Multisensory integration and maternal sensitivity are related to each other and predictive of expressive vocabulary in 24-month-olds.

Multisensory integration (MSI) is the ability to combine temporally synchronous, amodally specified sensory information to create rich, coordinated perceptual experiences. In early development, attention is directed toward such information in both social contexts (e.g., human speakers) and nonsocial contexts (e.g., multimodal toys). Parenting behaviors may support and sculpt multisensory integration by providing children with opportunities to experience amodally specified information (e.g., contingent face-to-face interactions). This study examined (a) whether 24-month-olds' MSI abilities differed as a function of context (social or nonsocial) and competition for attention (low or high), (b) whether MSI predicted expressive vocabulary, and (c) whether maternal sensitivity (MS) was related to both MSI and language. A total of 32 24-month-olds were tested in the Multisensory Attention Assessment Protocol, an audiovisual task that presents laterally positioned social/nonsocial events with and without a central distractor. Their mothers completed the MacArthur-Bates Communicative Development Inventories and participated in a free-play period with their children for MS coding. Results showed MSI in both social and nonsocial conditions (i.e., toddlers paid more attention to the "match"), but only the ability to maintain attention to the social match was related to toddlers' expressive vocabulary. In addition, MS was positively correlated with toddlers' expressive language and social MSI performance. Taken together, the pattern of results shows important relations between emerging integration abilities and parenting behavior as well as the ability of both factors to positively influence word learning during early toddlerhood.