Aversion Therapy and Covert Sensitisation | AQA A-Level Psychology Revision

Revision Notes
Aug 7
31 min read

Updated: Aug 14

For 7182 specification, first teach in September 2025

AQA A-Level Psychology | Free Revision Notes

Estimated study time: 65 to 80 minutes

Aversion therapy and covert sensitisation A-Level Psychology revision examines behavioural interventions that attempt to replace the attraction of an addictive substance or activity with an unpleasant conditioned response. Aversion therapy pairs addiction-related cues with a real noxious stimulus, whereas covert sensitisation uses vivid imagined consequences.

You will learn how both therapies apply classical conditioning, why avoidance may replace approach behaviour and how effectiveness depends on motivation, imagination and long-term transfer. You will also evaluate ethical concerns, dropout and relapse. AQA explicitly requires both interventions as ways of reducing addiction.

Learning Objectives 🎯

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

Define behavioural interventions for addiction.
Explain aversion therapy using classical conditioning.
Identify the NS, UCS, UCR, CS and CR within aversion therapy.
Explain the procedure used in covert sensitisation.
Distinguish real and imagined aversive conditioning.
Apply both treatments to substance and behavioural addictions.
Evaluate behavioural interventions in terms of effectiveness, ethics, suitability and relapse.
Compare aversion therapy and covert sensitisation with drug therapy and CBT.

Revision Notes 📚

Aversion Therapy and Covert Sensitisation A-Level Psychology Revision Focus

Behavioural interventions attempt to change addiction by altering learned associations between:

The addictive substance or activity.
Environmental cues.
Pleasure or reward.
Unpleasant consequences.
Approach and avoidance responses.

The two interventions required by AQA are:

Aversion therapy
Covert sensitisation

Both are based primarily on classical conditioning.

The central aim is:

Replace the learned attraction to an addictive substance or behaviour with a conditioned aversion

AQA describes both therapies as pairing an unpleasant noxious event with the undesired addictive behaviour. The noxious event is real in aversion therapy and imagined in covert sensitisation. Through repeated pairing, the addiction-related cue becomes a conditioned stimulus that produces fear or avoidance.

The Behavioural Approach to Treatment

Behaviour Is Learned

The behavioural approach assumes that addictive behaviour may be learned through experience.

For example, smoking may have become associated with:

Pleasure.
Relaxation.
Social interaction.
Relief from withdrawal.
Particular environmental cues.

Gambling may have become associated with:

Financial wins.
Excitement.
Escape.
Social approval.
Unpredictable reinforcement.

If these associations were learned, behaviourists argue that new associations can also be learned.

Counterconditioning

Counterconditioning involves replacing an existing learned response with a different response.

Before treatment:

Addictive cue → pleasure, craving or approach

After successful treatment:

Addictive cue → discomfort, disgust, fear or avoidance

The original cue remains present, but its learned meaning changes.

Approach Behaviour

An approach response involves moving towards or engaging with the addictive stimulus.

Examples include:

Lighting a cigarette.
Entering a casino.
Opening a gambling application.
Purchasing alcohol.
Seeking an addictive substance.

Avoidance Behaviour

An avoidance response involves moving away from or refusing the addictive stimulus.

Examples include:

Refusing a cigarette.
Closing a gambling application.
Leaving a gambling environment.
Feeling repelled by the substance.
Avoiding the previously attractive activity.

Behavioural intervention attempts to condition the second response.

Classical Conditioning

What Is Classical Conditioning?

Classical conditioning is learning through association.

A neutral stimulus is repeatedly paired with an unconditioned stimulus that naturally produces a response.

Eventually, the neutral stimulus becomes a conditioned stimulus capable of producing a conditioned response by itself.

Essential Terminology

Term	Meaning
Neutral stimulus	A stimulus that does not initially produce the target response
Unconditioned stimulus	A stimulus that naturally produces a response
Unconditioned response	The natural response to the unconditioned stimulus
Conditioned stimulus	The previously neutral stimulus after conditioning
Conditioned response	The learned response to the conditioned stimulus

Standard Conditioning Sequence

Before conditioning

NS → no conditioned response

UCS → UCR

During conditioning

NS + UCS → UCR

After conditioning

CS → CR

This structure should be applied explicitly when explaining aversion therapy or covert sensitisation.

Aversion Therapy

What Is Aversion Therapy?

Aversion therapy is a behavioural intervention in which the addictive substance, activity or related cue is repeatedly paired with a real unpleasant stimulus.

The aim is for the addiction-related cue to become associated with:

Discomfort.
Fear.
Disgust.
Anxiety.
Nausea.
Avoidance.

The previously attractive stimulus becomes aversive.

AQA identifies electric shock as one real noxious stimulus that has been used in aversion therapy for gambling addiction.

The Basic Procedure

A general aversion-therapy programme involves:

Identifying the addictive substance, behaviour or cue.
Selecting an appropriate unpleasant stimulus.
Presenting the addiction-related cue.
Administering the unpleasant stimulus.
Repeating the pairing.
Testing whether the addiction-related cue now produces discomfort or avoidance.
Assessing whether addictive behaviour decreases.

Before Conditioning

Before treatment, the addictive stimulus may produce:

Pleasure.
Anticipation.
Craving.
Excitement.
An urge to approach.

For example:

The sight of a gambling application may produce excitement and an urge to bet.

The gambling cue is not yet associated with the treatment’s unpleasant response.

During Conditioning

The addiction-related cue is repeatedly presented with a real noxious stimulus.

For example:

A gambling cue is repeatedly paired with an unpleasant electric stimulus.

The unpleasant stimulus naturally produces discomfort.

After Conditioning

Following repeated pairings, the addiction-related cue may produce discomfort even when the noxious stimulus is absent.

The person may then:

Feel anxious when seeing the gambling cue.
Experience an aversive reaction.
Avoid the gambling activity.
Become less likely to perform the addictive response.

Aversion Therapy Conditioning Diagram

Before treatment

Gambling cue or activity = NS → excitement or no aversion

Real unpleasant stimulus = UCS → discomfort or fear = UCR

During treatment

Gambling cue or activity = NS + unpleasant stimulus = UCS → discomfort = UCR

After treatment

Gambling cue or activity = CS → learned discomfort or avoidance = CR

AQA’s 2024 mark scheme uses this same conditioning rationale: the undesired behaviour begins as a neutral stimulus, is paired with a real noxious UCS and becomes a CS that elicits avoidance.

