Routine-Noun Index and Maternal Working Hours in Infant Statistical Learning

Infant language acquisition reflects both innate mechanisms, like statistical learning (SL), and the structure of daily life. Routine activities provide repeated linguistic input, and maternal work hours may modulate the quantity and consistency of this input. This study examined the associations between the routine-noun index (a proxy for routine-linked lexical experience) and maternal working hours and SL in 108 infants (24-27 months old 53% female). Higher routine-noun index predicted lower SL accuracy in between-category novel word-referent learning trials, especially when maternal working hours were low, highlighting a trade-off between the benefits of scripted talk and the need for linguistic variability. Higher maternal working hours may offer more diverse language experiences from alternative caregivers, potentially reducing the negative effects on SL. No other demographic factors were significantly related to SL or vocabulary size. These findings suggest that a higher routine-noun index may co-occur with input that is more predictable and context-bound, thereby restricting exposure to varied input, which could relate to SL performance. Further research is needed to clarify these associations.