Baillargeon’s explanation | 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

Baillargeon argued that infants possess an earlier and more sophisticated understanding of the physical world than Piaget’s research suggested. These Baillargeon’s explanation A-Level Psychology revision notes examine infants’ expectations about hidden objects, movement, solidity and support.

Because infants cannot explain their knowledge verbally, Baillargeon used violation-of-expectation research. Infants are shown possible and apparently impossible events, and their looking time is measured. Longer looking at impossible events is interpreted as evidence that the event contradicted an existing expectation. AQA requires knowledge of early infant abilities, knowledge of the physical world and violation-of-expectation research.

Learning Objectives 🎯

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

• Explain Baillargeon’s account of early infant abilities.

• Explain what infants may understand about the physical world.

• Describe the familiarisation and test stages of violation-of-expectation research.

• Explain how looking time is used to infer infant expectations.

• Describe examples of Baillargeon’s experimental procedures.

• Compare Baillargeon’s conclusions with Piaget’s account of object permanence.

• Evaluate the validity and usefulness of violation-of-expectation research.

Revision Notes 📚

Baillargeon’s explanation A-Level Psychology revision overview

Renée Baillargeon investigated what very young infants understand about physical objects.

Her research challenged Piaget’s conclusion that infants develop object permanence at approximately 8 to 9 months.

Baillargeon proposed that much younger infants possess expectations about:

• Objects continuing to exist when hidden.

• Objects following continuous paths.

• Solid objects being unable to pass through one another.

• Unsupported objects falling.

• The relationship between the size of an object and the space through which it can pass.

These expectations form part of the infant’s early knowledge of the physical world.

AQA mark schemes recognise Baillargeon’s finding that object perception and object permanence may be present in infants from approximately 2 to 3 months.

The central claim

Baillargeon’s central claim is:

Infants understand more about objects than their physical actions reveal.

A young infant may fail to reach for a hidden toy because they:

• Lack motor coordination.

• Cannot remove a cover.

• Forget the precise location.

• Lose interest in retrieving it.

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

Baillargeon therefore measured infants’ looking behaviour rather than their ability to reach for an object.

Early infant abilities

Infants as active interpreters

Baillargeon did not describe infants as receiving an unstructured collection of sights and sounds.

Infants appear able to form expectations about:

• What objects are.

• How objects move.

• What should happen when objects collide.

• What happens when an object becomes hidden.

• Which physical events are possible.

When an event contradicts these expectations, infants may look at it for longer.

Physical reasoning

Physical reasoning is the ability to form expectations about objects and physical events.

For example, an infant may expect that:

• A ball passing behind a screen will emerge from the other side.

• A large object cannot pass through a smaller opening.

• A rotating screen cannot pass through a solid box.

• An object cannot suddenly disappear while moving along a track.

Infants cannot explain these principles verbally.

Their knowledge is inferred from behavioural responses such as preferential looking.

Implicit knowledge

Baillargeon’s research is usually interpreted as showing implicit knowledge.

Implicit knowledge is understanding demonstrated through behaviour without a verbal explanation.

An infant may behave as though they know that an event is impossible without being able to:

• State the physical rule.

• Explain why the rule applies.

• Use the rule consciously in every situation.

This distinction matters.

Looking longer at an impossible event does not demonstrate adult-like scientific understanding. It suggests an early expectation that the event should not have occurred.

Knowledge of the physical world

The phrase knowledge of the physical world refers to infants’ expectations about how objects exist, move and interact.

Several connected principles have been investigated.

Object permanence

Object permanence is the understanding that objects continue to exist when they are out of sight.

For example:

A toy train enters a tunnel. The infant expects the train to continue existing while hidden and to emerge from the other side.

Baillargeon’s findings suggest that some form of object permanence may be present much earlier than Piaget proposed.

The original Piagetian account is covered in hidden-object searches and the A-not-B error.

Persistence

The principle of persistence is the expectation that an object continues to exist and retains its physical properties while hidden.

An object should not:

• Disappear without explanation.

• Change size while behind a screen.

• Transform into a completely different object.

• Pass through a solid obstruction.

Persistence includes object permanence but also concerns the continuing physical identity of an object.

Continuity

The principle of continuity is the expectation that objects move along continuous paths.

An object should not:

• Disappear from one location.

• Reappear somewhere else without travelling between them.

• Teleport across a barrier.

• Occupy two unconnected locations during one movement.

For example:

If a train enters a tunnel, it should move continuously through the hidden space before emerging.

Solidity

The principle of solidity is the expectation that two solid objects cannot occupy the same physical space at the same time.

Therefore:

• A moving screen should stop when it reaches a solid box.

• A truck should not pass through a barrier.

• A ball should not travel through a solid wall.

• One object should not move directly through another.

Baillargeon investigated solidity using events in which one object appeared to pass through another while hidden from view.

Support

The principle of support is the expectation that objects require sufficient physical support to remain stable.

