Responding to joint attention as a developmental catalyst: Longitudinal associations with language and social responsiveness.

Joint attention (JA), infants' ability to engage in triadic attention with another person and a separate object or event, emerges in infancy. Responding to joint attention (RJA) develops earlier than initiating joint attention (IJA) and may benefit from a reconceptualization from a competence to a skill that varies in performance. Investigating associations between RJA performance and important skills of toddlerhood such as language, social responsiveness, and executive function (EF) in typically developing samples can better elucidate how RJA may serve as a developmental precursor to later dimensional skills, with implications for both typical and atypical development. Here, 210 (82% White) infants completed the Dimensional Joint Attention Assessment (DJAA), a naturalistic play-based assessment of RJA, at 8-15 months. At 16-38 months social responsiveness, verbal ability, and EF were assessed. Multilevel models showed that DJAA scores were associated with later verbal abilities and parent-reported social responsiveness. Exploratory analyses showed trend-level associations between RJA and EF. Results establish the content validity of the DJAA as a measure of RJA, and longitudinal associations with later verbal ability and social responsiveness. Future work should examine EF emergence and consolidation, and RJA and later EF associations.