Object permanence is the term used to describe the awareness that objects continue to exist even when they are no longer visible.

Jean Piaget conducted experiments with infants which led him to conclude that this awareness was typically achieved at eight to nine months of age, during the sensorimotor stage of cognitive development. Infants before this age are too young to understand object permanence, which explains why infants at this age do not cry when their mothers are gone. "Out of sight, out of mind."

In more recent years, the original Piagetian object permanence account has been challenged by a series of infant studies suggesting that much younger infants do have a clear sense of objects persisting when out of sight.

See also

• Developmental psychology
• psychology