Discuss the two-process model of phobias

Question 10 Mark Scheme

Discuss the two-process model of phobias. Refer to an unfamiliar phobia in your answer.

[16 marks]

What is expected in the answer?

The command word “discuss” requires students to explain how the two-process model accounts for both the acquisition and maintenance of phobias, then evaluate how successfully the model explains phobic behaviour. Because the question requires reference to an unfamiliar phobia, students should apply classical and operant conditioning to a specific example throughout rather than simply describing the model in abstract terms.

The current specification explicitly requires the two-process model, including classical and operant conditioning, as the behavioural explanation of phobias.

Marks for this question: AO1 = 6, AO2 = 4, AO3 = 6

This follows the allocation used for the previous 16-mark two-process model question requiring application to a phobia: AO1 = 6, AO2 = 4 and AO3 = 6.

Level	Marks	Description
4	13–16	Knowledge of the two-process model is accurate and generally well detailed. Application to the unfamiliar phobia is effective. Discussion is thorough and effective. The answer is clear, coherent and focused, with effective use of specialist terminology.
3	9–12	Knowledge of the two-process model is evident but there are occasional inaccuracies or omissions. Application and/or discussion is mostly effective. The answer is mostly clear and organised but occasionally lacks focus.
2	5–8	Limited knowledge of the two-process model is present. The response is mainly descriptive. Discussion and/or application to the unfamiliar phobia is of limited effectiveness.
1	1–4	Knowledge of the model is very limited. Discussion and/or application is limited, poorly focused or absent. There are substantial inaccuracies or inappropriate use of terminology.
0	0	No relevant content.

These descriptors closely follow the official 16-mark two-process model mark scheme.

Indicative content

AO1: The two-process model

Credit relevant knowledge such as:

• The two-process model explains phobias through two different learning processes.

• Classical conditioning explains how a phobia is acquired.

• Operant conditioning explains how the phobia is maintained.

• A previously neutral stimulus becomes associated with a naturally fear-provoking event.

• Following conditioning, the previously neutral stimulus alone produces fear.

• Fear may generalise to similar objects or situations.

• Avoidance or escape reduces anxiety.

• The reduction in anxiety acts as negative reinforcement.

• Because avoidance is reinforced, the person continues avoiding the phobic stimulus and the fear persists.

These are the central features identified in the 16-mark mark scheme.

Classical conditioning and acquisition

Credit relevant explanation such as:

• Before conditioning, the object or situation is a neutral stimulus (NS).

• A naturally frightening or painful event acts as an unconditioned stimulus (UCS).

• It naturally produces fear or anxiety, the unconditioned response (UCR).

• If the neutral stimulus occurs alongside the frightening event, an association may form.

• The neutral stimulus becomes a conditioned stimulus (CS).

• It can then produce fear without the original frightening event.

• Fear is now the conditioned response (CR).

• A severe event may result in one-trial learning.

• The conditioned fear may also undergo stimulus generalisation, spreading to similar stimuli.

• 
  

The official mark scheme specifically identifies association, traumatic experience, one-trial learning and generalisation as relevant features of acquisition.

Operant conditioning and maintenance

Credit relevant explanation such as:

• Once a phobia has developed, the individual may avoid or escape the feared stimulus.

• Avoidance immediately reduces fear or anxiety.

• Removing this unpleasant emotional state acts as negative reinforcement.

• The avoidance behaviour becomes more likely to occur again.

• Continued avoidance prevents the person from discovering that the feared stimulus may actually be safe.

• The phobia is therefore maintained.

The mark scheme describes avoidance of the phobic stimulus as negatively reinforcing because the resulting relief acts as a reward.

AO2: Application to an unfamiliar phobia

Any plausible unfamiliar phobia can be used if the conditioning processes are applied accurately.

For example, consider a person who develops a phobia of escalators after falling on one as a child.

Acquisition

• Before the accident, an escalator is a neutral stimulus.

• Falling and being injured is an unconditioned stimulus.

• The fall naturally produces fear and pain, the unconditioned response.

• The escalator becomes associated with the frightening accident.

• The escalator becomes a conditioned stimulus.

• Seeing or approaching an escalator later produces a conditioned fear response.

• The fear may generalise to other moving stairways or similar moving platforms.

Maintenance

• The person begins avoiding escalators and uses stairs or lifts instead.

• Avoiding the escalator reduces anxiety.

• The removal of anxiety is negative reinforcement.

• Using stairs or lifts becomes increasingly likely.

• The person rarely experiences an escalator without anything bad happening, so the fear continues.

The 2024 dog-phobia question similarly required both classical and operant conditioning to be applied, including the conditioned association, generalisation and negative reinforcement of avoidance.

AO3: Discussion and evaluation

Research supports acquisition through classical conditioning

A strength of the model is that fear responses can be learned through association.

