Object Permanence

Object permanence is a foundational concept in infant cognition, referring to a child’s understanding that objects continue to exist even when they cannot be seen, heard, or touched.

This ability depends on the development of mental representations, or schemas, which allow the infant to retain the idea of the object in their mind.

For example, when a toy is hidden under a blanket, a child who has developed object permanence will search for it, knowing it still exists.

In contrast, infants who have not yet reached this stage may act as though the toy has vanished.

The emergence of object permanence is a key cognitive milestone. It typically occurs around 8 months of age.

According to Jean Piaget, the development of object permanence marks the transition from the sensorimotor stage to the preoperational stage. The sensorimotor stage is Piaget’s first stage of cognitive development, running from birth to about age two.

Simple games like peek-a-boo help illustrate and reinforce this emerging skill, making them valuable tools in early learning.

Why is object permanence important?

Developing object permanence offers several key benefits that support a child’s broader cognitive and emotional growth. This ability rests on the child’s growing mental representations, or schemas, of the world.

As part of brain development, the capacity for object permanence shows that memory, attention, and the neural pathways involved in reasoning and perception are becoming more advanced.

This is real developmental work.

This creates a cascade of benefits across emotional, cognitive, and language development. Children start to experience the world as stable and predictable, even when parts of it are briefly out of view.

• Emotional and Attachment: Caregivers feel more stable and predictable once a child understands they still exist when out of sight.
• Cognitive and Problem-Solving: Children learn to predict outcomes and act on the world in intentional ways.
• Spatial Awareness and Language: Tracking hidden objects builds the same reasoning children later use for spatial understanding and symbolic language.

Emotional and Attachment Benefits

Emotional attachment becomes more stable once a child understands that caregivers continue to exist even when they leave the room.

This realization significantly reduces separation anxiety and helps children feel more secure in their relationships. The child feels safer.

This link between cognition and emotion explains a pattern many parents notice. Separation anxiety often peaks between about 8 and 14 months, the same window in which infants first show clear search behavior for a fully hidden object.

Timing is not a coincidence.

At this stage, infants represent a caregiver as continuing to exist while out of the room. That is a real gain. They do not yet see that caregiver as someone who can be reliably found again after a long delay.

Understanding this timing helps parents make sense of why separation distress can appear so suddenly. It also explains why that distress eases as the child’s sense of the caregiver’s continued existence grows more secure.

Cognitive and Problem-Solving Benefits

Object permanence also sharpens thinking. Building on this emotional foundation, it enhances cognitive abilities in several ways.

Children develop an improved understanding of cause and effect, learning to predict outcomes based on their own actions.

For example, they begin to understand that a toy hidden under a blanket can be found again through purposeful searching.

Cause and effect just clicked.

This leads to stronger problem-solving skills as children realize they can act on the world in intentional ways. This same coordination of memory, intention, and action is why object-permanence tasks appear in standard infant assessments.

The link runs deep.

The Bayley Scales of Infant Development use them as one of the more reliable early markers of cognitive development. It also echoes Piaget’s account of this age: infants begin combining separate actions, like moving a barrier and reaching for a toy, into one purposeful sequence.

Spatial Awareness and Language Development

Object permanence also supports spatial awareness. It does the same for object tracking abilities.

These skills help children navigate their physical environment and understand relationships between objects in space.

Tracking an object across several hiding places calls on spatial reasoning. So does working out where an object must be without having seen it move, the same reasoning children rely on as they explore their surroundings.

Space and objects go together.

Finally, object permanence lays the groundwork for more complex cognitive abilities, particularly language acquisition.

It helps children understand that words can refer to things that are not immediately present, like a parent or a favorite toy. This creates the conceptual bridge needed for symbolic thinking and communication.

Words work the same way.

Inferring where a hidden object must be, without having seen it move, calls on a similar kind of reasoning. That same reasoning helps a child understand that a spoken word can stand for something not currently in view.

Help Your Child Develop Object Permanence

Rather than an all-or-none achievement, research suggests object permanence emerges gradually as a progression of knowledge and skills from reflexes to representation.

Caregivers can promote development through play allowing intention, cause-and-effect reasoning, and representational abilities to unfold.

Playing interactive games that involve temporarily hiding and revealing toys is an excellent way to help your child learn that objects still exist when out of sight.

