Object permanence and conservation | AQA A-Level Psychology Revision

For 7182 specification, first teach in September 2025

AQA A-Level Psychology | Free Revision Notes

Estimated study time: 60 minutes

Object permanence and conservation demonstrate how children’s understanding changes during cognitive development. These Object permanence and conservation A-Level Psychology revision notes explain how infants begin representing objects that are no longer visible and how older children learn that quantity remains unchanged despite changes in appearance.

Both abilities are characteristics of Piaget’s stages of intellectual development and must be understood through the wider processes of schemas, assimilation, accommodation and equilibration. AQA explicitly includes object permanence and conservation within Piaget’s account of cognitive development.

Learning Objectives 🎯

By the end of this revision page, you should be able to:

• Define object permanence.

• Explain how Piaget investigated object permanence.

• Explain the A-not-B error.

• Define conservation and describe different conservation tasks.

• Explain how centration, irreversibility, decentration and reversibility affect conservation.

• Apply Piaget’s concepts to unfamiliar developmental scenarios.

Revision Notes 📚

Object permanence and conservation overview

Object permanence and conservation occur at different points in Piaget’s stage theory.

Ability	Piagetian stage	Approximate age
Object permanence	Sensorimotor stage	Develops at approximately 8 to 9 months
Conservation	Concrete operational stage	Develops from approximately 7 years

The abilities concern different forms of understanding.

• Object permanence concerns whether an unseen object continues to exist.

• Conservation concerns whether a quantity stays the same when its appearance changes.

Both involve moving beyond immediate perception.

A child with object permanence understands:

“I cannot see the object, but it still exists.”

A child who can conserve understands:

“The quantity looks different, but it is still the same.”

Object permanence

What is object permanence?

Object permanence is the understanding that an object or person continues to exist even when it cannot currently be seen, heard or touched.

For example:

A toy is covered with a blanket. An infant with object permanence understands that the toy remains beneath the blanket.

Object permanence requires a mental representation of the hidden object.

A mental representation is an internal image or understanding of something that is not currently available to the senses.

Object permanence during the sensorimotor stage

Piaget placed the development of object permanence within the sensorimotor stage, which lasts from birth to approximately 2 years.

During this stage, infants learn mainly through:

• Sensory experience.

• Physical movement.

• Repeated actions.

• Trial and error.

• Interaction with objects.

Early in the stage, knowledge is closely tied to what the infant can currently perceive.

Later, infants become able to represent objects mentally.

This transition is an important change because the infant’s understanding is no longer restricted entirely to immediate sensory experience.

The relationship between this ability and Piaget’s wider stage theory is explored in sensorimotor cognitive development.

Before object permanence

Piaget suggested that a young infant may behave as though a hidden object no longer exists.

For example:

1. An infant is shown an attractive toy.

2. The toy is completely covered with a cloth.

3. The infant does not search for it.

4. Attention moves elsewhere.

Piaget interpreted this failure to search as evidence that the infant lacked a mental representation of the unseen toy.

This does not mean the infant consciously thinks:

“The toy has stopped existing.”

Instead, Piaget argued that the infant’s current cognitive system cannot represent the object independently of direct perception.

Developing object permanence

At approximately 8 to 9 months, infants begin searching for hidden objects.

For example:

1. The infant watches a toy being placed beneath a cloth.

2. The infant reaches towards the cloth.

3. The infant removes it.

4. The infant retrieves the toy.

Piaget interpreted this behaviour as evidence of object permanence.

The infant must understand that:

• The toy continues to exist.

• It remains in a particular location.

• Removing the cloth will make it visible again.

AQA’s 2021 mark scheme identifies Piaget’s covered-toy procedure and the infant’s search as the main evidence he used to place object permanence at approximately 8 or 9 months.

Object permanence as a developing ability

Object permanence does not necessarily appear in one complete step.

An infant may initially:

• Search for a partly covered object.

• Search for a completely covered object.

• Make errors when the object changes location.

• Later track more complex movements of hidden objects.

The representation becomes increasingly stable and independent of the infant’s most recent actions.

Partially hidden objects

An infant may retrieve an object when part of it remains visible before successfully retrieving a completely covered object.

A partly visible object provides a strong perceptual clue.

A fully hidden object requires the infant to rely more strongly on mental representation.

People permanence

The same general idea can be applied to people.

An infant gradually learns that a parent or carer continues to exist when they:

• Leave the room.

• Move behind a door.

• Cover their face.

• Are temporarily out of sight.

The development of this understanding helps explain why games such as peekaboo become predictable and enjoyable.

