Word Learning from Infant-Directed Speech in Autistic Children - PROJECT SUMMARY Caregivers frequently use infant-directed speech (IDS), commonly known as “parentese”, when speaking to young children. Compared to adult-directed speech (ADS), IDS is typically characterized by greater pitch variation, longer duration, and louder volume. IDS facilitates early language development in typically developing (TD) children. However, we do not know whether the facilitative effect of IDS on language learning can be generalized to clinical populations such as autistic children given that core autism features (e.g., sensory and social communication differences) may interact with how they process and learn from IDS. Most autistic children do not reach age-appropriate language ability even if they receive timely early intervention. Determining if autistic children can learn language from IDS, a common way language input is provided to young children, is a critical first step toward understanding whether language input needs to be adjusted to optimize their language development. The overall objective of this research is to determine whether IDS facilitates novel word learning in autistic children and to investigate if the effect of IDS is conditional upon input factors (recorded IDS vs live IDS presented in social interaction) and child factors (extreme responses to auditory input, social motivation). In Aim 1, we will use a video-based word learning paradigm to determine the effect of recorded IDS on novel word learning in autistic children compared to language-matched TD peers. In Aim 2, we will focus on the effect of live IDS on novel word learning: an experimenter will teach children two novel words, presented in live IDS or live ADS, during social interaction. In Aim 3, we will examine whether child factors (extreme responses to auditory input, social motivation) explain variability in word learning accuracy from recorded IDS and live IDS in the autistic group. Children’s extreme responses to auditory input (including hyper- and hypo-responsiveness) and social motivation will be measured using caregiver questionnaires and will be used to predict word learning accuracy from recorded IDS (Aim 1) and live IDS (Aim 2) in the autistic group. Our central hypothesis is that both input and child factors will impact the effect of IDS on word learning in autistic children. On a group level, autistic children may find both recorded and live IDS overstimulating and thus not benefit as much from IDS as compared to TD children. On an individual level, we predict that extreme auditory responsiveness will be negatively associated with word learning from recorded and live IDS whereas social motivation will be positively associated with word learning from live IDS. Findings from this work will (a) provide theoretical implications into how children’s sensory and social profiles interact with the relationship between IDS and word learning and (b) illuminate whether IDS may be leveraged in clinical settings to support language development in autistic children. Data derived from this project will serve as pilot data for future R01 proposals that investigate the relationships among early IDS exposure, attention to IDS, and vocabulary outcomes in autistic children and whether IDS or attention to IDS in autistic children is malleable to improve language outcomes in this population.