Here are some easy activities:

• Play Peekaboo. Cover your face or hide a toy behind your hands, then reveal. Ask, “Where’s the toy?” before showing it again. This teaches object permanence skills.
• Hide Toys. Hide your child’s favorite toy under blankets or behind furniture. Encourage them to search for the hidden object, then celebrate when they find it. Retrieving hidden items promotes the understanding that unseen toys still exist.
• Read Hide & Seek Books. Books featuring lift-the-flap activities allow your child to actively engage with finding hidden objects on the page. Choose sturdy board books they can handle.
• Play Hunting Games. Have your child close their eyes while you hide a toy. Give warm praise when they successfully locate and retrieve the toy you hid. This makes learning object permanence concepts fun!

Playing interactive hiding games provides natural opportunities to develop your child’s understanding that objects continue existing separately from their own perception.

Have fun promoting this key cognitive skill!

What is an object permanence box and how is it used?

An object permanence box is an educational toy designed to help infants develop the understanding that objects continue to exist even when they are out of sight.

Typically, the box has a hole on the top and a tray or drawer at the bottom.

A small ball or object is placed into the hole, disappears briefly, and then reappears in the tray below.

How it’s used:

This tool is often used in Montessori environments and is ideal for infants around 6–12 months who are just beginning to grasp the idea of object permanence.

• During infant play, a caregiver or child drops a ball into the hole.

• The ball disappears briefly, then reappears in the tray below, encouraging the child to retrieve it.

• This repeated action reinforces the idea that objects are still there, even when not visible.

Why it’s helpful:

Often used in the Montessori method, the object permanence box supports both cognitive and physical development.

It encourages focused attention, early problem-solving, and hand-eye coordination.

Additionally, retrieving the ball strengthens fine motor skills. Infants practice grasping and movement control, skills essential for later tasks like feeding and writing.

As part of a well-rounded set of educational toys, the object permanence box combines learning and play in a way that aligns with natural developmental stages.

Using an object permanence box promotes:

• Infant cognition and mental representation.

• Search behavior and problem-solving skills.

• Early understanding of cause and effect.

Stages of Object Permanence

Piaget (1954) identified six stages in the development of object permanence. These stages represent a gradual progression from a lack of object permanence to a sophisticated understanding of objects and their movements:

Substage	Age	What happens
1. Reflexive schemes	0–1 month	No search behavior at all; sensory contact is the object.
2. Primary circular reactions	1–4 months	Brief visual pursuit of a vanishing object, but no search.
3. Secondary circular reactions	4–8 months	Reaches for a partially hidden object, but not a fully covered one.
4. Coordination of secondary circular reactions	8–12 months	First coordinated search for a fully hidden object, but produces the A-not-B error.
5. Tertiary circular reactions	12–18 months	Follows visible sequential displacements, searching where the object was last seen.
6. Invention of new means	18–24 months	Handles invisible displacements; object permanence is complete.

Birth to 4 Months: Initial Lack of Permanence

During the first two stages of sensorimotor development (0-4 months), infants perceive objects as fleeting sensory experiences, directly tied to their actions.

When an object disappears from their visual field, it ceases to exist for them. To them, it is simply gone. For instance, a newborn may show distress when the breast is removed but will not search for it, as if it has vanished entirely.

At this point, the world is a series of disconnected sensory images that appear and disappear based on the infant’s immediate actions.

Reflexes come first.

As early as the second day of life, infants seem to “seek” with their lips the breast that has escaped them. Similarly, infants as young as 3 days old will search for their thumbs that have brushed their mouths.

This suggests an early awareness of the continued existence of objects even when they are not in direct contact.

4 to 8 Months: Beginning of Permanence

During the third stage, infants begin to exhibit behaviors suggesting a rudimentary understanding of object permanence. 

Around 4 to 6 months old, infants will visually follow objects that move out of their reach and even attempt to grasp them with their hands.

This behavior shows a developing coordination between vision and touch. It also reflects a more active engagement with the object.

Around 5 to 7 months old, infants begin to remove obstacles blocking their view, engaging in a rudimentary form of hide-and-seek.

While this might seem to demonstrate object permanence, Piaget argued that it is more about extending the visual accommodation movement.

The infant is simply trying to re-establish visual contact, not demonstrating an understanding of the object’s continued existence behind the screen.