Piaget’s hidden-object task

The basic procedure

Piaget’s procedure can be organised into four stages.

1. The researcher attracts the infant’s attention with a toy.

2. The infant watches while the toy is covered.

3. The researcher observes whether the infant searches.

4. Searching is interpreted as evidence of object permanence.

The dependent measure is therefore usually:

• Whether the infant searches.

• Where the infant searches.

• How accurately the object is retrieved.

Applying the procedure

Consider the following scenario:

A researcher shows nine-month-old Eva a rattle. Eva watches as the researcher places the rattle under a cloth. Eva immediately removes the cloth and reaches for the rattle.

A developed answer would state:

• Eva demonstrates object permanence.

• She understands that the rattle continues to exist while hidden.

• Her search suggests that she possesses a mental representation of the rattle.

• This ability is characteristic of later sensorimotor development.

Failure to search

Consider a second scenario:

Four-month-old Ben watches a toy being covered but does not attempt to retrieve it.

Piaget might conclude that:

• Ben has not yet developed object permanence.

• His understanding is tied to immediate sensory information.

• Once the toy is no longer visible, he does not represent it as continuing to exist.

However, a careful evaluation would recognise that failure to search could also result from:

• Limited motor control.

• Lack of motivation.

• Poor attention.

• Memory demands.

• Tiredness.

This is one reason later psychologists developed methods that did not require infants to retrieve an object.

The A-not-B error

What is the A-not-B error?

The A-not-B error occurs when an infant repeatedly searches for a hidden object in its original location, even after seeing it moved to a new location.

The typical procedure involves two hiding places:

• Location A.

• Location B.

The procedure

1. The researcher hides a toy at location A.

2. The infant retrieves it from A several times.

3. The infant then watches the toy being hidden at location B.

4. The infant searches at A rather than B.

The object is now at B, but the infant repeats the previously successful response.

Piaget’s interpretation

Piaget interpreted the error as evidence that the infant’s object representation remained incomplete.

The infant’s understanding was influenced by:

• The repeated action of searching at A.

• The previous reward of finding the object at A.

• The motor schema associated with location A.

The infant did not yet represent the hidden object independently enough to update its location accurately.

The role of schemas

The infant has developed a successful action schema:

Lift the cover at A → find the toy

After the object moves, the schema no longer matches reality.

The infant needs to accommodate their understanding by representing the toy’s new location.

This links object permanence with schema adaptation and cognitive conflict.

Alternative explanations of the A-not-B error

The error might also reflect limitations involving:

• Working memory.

• Inhibiting a previously rewarded response.

• Attention.

• Planning a new movement.

The infant may understand that the toy still exists while struggling to control where they search.

The A-not-B error therefore does not necessarily show a complete absence of object permanence.

Applying the A-not-B error

Ten-month-old Theo finds a toy under the left-hand cloth four times. Theo then watches the toy being placed under the right-hand cloth but reaches towards the left.

A strong explanation would state:

• Theo makes the A-not-B error.

• Location A is the left-hand cloth, where he has previously found the toy.

• Location B is the right-hand cloth, where the toy is now hidden.

• Theo repeats the previously successful search response.

• This suggests that his representation of the object’s changing location is not yet fully developed.

Object permanence and symbolic thought

Object permanence contributes to the development of symbolic thought.

Once an infant can represent an absent object, they can begin to understand that:

• A word can refer to an unseen object.

• A picture can represent a real person.

• An object can be remembered when it is not present.

• An action can be imitated after a delay.

These abilities help prepare the child for the pre-operational stage, where language, images and pretend play become increasingly important.

Deferred imitation

Deferred imitation occurs when a child copies behaviour after a delay, when the original model is no longer present.

This requires the child to retain a mental representation of the observed action.

It reflects the same broad developmental shift involved in object permanence:

understanding can continue when the original stimulus is absent

Evaluating Piaget’s object-permanence task

Strength: an observable behavioural measure

Piaget used a clear behavioural response:

• Searching.

• Reaching.

• Retrieving.

The procedure does not depend on an infant explaining their understanding verbally.

This is valuable because preverbal infants cannot answer direct questions about whether an object still exists.

Strength: the procedure can be replicated

The hidden-object task can be repeated using:

• Similar objects.

• Standard hiding locations.

• Infants of different ages.

• Consistent instructions.

This allows psychologists to compare findings and investigate developmental change.

Limitation: motor ability may affect performance

Searching for a hidden object requires the infant to:

• Reach.

• Remove a cover.