Applying Aversion Therapy to Gambling

Consider this scenario:

Ethan finds online gambling highly exciting. He places bets whenever he sees a gambling application on his phone.

An aversion programme could involve:

Presenting gambling-related images or simulated betting situations.
Pairing those cues with a real unpleasant stimulus.
Repeating the association across several trials.
Conditioning gambling cues to produce discomfort.
Reducing Ethan’s desire to open the application.
Encouraging avoidance of future betting situations.

The conditioning terms would be:

Component	Application
NS	Gambling application or betting cue before treatment
UCS	Real unpleasant stimulus
UCR	Natural discomfort or fear
CS	Gambling application after conditioning
CR	Learned aversion or avoidance

AQA Application to Gambling

In the June 2024 assessment, AQA accepted pairing images of a casino with negative or noxious consequences to produce conditioned avoidance. The mark scheme also notes that electric shocks have historically been used in aversion therapy for gambling addiction.

What Aversion Therapy Is Trying to Change

Before treatment:

Gambling cue → excitement → betting

After treatment:

Gambling cue → aversion → avoidance

The treatment does not change the mathematical probability of winning.

It changes the emotional and behavioural response to gambling cues.

Applying Aversion Therapy to Substance Addiction

The same principles could be applied to a substance-related cue.

For example:

A person’s sight or use of an addictive substance is repeatedly paired with a real unpleasant experience.

Through conditioning:

The substance becomes a CS.
The unpleasant response becomes a CR.
Attraction may be replaced by disgust or avoidance.
Substance-seeking behaviour may decrease.

A strong AQA answer does not need to provide clinical instructions. It should explain:

Addiction-related cue + genuine unpleasant stimulus → conditioned aversion → reduced addictive behaviour

The Role of Repetition

One pairing may be insufficient.

Repeated pairing helps establish a stronger association between:

The addictive cue.
The unpleasant outcome.

The treatment may become more effective when:

The pairing is consistent.
The aversive stimulus is sufficiently noticeable.
Relevant addiction cues are included.
The client remains engaged.
The conditioned response transfers outside treatment.

Why Timing Matters

The unpleasant stimulus should be closely associated with the addictive cue.

If a long delay occurs, the person may not learn that the two events are connected.

This is called contiguity.

The cue and noxious stimulus must occur close enough together for the association to develop.

Contingency

Contingency refers to the reliability with which one event predicts another.

If the addictive cue consistently predicts the unpleasant stimulus during treatment, the association is clearer.

If the unpleasant event occurs randomly and is unrelated to the cue, conditioning may be weaker.

From Aversion to Avoidance

The intended process is:

The addictive cue is presented.
The cue predicts an unpleasant experience.
The cue begins producing anticipatory discomfort.
The person avoids the addictive substance or behaviour.
The original approach response becomes weaker.
Addictive behaviour decreases.

AQA’s 2024 mark scheme states that repeated pairing can turn the undesired behaviour into a conditioned stimulus eliciting fear or avoidance, leading to extinction of the unwanted behaviour.

What Is Extinguished?

In this context, extinction refers to the reduction of the previous addictive response.

The treatment aims to weaken:

Approach behaviour.
Consumption.
Gambling.
Cue-triggered engagement.

It does not mean that the person forgets the addiction or that every previous association disappears.

Covert Sensitisation

What Is Covert Sensitisation?

Covert sensitisation is a behavioural intervention in which the person vividly imagines the addictive behaviour together with an unpleasant or noxious consequence.

The word covert means that the conditioning occurs mentally rather than through a directly administered physical stimulus.

The person might imagine:

Disgusting sensory experiences.
Sickness.
Humiliation.
Financial devastation.
Social rejection.
Frightening consequences.
Other personally aversive outcomes.

AQA describes covert sensitisation as using vivid guided imagery involving visual, auditory, olfactory or tactile details.

Covert Does Not Mean Secret

Covert sensitisation is not:

Treatment carried out without the client’s knowledge.
Hidden punishment.
Secret monitoring.
A disguised form of medication.

It is called covert because the aversive event is imagined internally.

The Covert Sensitisation Procedure

A general programme may involve the following stages.

Stage 1: Identify the Addictive Behaviour

The therapist identifies:

The addictive substance or activity.
Situations in which it occurs.
Cues that trigger craving.
The rewards maintaining it.
Consequences that the client personally finds aversive.

Stage 2: Relaxation

The person may first be taught to relax.

AQA’s 2020 mark scheme includes relaxation before the therapist introduces vivid guided imagery.

Relaxation can help the person:

Focus attention.
Follow the imagery.
Remain engaged.
Produce a detailed mental scene.

Relaxation is not the main conditioning mechanism.

The key process is pairing the addictive cue with imagined aversion.

Stage 3: Imagine the Addictive Cue

The person imagines:

Seeing the addictive substance.
Preparing to use it.
Entering the relevant environment.
Beginning the addictive behaviour.
Experiencing the usual trigger.

The scene should be specific to the individual.

For example, a gambler might imagine:

Opening a betting application.
Entering a casino.
Handling betting money.
Selecting a high-stakes game.
Hearing gambling-machine sounds.

Stage 4: Introduce an Imagined Noxious Consequence

The scene then becomes unpleasant.

The person may imagine:

Severe financial loss.
Losing essential possessions.
A disgusting sensory experience.
Feeling physically sick.
Public embarrassment.
An upsetting personal consequence.

The unpleasant consequence must be vivid enough to produce a genuine emotional reaction.

Stage 5: Repeat the Association

The addictive cue and imagined noxious event are paired repeatedly.

The aim is for the person eventually to experience discomfort when:

Imagining the addiction.
Encountering the relevant cue.
Considering performing the behaviour.

Stage 6: Conditioned Avoidance

The addiction-related cue becomes a conditioned stimulus.

It produces:

Disgust.
Anxiety.
Fear.
Anticipated negative consequences.
Avoidance.

The person becomes less likely to carry out the addictive behaviour.

The Importance of Vivid Imagery

The imagined scene should be:

Detailed.
Personalised.
Emotionally meaningful.
Multisensory.
Easy for the client to recreate.

The client might imagine:

What they can see.
What they can hear.
What they can smell.
What they can feel.
Their emotional response.
The consequences for other people.

AQA states that more vivid or graphic imagery may make covert sensitisation more effective.

