Object permanence

A major development is object permanence: understanding that an object continues to exist even when it cannot be seen. Piaget placed its emergence at around 8 months. Before this understanding develops, a hidden toy may no longer be treated as something that can be searched for; afterwards, the infant can recognise that it still exists behind the covering.

A major achievement is object permanence, the understanding that an object still exists when it cannot be seen. Piaget proposed that young infants initially lack this understanding: when a toy disappears, they behave as though it no longer exists. At around , searching for a hidden toy indicates that object permanence is developing.