An object placed entirely beyond the edge of a platform should fall.

An object with enough of its surface resting on a platform may remain upright.

Infants’ expectations about support become more detailed with development and experience.

Gravity

Infants may also develop expectations that unsupported objects fall downwards rather than:

• Floating upwards.

• Remaining suspended without support.

• Moving in physically unexplained ways.

Baillargeon’s broader account therefore concerns more than object permanence. It concerns an early system for interpreting physical events.

How physical knowledge develops

An early physical-reasoning system

Baillargeon’s findings are often interpreted as evidence that infants possess an early physical-reasoning system.

This system allows infants to:

1. Represent physical objects.

2. Track objects when they become hidden.

3. Form expectations about possible outcomes.

4. Compare an observed outcome with the expected outcome.

5. Detect some violations of physical principles.

The system is basic rather than complete.

Infants’ knowledge becomes more detailed as they gain experience.

Initial principles and later learning

A balanced account distinguishes between:

• Basic expectations that appear very early.

• More precise knowledge that develops through experience.

For example, an infant might initially expect that unsupported objects fall.

Later, the infant learns more specific information about:

• How much support an object requires.

• The importance of its shape.

• The location of its centre of mass.

• Whether a supporting surface is stable.

Baillargeon’s account therefore does not require infants to be born with complete knowledge of physics.

It proposes an early framework that becomes progressively refined.

Nativism and constructivism

Nativist interpretation

A nativist explanation proposes that some knowledge or cognitive capacities are present from birth or develop with very little learning.

Baillargeon’s finding that infants as young as 2 to 3 months respond to impossible events can be interpreted as evidence for an innate or early-developing understanding of objects.

The infant has had relatively little time to acquire the knowledge through extensive physical exploration.

Constructivist interpretation

A constructivist explanation proposes that children build knowledge through experience.

Piaget argued that object permanence developed as infants:

• Acted on objects.

• Formed schemas.

• Assimilated experiences.

• Accommodated their understanding.

• Progressed through the sensorimotor stage.

This links with schemas, assimilation, accommodation and equilibration

A cautious conclusion

Baillargeon’s evidence does not prove that all physical knowledge is fully innate.

Even a 2-month-old infant has experienced:

• Objects moving.

• People disappearing and returning.

• Physical support.

• Gravity.

• Repeated visual patterns.

The findings show that knowledge appears earlier than Piaget proposed, but they do not establish exactly how much is inherited and how much is learned.

Piaget and Baillargeon compared

Piaget	Baillargeon
Object permanence develops at approximately 8 to 9 months	Object knowledge may be evident from approximately 2 to 3 months
Infant must search for a hidden object	Infant’s looking time is measured
Emphasises physical action and schema development	Emphasises early expectations about physical events
Failure to retrieve suggests limited representation	Failure to retrieve may reflect motor limitations
Mainly constructivist	More consistent with a nativist or early-core-knowledge account
Measures overt search behaviour	Measures implicit response to possible and impossible events

Different methods produce different conclusions

Piaget required the infant to:

• Remember the object.

• Remember its location.

• Reach towards it.

• Remove an obstruction.

• Inhibit other responses.

Baillargeon required the infant mainly to:

• Attend to an event.

• Represent what happened while an object was hidden.

• Compare the outcome with an expectation.

The difference in findings may therefore reflect differences in task demands.

Competence and performance

Competence is the knowledge or ability a person possesses.

Performance is the behaviour produced in a particular task.

Baillargeon argued that Piaget may have underestimated competence because his task demanded a complex physical performance.

An infant may understand that a toy remains beneath a cloth while being unable to retrieve it.

Violation of expectation

What is violation of expectation?

A violation of expectation occurs when an observed event conflicts with what the infant appears to expect.

The AQA specimen mark scheme defines it as a situation in which what is expected is not what happens.

For example:

An infant expects a tall carrot moving behind a screen to appear through a high window. The carrot fails to appear.

The event violates the infant’s expectation.

The central assumption

Violation-of-expectation research is based on the assumption that infants:

look longer at events that are surprising, unexpected or impossible

The researcher compares looking time for:

• A possible event.

• An impossible or unexpected event.

If infants look longer at the impossible event, the researcher infers that:

1. The infant represented the relevant object.

2. The infant formed an expectation.

3. The observed event contradicted that expectation.

Preferential looking

Preferential looking occurs when an infant looks at one stimulus or event for longer than another.

The preference may be interpreted as evidence that the events are perceived differently.

In violation-of-expectation studies, the key dependent variable is usually:

time spent looking at the event

AQA’s 2023 mark scheme identifies looking time or preferential looking as the dependent variable used in Baillargeon’s research.

The stages of violation-of-expectation research

Stage 1: Familiarisation

During the familiarisation stage, the infant repeatedly watches a possible event.

The purpose is to:

• Familiarise the infant with the apparatus.

• Show how the objects normally move.

• Establish an expectation.

• Reduce looking caused simply by the apparatus being new.

