Baby nicholas watches as his mother leaves the room, but he does not cry because he understands that his mother still exists even though he cannot see her. this is an example of behavior in which of piaget's substages?

The sixth (and last) substage: mental combination.

Explanation:

Baby Nicholas has developed what Piaget called object permanence. This happens in the last substage of the sensorimotor stage, which is when the infant is between 18 and 24 moths old. It’s the stage of mental combination. During this stage the child starts developing symbolic thought and can make mental representation of objects. It is also during this period that babies have object permanence. This means that they can understand that an object exists even if they cannot see it.

i feel as if they would both catch on before to long because they would see them to frequent