On a near-daily basis, walking infants retrieve desired objects from their environments. This largely involves learning to control and coordinate their upper and lower limbs (e.g., hands, arms, legs), but also requires planning and problem-solving. Most research on how these skills develop has focused on experienced infant walkers, but we know little about early motor-cognitive coordination in new walkers. In the current study, we developed a whole-body object-retrieval task to examine how newly-walking infants coordinate their hands and bodies to problem-solve. One pilot infant was observed in 5 consecutive weekly sessions, beginning one month after walking onset. At each session, we assessed the infant’s hand preference while seated using a reach-and-grasp task. Next, she completed an object-retrieval task, in which she retrieved objects from two different drawers of a custom-modified infant-sized dresser. For each of 8 object-retrieval trials, we coded how the infant used her hands and body strategically to open the drawer and retrieve the object (e.g., hand and body location in relation to the dresser, and specific hand and posture usage when opening the drawer and retrieving the object). The infant exhibited a more stable hand preference during both tasks over time, and did not frequently use her secondary hand for postural support during object retrieval. When retrieving the object from the lower drawer, the infant required more attempts and postural adjustments to successfully retrieve the object compared to the upper drawer. The infant adopted various inappropriate postures for the lower drawer before successful retrievals (e.g., sitting and blocking the drawer with her body), but consistently stood while retrieving the object in upper-drawer trials. Studying learning in action could clarify overlaps between motor and cognitive development by demonstrating how newly-walking infants adjust their motor behaviors concurrently with problem-solving strategies to achieve their goals.