For example, the infant may repeatedly see:

• A screen rotating freely.

• A carrot moving behind a screen.

• A train entering and leaving a tunnel.

Habituation

Some procedures continue the repeated presentation until the infant becomes habituated.

Habituation is a reduction in response after repeated exposure to the same stimulus.

The infant may gradually look for less time because the event has become familiar.

A reduction in looking helps show that later increased attention is not simply due to the apparatus being generally interesting.

Stage 2: Test trials

During the test stage, the infant sees possible and impossible outcomes.

Possible event

The event follows ordinary physical rules.

For example:

• A screen stops when it reaches a hidden box.

• A tall carrot appears through an opening.

• A train emerges from a tunnel.

Impossible event

The event violates a physical expectation.

For example:

• A screen appears to rotate through a solid box.

• A tall carrot fails to appear through an opening.

• A train disappears while passing through a tunnel.

Stage 3: Measuring looking time

Observers record how long the infant looks at each event.

Looking time may be recorded using:

• Trained observers.

• Video recordings.

• Eye-tracking equipment.

• Computerised timing.

The possible and impossible looking times are compared.

Stage 4: Making an inference

Longer looking at the impossible event is interpreted as evidence that the infant:

• Expected the possible outcome.

• Detected a violation.

• Possessed some relevant physical knowledge.

This is an inference because the researcher cannot ask the infant why they looked for longer.

A complete violation-of-expectation sequence

The procedure can be memorised as:

1. Familiarise the infant with a possible event.

2. Present possible and impossible test events.

3. Measure looking time.

4. Compare the two conditions.

5. Infer an expectation if the impossible event receives longer looking.

📌 Exam tip: Do not define violation of expectation as simply “the infant looks at something unusual”. State that the observed event conflicts with an expectation and that looking time is used to infer the infant’s understanding.

The drawbridge study

Basic aim

The drawbridge procedure investigated whether infants understood that:

• A hidden object continues to exist.

• A solid screen cannot move through the object.

Familiarisation event

Infants repeatedly watched a screen rotate backwards and forwards through an arc.

The screen moved freely when no object was behind it.

Test event

A solid box was placed behind the screen.

Two outcomes could then be shown.

Possible event

The screen rotated until it reached the hidden box and then stopped.

This event was physically possible because the box prevented further movement.

Impossible event

The screen appeared to rotate through the space occupied by the hidden box.

The researchers secretly removed or lowered the box so that the screen could complete the

movement, but the infant had seen the box placed behind it.

Findings

Infants looked longer at the impossible event.

Conclusion

Baillargeon concluded that the infants appeared to understand that:

• The box continued to exist while hidden.

• The box occupied physical space.

• The screen should have been blocked by it.

The study therefore provides evidence of:

• Object permanence.

• Solidity.

• Early physical reasoning.

The tall-carrot study

Basic aim

The carrot procedure investigated whether infants could:

• Represent the height of a hidden object.

• Track its continuous movement.

• Predict when part of it should become visible.

Familiarisation event

Infants watched a short carrot and a tall carrot move from one side of a screen to the other.

Both carrots temporarily disappeared behind the screen.

Test screen

A screen containing a window was introduced.

The window was high enough for the top of the tall carrot to appear as it passed behind the screen.

The short carrot was not tall enough to appear.

Possible event

The tall carrot became visible through the window as it moved behind the screen.

The short carrot remained hidden.

Impossible event

The tall carrot failed to appear through the window.

It seemed to become shorter, disappear or move along an impossible path while hidden.

Findings

Infants looked longer when the tall carrot did not appear in the window.

Conclusion

The infants appeared to represent:

• The continuing existence of the carrot.

• Its height.

• Its path behind the screen.

They expected the tall carrot to remain tall while hidden.

AQA’s 2023 examiner report noted that many successful students described the carrot study in detail before evaluating violation-of-expectation research.

The train and tunnel procedure

Familiarisation

An infant watches a train:

1. Move along a track.

2. Enter a tunnel.

3. Emerge from the other side.

The event demonstrates a continuous movement.

Possible test event

The train enters the tunnel and emerges as expected.

Impossible test event

The train enters the tunnel but fails to appear at the other end, despite there being no visible explanation for its disappearance.

Interpretation

If infants look longer at the impossible event, this may suggest that they expect:

• The train to continue existing while hidden.

• The train to move along a continuous path.

• The train to emerge from the tunnel.

AQA’s 2023 mark scheme includes the train-and-tunnel procedure as a creditworthy example of violation-of-expectation research.

The truck and ramp procedure

Basic event

A truck rolls down a ramp and passes behind a screen.

An object or barrier is placed in the truck’s expected path.

Possible event

The truck is blocked by the object and does not emerge beyond it.

Impossible event

The truck appears on the other side as though it passed through the solid obstruction.

Interpretation

Longer looking at the impossible event suggests an expectation that:

• The hidden object continues to exist.

• The truck travels along a continuous path.