• Coordinate movement.

• Maintain the object’s location in memory.

A young infant may understand that the object exists while lacking the motor control needed to retrieve it.

Piaget may therefore have underestimated cognitive competence by measuring behavioural performance.

Limitation: motivation may affect searching

An infant may fail to search because:

• The toy is not sufficiently attractive.

• The infant is tired.

• Attention has shifted.

• The child is anxious in the research setting.

Failure to search does not necessarily mean the infant believes the object has ceased to exist.

Limitation: the task includes several cognitive demands

Successful retrieval may require:

• Object permanence.

• Memory for the hiding place.

• Focused attention.

• Motor planning.

• Inhibition of another response.

A poor result cannot be attributed with certainty to object permanence alone.

Baillargeon’s challenge

Baillargeon used violation-of-expectation research to investigate infants’ understanding of hidden objects without requiring physical retrieval.

Infants as young as 2 to 3 months looked longer at events that appeared physically impossible than at possible events.

This suggests that some knowledge of hidden objects may develop earlier than Piaget proposed. AQA mark schemes explicitly contrast Piaget’s estimate of around 8 months with Baillargeon’s evidence from much younger infants.

Baillargeon’s explanation and specific experiments are covered fully in early knowledge of the physical world.

Caution when interpreting looking time

Longer looking may indicate:

• Surprise.

• Interest.

• Novelty.

• A perceptual difference.

It does not necessarily prove that the infant understands why an event is impossible.

Piaget’s search task and Baillargeon’s looking-time method may therefore measure different aspects of infant cognition.

Conservation

What is conservation?

Conservation is the understanding that a quantity or property remains unchanged despite a transformation in its appearance.

A child who can conserve understands that quantity remains constant when:

• Objects are spread apart.

• A substance is reshaped.

• Liquid is poured into a differently shaped container.

The transformation changes the appearance, but not the underlying quantity.

AQA’s June 2023 mark scheme defines conservation through properties such as number, mass and volume remaining constant despite changes in appearance.

Conservation and developmental stages

Piaget associated failure of conservation with the pre-operational stage, approximately 2 to 7 years.

Children typically begin succeeding during the concrete operational stage, from approximately 7 years.

The transition involves changes in reasoning, including the development of:

• Decentration.

• Reversibility.

• Identity.

• Compensation.

Types of conservation

Piaget investigated several forms of conservation.

Type of conservation	What remains unchanged?	Typical transformation
Number	Number of objects	One row is spread out
Liquid volume	Amount of liquid	Liquid is poured into a differently shaped container
Mass	Amount of material	A ball of modelling clay is reshaped
Length	Length of an object	Objects are repositioned
Area	Amount of space covered	Objects are rearranged
Weight	Weight of an object	Material changes shape

For A-Level answers, the clearest examples are usually:

• Number.

• Liquid.

• Mass.

The standard conservation task

Conservation tasks usually contain three stages.

Stage 1: Establish equality

The child sees two equal quantities.

For example:

• Two identical rows of counters.

• Equal liquid in identical glasses.

• Two equal balls of modelling clay.

The researcher checks that the child agrees they are equal.

Stage 2: Transformation

The researcher changes the appearance of one quantity.

For example:

• One row of counters is spread out.

• Liquid is poured into a taller glass.

• One ball of clay is rolled into a sausage shape.

The transformation occurs in full view of the child.

Stage 3: Post-transformation question

The child is asked whether the two quantities remain the same.

A conserving child understands that the quantity is unchanged.

A non-conserving child judges the quantity from its new appearance.

Conservation of number

Procedure

The child is shown two rows containing the same number of counters.

Initially, the counters are aligned:

● ● ● ● ●● ● ● ● ●

The researcher then spreads one row apart:

● ● ● ● ●● ● ● ● ●

The child is asked whether both rows still contain the same number.

Pre-operational response

A pre-operational child may say that the longer row contains more.

This response demonstrates:

• Centration on length.

• Failure to consider spacing.

• Dependence on visual appearance.

• Lack of reversibility.

Concrete operational response

A conserving child may explain:

• “They still have the same number.”

• “You only spread them out.”

• “None were added or removed.”

• “You could move them back.”

These explanations demonstrate logical operations rather than reliance on appearance.

Conservation of liquid

Procedure

The child sees equal amounts of liquid in two identical glasses.

The researcher pours the liquid from one glass into a taller, thinner container.

The child is asked whether the amount of liquid remains equal.

Pre-operational response

The child may claim that the taller glass contains more liquid.