8 to 12 Months:  Practical Permanence

Between 8-12 months, a significant shift occurs. Infants now actively search for objects hidden behind screens, indicating a more developed understanding of object permanence.

They can remove obstacles to retrieve a hidden object, suggesting they understand its continued existence behind the barrier.

This stage is marked by the coordination of secondary schemas and their application to new situations. 

This means that infants can combine learned actions to achieve a goal, such as using their hand to move a cloth covering a toy.

However, this understanding is still limited. Infants struggle to grasp the concept of sequential displacements.

If an object is hidden in multiple locations, they often search in the place it was first hidden. This suggests they still link object permanence to specific locations rather than understanding its continuous existence across displacements.

 At this stage, the object is still understood in relation to specific actions and contexts, not as a fully independent entity

12 to 18 Months: Object Permanence in Perceived Displacements

Around 12-18 months, infants become capable of tracking visible sequential displacements. They will search for an object in the location where it was last seen, even if it was hidden multiple times.

This indicates that the object is now understood as a permanent entity that maintains its identity across movements within the child’s visual field.

However, challenges arise when displacements occur outside the field of direct perception.

If the infant doesn’t see the object being moved, their understanding falters, and they revert to searching in the last place they saw the object

18 to 24 Months: Complete Object Permanence

From 18 months onward, infants achieve a more complete understanding of object permanence, encompassing invisible displacements.

Representational thought develops, allowing infants to hold mental representations of unseen objects – demonstrating object permanence (Piaget, 1954; Wang et al., 2004).

Infants can now mentally represent the object’s movements, even those they haven’t directly witnessed.

This ability to reason about unseen events marks a significant step towards representational thought, as the child is no longer solely reliant on immediate sensory information.

They understand the object’s continuous existence and can deduce its location even after invisible displacements.

This stage coincides with the emergence of tertiary circular reactions. Infants now actively experiment with objects to discover their properties and the effects of different actions upon them.

For example, an infant might repeatedly drop different objects from various heights to observe the varying effects.

This experimentation contributes to a deeper understanding of object properties and their independent existence.

Blanket and Ball Study

How is object permanence tested in infants?

Object permanence is typically tested in infants using variations of the hidden object task, a method widely used in developmental psychology.

In this task, an object – such as a toy – is visibly placed under a cloth or behind a screen while the infant watches.

Researchers then observe the infant’s behavior to see if they attempt to retrieve the hidden object.

Infants who have developed object permanence will show clear search behavior, such as lifting the cloth or reaching behind the screen, indicating they understand the object still exists.

Aim:

Infants progress from a world where objects exist only in relation to their actions. They move toward a world where objects have an independent existence and can be mentally represented even when hidden.

The use of simple objects like balls and blankets allowed Piaget to create experimental scenarios that reveal the underlying cognitive processes involved in this development.

Piaget (1954) wanted to investigate at what age children acquire object permanence.

Method:

Piaget hid a toy under a blanket, while the child was watching, and observed whether or not the child searched for the hidden toy.

Piaget ran systematic variants of this procedure on his own three children, Jacqueline, Lucienne and Laurent. These included partially covering the object, hiding it under two cloths in succession, and hiding it inside a container that was then moved before being revealed under a different cover.

Searching for the hidden toy was evidence of object permanence.

The child’s ability to search for a hidden object, even after multiple displacements, indicates a mental representation of the object’s existence and location. Piaget assumed that the child could only search for a hidden toy if s/he had a mental representation of it.

Results:

When a ball or other desirable object is hidden under a blanket, infants under 8 months often do not attempt to retrieve it.

This lack of search behavior suggests that they do not yet understand that the object continues to exist when out of sight. To them, it’s as if the object has simply vanished.

A significant shift occurs around 8-9 months of age when infants begin to actively search for objects hidden under blankets. They start to understand that objects can exist independently of their own actions and are not simply annihilated when out of sight.

This is real progress.

However, their understanding of object permanence is still limited at this stage. They often fail to track the object’s movements and tend to search for it in its initial hiding place. This happens even after they have watched it get moved to a new location.

This behavior, termed the “A-not-B error,” suggests that infants still struggle to differentiate between the object and the specific location where they first found it.

Conclusion

Children around 8 months have object permanence because they can form a mental representation of the object in their minds.

