Object permanence

Object permanence is the understanding that objects continue to exist even when they cannot be observed (seen, heard, touched, smelled or sensed in any way). This is a fundamental concept studied in the field of developmental psychology, the subfield of psychology that addresses the development of infants' and children's social and mental capacities. There is not yet scientific consensus on when the understanding of object permanence emerges in human development.

Jean Piaget, the Swiss psychologist who first studied object permanence in infants, argued that object permanence is one of an infant's most important accomplishments, as, without this concept, objects would have no separate, permanent existence. In Piaget's theory of cognitive development, infants develop this understanding by the end of the "sensorimotor stage," which lasts from birth to about two years of age. Piaget thought that an infant's perception and understanding of the world depended on their motor development, which was required for the infant to link visual, tactile and motor representations of objects. According to this view, it is through touching and handling objects that infants develop object permanence.

Child development expert Jean Piaget conducted experiments that collected behavioral tests on infants. Piaget studied object permanence by observing infants' reactions when a favorite object or toy was presented and then was covered with a blanket or removed from sight. Object permanence is considered to be one of the earliest methods for evaluating working memory. An infant that has started to develop object permanence might reach for the toy or try to grab the blanket off the toy. Infants that have not yet developed this might appear confused. Piaget interpreted these behavioral signs as evidence of a belief that the object had ceased to exist. Reactions of most infants that had already started developing object permanence were of frustration because they knew it existed, but didn't know where it was. However, the reaction of infants that had not yet started developing object permanence was more oblivious. If an infant searched for the object, it was assumed that they believed it continued to exist.

Piaget concluded that some infants are too young to understand object permanence, which explains why they do not cry when their mothers are gone ("out of sight, out of mind"). A lack of object permanence can lead to A-not-B errors, where children reach for a thing at a place where it should not be. Older infants are less likely to make the A-not-B error because they are able to understand the concept of object permanence more than younger infants. However, researchers have found that A-not-B errors do not always show up consistently. They concluded that this type of error might be due to a failure in memory or the fact that infants usually tend to repeat a previous motor behavior.

...
Wikipedia