The child focuses on:

• Height.

The child fails to consider:

• Width.

• The fact that nothing was added.

• The possibility of reversing the transformation.

Concrete operational response

A conserving child understands that the amount remains the same because:

• The taller glass is narrower.

• No liquid was added or removed.

• The liquid could be poured back into the original glass.

Conservation of mass

Procedure

The child is shown two equal balls of modelling clay.

The researcher changes one ball into a long, thin shape.

The child is asked whether the amount of clay is still the same.

Pre-operational response

The child may say that the longer shape contains more clay.

The child focuses on its length and ignores the reduced thickness.

Concrete operational response

A conserving child understands that:

• The same clay remains present.

• Nothing was added or removed.

• The long shape could be rolled back into a ball.

Why pre-operational children fail conservation

Piaget explained conservation failure through several related cognitive limitations.

Centration

Centration is the tendency to focus on one noticeable aspect of a situation while ignoring other relevant dimensions.

Examples include focusing only on:

• Length in a row-of-counters task.

• Height in a liquid task.

• Length in a clay task.

A pre-operational child may be unable to coordinate height and width simultaneously.

Irreversibility

Irreversibility is difficulty mentally reversing a transformation.

For example, the child cannot easily imagine:

• Moving the counters back together.

• Pouring the liquid into the original glass.

• Rolling the clay back into a ball.

If the child could reverse the transformation mentally, they would recognise that the original quantity would be restored.

Dependence on appearance

Pre-operational thinking is strongly influenced by immediate visual information.

A taller liquid level looks like more.

A longer row looks like more.

The child has not yet learned to separate:

• Appearance.

• Underlying quantity.

Limited understanding of identity

The child may fail to recognise that the material itself has not changed.

A conserving child understands:

• It is the same liquid.

• They are the same counters.

• It is the same piece of clay.

Nothing has been added or removed.

Why concrete operational children succeed

Decentration

Decentration is the ability to consider more than one dimension of a problem.

For example, the child considers:

• Height and width.

• Length and spacing.

• Length and thickness.

This allows the child to move beyond the most visually striking feature.

Reversibility

Reversibility is the ability to mentally undo a transformation.

A child can reason:

“If you poured the liquid back, it would look the same as before.”

This provides a logical reason for conservation.

Identity

The child understands that the substance or set remains identical.

For example:

• No counters were added or removed.

• No water was added or removed.

• No clay was added or removed.

Compensation

Compensation is the understanding that a change in one dimension can be balanced by a change in another.

For example:

“The liquid is taller, but the glass is also thinner.”

The increased height is compensated for by reduced width.

Explanations used by conserving children

A child may justify conservation through several forms of reasoning.

Explanation	Example
Identity	“It is the same water.”
Reversibility	“You can pour it back.”
Compensation	“This glass is taller, but it is thinner.”
No addition or subtraction	“You did not add any counters.”

These explanations provide stronger evidence of understanding than a correct answer alone.

A child could guess that the quantities are equal.

A reasoned explanation demonstrates the cognitive process behind the answer.

Applying conservation to developmental tasks

Application example 1: conservation of number

Five-year-old Sofia sees two rows of six buttons. The researcher spreads one row out, and Sofia says that the spread-out row now has more buttons.

A developed explanation would state:

• Sofia fails conservation of number.

• She is likely to be thinking pre-operationally.

• She centres on the increased length of the row.

• She ignores the greater spacing between the buttons.

• She does not recognise that no buttons were added or removed.

• She cannot mentally reverse the transformation.

Application example 2: conservation of liquid

Eight-year-old Raj says that two glasses still contain the same amount after liquid from one glass is poured into a taller, thinner glass. Raj explains that the liquid could be poured back.

A developed explanation would state:

• Raj demonstrates conservation of liquid volume.

• His explanation shows reversibility.

• He can mentally undo the transformation.

• He is not misled by the height of the liquid.

• This reasoning is characteristic of the concrete operational stage.

Application example 3: conservation of mass

Ella says that a long clay sausage contains more clay than the original ball because it reaches farther across the table.

A developed explanation would state:

• Ella fails conservation of mass.

• She centres on the length of the clay.

• She ignores the reduced thickness.

• Her judgement is dominated by appearance.

• She does not yet demonstrate decentration or reversibility.

Conservation does not develop simultaneously

A child may succeed in one type of conservation before another.

For example, a child may conserve:

1. Number.

2. Length.

3. Mass.

4. Weight.

5. Volume.

This gradual pattern is sometimes described as horizontal décalage.