Watson and Rayner's Little Albert study demonstrated that fear could be conditioned when a previously neutral stimulus was repeatedly paired with a frightening noise.

This supports the basic principle that an initially neutral object can acquire the ability to produce fear through classical conditioning.

Watson and Rayner are explicitly identified as relevant supporting evidence in the two-process model mark scheme.

However, evidence that fear can be conditioned does not demonstrate that all naturally occurring phobias develop in this way.

Evidence from traumatic experiences provides support

Research examining people's experiences before developing phobias can also support the model.

The official mark scheme identifies DiNardo et al. as relevant evidence when evaluating whether phobias are associated with traumatic experiences.

If people with a particular phobia are more likely to report a previous frightening encounter with the phobic stimulus, this is consistent with acquisition through classical conditioning.

For the escalator example, a clear frightening accident before the development of the fear would fit the prediction of the model particularly well.

However, retrospective reports cannot always establish that the traumatic event actually caused the phobia.

Not all phobias follow a traumatic experience

A major limitation is that many people with phobias cannot identify a traumatic conditioning event that preceded their fear.

The official mark scheme explicitly identifies the fact that not all phobias result from trauma as a limitation.

If classical conditioning were a complete explanation, a relevant frightening experience should normally be identifiable.

Conversely, many people experience frightening events without subsequently developing phobias.

Therefore, conditioning may explain some phobias particularly well, but it does not fully explain individual differences in vulnerability.

Biological preparedness provides an alternative explanation

Some phobias are much more common than others.

People frequently develop fears of stimuli that may have posed threats during human evolution, whereas intense phobias of harmless modern objects are less common.

An evolutionary preparedness explanation proposes that humans may be biologically prepared to acquire certain fears more readily.

Preparedness is explicitly identified as an alternative evolutionary explanation in the official mark scheme.

This challenges the idea that all neutral stimuli are equally likely to become phobic through conditioning.

It may therefore be easier to condition fear to some objects than others because biological and learning factors interact.

The model may neglect cognitive factors

Another limitation is that the two-process model is primarily behavioural.

It focuses on:

• learned associations

• reinforcement

• observable avoidance.

However, people with phobias also have cognitive characteristics, such as irrational beliefs and exaggerated expectations of danger.

The official mark scheme specifically identifies the model's neglect of cognitive aspects of phobias as a limitation.

For example, a person with an escalator phobia might believe that escalators are highly likely to collapse or trap them. Such beliefs may contribute to maintaining the fear in addition to reinforcement of avoidance.

The two-process model may therefore provide a useful behavioural explanation without being a complete account of phobias.

Avoidance may sometimes be motivated by perceived safety

The model assumes avoidance continues because escaping from fear is negatively reinforcing.

However, avoidance may also occur because the person believes it is the only way to remain safe.

The official mark scheme recognises alternative explanations for avoidance, such as safety, as a limitation of the two-process account.

For example, the person afraid of escalators might use the stairs because they genuinely believe an escalator accident is likely, rather than simply because using the stairs reduces anxiety.

This suggests that cognitive expectations may interact with reinforcement in maintaining avoidance.

Behavioural therapies provide practical support

A strength of the model is that it led to effective behavioural treatments.

Both systematic desensitisation and flooding involve exposure to the feared stimulus and reduce avoidance. The person learns that anxiety can fall without escaping and that the expected harmful outcome does not occur.

The current specification includes both treatments alongside the two-process model.  The 2020 mark scheme specifically identifies behavioural therapies based on counterconditioning, such as systematic desensitisation, as relevant support for the explanation.

If reducing avoidance weakens the phobia, this supports the proposal that avoidance helps maintain fear.

However, the success of a treatment does not necessarily prove that the model correctly explains how the phobia originally developed.

The model separates acquisition and maintenance effectively

An important strength is that the model explains why a fear may continue long after the original frightening event has ended.

Classical conditioning alone can explain how fear begins, but it does not adequately explain why it persists.

Adding operant conditioning solves this problem:

fear → avoidance → anxiety decreases → avoidance is reinforced → continued fear

This is useful because it distinguishes the cause of the original fear from the processes that keep the phobia going.

The examiner report for the previous 16-mark question noted that the strongest students showed clear and accurate distinctions between classical and operant conditioning.

Example answer

The two-process model explains phobias using two forms of learning. Classical conditioning explains how a phobia is acquired, while operant conditioning explains why it continues.

For example, imagine someone who develops a fear of escalators after falling badly on one as a child. Before the accident, the escalator is a neutral stimulus because it does not automatically cause fear. Falling and being injured is an unconditioned stimulus, which naturally causes fear and pain as an unconditioned response.

