Locomotion development and infants' object interaction in a day-care environment.

This longitudinal study examined the relationship between the development of locomotion and infants' interaction with others involving objects. Observations took place in a multi-person situation-a day-care class-for one-year-old infants for 1 year. The study participants were 13 infants and 7 caregivers (all Japanese). Frequencies of infants' manual contact with objects and moving before contact with them did not differ according to locomotion developmental level. However, infants who began walking engaged in more social interactions than those who were cruising or crawling. Throughout all locomotor developmental periods, social interactions increased in frequency when more caregivers were present. As infants began to walk, they moved more prior to social interactions, had more frequent bidirectional and triadic social interactions, and moved and interacted more often with others during a single object episode. These results suggest that crawlers' engagement with objects is relatively object-oriented, while for walkers, locomotion seems to be driven by social stimuli. Infants who have begun to walk moved among caregivers and peers in a multi-person environment and developed more elaborated social interactions through objects.