How infants learn (to walk): Transitions are a fundamental component of practice

Learning to walk-like learning any motor skill-requires practice. But what are the critical components of infants' natural practice regimen? Traditionally, researchers focus on practicing the target behavior (e.g., days since walk onset, number of steps/hr). However, part of what makes skills truly functional is the ability to enter the task space (here, transitions from nonupright to upright postures), produce and pause the target behavior (transitions between standing and walking), and use the behavior in varied contexts (e.g., walking from one surface to another and from one place to another). Thus, we expanded the concept of practice to include moment-to-moment, self-generated transitions that require rapid adaptations to ever-changing affordances. During 2 hr of spontaneous home activities, regardless of age, infants (13-, 18-, and 23-month-olds, N = 12 per age; half girls, half boys; 72% White, 28% Black, Asian, or mixed race; 83% non-Hispanic, 17% Hispanic; 94.4% college educated; living in urban city) generated immense numbers of transitions/hr (total M = 642, range = 153-1,179). Infants accumulated such large numbers of transitions for three reasons: (1) Infants continually pushed their limits; (2) bouts of walking, standing, sitting, and crawling were frequent (e.g., M = 206.2 walking bouts/hr) but brief in duration (e.g., M = 2.1 s per bout of walking); and (3) infants repeatedly revisited surfaces and places, regardless of home size and layout. Transitions are a unique form of variability that promote skill acquisition via practice adapting ongoing behaviors to variations in posture, tasks, and features of the environment. (PsycInfo Database Record (c) 2026 APA, all rights reserved).