• Two solid objects cannot pass through one another.

Possible and impossible events compared

Possible event	Impossible event	Suggested infant knowledge
Screen stops at a box	Screen passes through the box	Object permanence and solidity
Tall carrot appears in the window	Tall carrot fails to appear	Persistence of height and continuous movement
Train emerges from a tunnel	Train disappears	Object permanence and continuity
Truck stops at a barrier	Truck passes through the barrier	Solidity and continuity
Supported object remains stable	Unsupported object appears to float	Support and gravity

Interpreting looking-time data

Consider the following hypothetical findings:

Event	Mean looking time
Possible event	8 seconds
Impossible event	15 seconds

The infants looked:

15−8=7

seconds longer at the impossible event.

A reasonable conclusion is:

The infants showed a looking preference for the impossible event, which is consistent with the event violating an expectation.

An unreasonable conclusion would be:

The study proves that every infant fully understands object permanence.

Looking time provides indirect evidence and must be interpreted cautiously.

Applying violation of expectation

Consider this scenario:

Infants watch a ball roll behind a screen. A solid wall is then placed behind the screen in the ball’s path. In one condition, the ball stops behind the wall. In another condition, the ball emerges on the other side. Infants look longer when the ball emerges.

A developed explanation would state:

• The ball stopping is the possible event.

• The ball emerging is impossible because it appears to have passed through the wall.

• Longer looking suggests that the impossible event violated the infants’ expectation.

• The infants appear to represent the hidden wall and ball.

• They may possess an expectation of solidity.

• The result is consistent with early knowledge of the physical world.

Applying the carrot procedure

Infants see a tall and a short toy rabbit move behind a screen containing a high window. The tall rabbit does not appear through the window, and infants look at this event for longer.

A developed explanation would state:

• The infants appear to remember the tall rabbit’s height.

• They expect its upper section to appear through the window.

• Its failure to appear violates the expectation that physical properties persist while hidden.

• Longer looking is used as the dependent measure of surprise.

• The finding suggests object representation and continuity.

What does longer looking mean?

Baillargeon’s interpretation

Baillargeon interpreted longer looking as evidence of:

• Surprise.

• Detection of an impossible event.

• An expectation about the physical world.

The infant looks longer because the event conflicts with what they believe should happen.

Alternative interpretation

Longer looking could instead show that the impossible event is:

• More novel.

• More visually interesting.

• More unusual.

• More complex.

• Different from the familiarisation event.

The infant might detect that the events differ without understanding which physical rule was violated.

This is the central validity issue in violation-of-expectation research.

Evaluating Baillargeon’s explanation

Strength: the method reduces motor demands

Piaget’s hidden-object tasks required infants to retrieve an object.

Baillargeon’s procedure requires looking rather than coordinated reaching.

This reduces possible confounding effects from:

• Weak motor control.

• Inability to lift a cover.

• Difficulty coordinating a search.

• Failure to inhibit a previous movement.

Baillargeon may therefore provide a purer measure of early cognitive competence.

The 2023 examiner report highlighted reasoned comparisons explaining how Baillargeon controlled problems such as limited motor skills more successfully than Piaget.

Strength: infants can be tested before they can speak

Very young infants cannot describe:

• What they expect.

• Why an event is impossible.

• Where they think an object has gone.

Looking time provides a way to investigate preverbal cognition.

Without this method, psychologists would have much less evidence about abilities during the first months of life.

Strength: controlled procedures

Violation-of-expectation studies use carefully constructed apparatus.

Researchers can control:

• The path followed by an object.

• The position of a screen.

• The presence of a barrier.

• The duration of each event.

• Which outcome is presented.

• The order of conditions.

Control allows researchers to compare responses to events that differ in a specific physical feature.

Strength: standardisation and replication

The same possible and impossible events can be shown to several infants using a standardised procedure.

This allows:

• Comparison between participants.

• Replication by other researchers.

• Calculation of average looking times.

• Testing of different physical principles.

• Examination of developmental changes.

Violation of expectation has become a widely used method for studying infants’ understanding of the physical world. AQA’s 2023 mark scheme recognises its adoption as a standard infant-research paradigm.

Strength: physiological evidence

Kaufman and colleagues found increased neural activity in the right temporal region when infants viewed an impossible event.

This physiological response supports the suggestion that infants process impossible events differently from possible events.

It reduces reliance on looking time as the only dependent measure.

AQA identifies this neural evidence as support for Baillargeon’s interpretation.

Limitation: looking time is an indirect measure

Researchers cannot observe an infant’s expectation directly.

They infer it from longer looking.

This creates a chain of inference:

longer looking → surprise → violated expectation → physical knowledge

A weakness at any point in this chain reduces the validity of the conclusion.

For example, an infant might look longer without being surprised.

Limitation: novelty rather than understanding

Cashon and Cohen proposed that longer looking may reflect attraction to novel stimuli rather than an understanding of impossible events.

