Moment-to-moment cascades: Infants' real-time locomotor posture structures opportunities for joint object play with caregivers.

-the view that development in one domain can induce change in another-provide unique flexibility for researchers to examine relations among multiple behaviors. Research using this theoretical framework has demonstrated that changes in infant locomotor development are met with concomitant changes in infants' interactions with objects and caregivers. However, little is known about how infants' real-time locomotor actions organize these larger associations across developmental time. This study mapped the progression of one potential moment-to-moment cascade pathway linking changes in infant locomotion, access to objects and caregivers, and joint object play. We observed 30 infant-caregiver dyads during three monthly sessions across the transition to walking ( = 11.98 months, range = 8.74-14.86) and examined whether and how infants' real-time locomotor actions shaped the unfolding of the cascade. Infants moved more frequently in supported upright postures (i.e., cruising, supported walking) compared to crawling at the prewalking session and compared to walking at walk onset. However, infants preferred to walk after spending 1 month as walkers. Regardless of how they moved, infants regularly encountered objects and caregivers during everyday exploration. But there was an effect of locomotor posture on joint object play. Specifically, dyads were most likely to engage in object play after supported upright bouts at the prewalking and walk onset sessions, but at the final walking session, they were most likely to do so after walking bouts. Taken together, this in-depth examination of moment-to-moment cascades highlights the contributions of the many timescales that drive developmental processes. (PsycInfo Database Record (c) 2024 APA, all rights reserved).