Visual Imagery

Examples include imagining:

A ruined bank balance.
A damaged home.
A disgusting substance.
Distressing physical consequences.

Auditory Imagery

Examples include imagining:

Alarms.
Arguments.
Distressing sounds.
Someone expressing disappointment.

Olfactory Imagery

Examples include imagining:

An overpowering unpleasant smell.
A smell associated with sickness.
A contaminated environment.

Tactile Imagery

Examples include imagining:

Unpleasant physical sensations.
Dirty or uncomfortable clothing.
Physical discomfort.

The strongest imagery will depend on what the person finds genuinely aversive.

Covert Sensitisation Conditioning Diagram

Before conditioning

Addictive cue = NS → craving, pleasure or no aversion

Imagined noxious experience = UCS → imagined disgust or fear = UCR

During conditioning

Imagined addictive cue = NS + imagined noxious experience = UCS → aversion = UCR

After conditioning

Addictive cue = CS → learned aversion or avoidance = CR

The noxious stimulus is imagined, but the learning principle remains classical conditioning.

Applying Covert Sensitisation to Gambling

Consider this scenario:

Nia gambles in an online casino every evening. She finds the colours, sounds and possibility of a large win exciting.

The therapist might ask Nia to:

Relax and focus on a guided image.
Imagine opening the online casino.
Imagine placing increasingly large bets.
Imagine losing all the money needed for rent and food.
Imagine the emotional and practical consequences.
Repeat the scene during several sessions.
Practise recalling the aversive image when gambling cues appear.

The intended outcome is:

Online casino cues → imagined financial devastation → conditioned aversion → reduced gambling

AQA’s 2024 mark scheme gives extreme poverty as an example of a noxious image that could be paired with casino imagery.

Applying Covert Sensitisation to a Substance

Suppose a person experiences strong attraction to an addictive substance.

They could be guided to imagine:

Preparing to use it.
Beginning consumption.
A personally disgusting or distressing consequence.
The physical and emotional effects.
Avoiding the substance afterwards.

Repeated mental pairing is intended to make the substance itself aversive.

AQA’s Applied Example

In November 2020, AQA asked students to explain how covert sensitisation could reduce an addiction involving chocolate.

The mark scheme credited:

Relaxation.
Vivid guided imagery.
Visual, auditory, olfactory or tactile noxious images.
Pairing the previously attractive substance with an imagined UCS.
Development of a conditioned aversion.
Future avoidance.

The examiner report noted that some students confused covert sensitisation with aversion therapy, showing the importance of distinguishing imagined and real stimuli.

Aversion Therapy and Covert Sensitisation Compared

Aversion therapy	Covert sensitisation
Uses a real unpleasant stimulus	Uses an imagined unpleasant stimulus
Conditioning occurs through direct external experience	Conditioning occurs through guided mental imagery
May produce a strong immediate response	Depends heavily on imagination
Greater protection-from-harm concerns	Generally less physically intrusive
May involve real discomfort	Avoidance is rehearsed covertly
May be harder to justify ethically	Often viewed as more dignified
Can be difficult to apply safely	Can be adapted to many addictions
Requires consent and cooperation	Requires motivation and vivid imagery
Based on classical conditioning	Based on classical conditioning
Aims to create a conditioned aversion	Aims to create a conditioned aversion

Central Similarity

Both therapies:

Begin with an addictive cue.
Introduce a noxious UCS.
Produce an aversive UCR.
Use repeated pairing.
Turn the addictive cue into a CS.
Attempt to produce an aversive CR.
Aim to reduce approach and increase avoidance.
Focus on learned behaviour.

Central Difference

The most important examination distinction is:

Aversion therapy uses a real noxious stimulus, whereas covert sensitisation uses an imagined noxious stimulus.

Choosing the Aversive Consequence

Individualisation

The same imagined or real consequence will not be equally aversive for every person.

Treatment should consider:

What the client dislikes.
The type of addiction.
The relevant cues.
The person’s life circumstances.
Ethical limits.
Ability to tolerate the procedure.
Capacity for imagination.

For a gambler, financial devastation may be meaningful.

For another client, damage to relationships may be more emotionally powerful.

The Consequence Must Be Relevant

A generic unpleasant scene may have limited impact.

A personally relevant consequence is more likely to:

Produce emotional arousal.
Be remembered.
Become associated with the addictive cue.
Be recalled during high-risk situations.

However, making imagery emotionally powerful also raises ethical concerns.

Behavioural Interventions and Nicotine Addiction

Aversion therapy could attempt to condition smoking-related cues to produce an unpleasant response.

Covert sensitisation could involve imagining:

Lighting a cigarette.
Smoking.
A vivid noxious consequence.
Feeling repelled by the cigarette.
Rejecting future smoking opportunities.

However, these interventions may not directly remove:

Physical nicotine dependence.
Neurochemical withdrawal.
Nicotinic-receptor adaptation.

This connects with biological treatments for physical dependence [Lesson 8: Drug therapy].

A person may develop an aversion while still experiencing withdrawal, so combined treatment may be needed.

Behavioural Interventions and Gambling Addiction

Gambling is suitable for covert sensitisation because the person can imagine:

The casino.
The betting application.
The act of placing a bet.
The loss of money.
Longer-term consequences.

AQA describes covert sensitisation as flexible enough for both addictive substances and addictive behaviours such as gambling.

Gambling and Aversion Therapy

AQA also recognises the use of real aversive stimuli, including electric shocks, in aversion therapy for gambling addiction.

This creates a clear ethical evaluation because:

The client is deliberately exposed to discomfort.
The procedure may be distressing.
The balance between benefit and harm must be considered.

Behavioural Interventions and Learning Theory

Aversion therapy and covert sensitisation are direct applications of classical conditioning.

They also interact with earlier learning processes.

Before Treatment

The addiction may have been maintained by:

Positive reinforcement from pleasure or wins.
Negative reinforcement through relief from withdrawal or distress.
Conditioned environmental cues.
Partial reinforcement.

During Treatment

A new association is established:

Addictive cue → aversion

After Treatment

The new conditioned aversion is intended to compete with:

Reward expectations.
Craving.
Excitement.
Conditioned approach behaviour.

This connects with:

conditioning and cue reactivity in smoking [Lesson 5: Learning theory and nicotine addiction]
partial and variable reinforcement in gambling [Lesson 6: Learning theory and gambling addiction]

Behavioural Interventions and Cognitive Bias

A gambler might possess beliefs such as:

“A win is due.”
“I have special skill.”
“My ritual affects the outcome.”
“A near miss means success is close.”

