Abstract
OBJECTIVE: With development, infants become increasingly responsive to the many attention-sharing cues of adults; however, little work has examined how this ability emerges in typical development or in the context of early autism spectrum disorder (ASD). This study characterized variation in the type of cue needed to elicit a response to joint attention (RJA) using the Dimensional Joint Attention Assessment (DJAA) during naturalistic play. METHOD: We measured the average redundancy of cue type required for infants to follow RJA bids from an experimenter, as well as their response consistency, in 268 infants at high (HR, n = 68) and low (LR, N = 200) familial risk for ASD. Infants were assessed between 8 and 18 months of age and followed up with developmental and clinical assessments at 24 or 36 months. Our sample consisted of LR infants, as well as HR infants who did (HR-ASD) and did not (HR-neg) develop ASD at 24 months. RESULTS: We found that HR and LR infants developed abilities to respond to less redundant (more sophisticated) RJA cues at different rates, and that HR-ASD infants displayed delayed abilities, identifiable as early as 9 months, compared to both HR-neg and LR infants. Interestingly, results suggest that HR-neg infants may exhibit a propensity to respond to less redundant (more sophisticated) RJA cues relative to both HR-ASD and LR infants. CONCLUSION: Using an approach to characterize variable performance of RJA cue-reading abilities, findings from this study enhance our understanding of both typical and ASD-related proficiencies and deficits in RJA development.