This study aimed to investigate how infants' object interactions changed during locomotor development, particularly concerning affordance perception. In this longitudinal study, we observed infants' daily activities in a daycare center for one year and examined their activities involving thin cloths in the room. Locomotor status and infants' activities were divided into several action categories. When they were crawlers or cruisers, the infants frequently engaged in stationary activities such as “object exploration” and “peek-a-boo” with their caregivers. After becoming independent walkers, most infants engaged more often in “wearing” & “carrying”. During the observation periods, the frequencies of social interactions were stable; however, after they could walk, most infants initiated social interactions more frequently. These findings suggest that locomotor development may be critical to the development of affordance perception of objects and that these developmental trends encourage infants to instigate social interactions.
