyads with NH children and those with children who use CIs (Aim 1). We will also determine and the effects of naming synchrony on word learning in CI users and NH children (Aim 2). Finally, the proposed project will assess language outcomes six months later and determine the extent to which differences in naming synchrony predict language outcomes after accounting for concurrent auditory processing and language abilities (Aim 3). To our knowledge, this is the first effort to investigate real-time micro-level properties of social interactions in children with CIs, which will lead to new insights into real-time parent-child interactions and language outcomes after implantation, and will potentially lead to new hypotheses for intervention studies involving precise feedback on parent-child coordination.