The term refers to different abilities based on a similar logical principle developing at different times.

This creates a challenge for a rigid stage account.

If one general concrete operational structure appears at approximately seven, psychologists might expect conservation tasks to be mastered at the same time.

Different performance across tasks suggests that:

• Experience matters.

• Task complexity varies.

• Development may be gradual.

• Knowledge may be specific to particular contexts.

Evaluating Piaget’s conservation research

Strength: innovative research

Piaget developed practical ways of investigating children’s reasoning.

The conservation tasks revealed not only whether children answered correctly but also:

• Which dimensions they noticed.

• How they justified an answer.

• How thinking changed with age.

This helped establish cognitive development as an important area of psychological research.

Strength: standardised and replicable procedures

The tasks use clearly structured procedures:

1. Establish equality.

2. Transform one quantity.

3. Ask the conservation question.

The same procedure can be repeated with children of different ages.

The June 2023 examiner report noted that successful evaluation often identified the replicability created by Piaget’s standardised procedures.

Strength: educational applications

Conservation tasks can help teachers identify how children understand quantity.

Practical activities involving:

• Water.

• Measuring containers.

• Counters.

• Modelling materials.

may allow children to explore transformations and develop more sophisticated schemas.

AQA’s 2023 mark scheme recognises the educational value of specialist play materials such as water and measuring cups.

Limitation: repeated questioning

In a standard conservation task, the child is asked:

1. Whether the quantities are equal before the transformation.

2. Whether they are equal after the transformation.

The child may assume:

“The adult asked again, so my first answer must no longer be correct.”

The child may change their answer because of the social demands of the task, not because they lack conservation.

McGarrigle and Donaldson’s naughty teddy study

McGarrigle and Donaldson used a more child-friendly conservation procedure.

A “naughty teddy” accidentally changed the arrangement rather than the researcher deliberately transforming it.

More young children gave conserving answers.

This suggests that children under seven may possess greater conservation ability than Piaget’s original findings indicated.

AQA’s 2023 mark scheme identifies the naughty-teddy research as evidence that child-friendly methods reveal conservation earlier.

Why accidental transformation matters

When the researcher deliberately changes the arrangement, the child may think the change must be important.

When a teddy changes it accidentally, the transformation appears irrelevant.

The child may therefore answer based on quantity rather than trying to interpret the adult’s intention.

Limitation: language demands

Terms such as:

• More.

• Same.

• Amount.

• Number.

• Less.

may be interpreted differently by young children.

A child may understand the quantity but misunderstand:

• The wording.

• What comparison is required.

• Whether the researcher is asking about appearance.

Limitation: performance and competence

Failure on a conservation task may reflect poor performance rather than a lack of underlying competence.

Performance may be affected by:

• Language.

• Attention.

• Memory.

• Anxiety.

• Familiarity with the materials.

• The relationship with the researcher.

Piaget may therefore have underestimated children’s understanding.

Limitation: artificial procedure

A conservation task may be unfamiliar to a child.

In ordinary life, children rarely see an adult:

• Align two rows.

• Spread one row apart.

• Ask the same question twice.

A more meaningful everyday context may produce better reasoning.

Limitation: stage boundaries may be too rigid

Children under seven can sometimes conserve when:

• The task is simplified.

• The transformation is accidental.

• Only one question is asked.

• Familiar materials are used.

This suggests that conservation may develop gradually rather than appearing suddenly at the beginning of the concrete operational stage.

Comparing object permanence and conservation

Feature	Object permanence	Conservation
Basic definition	Understanding that hidden objects continue to exist	Understanding that quantity remains unchanged despite altered appearance
Main stage	Sensorimotor	Concrete operational
Piaget’s approximate age	8 to 9 months	Around 7 years
Typical task	Covering or hiding a toy	Transforming rows, liquid or clay
Expected successful behaviour	Searching for the object	Saying the quantities remain equal
Main cognitive achievement	Mental representation of an unseen object	Logical operations applied to transformations
Main methodological concern	Motor ability may affect searching	Language and repeated questions may affect answers
Important later challenge	Baillargeon	McGarrigle and Donaldson

Central similarity

Both abilities require the child to move beyond immediate appearance.

In object permanence:

• The object looks absent.

• The child understands that it still exists.

In conservation:

• The quantity looks different.

• The child understands that it remains equal.

Central difference

Object permanence is an early representational ability.

Conservation is a later logical ability.

Object permanence requires the child to represent an unseen object.

Conservation requires the child to understand and mentally reverse a transformation.

