Walking and Talking

Developmental researchers typically focus on only one domain of expertise. However, children’s development typically does not adhere to researchers’ siloed expertise. Instead, multiple psychological domains develop simultaneously and changes in one domain can cascade into developmental changes in domains far afield from the original accomplishment. This experiment focuses on the developmental relations between walking and talking. Learning to walk allows infants to explore the environment in new ways. Compared with crawling, walking infants go more places, see more of the surrounds, and access more distal toys for play. We test whether the changes instigated by walking have a cascading effect on infants’ language experiences. The central hypothesis is that walking prompts a developmental cascade, wherein: (1) walkers explore a wider variety of places and objects than crawlers; (2) enhanced exploration elicits different forms of language input from caregivers; and (3) differences in language input are related to infants’ receptive and productive vocabularies. Infants—half crawlers, half walkers—and their caregivers play together with toys in two conditions: (1) toys dispersed throughout a large playroom (high incentive to locomote); and (2) toys clustered in a pile (high incentive to remain stationary). We predict a walking status × condition interaction: Walkers will locomote more and access more toys than crawlers in the dispersed condition; in turn, caregivers will spontaneously respond with more diverse language input to walkers. However, when toys are clustered, crawlers and walkers will produce similarly low amounts of locomotion and similarly frequent interactions with toys, and caregivers will respond with similar language inputs to infants.