The ability to represent objects mentally allows infants to start forming a sense of past, present, and future.

They can recall past events involving objects that are no longer present and anticipate future events based on their understanding of object permanence.

Evaluation:

Piaget assumed the results of his study occurred because the children under 8 months did not understand that the object still existed underneath the blanket. That is why they did not reach for it.

However, there are alternative reasons why a child may not search for an object rather than a lack of understanding of the situation.

The child could become distracted or lose interest in the object, lacking the motivation to search for it. Or the child simply may not yet have the physical coordination to carry out the motor movements needed to retrieve the object (Mehler & Dupoux, 1994).

Critical Evaluation

While Piaget’s work on object permanence has been immensely influential, his theory has faced some criticisms:

• Underestimation of Infants’ Abilities: Looking-time studies suggest infants develop some aspects of object permanence earlier than Piaget’s reaching tasks could detect.
• Emphasis on Motor Development: Critics argue cognitive understanding may precede the motor skills infants need to demonstrate it, such as reaching and grasping.
• Social and Cultural Influences: Piaget’s theory pays little attention to how caregiver interaction and cultural practices shape the pace of object-permanence development.

The A-not-B Error

The A-not-B error is one of the most famous findings in infant cognition.

An infant who has repeatedly retrieved a hidden toy from one location (A) continues to search there, even after watching it moved to a new location (B).

‘s location.

There are multiple interpretations for this error:

• Egocentric Spatial Understanding: Infants may still link locations to their own body rather than to objective points in space, so they associate the toy with where they previously found it (A).
• Limited Working Memory: Infants’ working memory for the new hiding place fades quickly, so they default back to the location tied to their past successful searches.
• Practical Action Schemas: Repeated success at A builds a strong action schema that can override the infant’s weaker, newer memory of the toy’s move to B.
• Prefrontal Maturation (Diamond, 1985): Diamond found the delay infants could tolerate before reaching correctly at B rose from near zero at 7.5 months to about 10 seconds by 12 months, tied to prefrontal-cortex maturation.
• Dynamic Field Theory (Thelen et al., 2001): Thelen and colleagues modeled the error as competition between current and remembered reach locations, and showed that changing the infant’s posture between trials abolishes the error.
• Social Re-Interpretation (Topál et al., 2008): Infants may misread the experimenter’s cues during the A trials as general information about “where the toy belongs,” and treat the B trial as an exception rather than a straightforward move. Removing eye contact from the experimenter sharply reduces the error.

Piaget’s own interpretation leaned toward practical action schemas and an incomplete differentiation between the object and the act of retrieving it.

Current research treats the A-not-B error as multiply determined: a mix of immature inhibitory control, motor habit, and interpretive factors, rather than a single failure of the object concept.

Bower and Wishart: Reaching in the Dark

Piaget’s search task asks a lot of a young infant: reaching, grasping, and pulling away a blanket, coordination that may not be available until around nine months of age.

Bower and Wishart (1972) asked whether a method that avoids this manual demand could reveal object permanence earlier than Piaget’s cloth-hiding task suggested.

The Bower and Wishart demonstration disproves Piaget’s strongest claim, rather than showing full adult-like object permanence in young infants. The sample was small, and the finding does not by itself reveal exactly what the infants were representing about the vanished object.

Violation of Expectation Research

A challenge to Piaget’s claims comes from a series of studies designed by Renee Baillargeon. She used a technique known as the violation of expectation (VOE) paradigm.

It exploits a simple fact. Infants tend to look longer at things they have not encountered before.

In a VOE experiment, an infant is first introduced to a novel situation. They are repeatedly shown this stimulus until they indicate, by looking away, that it is no longer new to them.

The logic is simple.

In Baillargeon et al.’s (1985, 1987) study, the habituation stimulus was a ‘drawbridge’ that moved through 180 degrees.

Baillargeon, Spelke, and Wasserman, aimed to assess object permanence in 5-month-old infants using a habituation paradigm.

This experiment tested the infants’ understanding of the solidity principle, the concept that solid objects cannot pass through each other.

Method:

A colored box was placed behind a screen that moved back and forth like a drawbridge. Infants were first habituated to the screen moving without the box present.