Applying both ideas in one scenario

A psychologist studies two children. Nine-month-old Jonah retrieves a toy hidden beneath a cloth. Six-year-old Layla says that a taller glass contains more water after the same liquid is poured into it.

Jonah

• Jonah demonstrates object permanence.

• He represents the toy while it is hidden.

• His behaviour is consistent with later sensorimotor development.

Layla

• Layla fails conservation of liquid volume.

• She centres on the liquid’s height.

• She ignores the narrower width.

• Her thinking is consistent with the pre-operational stage.

The children’s answers demonstrate different points in cognitive development.

A strategy for applying Piaget’s ideas

Step 1: Identify what changed

Did the object:

• Disappear from sight?

• Move to another hiding place?

• Change appearance?

• Change arrangement?

Step 2: Identify the child’s response

Did the child:

• Search?

• Search in the wrong location?

• Judge from appearance?

• Explain that nothing was added?

• Mentally reverse the transformation?

Step 3: Name the concept

Possible concepts include:

• Object permanence.

• A-not-B error.

• Conservation.

• Centration.

• Irreversibility.

• Decentration.

• Reversibility.

Step 4: Explain the psychological process

Do not merely label the behaviour.

Explain what the response demonstrates about the child’s understanding.

Step 5: Link to the developmental stage

Use age and behaviour together.

A strong application structure is:

scenario detail → psychological concept → explanation → Piagetian stage

Overall conclusion

Object permanence and conservation demonstrate two major changes in children’s thinking.

Object permanence develops during the sensorimotor stage and allows the infant to represent objects that are no longer visible.

Conservation develops later, during the concrete operational stage, and allows the child to understand that quantity remains unchanged despite transformations in appearance.

Piaget’s tasks were innovative and influential, but later research suggests that his methods sometimes underestimated children’s abilities.

• Searching requires motor control and memory.

• Conservation tasks may involve confusing language and repeated questions.

• Child-friendly methods often produce earlier success.

Piaget successfully identified important developmental abilities, but their emergence may be more gradual and dependent on task demands than his original stage timetable suggested.

Hints from the Examiner Reports 💡

Examiner hint: Give both parts of the conservation definition. State what remains constant and explain that appearance has changed. In 2023, students generally knew the concept and gained the second mark by providing a relevant example.

Examiner hint: Use a precise example. Suitable examples include:

• Number after counters are spread apart.

• Liquid after it is poured into a taller glass.

• Mass after clay is reshaped.

Examiner hint: Do not confuse object permanence with conservation. Object permanence concerns continued existence when hidden. Conservation concerns unchanged quantity after a transformation.

Examiner hint: When applying Piaget, name the cognitive process. Do not only write that a younger child “gets the answer wrong”.

Examiner hint: For a conservation failure, explain:

centration + appearance-based judgement + irreversibility

For success, explain:

decentration + reversibility + identity or compensation

Examiner hint: Evaluation should be attached to the task being discussed. The 2023 examiner report noted that students found limitations easier than strengths. Effective limitations often used the naughty-teddy procedure, while effective strengths focused on standardisation and replicability.

Examiner hint: When discussing object permanence research, distinguish Piaget’s search measure from Baillargeon’s looking-time measure.

Examiner hint: Do not assume that failure to search proves a lack of knowledge. Explain how motor skills, attention or motivation may interfere with performance.

Examiner hint: A reasoned comparison should explain why Baillargeon’s method reduces the need for coordinated reaching. The examiner report recognised this control of possible confounding variables as an effective comparison with Piaget.

Examiner hint: Avoid claiming that later findings completely disprove Piaget. They more directly challenge his methods and the age at which he believed the abilities appeared.

Common Mistakes ⚠️

Mistake: Defining object permanence as recognising an object

Why this is incorrect:

Object permanence specifically concerns continued existence when an object is no longer perceived.

How to improve:

Include the phrase “when out of sight” or “when hidden”.

Mistake: Saying object permanence begins at birth in Piaget’s theory

Why this is incorrect:

Piaget placed its development at approximately 8 to 9 months.

How to improve:

Distinguish Piaget’s prediction from Baillargeon’s evidence of earlier understanding.

Mistake: Assuming no search means no understanding

Why this is too certain:

Searching also requires motor coordination, attention, memory and motivation.

How to improve:

State that Piaget interpreted the behaviour as a lack of object permanence, then consider alternative explanations.

Mistake: Saying the A-not-B error means the infant thinks the toy is gone

Why this is incorrect:

The infant searches for the toy, but searches in its previous location.

