Answer:
Sensorimotor to preoperational stage
Step-by-step explanation:
During development, object permanence is one of the hallmark characteristics of the transition from the sensorimotor stage to the preoperational stage. Object permanence is the ability for a child to understand that even though an object may be hidden, it still exists and did not "disappear". Think about the peak-a-boo game. The reason it works on little babies is that they truly believe that you have disappeared whereas a child that is a bit older will realize that you are just hiding. Hope that helps :)