Aversion therapy may make gambling unpleasant without directly correcting these beliefs.

The person might still believe that gambling is profitable or controllable.

This connects with irrational gambling beliefs and cognitive bias [Lesson 7: Cognitive explanations of gambling addiction].

CBT may be more appropriate where distorted thinking is central.

Behavioural Interventions and Physical Dependence

A behavioural intervention changes learned associations.

It does not directly reverse:

Receptor adaptation.
Neurochemical tolerance.
Physical withdrawal.
Substance metabolism.

A nicotine-dependent smoker might therefore experience two competing responses:

Conditioned aversion towards smoking.
Physical craving caused by withdrawal.

This could reduce treatment effectiveness unless physical dependence is also addressed.

Evaluating Behavioural Interventions

Strength: Based on Established Behaviourist Principles

Both interventions are based on classical conditioning.

This provides a clear and testable mechanism:

Present the addiction-related cue.
Pair it with a noxious stimulus.
Repeat the association.
Measure whether aversion develops.
Measure whether addictive behaviour decreases.

AQA identifies established scientific behaviourist principles as a strength of covert sensitisation.

Why This Is Scientifically Useful

The treatment involves variables that can be operationalised:

Number of pairings.
Intensity of aversion.
Frequency of addictive behaviour.
Craving ratings.
Avoidance.
Relapse.
Treatment completion.

This allows researchers to compare:

Before and after treatment.
Different behavioural interventions.
Treatment and control groups.
Short and long-term outcomes.

Strength: Observable Outcomes

Behavioural therapies focus on measurable behaviour.

Possible outcome measures include:

Cigarettes smoked.
Gambling sessions.
Money staked.
Time spent gambling.
Substance use.
Avoidance of relevant cues.
Relapse.

This can provide evidence beyond a client simply reporting that their thinking has changed.

Limitation of Observable Measures

A person may stop the behaviour temporarily while still experiencing:

Craving.
Distress.
Irrational beliefs.
Psychological dependence.

Observable avoidance does not necessarily demonstrate complete recovery.

Strength: Covert Sensitisation Is More Ethical Than Traditional Aversion Therapy

Covert sensitisation uses imagination instead of directly administering a physically unpleasant event.

It may therefore be:

Less traumatic.
Less physically intrusive.
More dignified.
Easier to justify ethically.
More acceptable to clients.

This comparison is explicitly recognised in AQA’s November 2020 mark scheme.

Ethical Advantage Is Relative

Covert sensitisation is more ethical than many traditional aversion procedures, but it is not completely free from ethical concerns.

The therapist deliberately asks the person to imagine distressing experiences.

The imagery may produce:

Anxiety.
Disgust.
Shame.
Emotional distress.

Informed consent and protection from harm remain important.

Strength: Covert Sensitisation Is Flexible

Covert sensitisation can be adapted to:

Smoking.
Substance misuse.
Gambling.
Other addictive behaviours.

The therapist does not need to reproduce the actual addictive behaviour or provide a real noxious stimulus.

The imagined scene can be matched to:

The person.
The addiction.
The trigger.
The personally feared consequence.

AQA identifies this flexibility across substances and behavioural addictions as a strength.

Strength: The Client Can Rehearse the Technique

The client may be able to recall the imagined aversive sequence when:

A craving occurs.
A gambling advertisement appears.
They enter a high-risk environment.
They feel tempted to relapse.

This gives covert sensitisation potential use outside the therapy room.

However, its effectiveness depends on whether the person can recreate the image vividly under genuine emotional pressure.

Limitation: Ethical Problems with Aversion Therapy

Aversion therapy deliberately causes discomfort.

AQA identifies ethical issues as a central limitation and notes the historical use of electric shocks for gambling addiction.

Relevant concerns include:

Protection from psychological or physical harm.
Informed consent.
Right to withdraw.
Dignity.
Whether the discomfort is proportionate.
The existence of less aversive alternatives.

Informed Consent

The client should understand:

What the procedure involves.
That it will be unpleasant.
Possible risks.
Possible benefits.
Alternative treatments.
Their right to stop.

Consent is not meaningful if the likely distress is concealed.

Right to Withdraw

The client must remain free to withdraw.

However, leaving treatment before sufficient pairings occur may prevent conditioning from developing.

This creates tension between:

Effective treatment.
Respecting autonomy.

The therapist cannot ethically force continued participation.

Limitation: High Dropout

AQA’s 2024 mark scheme identifies high dropout rates as a concern for both aversion therapy and covert sensitisation.

Clients may stop because they:

Find the procedure unpleasant.
Do not want to imagine distressing consequences.
Feel embarrassed.
Doubt the treatment.
Lack motivation.
Experience little early improvement.
Prefer another therapy.

Why Dropout Matters

A treatment may be effective among clients who complete it but less effective overall if many clients leave.

Researchers should distinguish:

Outcomes among treatment completers.
Outcomes among everyone who began treatment.

A therapy cannot benefit a client who refuses or abandons it.

Limitation: Covert Sensitisation Requires Imagination

The client must be able to:

Produce vivid images.
Maintain concentration.
Experience an emotional reaction to imagination.
Follow guided imagery.
Recreate the scene independently.

AQA states that effectiveness may be limited when the client lacks the capacity for imagination.

Individual Differences in Imagery

Some people create vivid multisensory images easily.

Others may:

Produce only weak images.
Become distracted.
Avoid disturbing details.
Feel little emotional response.
Struggle with guided visualisation.

The same programme may therefore have different effects across clients.

Limitation: Motivation Is Required

The client must engage actively.

They need to:

Attend sessions.
Follow instructions.
Imagine the scenes accurately.
Tolerate discomfort.
Repeat the association.
Use the technique during temptation.
Avoid deliberately weakening the imagery.

AQA identifies poor motivation as a limitation of covert sensitisation.

A client attending only because of external pressure may not engage honestly.

Limitation: May Address Behaviour Rather Than the Cause

Behavioural interventions focus on changing:

The response.
The cue-response association.
Approach and avoidance.

They may not address why the addiction developed.

Possible underlying factors include:

Genetic vulnerability.
Neurochemical dependence.
Chronic stress.
Family modelling.
Peer influence.
Cognitive bias.
Trauma.
Low self-efficacy.
Social isolation.