How to improve:

Explain that the infant has some object permanence but difficulty updating the object’s location or inhibiting a previously rewarded response.

Mistake: Confusing location A and location B

Why this is incorrect:

A is the original hiding place. B is the new location.

How to improve:

State the locations explicitly when applying the concept.

Mistake: Defining conservation as protecting the environment

Why this is incorrect:

In cognitive development, conservation concerns the constancy of quantity.

How to improve:

Mention number, mass or liquid volume remaining unchanged.

Mistake: Saying a change in appearance produces a change in quantity

Why this is incorrect:

That response demonstrates failure of conservation.

How to improve:

Explain that no material or objects were added or removed.

Mistake: Saying conservation develops during the sensorimotor stage

Why this is incorrect:

Conservation is associated with concrete operational thinking.

How to improve:

Link sensorimotor development with object permanence and concrete operations with conservation.

Mistake: Confusing centration with concentration

Why this is incorrect:

Centration is not a general inability to pay attention.

How to improve:

Explain that the child focuses on one dimension, such as height, while ignoring width.

Mistake: Saying reversibility means physically performing the action again

Why this is incomplete:

Piagetian reversibility is a mental operation.

How to improve:

Explain that the child imagines undoing the transformation.

Mistake: Naming the stage using age alone

Why this is incomplete:

Age is approximate and does not explain the child’s reasoning.

How to improve:

Use the child’s behaviour, such as searching, centration or reversibility.

Mistake: Saying McGarrigle and Donaldson supported Piaget’s age boundary

Why this is incorrect:

Their child-friendly procedure showed conservation among younger children.

How to improve:

Use the finding to argue that Piaget may have underestimated competence.

Mistake: Claiming a standardised task must be valid

Why this is incorrect:

Standardisation supports reliability and replication, but the task may still include confusing wording or artificial demands.

How to improve:

Evaluate reliability and validity separately.

Exam-Style Questions ✍️

Questions

1. What is meant by object permanence?[2 marks]

2. Outline how Piaget investigated object permanence.[3 marks]

3. Explain what is meant by the A-not-B error.[4 marks]

4. Eight-month-old Lila watches a toy being placed beneath a blanket. Lila lifts the blanket and retrieves the toy.

Explain Lila’s behaviour using Piaget’s theory.[3 marks]

5. A researcher repeatedly hides a toy beneath a red cloth. After the infant has retrieved it several times, the researcher hides it beneath a blue cloth while the infant watches. The infant reaches towards the red cloth.

Explain the infant’s behaviour.[4 marks]

6. What is meant by conservation? Use an example in your answer.[2 marks]

7. Four-year-old Jacob sees equal amounts of liquid in two glasses. The liquid from one glass is poured into a taller, narrower glass. Jacob says the taller glass contains more.

Explain Jacob’s answer using Piaget’s theory.[4 marks]

8. Eight-year-old Ava says that two pieces of clay still contain the same amount after one is rolled into a long shape. Ava explains that it could be rolled back into a ball.

Explain Ava’s answer.[4 marks]

9. Explain one strength and one limitation of Piaget’s conservation research.[6 marks]

10. A psychologist tests conservation using two procedures.

Procedure	Number of 6-year-olds giving a conserving answer
Researcher deliberately changes the counters	14
Toy accidentally changes the counters	26

There were 40 children in each condition.

a) Calculate the percentage of conserving answers in the deliberate-change condition.[2 marks]

b) Calculate the percentage of conserving answers in the accidental-change condition.[2 marks]

c) Explain what the results suggest about Piaget’s conservation tasks.[3 marks]

11. Compare object permanence and conservation as features of Piaget’s theory.[6 marks]

12. Discuss what psychological research has told us about children’s understanding of object permanence and conservation.[16 marks]

Answers and Mark Scheme

Question 1

Award up to two marks:

• Object permanence is the understanding that objects or people continue to exist.

• This remains true when they are hidden, out of sight or otherwise unavailable to the senses.

Question 2

Award up to three marks:

• Piaget showed an infant an attractive object.

• The object was covered or hidden while the infant watched.

• Piaget observed whether the infant searched for or retrieved the object.

• Searching was interpreted as evidence of object permanence.

Question 3

Award up to four marks:

• An object is repeatedly hidden at location A and retrieved by the infant.

• The infant then watches the object being moved to location B.

• The infant continues searching at A.

• The response may reflect a previously successful motor schema, limited representation of the new location or difficulty inhibiting the old response.

Question 4

Award up to three marks:

• Lila demonstrates object permanence.

