Effect of carrying objects on walking characteristics and language abilities in 13- and 24-month-olds.

Learning to walk leads to an increase in language abilities; however, the underlying mechanisms accounting for this relation remain unclear. Investigating the quality of early gait control may offer some insights. The purpose of this study was to (a) quantify how 13-month-olds (n = 39; 39% male) and 24-month-olds (n = 39; 59% male) adapt gait based on task (carrying vs. not carrying objects), object characteristics (size and weight), and environmental constraints (free play vs. structured) and to (b) assess how changes in gait relate to language abilities. To assess gait differences, Midwestern participants engaged in a free-play session and structured task with toys varying in size and weight while wearing motion capture markers. Parents completed an age-appropriate version of the MacArthur-Bates Communicative Development Inventory to measure language abilities. During free play, 13-month-olds were selective when choosing what to carry basing their decisions on object weight over size and adapting their upper-body control based on weight. Neither age group modified lower-body gait due to object characteristics but did reorganize their upper-body control. These upper-body adaptations were dependent upon age, environmental context, and task. Importantly, more mature upper-body control and more time spent in motion during free play were significant predictors of 13-month-olds' language abilities. Gait improvements may offer new opportunities for language learning; increased stability may allow young children to better focus on the objects, potentially enhancing word learning opportunities. Early movements and functional behavior during free play may be important predictors underlying the association between the onset of walking and language development. (PsycInfo Database Record (c) 2023 APA, all rights reserved).