Individuals diagnosed with autism spectrum disorder (ASD) demonstrate atypical development of receptive language and object category knowledge. Yet, little is known about the emerging relation between these two competencies in this population. The present study utilized a gaze-based paradigm, the visual array task (VAT), to examine the relation between object label and object category knowledge in a sample of toddlers at heightened genetic risk for developing ASD. Eighty-eight toddlers with at least one typically developing older sibling (low-risk; LR) or one older sibling diagnosed with ASD (high-risk; HR) completed the VAT at 17 (LR n = 20; HR n = 27) and/or 25 months of age (LR n = 42; HR n = 22). Results indicated that the VAT was both a sensitive measure of receptive vocabulary as well as capable of reflecting gains in category knowledge for toddlers at genetic risk of developing ASD. Notably, an early emerging difference in the relation between target label knowledge and category knowledge for the groups was observed at 17 months of age but dissipated by 25 months of age. This suggests that while the link between receptive vocabulary and category knowledge may develop earlier in LR groups, HR groups may potentially catch up by the second year of life. Therefore, it is likely meaningful to consider differences in category knowledge when conceptualizing the receptive language deficits associated with HR populations. During language learning, typically developing children are sensitive to the common features of category members and use this information to generalize known object labels to newly encountered exemplars. The inability to identify similarities between category members and/or utilize this information when learning new object referents at 17 months of age may be a potential mechanism underlying the delays observed in HR populations.
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