Because the escalator is present during the frightening accident, it becomes associated with the fear. The escalator therefore becomes a conditioned stimulus and later produces fear as a conditioned response even when no accident occurs. The fear might also generalise to other escalators or similar moving walkways.

The second process is operant conditioning. The person may start using stairs or lifts whenever an escalator is available. Doing this immediately reduces their anxiety. The removal of an unpleasant feeling is negative reinforcement, so avoiding escalators becomes more likely in the future. Because the person keeps avoiding escalators, they do not have the opportunity to learn that they can use one safely. The phobia is therefore maintained.

One strength of the model is support for classical conditioning. Watson and Rayner showed that Little Albert could develop a fear of a previously neutral stimulus after it was paired with a frightening noise. This demonstrates that fear can be acquired through association and therefore supports the first process of the model.

There is also evidence that traumatic experiences can be associated with later phobias. This is consistent with the idea that a frightening event can condition fear of a previously neutral stimulus. The escalator example would fit this explanation well because the fear begins following a clear accident.

However, not everyone with a phobia can identify a traumatic event that caused it. Some people develop fears without ever having had a frightening experience with the object, while other people have traumatic experiences but do not develop phobias. This suggests that classical conditioning cannot be a complete explanation.

One alternative is biological preparedness. Humans may be more biologically ready to develop fears of stimuli that posed evolutionary threats. This could explain why some fears are acquired more easily than others. The two-process model may therefore underestimate biological influences on which phobias people develop.

The model also focuses almost entirely on behaviour and may neglect cognitive factors. A person with a phobia may have irrational beliefs about the danger of the stimulus. Someone afraid of escalators may believe that escalators frequently collapse or trap people. These beliefs could maintain the phobia alongside negatively reinforced avoidance.

A strength of the operant conditioning part of the model is that it helps explain why phobias continue. Avoidance produces immediate relief, so the behaviour is repeatedly reinforced. This also helps explain why exposure treatments can work. If a person remains in contact with the phobic stimulus rather than escaping, they can discover that anxiety decreases without avoidance and that the feared outcome does not occur.

However, the success of exposure therapy does not necessarily prove that the phobia was originally acquired through classical conditioning. It provides stronger support for the model's explanation of maintenance than for its explanation of acquisition.

Overall, the two-process model provides a useful explanation because it separates the development of a phobia through classical conditioning from its maintenance through negatively reinforced avoidance. It explains an unfamiliar phobia such as fear of escalators particularly well when there is a clear traumatic event followed by avoidance. However, not all people remember traumatic experiences, biological preparedness and cognitive factors may also be important, so the model is best viewed as a partial rather than complete explanation of phobias.

Indicative mark: 16/16

Examiner-style commentary

This would be a strong Level 4 response because the student clearly separates the two processes and applies both consistently to the unfamiliar escalator phobia.

The AO1 accurately explains:

• acquisition through classical conditioning

• NS, UCS, UCR, CS and CR

• stimulus generalisation

• maintenance through operant conditioning

• avoidance and negative reinforcement.

The AO2 is integrated rather than bolted onto the end. The escalator is identified as the neutral stimulus, the accident as the frightening event, fear is conditioned to escalators, and subsequent use of stairs or lifts is negatively reinforced.

This is particularly important because the 2024 examiner report found that application questions on the two-process model required both classical and operant conditioning to be applied to the novel phobia. Most students did this successfully, while incomplete application restricted performance.

The AO3 also reflects the official 16-mark guidance:

• Watson and Rayner and traumatic experiences provide support;

• not all phobias originate in trauma;

• evolutionary preparedness provides an alternative;

• cognitive factors may be neglected;

• avoidance may involve perceived safety as well as reinforcement;

• successful behavioural therapies provide practical support.

The 2020 examiner report gives a particularly useful warning. Strong responses showed clear distinctions between classical and operant conditioning and used evidence and therapies specifically to evaluate the model. Weaker answers confused the two processes or mentioned Little Albert and systematic desensitisation without explaining why they were relevant.

How a weaker answer could be improved

A weaker answer might say:

“The person fell on an escalator and became scared of escalators through classical conditioning. They avoid escalators through operant conditioning.”

That identifies both processes, but it lacks the detail needed for strong AO1 and AO2.

A better applied chain is:

escalator initially NS → frightening fall is UCS producing fear as UCR → escalator becomes associated with the accident → escalator becomes CS producing fear as CR → person avoids escalators → anxiety falls → relief negatively reinforces avoidance → phobia is maintained.

Evaluation should be just as explicit:

Little Albert developed conditioned fear → shows that fear can be acquired through association → supports the acquisition part of the model, but does not show that all naturally occurring phobias develop from conditioning.

The key is to keep the distinction crystal clear throughout:

Classical conditioning = acquisitionOperant conditioning = maintenance.