Behaviors emerge, in part, from the interplay of infant abilities and caregiver–infant interactions. Cross-cultural and developmental studies suggest caregiver handling and positioning influence infant development. In this prospective, longitudinal study, the effects of 3 weeks of enhanced handling and positioning experiences provided to 14 infants versus control experiences provided to 14 infants at 2 months of age were assessed with follow-up through 15 months of age. Behaviors in prone were immediately advanced. Short-term advancements occurred in multiple behaviors, including prone, head control, reaching, and sitting behaviors. Longer term advancements, up to 12 months after the experience period, occurred in object transfer, crawling and walking behaviors. This suggests broad and long-lasting changes can arise via brief periods of change in caregiver–infant interactions.