Proceedings of the Annual Meeting of the Cognitive Science Society

We investigated the role of socially contingent interactions between infants and their parents in shaping infants’ language development. This hypothesis is motivated by a broader theory that socially contingent interactions lead to a qualitative shift in infants’ understanding of the nature of words. We predicted that infants of ‘more contingent’ parents would experience this shift sooner and will have larger vocabularies (a proxy measure) than infants of ‘less contingent’ parents. In contrast to previous investigations, we evaluated the unique contribution of social contingency, separate from the effects of language input and attentional spotlighting. We annotated a longitudinal video-corpus of naturalistic parent-infant interactions when infants were 9 and 12 months to predict their vocabulary at 12 and 18 months. We showed that infants’ experience with social continency is significantly associated with receptive and productive vocabulary size and that these associations are separate from the effects of language input and attentional spotlighting.