• She understands that the toy continues to exist when hidden.

• Lifting the blanket suggests that she holds a mental representation of its location.

• The behaviour is consistent with later sensorimotor development.

Question 5

Award up to four marks:

• The infant demonstrates the A-not-B error.

• The red cloth is location A, where the toy was previously found.

• The blue cloth is location B, where the toy is now located.

• The infant repeats the previously rewarded search response at A.

• The infant may have difficulty updating the object’s location or inhibiting the old response.

Question 6

Award up to two marks:

• Conservation is the understanding that a property such as number, mass or volume remains constant despite a change in appearance.

• One relevant example, such as understanding that liquid remains equal after being poured into a taller glass.

Question 7

Award up to four marks:

• Jacob fails conservation of liquid volume.

• He demonstrates centration by focusing on height.

• He ignores the fact that the taller glass is narrower.

• He is unable to reverse the transformation mentally.

• His judgement is dominated by appearance, which is characteristic of pre-operational thought.

Question 8

Award up to four marks:

• Ava demonstrates conservation of mass.

• She understands that reshaping the clay does not change its quantity.

• Her statement that it could be rolled back demonstrates reversibility.

• She is not misled by the clay’s increased length.

• This is characteristic of concrete operational thinking.

Question 9

Award up to three marks for a developed strength and three for a developed limitation.

Possible strength:

Piaget used carefully constructed, standardised procedures. This allows the tasks to be replicated with different children and supports reliable comparisons between ages.

Possible limitation:

The same question is asked before and after the transformation. Younger children may assume the researcher expects a different answer, so failure may reflect task demands rather than a genuine lack of conservation.

Alternative creditworthy strengths include:

• Innovative contribution.

• Detailed evidence about children’s reasoning.

• Educational applications.

Alternative limitations include:

• Child-unfriendly procedure.

• Language demands.

• Artificial setting.

• McGarrigle and Donaldson’s contradictory evidence.

• Limited original sample.

• Performance may underestimate competence.

Question 10a

4014​×100=35%

Award one mark for correct working and one for the answer:

35%

Question 10b

4026​×100=65%

Award one mark for correct working and one for the answer:

65%

Question 10c

Award up to three marks:

• More children conserved when the toy changed the counters accidentally.

• The difference is 30 percentage points.

• The adult’s deliberate transformation or repeated questioning may create task demands.

• Piaget’s original task may therefore underestimate the conservation ability of children under seven.

• Child-friendly methods may reveal competence earlier.

Do not claim statistical significance because no inferential-test result is provided.

Question 11

Award up to six marks for direct comparison.

Possible content:

• Both are characteristics within Piaget’s theory of cognitive development.

• Both require the child to move beyond immediate appearance.

• Object permanence concerns continued existence when an object is hidden.

• Conservation concerns unchanged quantity following a visible transformation.

• Object permanence develops during the sensorimotor stage.

• Conservation develops during the concrete operational stage.

• Piaget investigated object permanence using hidden-object searches.

• He investigated conservation using transformations of number, liquid or mass.

• Object permanence requires mental representation.

• Conservation requires logical operations such as decentration and reversibility.

• Both original procedures may underestimate competence because of additional task demands.

Higher marks require connected comparison rather than two separate descriptions.

Question 12

A strong response should include:

Knowledge and understanding

• Definition of object permanence.

• Piaget’s hidden-object procedure.

• Development at approximately 8 to 9 months.

• Mental representation.

• The A-not-B error.

• Definition of conservation.

• Conservation of number.

• Conservation of liquid.

• Conservation of mass.

• Pre-operational failure.

• Centration.

• Irreversibility.

• Concrete operational success.

• Decentration.

• Reversibility.

• Identity and compensation.

Discussion

• Piaget’s innovative contribution.

• Standardised and replicable procedures.

• Educational applications.

• Motor demands in object-permanence tasks.

• The competence-performance distinction.

• Attention and motivation as confounding variables.

• Baillargeon’s evidence of earlier abilities.

• Limitations of interpreting longer looking as understanding.

• Repeated questioning in conservation tasks.

• McGarrigle and Donaldson’s naughty-teddy procedure.

• Language and social demands.

• Evidence that conservation develops gradually.

• The possibility that Piaget’s stages are less rigid than proposed.

• The value of Piaget’s broad developmental account despite problems with task design and timing.

Higher-level responses will keep object permanence and conservation clearly distinct, apply specialist terminology accurately and explain how later research challenges Piaget’s methods or age estimates rather than simply stating that his theory was wrong.