AQA identifies the behaviourist focus on outward behaviour and failure to address the original cause as an important limitation.

Example

A person may stop gambling because casino cues have become aversive but continue to believe:

Gambling is a reliable way to make money.
A win is due.
They possess special skill.

If the conditioned aversion weakens, these beliefs may promote relapse.

Limitation: Relapse

A relapse occurs when a person returns to addictive behaviour after treatment.

Relapse may occur because:

The conditioned aversion weakens.
The person encounters new cues.
The treatment occurred in only one setting.
The original rewards remain powerful.
Physical withdrawal continues.
Stress increases.
The underlying cause was not addressed.
The person stops rehearsing the imagery.

AQA questions the sustainability and long-term effectiveness of covert sensitisation and identifies relapse as a consequence of failing to address underlying causes.

Short-Term and Long-Term Effectiveness

Short-Term Outcomes

Immediately after treatment, the person may report:

Increased disgust.
Lower craving.
Avoidance of the addictive cue.
Reduced substance use.
Reduced gambling.

Long-Term Outcomes

A stronger assessment considers whether:

Behaviour remains reduced months later.
The conditioned aversion survives outside therapy.
Relapse decreases.
New triggers are managed.
The person develops healthier coping strategies.

AQA’s 2024 mark scheme distinguishes short-term and long-term effects and notes evidence that aversion therapy may be less effective over the longer term than covert sensitisation.

Why Aversion May Weaken

The person repeatedly encounters the addictive cue without the treatment’s noxious stimulus.

For example:

A gambling application is seen many times without an electric shock.

The learned aversion may weaken because the CS is presented without the UCS.

The original reward may then regain influence.

Extinction of the Conditioned Aversion

The conditioned aversion itself may undergo extinction.

The process is:

The addictive cue has become a CS.
It produces an aversive CR.
Outside treatment, the cue appears without the noxious UCS.
Repeated unreinforced exposure weakens the aversion.
Addictive approach behaviour may return.

This creates a difficult treatment problem:

The therapy relies on conditioning, but everyday life may gradually weaken that conditioning.

Booster sessions or continued rehearsal may be needed, although the supplied AQA material does not prescribe a standard maintenance schedule.

Generalisation

Generalisation occurs when the conditioned response transfers to similar stimuli.

A useful treatment would ideally produce aversion across:

Different gambling applications.
Different casinos.
Different cigarette brands.
Different high-risk settings.
Real and imagined cues.

Limited Generalisation

If treatment uses only one very specific cue, the person might avoid that cue while responding normally to others.

For example:

Avoiding one gambling website.
Continuing to use another.
Avoiding one casino.
Continuing to bet on sport.

A broad range of relevant cues may therefore be needed.

Discrimination

Discrimination occurs when the conditioned response is restricted to a particular stimulus.

This may be a limitation if:

The client associates aversion only with the therapy-room image.
Real-life cues do not trigger the conditioned response.
The person recognises that no genuine noxious consequence will occur outside treatment.

Successful treatment requires transfer from the therapeutic procedure to everyday addictive behaviour.

Strength: Evidence Can Be Used to Compare Interventions

The June 2024 mark scheme names McConaghy (1983) as relevant evidence concerning covert sensitisation for gambling dependency.

However, the supplied AQA mark scheme does not provide:

The procedure.
Sample size.
Numerical findings.
Follow-up duration.

Students should not invent these details.

A safe examination use is:

Research such as McConaghy’s work has been used to evaluate covert sensitisation for gambling dependency, providing a basis for comparing behavioural interventions.

Evidence is strongest when the method and findings have been learned accurately from verified teaching materials.

Limitation: Measuring Effectiveness

Possible measures include:

Measure	What it indicates	Limitation
Self-reported craving	Subjective desire	May be affected by social desirability
Avoidance of cues	Conditioned response	May not show long-term recovery
Frequency of behaviour	Behavioural change	May rely on truthful reporting
Financial records	Changes in gambling	Not relevant to every addiction
Biological tests	Substance use	Cover only particular periods
Relapse rate	Long-term return to addiction	Relapse may be hidden
Treatment completion	Acceptability	Completion does not prove effectiveness

No single measure captures every treatment aim.

Limitation: Demand Characteristics

Clients know that the therapy is designed to make the addictive behaviour unpleasant.

They may:

Report disgust because it is expected.
Avoid the behaviour temporarily to please the therapist.
Guess the aim of the study.
exaggerate improvement.

Observed change may reflect expectations rather than conditioned aversion alone.

Counterargument

Behavioural measures taken outside therapy, such as reduced gambling or independently verified abstinence, would provide stronger evidence than immediate self-report.

Environmental Reductionism

Behavioural interventions may be described as environmentally reductionist because they reduce addiction to:

Stimuli.
Associations.
Conditioned responses.
Observable behaviour.

This has advantages:

Variables are clearly defined.
Procedures can be standardised.
Outcomes can be measured.
Treatments can be tested.

However, the explanation may overlook:

Biological dependence.
Irrational beliefs.
Personal meaning.
Relationships.
Social context.
Emotional causes.

A learned aversion may therefore treat only one level of a complex addiction.

Environmental Determinism

The behavioural approach may suggest that behaviour is controlled by learned associations.

The person may appear to move from:

Reward-controlled addiction

to:

Aversion-controlled avoidance

This could underestimate:

Conscious choice.
Personal values.
Self-reflection.
Motivation.
Decision-making.

However, covert sensitisation requires active participation and imagination, so the client is not entirely passive.

Behavioural Interventions Compared with Drug Therapy

Behavioural interventions	Drug therapy
Change learned associations	Changes biological processes
Use classical conditioning	Acts on receptors or neurotransmitters
Aim to create aversion	Aims to reduce withdrawal, craving or reward
Can apply to behavioural addiction	Especially suitable for substance dependence
May involve ethical distress	May produce physical side effects
Do not directly treat withdrawal	Can directly manage physical dependence
May weaken over time	Benefits may depend on continued medication
Avoid substitute dependency	May create or maintain dependency on medication

The therapies may be combined when both learning and physical dependence are important.

