Baby Hugh enjoys playing with his dad's keys, but when his dad takes them away, Hugh does not search for them. Piaget would say that is because Hugh does not understand .

object permanence

Explanation: It is through touching and handling objects that infants develop object permanence.

Object permanence is the understanding that objects continue to exist even when they cannot be seen, heard, touched, smelled or sensed in any way.

Hugh does not search for them because he understands that his dad's keys are not gone forever even though he can't see them.