The infant may notice:

“This event is different.”

They may not understand:

“The event violates the principle that solid objects cannot pass through one another.”

AQA mark schemes recognise novelty and interest as alternative explanations of looking-time findings.

Limitation: surprise is not adult-like knowledge

Even when longer looking reflects surprise, the infant’s expectation may be relatively simple.

For example, the infant may have learned:

“The screen normally stops.”

This is different from understanding the abstract principle:

“A solid object occupies space and prevents another solid object from passing through it.”

Researchers risk overstating infant knowledge by interpreting a visual preference as a sophisticated concept.

Limitation: possible perceptual differences

The possible and impossible events may differ in perceptual features.

For example:

• One event may involve longer movement.

• One may reveal the object for a different duration.

• One may contain more visual change.

• One may be more unusual following familiarisation.

The infant’s response could be caused by perceptual interest rather than physical reasoning.

Researchers must match the conditions as closely as possible.

Limitation: infant arousal affects looking time

Looking time may vary because the infant is:

• Hungry.

• Tired.

• Distracted.

• Overstimulated.

• Anxious.

• Unusually alert.

These factors are difficult to control completely in very young participants.

AQA’s 2023 mark scheme identifies arousal as a difficulty when assessing cognitive processing in infants.

Limitation: attention remains important

Baillargeon reduces the demand for physical search, but the infant still needs to:

• Watch the familiarisation event.

• Track the hidden object.

• Attend to the test outcome.

• Remain alert long enough for looking time to be measured.

A failure to look longer could reflect reduced attention rather than a lack of physical knowledge.

Limitation: observer interpretation

When human observers record where an infant is looking, judgement may be required.

An observer might be influenced by knowing:

• Which condition is being presented.

• The expected hypothesis.

• Whether an event is possible or impossible.

Reliability and objectivity can be improved by:

• Using observers who are blind to the condition.

• Recording trials on video.

• Using eye-tracking technology.

• Testing inter-observer reliability.

Limitation: participant attrition

Infant studies may exclude participants who:

• Cry.

• Fall asleep.

• Fail to watch the apparatus.

• Move excessively.

• Do not complete enough trials.

If many infants are removed, the final sample may contain particularly calm or attentive infants.

This creates a possible sampling bias and limits generalisation.

Limitation: artificial events

A rotating screen that apparently passes through a box is not a normal everyday experience.

The procedure may therefore lack ecological validity.

However, artificial control is partly necessary because researchers need to create:

• A clearly possible event.

• A closely matched impossible event.

• A measurable behavioural response.

There is a trade-off between experimental control and natural behaviour.

Limitation: the method may assess implicit rather than explicit knowledge

Violation-of-expectation research may show that an infant detects an unusual physical outcome.

Piaget’s search task requires the infant to use knowledge to guide deliberate action.

The two tasks may therefore assess different levels of understanding.

Baillargeon’s task	Piaget’s task
Detects an unexpected visual event	Uses knowledge to retrieve an object
May measure implicit expectation	Measures action based on object representation
Has low motor demands	Has high motor demands
Can be completed by younger infants	Requires greater physical development

Baillargeon may reveal an early form of object knowledge, while Piaget may reveal when that

knowledge can guide coordinated action.

Limitation: early ability does not prove innateness

A finding in a 2- or 3-month-old does not reveal exactly where the expectation came from.

The infant may have developed it through:

• Repeated observation of objects.

• Early visual experience.

• Rapid statistical learning.

• Maturation.

• An interaction of inherited and learned processes.

Baillargeon challenges Piaget’s timetable more clearly than she proves a completely nativist explanation.

Baillargeon as a challenge to Piaget

Piaget’s conclusion

Piaget concluded that object permanence develops at approximately 8 to 9 months because younger infants did not search for covered objects.

Baillargeon’s conclusion

Baillargeon found that much younger infants looked longer when hidden objects appeared to:

• Disappear.

• Pass through other objects.

• Change size.

• Violate expected physical paths.

She concluded that infants possess earlier object knowledge than Piaget recognised.

Why Piaget may have underestimated infants

Piaget’s task required several abilities at the same time:

1. Represent the hidden object.

2. Remember its location.

3. Plan a movement.

4. Reach towards the cover.

5. Remove the cover.

6. Retrieve the object.

Failure at any stage could prevent a successful search.

Baillargeon’s method removes several of these requirements.

Does Baillargeon disprove Piaget?

Baillargeon does not disprove every part of Piaget’s theory.

Her findings more specifically challenge:

• The age at which object permanence appears.

• The validity of using search behaviour as the only measure.

• The view that infants’ representations depend entirely on physical action.

Piaget may still be correct that experience and action contribute to increasingly advanced object understanding.

A balanced conclusion is:

Infants show early implicit expectations about objects, but their ability to act deliberately on those representations develops later.

Research-method analysis

Independent variable

The independent variable is usually the type of event:

• Possible.

• Impossible.

