Proceedings of the Annual Meeting of the Cognitive Science Society

Shared book reading positively effects language development, yet the causal pathways of this relationship are not un-derstood. Evidence shows that the book complexity modulates caregiver talk, but the link between the book linguisticcomplexity and child syntactic development remains unclear (Noble, et al. 2017). This project describes the speech gen-erated during book reading to see how it differs from typical child-directed speech and whether the picture-book sentencecomplexity is present in the speech that children hear. 10 families with children aged 30-37 months (MBCDI raw vocab-ulary 350-675 out of 680 total) recorded 6-12 picture-book reading sessions in their homes. The books were controlledfor word length (short: 125 words vs long: 1472 words) and syntactic complexity according to the 8 categories analyzedin Montag (2019): complex (17 tokens) vs. simple (0-7 tokens). The caregiver and child speech syntactic complexitymodulation as a function of picture-book syntactic complexity will be discussed.