object permanence
object permanence, the understanding that objects continue to exist outside one’s sensory experience. Its emergence is a major milestone in child cognitive development and signals the ability to form mental representations of objects and events.
According to Swiss psychologist Jean Piaget, the emergence of object permanence is the main landmark of the sensorimotor stage of development. If an infant’s toy is hidden from view, an infant who has developed object permanence will understand that the toy still exists and may attempt to look for it. By contrast, an infant without object permanence may become confused or upset in the same scenario, not understanding that the toy is still there; to the infant, it no longer exists.
Although object permanence was originally thought to emerge at about 8 to 9 months of age, further research has suggested that infants as young as 3.5 months old may possess some form of object permanence. Similar to other milestones, the emergence of object permanence may occur at different times in different children because of differing rates of development. Hiding and reshowing toys, using pop-up books, and playing games, including peek-a-boo, may help a baby practice and develop the cognitive skill.
Sometimes a lack of object permanence is incorrectly attributed to attention-deficit/hyperactivity disorder (ADHD). In fact, difficulties with remembering the placement or existence of objects in those with ADHD are related to deficits in working memory.
Origins
The development of object permanence was first addressed by Piaget in his influential book La Construction du réel chez l’enfant (1950; The Construction of Reality in the Child, 1954). On the basis of a series of experiments, Piaget proposed that object permanence emerges over the course of six stages in the first two years of an infant’s life. In the first two stages, from birth to about 4 months, infants see the world as a series of images without permanence and explore the world through reflexes and early habits. In the third stage, from about 4 to 8 months, they begin to perform intentional actions and thereby establish a more solidified experience of the world; at this stage, however, they do not look for objects outside their sensory realm.
Piaget posited that the beginnings of object conception emerge in the fourth stage, from 8 to 12 months, when infants begin to understand causality of action and search for objects that have disappeared. The fifth stage, from 12 to 18 months, is characterized by trial-and-error actions, which demonstrate children’s understanding of the permanence of objects that they actively observe being hidden but not those where the occlusion process occurs outside their field of perception. The sixth stage occurs between 18 and 24 months of age, when children are able to detect the displacement of hidden objects, signaling the ability to form mental representations of items and full development of object permanence.
Criticisms of Piaget’s theory
Although Piaget’s studies and observations were successfully replicated by others, his conclusions on the development of object permanence eventually came under scrutiny. For example, his conclusion that infants who fail to look for a hidden object lack object permanence was criticized by his contemporaries, who pointed to factors such as distraction, loss of interest, or lack of physical capability as feasible alternative explanations. In addition, a substantial body of research has provided evidence that the foundations of object permanence emerge at a much younger age than Piaget originally suggested. Indeed, some studies have found evidence for the phenomenon in infants as young as 3.5 months old. While the results of some of these studies have been subject to differing interpretations, together they suggest a significantly more complex picture of object permanence development than initially conceptualized by Piaget.
Object permanence in other species
Species other than humans also exhibit evidence of some form of object permanence. Dogs, cats, birds, and primates can solve item displacement tasks that require abilities consistent with Piaget’s fourth and fifth stages of object permanence development. Reportedly, African gray parrots, parakeets, and other species of parrot as well as chimpanzees, orangutans, and other apes have even displayed evidence of object permanence that has developed through all six of Piaget’s stages.