Crawling and walking infants encounter objects differently in a multi-target environment.

From birth, infants move their bodies in order to obtain information and stimulation from their environment. Exploratory movements are important for the development of an infant's understanding of the world and are well established as being key to cognitive advances. Newly acquired motor skills increase the potential actions available to the infant. However, the way that infants employ potential actions in environments with multiple potential targets is undescribed. The current work investigated the target object selections of infants across a range of self-produced locomotor experience (11- to 14-month-old crawlers and walkers). Infants repeatedly accessed objects among pairs of objects differing in both distance and preference status, some requiring locomotion. Overall, their object actions were found to be sensitive to object preference status; however, the role of object distance in shaping object encounters was moderated by movement status. Crawlers' actions appeared opportunistic and were biased towards nearby objects while walkers' actions appeared intentional and were independent of object position. Moreover, walkers' movements favoured preferred objects more strongly for children with higher levels of self-produced locomotion experience. The multi-target experimental situation used in this work parallels conditions faced by foraging organisms, and infants' behaviours were discussed with respect to optimal foraging theory. There is a complex interplay between infants' agency, locomotor experience, and environment in shaping their motor actions. Infants' movements, in turn, determine the information and experiences offered to infants by their micro-environment.