Object Permanence

Object permanence is the understanding that an object continues to exist even when it cannot currently be sensed, a fundamental concept studied in developmental psychology, though researchers have not reached scientific consensus on exactly when it emerges in human development. The Swiss psychologist Jean Piaget, who first studied the concept in infants, argued that it is one of an infant's most important accomplishments, since without it objects would have no separate, permanent existence in the infant's mind; in his theory of cognitive development, infants build this understanding by the end of the sensorimotor stage, which lasts from birth to about two years of age, largely through touching and handling objects to link visual, tactile and motor representations together.