Dependent variable

The dependent variable is usually:

• Looking time in seconds.

Experimental design

Many procedures use a repeated-measures design because the same infant views both possible and impossible events.

Strength

Individual differences between infants are controlled because each child acts as their own comparison.

Limitation

Order effects may occur.

For example, the infant may become:

• Tired.

• Habituated.

• Less attentive during later trials.

Researchers can counterbalance the order of possible and impossible events.

Operationalisation

Surprise is operationalised as:

increased looking time

This is objective in the sense that looking duration can be measured numerically.

However, the validity of the operationalisation remains open to question because long looking may represent interest rather than surprise.

Reliability

Reliability may be improved by:

• Standardising the apparatus.

• Presenting events for the same duration.

• Using clear stopping criteria.

• Recording trials.

• Using multiple observers.

• Checking inter-observer reliability.

Ethical considerations

Infants cannot provide informed consent.

Consent must therefore be obtained from a parent or guardian.

Researchers should also:

• Avoid distress.

• Stop if the infant becomes upset.

• Minimise tiredness.

• Allow the parent to withdraw the child.

• Keep identifying information confidential.

Applying research methods to a scenario

Researchers show each infant a possible event followed by an impossible event. They record looking time using a stopwatch while knowing which condition is being presented.

Possible methodological issues include:

Order effects

Every infant sees the possible event first.

Longer or shorter looking during the second event could be caused by:

• Tiredness.

• Reduced attention.

• Novelty.

The order should be counterbalanced.

Observer bias

The observer knows when the impossible event is presented.

This knowledge may unconsciously affect when they start or stop the timer.

A blind observer or automated eye tracker would improve objectivity.

Validity

Longer looking is interpreted as surprise.

However, the impossible event may simply contain more movement or novelty.

The events should be closely matched.

Overall conclusion

Baillargeon proposed that infants possess early expectations about the physical world.

Violation-of-expectation research suggests that infants can represent:

• Hidden objects.

• Object height and size.

• Continuous movement.

• Solidity.

• Physical support.

The standard procedure involves:

1. A familiarisation stage.

2. Possible and impossible test events.

3. Measurement of looking time.

4. An inference that longer looking reflects a violated expectation.

The research challenges Piaget’s conclusion that object permanence first appears at approximately 8 to 9 months. Baillargeon’s method reduces the motor demands involved in retrieving a hidden object and has become highly influential in infant cognition research.

However, looking time is an indirect measure. Longer looking may reflect:

• Novelty.

• Interest.

• Perceptual differences.

• Arousal.

The strongest conclusion is that infants possess earlier implicit expectations than Piaget recognised, but violation-of-expectation findings should not be treated as proof of complete adult-like knowledge or of a wholly innate understanding of physics.

Hints from the Examiner Reports 💡

Examiner hint: Describe one violation-of-expectation study in accurate detail. In 2023, many successful students used the tall-carrot procedure and then evaluated the general method.

A clear description should contain:

1. The familiarisation event.

2. The possible event.

3. The impossible event.

4. Looking time as the dependent variable.

5. The conclusion drawn from longer looking.

Examiner hint: The 2023 question allocated three marks to AO1 and five to AO3. Do not spend

the whole response describing several experiments without evaluating the method.

Examiner hint: Define violation of expectation precisely:

What the infant expects is not what happens.

AQA accepts a general definition or one placed in the context of the carrot or truck procedure.

Examiner hint: Make the comparison with Piaget explicit. State that Baillargeon’s looking-time procedure reduces the motor demands involved in Piaget’s search task.

Examiner hint: Do not claim that longer looking automatically proves object permanence. Explain the inferential chain from looking to surprise and then to physical knowledge.

Examiner hint: Develop the novelty criticism. The infant may recognise that the impossible event is different without understanding why it is physically impossible.

Examiner hint: Use Kaufman’s neural evidence as support, then explain why physiological differences still do not tell researchers exactly what the infant understood.

Examiner hint: Avoid describing familiarisation as the impossible stage. Familiarisation normally presents repeated possible events.

Examiner hint: Do not muddle the expected outcome:

• Tall carrot should appear in the high window.

• Screen should stop when it reaches the hidden box.

• Train should emerge from the tunnel.

Examiner hint: Use cautious conclusion language:

• “Suggests”.

• “Is consistent with”.

• “Infants appear to expect”.

• “Provides indirect evidence”.

Common Mistakes ⚠️

Mistake: Saying Baillargeon asked infants what they expected

Why this is incorrect:

The participants were preverbal infants.

How to improve:

Explain that expectations were inferred from looking time.

Mistake: Defining violation of expectation as any surprising event

Why this is incomplete:

The method requires an event that conflicts with a predicted physical outcome.

How to improve:

Identify the expectation and the event that violated it.

Mistake: Forgetting the familiarisation stage

Why this is incorrect:

Infants are usually shown the possible movement repeatedly before the crucial comparison.

How to improve:

Describe familiarisation before the test events.

