What you'll learn

• How operant conditioning explains behaviour change through consequences.
• What behaviour modification is and how it is used in real settings.
• How shaping builds a complex behaviour gradually using reinforcement.
• How to evaluate behaviour modification for AO3, including evidence, ethics and practical limitations.

Starting point: operant conditioning

Before you can understand behaviour modification, you need the basic idea of operant conditioning.

The word operant means an action that “operates” on the environment. For example, a child asks politely, the parent gives attention, and the child becomes more likely to ask politely again.

This approach is linked to Thorndike’s Law of Effect (Thorndike, 1911), which states that behaviours followed by satisfying consequences are more likely to be repeated. It was developed further by Skinner (1938), who studied rats and pigeons in controlled “Skinner boxes” to show how reinforcement and punishment affect behaviour.

The ABC model

A useful way to apply operant conditioning is the ABC model:

• Antecedent: what happens before the behaviour.
• Behaviour: the observable action or response.
• Consequence: what happens after the behaviour.

For example, the antecedent might be “the teacher asks a question”, the behaviour might be “the student calls out”, and the consequence might be “the teacher gives attention”.

The diagram below shows how the ABC model links to reinforcement, punishment, extinction and shaping.

Consequences: reinforcement, punishment and extinction

Reinforcement

There are two types:

• Positive reinforcement: something desirable is added after the behaviour, such as praise, tokens or attention.
• Negative reinforcement: something unpleasant is removed after the behaviour, such as stopping nagging when homework is completed.

Punishment

There are also two types:

• Positive punishment: something unpleasant is added, such as a telling-off.
• Negative punishment: something desirable is removed, such as losing phone privileges.

Punishment may stop a behaviour quickly, but it does not necessarily teach the person what to do instead. It can also create fear, anger or avoidance.

Extinction

For example, if a child has learned that tantrums lead to attention, consistently removing that attention may reduce tantrums over time. However, there may be an extinction burst, which is a temporary increase in the behaviour before it reduces.

What is behaviour modification?

It is often used in schools, clinical settings, parenting programmes, prisons and care environments. The aim is not just to “reward good behaviour” vaguely. A good behaviour modification programme is planned, measured and consistent.

A key term is target behaviour, which means the specific behaviour the programme aims to increase or decrease. The behaviour must be operationalised, meaning defined clearly enough that different observers would know exactly what to record.

For example, “be better behaved” is too vague. “Remain seated during independent work for 10 minutes” is operationalised.

Another key term is baseline, which is the level of behaviour before the intervention begins. Measuring the baseline helps you judge whether the programme has actually worked.

Token economies

A common behaviour modification technique is a token economy.

The tokens are secondary reinforcers, meaning they have value because they can be exchanged for something else. The rewards they are exchanged for are called backup reinforcers, such as extra activity time, snacks or privileges.

For example, in a classroom, students may earn points for completing work, helping others or arriving on time. Later, they exchange the points for a chosen reward.

Evidence for token economies includes applied work by Ayllon and Azrin (1968), who used token systems to increase adaptive behaviours in psychiatric settings. More recent reviews, such as Maggin et al. (2011), suggest token economies can improve classroom behaviour, although effectiveness depends on consistency, suitable rewards and good implementation.

What is shaping?

Sometimes the desired behaviour does not happen at all yet. In that case, you cannot simply reinforce the final behaviour because there is nothing to reward. This is where shaping is useful.

A successive approximation is a behaviour that is closer to the target behaviour than the person’s current behaviour. The psychologist, teacher or caregiver reinforces each closer step, then gradually raises the standard.

Shaping often uses differential reinforcement, which means reinforcing the desired or closer behaviour while not reinforcing less desired behaviours.

For example, if a child does not speak in class, the teacher might first reinforce eye contact, then whispering to a peer, then answering quietly, and eventually answering aloud.

How shaping works step by step

A shaping programme usually follows this sequence:

1. Define the final target behaviour clearly.
2. Measure the baseline behaviour.
3. Choose a reinforcer that is genuinely motivating for that person.
4. Reinforce the first small step towards the target.
5. Once that step is reliable, only reinforce a closer approximation.
6. Continue until the final target behaviour is reached.
7. Gradually reduce artificial rewards so the behaviour is maintained naturally.

This last stage is important. Maintenance means the behaviour continues over time. Generalisation means the behaviour happens in other settings, not just in the training situation.

Reinforcement schedules

A reinforcement schedule is the pattern of how often reinforcement is given.

• Continuous reinforcement means reinforcing the behaviour every time it occurs. This is useful early in learning because it makes the link between behaviour and consequence clear.
• Intermittent reinforcement means reinforcing only some correct responses. This is useful later because behaviour often becomes more resistant to extinction.

In shaping, continuous reinforcement is usually useful at the start. Later, intermittent reinforcement helps the behaviour last without needing constant rewards.

AO3 evaluation: strengths

Behaviour modification is practical and measurable

A major strength is that behaviour modification focuses on observable behaviour. This makes it easier to measure change objectively.

For example, rather than saying “the child is more cooperative”, a researcher or teacher can record “the child completed four out of five tasks without refusal”. This improves reliability because observers can agree on what happened.

It has useful real-world applications

Behaviour modification has been used in schools, mental health settings, parenting programmes and interventions for developmental difficulties. Reinforcement-based approaches can help increase adaptive behaviours such as communication, self-care and classroom engagement.

For example, Eldevik et al. (2009) reviewed early behavioural interventions for autistic children and found evidence of benefits for some children, although outcomes varied. This supports the idea that operant principles can be useful when applied carefully and individually.

It is based on controlled research

Skinner’s work had strong control over variables, which helps establish cause and effect. In a Skinner box, the researcher could control the consequence after a response and measure how response rates changed.

However, this strength also creates a limitation: much early evidence came from animal studies in artificial environments, so generalising directly to complex human behaviour can be difficult.

AO3 evaluation: limitations and ethics

It can be reductionist

Behaviour modification can be criticised as reductionist, meaning it explains complex behaviour in a simplified way. It focuses heavily on external consequences and may ignore thoughts, emotions, biological factors, social relationships and personal meaning.

For example, a child refusing schoolwork may not simply need more rewards. They may be anxious, struggling with literacy, or reacting to peer problems.

It may create dependency on rewards

If rewards are used badly, the person may only perform the behaviour when rewards are available. This is why reinforcement should be faded gradually and replaced with natural reinforcers.

There is also a debate about whether external rewards can reduce intrinsic motivation, which is motivation that comes from interest or satisfaction in the activity itself.

Ethical issues matter

Behaviour modification can involve controlling another person’s behaviour, so ethics must be considered carefully. Under the BPS Code of Ethics and Conduct (2009), psychologists should consider consent, protection from harm, confidentiality, right to withdraw, deception and debriefing.

With children or vulnerable people, valid consent may need to come from parents, guardians or carers, but the person’s own assent and dignity still matter. Punishment-based programmes are especially ethically risky because they may cause distress or harm.

Bringing it together for essays

For AO1, clearly describe operant conditioning, behaviour modification and shaping. For AO2, apply the ABC model to the scenario. For AO3, evaluate using evidence, real-world usefulness, reductionism, maintenance and ethics.