After habituation, a box was placed behind the screen, and the infants were shown two test events:

• Possible Event: The screen moved until it reached the box and stopped.
• Impossible Event The screen moved through the space occupied by the box, completing a 180-degree arc before returning to its starting position. The drawbridge appeared to pass through the box and ended up lying flat, and the box apparently disappeared.

The researchers reasoned that if the infants understood that the box continued to exist behind the screen, they should find the impossible event surprising, as it violated the solidity principle.

This surprise would manifest in longer looking times at the impossible event.

The logic works either way.

There was a simpler worry.

The researchers ran a control experiment to rule out the possibility that infants simply preferred the bigger, 180-degree movement itself. In it, the box was placed beside the screen, out of its path.

In this case, infants showed no preference for either the 180-degree or the 120-degree screen movement.

Results:

Baillargeon found that infants spent much longer looking at the impossible event.

She concluded that this indicated surprise on the infants’ part. They were surprised because they had expectations about the behavior of physical objects that the impossible event had violated.

In other words, the infants knew that the box still existed behind the drawbridge and, furthermore, that they knew that one solid object could not just pass through another.

The infants in this study were five months old, at which Piaget would say that such knowledge is beyond them.

Critical Evaluation

Many studies suggest infants as young as 2.5 months can represent hidden objects, using a violation-of-expectation (VOE) method.

In VOE studies, longer looking at an unexpected versus expected event provides evidence infants have an expectation, detect its violation, and are surprised (Baillargeon & Luo, 2002).

Not everyone agrees.

However, some have proposed “transient preference” accounts questioning these interpretations (Bogartz, Shinskey, & Speaker, 1997; Thelen & Smith, 1994).

These accounts agree on one thing. Familiarization trials, on this view, create superficial preferences for unexpected events, without any real expectation behind them.

For example, infants may build event-sequence predictions that unexpected events disrupt, or attend only to novel elements due to limited processing. Or they may simply prefer events that resemble unfinished familiarization processing. The jury is still out.

The debate centers on whether young infants truly represent hidden objects or just show transient preferences in VOE tasks. Resolving this has implications for understanding cognitive development in infancy.

Adaptive Process View

There is a debate about when infants achieve “object permanence” – knowing objects still exist when out of sight. The two main measures disagree.

In some tasks, even young infants show expectations suggesting they understand object permanence. Yet in other tasks, infants don’t retrieve hidden objects until around 8 months.

The traditional view is that early successes reflect having the object permanence concept, while failures reflect deficits in abilities to act on this knowledge.

An alternative “adaptive process” view sees infants’ knowledge as graded, embedded in behavior-generating mechanisms, and gradually strengthened with experience.

According to this view, different behaviors place differing demands on emerging knowledge representations.

The adaptive process view proposes that infants’ knowledge is graded rather than all-or-none (Munakata et al., 1997). Knowledge exists on a continuum that gradually strengthens over time through repeated experiences.

This knowledge is embedded within the neural mechanisms that generate observable behaviors (Thelen & Smith, 1994), rather than taking the form of abstract, explicit principles.

The adaptive process view proposes that infants’ knowledge is:

• Graded – Knowledge is not all-or-none. Instead, there are degrees of knowledge that strengthen gradually over time.
• Embedded – Knowledge is embedded within the mechanisms and neural systems that generate observable behavior. It does not take the form of abstract, explicit principles.
• Strengthened through experience – As infants accumulate experiences, the connections between relevant neurons are gradually strengthened. This serves to solidify internal representations of concepts like object permanence.

Different behaviors make different demands on available knowledge representations (Smith & Thelen, 1993). Some demand more than others.

For example, merely looking at an event relies only on weakly activated representations. Reaching for hidden objects, by contrast, requires stronger representations that can overcome conflicting perceptual information (Munakata et al., 1997).

Therefore, failures on some tasks do not necessarily indicate a complete lack of knowledge.

That is the key point.

Rather, success or failure is dependent on whether the existing state of knowledge representations is sufficient to drive that specific behavior in that specific context (Fischer & Bidell, 1991).

Over time, as connections strengthen through repeated experiences, behavior becomes increasingly flexible as infants become able to succeed across more varying situations and tasks.

Knowledge thus emerges gradually from the dynamics of neural systems adapting to make sense of the environment (Thelen & Smith, 1994).