Mistake: Saying the infant is familiarised with the impossible event

Why this is usually incorrect:

The familiarisation stage normally establishes the ordinary possible movement.

How to improve:

Separate familiarisation from the impossible test event.

Mistake: Calling looking time the independent variable

Why this is incorrect:

Looking time is measured as the dependent variable.

How to improve:

Use:

• IV: possible or impossible event.

• DV: looking time.

Mistake: Claiming longer looking proves surprise

Why this is too certain:

Longer looking might reflect novelty, interest or perceptual complexity.

How to improve:

State that researchers infer surprise.

Mistake: Claiming longer looking proves adult-like physics

Why this is incorrect:

Infants may possess a basic implicit expectation without understanding an abstract physical rule.

How to improve:

Distinguish early expectation from explicit scientific reasoning.

Mistake: Saying Baillargeon found object permanence at eight months

Why this is incorrect:

That is Piaget’s approximate estimate.

How to improve:

Baillargeon found evidence of object knowledge in infants as young as approximately 2 to 3 months.

Mistake: Saying Piaget’s infants could not see the hidden object, so they had no object permanence

Why this is incomplete:

Failure to retrieve an object may reflect motor and memory demands.

How to improve:

Use the competence-performance distinction.

Mistake: Describing the tall carrot as appearing in the impossible event

Why this is incorrect:

The tall carrot should appear through the window. Failure to appear is the impossible event.

How to improve:

Ask what should happen if the carrot remains tall behind the screen.

Mistake: Saying the drawbridge should pass through the box

Why this is incorrect:

A solid box should stop the screen.

How to improve:

Identify the full rotation as impossible once the box has been placed behind it.

Mistake: Claiming the research proves knowledge is innate

Why this is too strong:

Infants have experienced the physical world for several weeks or months.

How to improve:

State that the findings are more consistent with nativism than Piaget’s account but cannot exclude rapid learning.

Mistake: Giving a generic artificiality criticism

Why this is incomplete:

The criticism must explain what is artificial and why it affects the conclusion.

How to improve:

Explain that rotating screens and disappearing carrots may produce perceptual novelty not normally encountered in everyday life.

Mistake: Saying eye tracking removes every validity problem

Why this is incorrect:

Eye tracking measures gaze accurately but does not reveal why the infant looked.

How to improve:

Separate measurement reliability from construct validity.

Exam-Style Questions ✍️

Questions

1. What is meant by violation of expectation?[1 mark]

2. Explain what is meant by knowledge of the physical world.[2 marks]

3. Outline how looking time is used in violation-of-expectation research.[3 marks]

4. Describe the two main stages of a violation-of-expectation investigation.[4 marks]

5. Infants see a tall object and a short object move behind a screen containing a high window. The tall object fails to appear in the window, and the infants look at this event for longer.

Explain the infants’ behaviour using Baillargeon’s explanation.[4 marks]

6. A rotating screen appears to pass through a solid box placed behind it. Infants look longer at this event than when the screen stops at the box.

Explain what the findings suggest about early infant abilities.[4 marks]

7. Explain one difference between Piaget’s and Baillargeon’s research into object permanence.[4 marks]

8. A researcher records the following mean looking times:

Condition	Mean looking time
Possible event	9 seconds
Impossible event	17 seconds

a) Calculate the difference in mean looking time.[1 mark]

b) Explain one conclusion and one limitation of the findings.[4 marks]

9. Explain one strength and one limitation of using looking time to investigate infant cognition.[6 marks]

10. A researcher knows whether each infant is watching the possible or impossible event and records looking time using a stopwatch.

Suggest one methodological improvement and explain why it would improve the investigation.[3 marks]

11. Discuss violation-of-expectation research into early infant abilities.[8 marks]

12. Discuss what Baillargeon’s research has told psychologists about infants’ knowledge of the physical world.[16 marks]

Answers and Mark Scheme

Question 1

Award one mark for:

• A violation of expectation occurs when what is expected is not what happens.

Accept an answer placed within a suitable physical-event example.

Question 2

Award up to two marks:

• Knowledge of the physical world means expectations about how objects exist, move or interact.

• Examples include understanding that hidden objects continue to exist or that solid objects cannot pass through each other.

Question 3

Award up to three marks:

• Infants are shown possible and impossible events.

• Researchers record how long the infant looks at each event.

• Longer looking at the impossible event is interpreted as surprise.

• Researchers infer that the event violated an existing physical expectation.

Question 4

Award up to four marks:

• During familiarisation, infants repeatedly watch an ordinary possible event.

• Their looking may decrease as the event becomes familiar.

• During test trials, infants see a possible and an impossible outcome.

• Looking time is recorded and compared.

• Longer looking at the impossible event is interpreted as a violation of expectation.

Question 5

Award up to four marks:

• The tall object should remain tall while hidden.

• It should therefore become visible through the high window.

• Failure to appear violates the expectation that its physical properties persist.

