What Is Object Permanence?

mother playing with baby
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Object permanence is the knowledge that an object continues to exist even when it can no longer be seen, heard, or perceived in any other way. First proposed and studied by renowned Swiss development psychologist Jean Piaget in the mid-1900s, object permanence is considered a key developmental milestone in the first two years of a child’s life.

Key Takeaways: Object Permanence

  • Object permanence is the ability to understand that an object still exists even when it can no longer be perceived in any way.
  • The concept of object permanence was studied by Swiss psychologist Jean Piaget, who proposed a series of six stages specifying when and how object permanence develops during the first two years of life.
  • According to Piaget, children first begin to develop an idea of object permanence at around 8 months old, but other studies suggest the ability starts at a younger age.


Piaget developed a stage theory of childhood development, which consisted of four stages. The first stage, called the sensorimotor stage, takes place from birth to approximately 2 years old and is when babies develop object permanence. The sensorimotor stage consists of six substages. At each of the substages, a new achievement in object permanence is expected.

To detail the substages in the development of object permanence, Piaget conducted simple studies with his own children. In these studies, Piaget hid a toy under a blanket while the infant watched. If the child searched for the hidden toy, it was seen as an indication of object permanence. Piaget observed that in general children were around 8 months old when they started to search for the toy.

Stages of Object Permanence

Piaget’s six substages in the achievement of object permanence during the sensorimotor stage are as follows:

Stage 1: Birth to 1 Month

Right after birth, infants have no concept of anything outside themselves. At this earliest substage, they experience the world through their reflexes, the reflex of sucking in particular.

Stage 2: 1 to 4 Months

Starting at around 1 month old, children start to learn through what Piaget called “circular reactions.” Circular reactions happen when an infant chances on a new behavior, like thumb-sucking, and then attempts to repeat it. These circular reactions involve what Piaget referred to as schemas or schemes — patterns of action that help infants understand the world around them. Infants learn to use multiple different schemes in circular reactions. For example, when a child sucks their thumb, they are coordinating the action of sucking with their mouth with their hand movements.

During Stage 2, infants still have no sense of object permanence. If they can no longer see an object or individual, they may look for a moment to where they last saw it, but they won’t attempt to find it. At this point in development, the saying "out of sight, out of mind" applies.

Stage 3: 4 to 8 Months

At around 4 months, babies start to observe and interact more with their surrounding environment. This helps them learn about the permanence of things outside themselves. At this stage, if something leaves their line of sight, they will look where the object fell. Also, if they put an object down and turn away, they can find the object again. Further, if a blanket covers part of a toy, they can find the toy. 

Stage 4: 8 to 12 Months

During Stage 4, true object permanence starts to emerge. At around 8 months old, children can successfully find toys completely hidden under blankets. Yet, Piaget found a limitation to babies’ new sense of object permanence at this stage. Specifically, although an infant could find a toy when it was hidden at point A, when the same toy was hidden at point B, infants would again look for the toy at point A. According to Piaget, infants at Stage 4 are unable to follow displacements to different hiding places.

Stage 5: 12 to 18 Months

At Stage 5, infants learn to follow the displacement of an object as long as the infant can observe the movement of the object from one hiding place to another. 

Stage 6: 18 to 24 Months

Finally, at Stage 6, infants can follow displacements even if they don’t observe how a toy moves from hidden point A to hidden point B. For example, if a ball rolls under a sofa, the child can infer the trajectory of the ball, enabling them to look for the ball at the end of the trajectory instead of the beginning where the ball disappeared.

Piaget suggested that it’s at this stage that representational thought emerges, which results in the ability to imagine objects in one’s mind. The ability to form mental representations of things they can’t see results in infants’ development of object permanence, as well as an understanding of themselves as separate and independent individuals in the world.

Challenges and Critiques

Since Piaget introduced his theory on the development of object permanence, other scholars have provided evidence that this ability actually develops earlier than Piaget believed. Psychologists speculate that Piaget’s reliance on infants’ reaching for a toy led him to underestimate the child’s knowledge of individual objects, because it overemphasizes infants' underdeveloped motor skills. In studies that observe what children look at, instead of what they reach for, infants appear to demonstrate an understanding of object permanence at younger ages. 

For example, across two experiments, psychologist Renée Baillargeon showed infants screens that rotated towards objects in back of them. As they rotated, the screens concealed the objects, but babies still expressed surprise when the screens didn't stop moving when they expected them to because the object should have forced the screens to stop. The results showed that infants as young as 7 months old can understand the properties of hidden objects, challenging Piaget’s ideas about when object permanence first starts developing in earnest.

Object Permanence in Non-Human Animals

Object permanence is an important development for humans, but we’re not the only ones who develop the ability to understand this concept. Research has shown that higher mammals, including apes, wolves, cats, and dogs, as well as some species of birds, develop object permanence. 

For instance, in one study, researchers tested cats and dogs’ object permanence with tasks that were similar to those used to test the ability in infants. When the reward was only a hidden toy, neither species managed to complete all the tasks, but they were successful when the tasks were adjusted to make the reward hidden food. These findings indicate that cats and dogs have completely developed object permanence.


  • Baillargeon, Renée. “Young Infants’ Reasoning About the Physical and Spatial Properties of a Hidden Object.” Cognitive Development, vol. 2, no. 3, 1987, pp. 179-200. http://dx.doi.org/10.1016/S0885-2014(87)90043-8
  • Crain, William. Theories of Development: Concepts and Applications. 5th ed., Pearson Prentice Hall. 2005.
  • Doré, Francois Y., and Claude Dumas. “Psychology of Animal Cognition: Piagetian Studies.” Psychological Bulletin, vol. 102, no. 2, 1087, pp. 219-233. http://dx.doi.org/10.1037/0033-2909.102.2.219
  • Fournier, Gillian. “Object Permanence.” Psych Central, 2018. https://psychcentral.com/encyclopedia/object-permanence/
  • McLeod, Saul. “The Sensorimotor Stage of Cognitive Development.” Simply Psychology, 2018. https://www.simplypsychology.org/sensorimotor.html
  • Triana, Estrella, and Robert Pasnak. “Object Permanence in Cats and Dogs.” Animal Learning & Behavior, vol. 9, no. 11, 1981, pp. 135-139.
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Vinney, Cynthia. "What Is Object Permanence?" ThoughtCo, Dec. 6, 2021, thoughtco.com/object-permanence-4177416. Vinney, Cynthia. (2021, December 6). What Is Object Permanence? Retrieved from https://www.thoughtco.com/object-permanence-4177416 Vinney, Cynthia. "What Is Object Permanence?" ThoughtCo. https://www.thoughtco.com/object-permanence-4177416 (accessed May 28, 2023).