Behavioural Interventions Compared with CBT

Behavioural interventions	Cognitive behaviour therapy
Focus on conditioned responses	Focuses on thoughts and behaviour
Pair addiction with aversion	Identifies and challenges distorted thinking
Can produce avoidance without insight	Requires reflection and active discussion
Does not directly correct cognitive bias	Directly targets beliefs and expectations
Covert sensitisation requires imagery	CBT requires verbal and cognitive engagement
May have ethical concerns	May be emotionally demanding
Relapse may occur if aversion weakens	Skills may transfer across situations
Based mainly on classical conditioning	Combines cognitive and behavioural methods

CBT is examined in challenging thoughts and developing coping behaviour [Lesson 10: Cognitive behaviour therapy].

Appropriateness of Aversion Therapy

Aversion therapy may be more appropriate when:

The addictive cue is clearly identifiable.
The client understands the procedure.
Other treatments have been considered.
The person gives informed consent.
A safe and proportionate noxious stimulus can be used.
The potential benefit outweighs the distress.

It may be less appropriate when:

The client is vulnerable to harm.
The procedure causes excessive distress.
A less aversive treatment is available.
Physical withdrawal is severe.
The addiction is driven mainly by cognitive beliefs.
The client is unwilling to participate.

Appropriateness of Covert Sensitisation

Covert sensitisation may be appropriate when:

The client can create vivid mental images.
Real aversion therapy would be unethical or impractical.
The addiction is behavioural, such as gambling.
The person is motivated.
Relevant consequences can be imagined.
The client prefers a less physically intrusive intervention.

It may be less appropriate when:

Imagery ability is limited.
Concentration is poor.
The person avoids unpleasant elements of the scene.
The addiction has strong physical withdrawal.
The person lacks motivation.
Imagined aversion does not transfer to real life.

A Combined Treatment Approach

Consider a smoker with:

Nicotine withdrawal.
Conditioned smoking cues.
The belief that smoking is needed for relaxation.
Friends who smoke.

A combined programme might include:

Drug therapy to reduce physical withdrawal.
Covert sensitisation to condition aversion to smoking cues.
CBT to challenge beliefs about relaxation.
Social support to manage peer influence.
Relapse-prevention work.

This addresses:

Biology.
Learning.
Cognition.
Social environment.

Applying Both Treatments to One Scenario

Reuben gambles every evening. He becomes excited when he hears casino sounds and believes gambling helps him escape from stress. He has lost money needed for household bills.

Aversion therapy

Casino sounds or simulated gambling would be presented.
These cues would be paired with a real unpleasant stimulus.
The gambling cues would become conditioned stimuli.
Reuben would develop discomfort or avoidance.

Covert sensitisation

Reuben would relax and imagine entering the casino.
He would imagine placing bets and losing money needed for household bills.
He would imagine the emotional and practical consequences vividly.
Repeated pairing would condition gambling-related cues to produce aversion.

Limits of both treatments

Neither directly teaches stress-management skills.
Neither necessarily challenges beliefs about gambling probability.
The conditioned aversion may weaken.
Reuben may need CBT and alternative coping strategies.

Overall Evaluation

Aversion therapy and covert sensitisation are behavioural interventions based on classical conditioning. Aversion therapy pairs the addictive substance, behaviour or cue with a real noxious stimulus. Following repeated pairings, the addiction-related cue becomes a conditioned stimulus that produces an aversive conditioned response and avoidance.

Covert sensitisation applies the same principle mentally. The client relaxes and vividly imagines the addictive behaviour followed by an unpleasant consequence. Visual, auditory, olfactory and tactile details may be used to make the imagined experience emotionally powerful.

Both approaches have a clear scientific rationale and can be applied to different addictions. Covert sensitisation is generally more flexible, dignified and ethically acceptable than traditional aversion therapy.

However, aversion therapy raises serious ethical concerns because it deliberately causes discomfort. Both treatments may have high dropout rates and questionable long-term effectiveness. Covert sensitisation also depends heavily on motivation and imagery ability. Most importantly, behavioural interventions may change outward behaviour without addressing genetic vulnerability, physical dependence, cognitive bias, stress or social influence.

The strongest conclusion is that these interventions may help selected, motivated clients, especially when combined with treatments addressing the wider biological, cognitive and social causes of addiction.

Key Words 🔑

Key word	Student-friendly definition	How it may be used in an exam
Behavioural intervention	A treatment that changes learned behaviour or associations	Introduce both therapies
Aversion therapy	Pairing an addictive cue with a real unpleasant stimulus	Explain the first intervention
Covert sensitisation	Pairing an imagined addictive cue with an imagined unpleasant consequence	Explain the second intervention
Classical conditioning	Learning through association between stimuli	Explain the treatment mechanism
Counterconditioning	Replacing one learned response with another	Explain attraction being replaced by aversion
Neutral stimulus	A stimulus that does not initially produce the target conditioned response	Identify the addiction cue before treatment
Unconditioned stimulus	A stimulus that naturally produces a response	Identify the real or imagined noxious event
Unconditioned response	The natural response to the UCS	Identify discomfort, fear or disgust
Conditioned stimulus	The previously neutral cue after conditioning	Identify the treated addictive cue
Conditioned response	The learned response to the CS	Identify aversion or avoidance
Noxious stimulus	An unpleasant stimulus producing discomfort or distress	Explain the UCS
Aversive stimulus	A stimulus that a person seeks to avoid	Describe the treatment consequence
Aversion	A strong feeling of dislike, disgust or avoidance	Explain the intended response
Guided imagery	Therapist-led creation of detailed mental scenes	Explain covert sensitisation
Multisensory imagery	Imagery involving sight, sound, smell or touch	Explain vivid covert treatment
Covert	Taking place mentally rather than through observable external stimulation	Distinguish the therapies
Overt	Directly observable or physically administered	Describe traditional aversion therapy
Approach behaviour	Moving towards or engaging with a stimulus	Explain the addictive response before treatment
Avoidance behaviour	Moving away from or refusing a stimulus	Explain the treatment outcome
Repetition	Presenting the pairing several times	Explain strengthening of conditioning
Contiguity	Closeness in time between two stimuli	Explain effective association
Contingency	Reliability with which one stimulus predicts another	Explain clear conditioning
Extinction	Weakening of a learned response when reinforcement or pairing no longer occurs	Explain reduced addiction or weakened aversion
Generalisation	Transfer of a conditioned response to similar cues	Evaluate real-world usefulness
Discrimination	Responding only to a particular cue	Explain limited treatment transfer
Relapse	Return to addictive behaviour after treatment	Evaluate long-term effectiveness
Dropout	Leaving treatment before completion	Evaluate acceptability
Motivation	Willingness to engage actively with treatment	Evaluate covert sensitisation
Imagery ability	Capacity to create vivid mental scenes	Evaluate individual suitability
Informed consent	Agreement based on understanding the procedure and risks	Evaluate ethical acceptability
Protection from harm	Ethical responsibility to avoid unnecessary physical or psychological harm	Evaluate aversion therapy
Behavioural reductionism	Explaining or treating addiction through simplified learned behaviour	Evaluate theoretical limits
Environmental determinism	The view that behaviour is governed by environmental learning	Discuss personal control
Appropriateness	Suitability of a treatment for a particular client and addiction	Judge treatment selection
Effectiveness	The extent to which treatment reduces addiction	Evaluate short and long-term outcomes
Combined treatment	Using several interventions to address different causes	Reach an interactionist conclusion

Hints from the Examiner Reports 💡

Distinguish the Two Treatments Clearly

The November 2020 examiner report found that some students confused covert sensitisation with aversion therapy.