Overall Critical Evaluation

Half a century of research has both confirmed and revised Piaget’s account of object permanence. His core finding, that infants pass through an orderly sequence of six sensorimotor stages, has held up well across later studies.

What has not held up is his claim that infants under 8 months have no representation of hidden objects at all.

Studies that measure looking time, rather than manual search, find structured expectations about hidden objects months earlier than Piaget’s timetable allowed (see Bower and Wishart, and Baillargeon, above).

The gap between the two timetables comes down to method. Manual search asks a lot of a young infant: remembering the hiding place, inhibiting an old response, and coordinating a reach-and-displace action.

Looking only requires noticing that something unexpected happened. This reveals knowledge months before the infant can act on it.

The A-not-B error illustrates the same point. Rather than a single failure of the object concept, current research treats it as multiply determined. Immature inhibitory control, motor habit, and how infants interpret an adult’s cues all play a part, as discussed above.

Violation-of-expectation findings are influential but not beyond challenge. Longer looking at an “impossible” event shows that infants notice something unexpected.

It does not by itself prove they hold a rich, adult-like concept of the object. Critics have proposed that some of this looking reflects simple perceptual novelty rather than a violated expectation about solidity.

The current mainstream view treats infant knowledge as graded and distributed rather than all-or-none. Infants have real but weak expectations about objects from early in life, and development is the gradual strengthening and coordination of those expectations with memory, attention, and motor skill.

Contemporary Research

Bremner, Slater, and Johnson (2015) reviewed four decades of research on object permanence for the journal Child Development Perspectives. The picture has changed.

Their review drew together violation-of-expectation experiments, eye-tracking studies of infants watching objects become occluded, brain-activity recordings, and reaching studies, to ask when and how object knowledge develops.

They concluded that infants show sensitivity to object persistence from the earliest ages researchers can test. Development, in their account, is not the sudden appearance of an object concept out of nothing.

Instead, it is the gradual integration of early perceptual persistence with the motor, executive, and inferential skills infants need to act on what they already sense.

This reframing has moved the field beyond a simple yes-or-no question, “does the infant have object permanence?” Researchers now study perceptual, cognitive, and motor development as separate but connected timetables that come together across the first two years.

The framework now informs current infant-cognition experiments and models of infant learning.

Applications: Assessment, Diagnosis and AI

Object-permanence tasks also do real work outside the lab. They appear in every major infant developmental scale, including the Uzgiris-Hunt Ordinal Scales of Psychological Development and the Bayley Scales of Infant Development.

Their value lies in their sensitivity to the 8-24 month window, and in how closely they track the emergence of representational thought.

Object permanence also enters the picture in atypical development.

Children on the autism spectrum most often reach object-permanence milestones on schedule. This is in contrast to theory-of-mind and joint-attention milestones, which are frequently delayed in autism.

Psychologist Simon Baron-Cohen has argued that this pattern is itself informative: autism appears to selectively affect the theory-of-mind system, while leaving domain-general object cognition largely intact.

Machines face a version of the same problem.

Object tracking has also become a target for artificial intelligence and robotics. Modern object-tracking systems, including deep-learning multi-object trackers and video-object-segmentation networks, are tested on their ability to keep track of an object’s identity across occlusion.

The idea is the same.

Developmental-robotics researchers have even used Piaget’s six-substage sequence as a design guide for infant-like learning agents. The human infant is treated as proof that a robust solution to the occlusion problem is possible.

Cross-Species and Cross-Cultural Evidence

Object permanence is not uniquely human. Researchers have applied Piaget’s sensorimotor scale, or adaptations of it, to a wide range of species.

Great apes, including chimpanzees, orangutans, gorillas and bonobos, succeed on Piaget’s most demanding invisible-displacement task, the hallmark of the final substage.

Dogs and cats succeed on visible displacements but tend to fail invisible ones.

Not every species succeeds equally.

Some corvids and the African grey parrot succeed on invisible displacements at levels comparable to great apes. This comparative pattern fits the idea that tracking hidden objects has real survival value for species that must track prey, competitors and social partners across occlusion.

Culture tells a related story.

The developmental sequence Piaget described also appears broadly universal across cultures. Cross-cultural studies generally support the same order of the six substages in widely different settings. What varies is not the order but the pace, with modest differences linked to child-rearing practices and opportunities for object exploration.

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