• Longer looking suggests that infants represented the hidden object and its height.

• The result is consistent with early object permanence or knowledge of continuity.

Question 6

Award up to four marks:

• The box should continue to exist while hidden behind the screen.

• A solid screen cannot pass through a solid box.

• The complete rotation therefore violates the expectation of solidity.

• Longer looking suggests infants represented the hidden box.

• The findings are consistent with early object permanence and physical reasoning.

Question 7

Award up to four marks:

• Piaget measured whether infants physically searched for a hidden object.

• Baillargeon measured looking time at possible and impossible events.

• Piaget placed object permanence at approximately 8 to 9 months.

• Baillargeon found evidence in infants as young as approximately 2 to 3 months.

• Baillargeon’s procedure reduces motor demands, whereas Piaget’s requires coordinated retrieval.

Question 8a

17−9=8

The difference is 8 seconds.

Question 8b

Award up to four marks.

Possible conclusion:

• Infants looked longer at the impossible event.

• This is consistent with it violating their physical expectation.

• They may understand the relevant object principle.

Possible limitation:

• Longer looking might reflect novelty or visual interest rather than surprise.

• The finding therefore does not prove that infants understand why the event is impossible.

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

Question 9

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

Possible strength:

Looking time allows researchers to investigate preverbal infants without requiring coordinated reaching or language. It may therefore reveal cognitive competence that Piaget’s search task underestimated.

Possible limitation:

Looking time is an indirect measure. Longer looking could represent novelty, interest or arousal rather than a violated physical expectation, reducing construct validity.

Alternative creditworthy points include:

• Objective quantitative data.

• Standardisation and replication.

• Use of eye tracking.

• Artificial procedures.

• Observer bias.

• Infant fatigue and attention.

• Participant attrition.

• Perceptual differences between conditions.

Question 10

Award one mark for a suitable improvement and up to two marks for explanation.

Possible answer:

• Use an observer who is blind to whether the event is possible or impossible.

• The observer’s expectation would be less likely to influence when timing begins or ends.

• This would reduce observer bias and increase objectivity.

Alternative improvements include:

• Automated eye tracking.

• Video recording.

• A second observer and an inter-observer reliability check.

• Counterbalancing the order of events.

• Matching possible and impossible events more closely.

Question 11

A strong response should include:

Knowledge and understanding

• Violation of expectation as an event conflicting with an infant’s expectation.

• Familiarisation or habituation.

• Possible and impossible events.

• Looking time as the dependent variable.

• Longer looking interpreted as surprise.

• One accurately described procedure, such as:

  • Tall carrot.

  • Drawbridge and box.

  • Train and tunnel.

  • Truck and barrier.

• Evidence of object permanence, continuity or solidity.

• Infants as young as approximately 2 to 3 months.

Discussion

• Reduced motor demands compared with Piaget.

• Ability to investigate preverbal infants.

• Controlled, replicable procedure.

• Looking time as indirect evidence.

• Novelty as an alternative interpretation.

• Kaufman’s physiological support.

• Infant arousal and attention.

• Artificiality and perceptual differences.

• Early ability does not prove innateness.

Higher-level answers will describe one investigation accurately and devote sufficient space to evaluating the validity of the method.

Question 12

A strong response should include:

Knowledge and understanding

• Baillargeon’s account of early infant abilities.

• Early physical-reasoning system.

• Object permanence and persistence.

• Continuity of movement.

• Solidity.

• Support or gravity.

• Implicit knowledge.

• Violation-of-expectation method.

• Familiarisation and habituation.

• Possible and impossible test events.

• Looking time or preferential looking.

• Drawbridge procedure.

• Tall-carrot procedure.

• Train, tunnel or truck procedure.

• Longer looking as evidence of violated expectation.

• Findings involving infants from approximately 2 to 3 months.

• Comparison with Piaget’s 8- to 9-month estimate.

Discussion

• Baillargeon reduces the motor demands of Piaget’s search task.

• Competence may have been underestimated by Piaget.

• Violation of expectation allows preverbal infants to be studied.

• Carefully controlled and replicable apparatus.

• Adoption as a widely used infant-research paradigm.

• Kaufman’s neural evidence supports different processing of impossible events.

• Looking time is an indirect measure.

• Longer looking may reflect novelty, interest or complexity.

• Detecting a difference is not the same as understanding a physical principle.

• Possible and impossible events may contain perceptual differences.

• Infant arousal, tiredness and attention may affect results.

• Observer bias and reliability issues.

• Attrition may create a biased sample.

• Artificial events may lack ecological validity.

• Baillargeon may measure implicit expectation, while Piaget measures knowledge guiding deliberate action.

• Evidence of early knowledge is consistent with nativism but does not prove that the knowledge is entirely innate.

• An interaction between early predispositions and experience may provide the best explanation.

Higher-level responses will explain what specific physical knowledge each procedure investigates and will distinguish evidence of an early expectation from proof of complete adult-like understanding.