Use this simple rule:

Aversion therapy: real noxious stimulus.
Covert sensitisation: imagined noxious stimulus.

Both use classical conditioning.

Use the Complete Conditioning Sequence

AQA’s June 2024 examiner report praised answers that made explicit links to behaviourist principles.

A strong explanation includes:

Addiction-related cue begins as an NS.
Noxious event is the UCS.
The UCS produces discomfort as the UCR.
NS and UCS are paired repeatedly.
The addictive cue becomes a CS.
The cue produces conditioned aversion or avoidance as the CR.

Apply the Therapy to the Stem

Weak answer:

The client imagines something unpleasant.

Improved answer:

The gambler imagines opening the casino application and then vividly imagines losing the money needed to pay rent, producing fear and disgust that become associated with the application.

The noxious image should be connected to the particular addiction and circumstances.

Include Vivid Sensory Details

The November 2020 mark scheme accepts:

Visual imagery.
Auditory imagery.
Olfactory imagery.
Tactile imagery.

Explain why they matter:

Vivid sensory details make the imagined consequence more emotionally powerful and improve the likelihood of conditioning.

Do Not Call Covert Sensitisation Covert Desensitisation

The therapy required by the specification is covert sensitisation.

It sensitises the client to unpleasant consequences.

It is not systematic desensitisation for phobias.

Explain Avoidance

Do not stop after stating that the client feels unpleasant.

Complete the behavioural effect:

The conditioned aversion makes the client less likely to approach or perform the addictive behaviour.

Compare Ethics Properly

A developed comparison is:

Traditional aversion therapy may expose the client to real physical or psychological discomfort, raising protection-from-harm concerns. Covert sensitisation uses imagined aversion, making it less intrusive and generally more dignified, although distressing imagery may still cause harm.

Evaluate Long-Term Outcomes

AQA’s 2024 mark scheme identifies short-term compared with long-term effectiveness as a key issue.

Ask:

Does aversion remain after treatment?
Does it transfer to real cues?
Does relapse decrease?
Were follow-up measures used?

Discuss Dropout

Do not merely state:

Some people drop out.

Develop the implication:

A highly unpleasant intervention may cause clients to withdraw before sufficient conditioning occurs. Effectiveness among treatment completers may therefore exaggerate effectiveness across everyone offered treatment.

Avoid Invented Studies

The June 2024 examiner report warned that some students appeared to invent efficacy studies and made speculative claims about treatment time and cost.

AQA names McConaghy’s research as relevant to covert sensitisation for gambling dependency but does not provide detailed findings in the supplied mark scheme. Do not invent its sample size or results.

Explain Relapse Through the Theory

A strong behavioural explanation is:

Outside therapy, the addictive cue may repeatedly occur without the noxious stimulus. The conditioned aversion may therefore undergo extinction, allowing the original rewarding association and addictive response to return.

Compare with Other Treatments

Useful comparisons include:

Drug therapy targets physical dependence.
CBT targets thoughts and coping skills.
Aversion therapy targets learned approach behaviour.
Covert sensitisation targets imagined associations.

Match the Intervention to the Addiction

The aversion may extinguish when the cue occurs without the noxious stimulus.

How to improve:

Discuss relapse and long-term follow-up.

Mistake 15

Mistake: Inventing research findings or exact success rates.

Why this is risky:

Unsupported evidence weakens accuracy.

How to improve:

Use named evidence only when its procedure and findings are known securely.

Exam-Style Questions ✍️

Question 1

What is meant by aversion therapy as a way of reducing addiction? [2 marks]

Question 2

What is meant by covert sensitisation? [2 marks]

Question 3

Explain one difference between aversion therapy and covert sensitisation. [3 marks]

Question 4

Outline how classical conditioning is involved in aversion therapy. [4 marks]

Question 5

Freya gambles online every evening. She finds the casino sounds and colourful displays exciting. She has recently lost money intended for household bills.

Explain how covert sensitisation could be used to reduce Freya’s gambling. [6 marks]

Question 6

A person undergoing aversion therapy is repeatedly shown gambling-related cues while experiencing a real unpleasant stimulus.

Identify the following:

The neutral stimulus.
The unconditioned stimulus.
The unconditioned response.
The conditioned stimulus.
The conditioned response.

[5 marks]

Question 7

A hypothetical study recorded treatment completion and abstinence from gambling.

Treatment	Number starting	Number completing	Number abstinent six months later
Aversion therapy	80	48	24
Covert sensitisation	80	64	40

Calculate the percentage of each starting group that remained abstinent six months later. Explain one conclusion and one limitation of the data. [6 marks]

Question 8

Explain one ethical limitation of aversion therapy. [3 marks]

Question 9

Explain one strength and one limitation of covert sensitisation. [6 marks]

Question 10

Discuss behavioural interventions for reducing addiction. Refer to aversion therapy and covert sensitisation in your answer. [16 marks]

Answers and Mark Scheme

Question 1

Award one mark for each of the following:

The addictive substance, behaviour or cue is paired with a real unpleasant stimulus.
Repeated association is intended to create a conditioned aversion and reduce the addictive behaviour.

Maximum: 2 marks

Question 2

Award one mark for each of the following:

The client imagines the addictive behaviour together with an imagined unpleasant consequence.
Repeated imagery is intended to condition aversion or avoidance.

Maximum: 2 marks

Question 3

Award marks as follows:

One mark for stating that aversion therapy uses a real unpleasant stimulus.
One mark for stating that covert sensitisation uses an imagined unpleasant stimulus.
One mark for an explicit comparison or shared classical-conditioning mechanism.

Possible answer:

Aversion therapy pairs the addictive cue with a real noxious stimulus, whereas covert sensitisation asks the client to imagine the addictive behaviour followed by a vivid unpleasant consequence. Both aim to establish a conditioned aversion through classical conditioning.

Question 4

Award one mark for each relevant linked point, up to four marks:

The addictive cue initially acts as a neutral stimulus.
A noxious stimulus is the unconditioned stimulus.
It naturally produces discomfort, fear or disgust as the unconditioned response.
The addiction-related cue and noxious stimulus are repeatedly paired.
The addictive cue becomes a conditioned stimulus.
It produces conditioned aversion or avoidance as the conditioned response.
Reduced approach behaviour is the intended result.

Question 5

Award up to six marks for effective application:

Freya would first be helped to relax and focus on guided imagery.
She would imagine opening the online casino.
The sounds and colourful displays would be included as gambling cues.
She would imagine placing bets.
She would vividly imagine losing the household-bill money.
Emotional and practical consequences could be included.
Visual and auditory details could strengthen the image.
The gambling cue acts initially as an NS.
The imagined financial devastation acts as the UCS.
It produces imagined fear, disgust or distress as the UCR.
Following repeated pairings, the gambling cues become CSs.
They should produce conditioned aversion and avoidance.
Freya should become less likely to gamble.

A full-mark answer should include relevant stem details and the conditioning process.

Question 6

Award one mark for each correct identification:

Neutral stimulus: The gambling cue before treatment.
Unconditioned stimulus: The real unpleasant stimulus.
Unconditioned response: Natural discomfort, fear or distress.
Conditioned stimulus: The gambling cue after repeated pairing.
Conditioned response: Learned aversion or avoidance.

Maximum: 5 marks

Question 7

Calculations

Aversion therapy:

8024×100=30%

Covert sensitisation:

8040×100=50%

Award one mark for each correct percentage.

Conclusion

Award up to two marks:

A greater proportion of the covert-sensitisation group remained abstinent.
The difference was 20 percentage points.
Covert sensitisation was also associated with greater treatment completion.
The results are consistent with covert sensitisation being more acceptable or effective over six months.

Limitation

Award up to two marks:

Participants may not have been randomly allocated.
The addictions may have differed in severity.
Abstinence may have relied on self-report.
Other treatments may have been used.
The data do not show why participants dropped out.
Six months may not represent permanent recovery.
The groups may have differed in motivation or imagery ability.
The findings demonstrate association rather than a definitive causal effect.

Question 8

Award one mark for identifying the issue and up to two marks for development.

Possible answer:

Aversion therapy deliberately exposes the client to a real noxious stimulus, so it may cause physical or psychological distress. This creates a conflict with protection from harm and requires genuine informed consent. The treatment may be difficult to justify where a less intrusive alternative, such as covert sensitisation, is available.

Other creditworthy points include:

Dignity.
Right to withdraw.
Proportionality of the unpleasant stimulus.
Potential coercion.
High dropout caused by distress.

Question 9

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

Possible strength:

Covert sensitisation is generally more ethical than traditional aversion therapy because the unpleasant event is imagined rather than physically administered. It can also be adapted to substances and behavioural addictions such as gambling by creating personally relevant noxious imagery.

Possible limitation:

The treatment depends on motivation and imagery ability. A client who cannot form vivid images or avoids imagining the most unpleasant details may experience little conditioned aversion. The treatment may therefore be ineffective for some individuals.

Other creditworthy strengths include:

Behaviourist scientific basis.
Flexibility.
Lower physical risk.
Potential use outside therapy.

Other creditworthy limitations include:

Relapse.
Long-term sustainability.
Behavioural reductionism.
Failure to address causes.
High dropout.
Limited real-world generalisation.

Question 10

A high-level response should include accurate knowledge and developed evaluation.

Indicative AO1 Content

Behavioural interventions.
Classical conditioning.
Counterconditioning.
Addiction-related cue as NS.
Noxious stimulus as UCS.
Discomfort or fear as UCR.
Repeated pairing.
Addiction-related cue becoming CS.
Aversion or avoidance becoming CR.
Aversion therapy involving a real noxious stimulus.
Electric shocks as an example recognised by AQA for gambling addiction.
Reduction of approach behaviour.
Covert sensitisation involving imagined noxious consequences.
Relaxation.
Guided imagery.
Visual, auditory, olfactory and tactile imagery.
Importance of vividness.
Conditioned avoidance.
Application to substance addiction.
Application to gambling addiction.
Similarities and differences between the interventions.

Indicative AO3 Content

Scientific basis in established classical-conditioning principles.
Clear and testable treatment mechanism.
Observable behavioural outcomes.
Covert sensitisation being less physically intrusive.
Greater dignity and ethical acceptability.
Flexibility across addictions.
McConaghy’s research as relevant evidence for gambling dependency.
Ethical problems with real noxious stimuli.
Protection from harm.
Informed consent.
Right to withdraw.
High dropout.
Motivation.
Capacity for vivid imagery.
Differences between clients.
Short-term compared with long-term effects.
Evidence that aversion therapy may be less effective long term than covert sensitisation.
Extinction of conditioned aversion.
Relapse.
Limited generalisation outside treatment.
Failure to address underlying causes.
Behavioural reductionism.
Environmental determinism.
Failure to treat physical dependence.
Failure to challenge cognitive bias.
Comparison with drug therapy.
Comparison with CBT.
Benefits of combined treatment.
Need to match treatment to the addiction and client.

Thirteen to sixteen marks: Knowledge of both behavioural interventions is accurate and generally detailed. Classical-conditioning terminology is applied correctly, and the real-imagined distinction is clear. Discussion is thorough and focused, considering ethics, effectiveness, relapse, client suitability and alternative treatments.

Nine to twelve marks: Knowledge is mostly accurate and discussion is generally effective. Both interventions are explained, although some conditioning terminology or evaluative arguments may lack depth.

Five to eight marks: Some relevant knowledge is present, but the response is mainly descriptive. The therapies may be named without a complete conditioning sequence, or evaluation may consist of undeveloped statements about ethics.

One to four marks: Knowledge is very limited or confused. The response may treat covert sensitisation as secret treatment, confuse it with systematic desensitisation or fail to distinguish real and imagined aversion.