Theory of Planned Behaviour: attitudes, subjective norms and perceived behavioural control
In the Theory of Planned Behaviour, intention (readiness to act) is shaped by attitude, subjective norms (perceived social pressure) and perceived behavioural control (belief about how easy or difficult).
Remember
Intention comes from attitude, subjective norms and perceived behavioural control; when a person with a positive attitude, supportive norms and a strong intention still does not act, the usual explanation is low perceived behavioural control.
The Theory of Planned Behaviour is a model of why a person does or does not act on a behaviour such as regular exercise. It proposes that behaviour follows from intention, which is a person's decision or readiness to act.
Three things shape intention. Attitude is the person's favourable or unfavourable evaluation of the behaviour, in other words whether it seems good or bad. Subjective norms are the perceived social pressure to do the behaviour or not, such as what friends and family would think. Perceived behavioural control is the belief about how easy or difficult the behaviour will be. It reflects barriers (such as lack of time, money or access) and facilitators (such as skills, support and opportunity), as the person sees them.
Intention makes the behaviour more likely, but a strong intention does not guarantee action. Perceived behavioural control can also act on behaviour directly, which is one reason why people who mean to exercise may still fail to do so. In one example, a student has a positive attitude, approving friends and a strong intention but doubts they can follow through because of shift work and poor access. Low perceived behavioural control is the usual explanation for that kind of gap.
Background factors such as genes or level of formal education are not among the three things that shape intention, although education may influence what a person believes.
Key facts
- Attitude
- the person's favourable or unfavourable evaluation of the behaviour, good or bad.
- Subjective norms
- the perceived social pressure to do the behaviour or not.
- Perceived behavioural control
- the belief about how easy or difficult the behaviour will be.
- Intention
- the readiness to act, which makes the behaviour more likely but does not guarantee it.
- Direct influence
- perceived behavioural control can influence behaviour directly as well as through intention.
- Gap between intention and action
- a positive attitude, supportive norms and a strong intention without action point to low perceived behavioural control, which is the usual explanation.
Exam traps
- Cues to action, meaning triggers that prompt a person to act, are not part of the Theory of Planned Behaviour, because they belong to the Health Belief Model, a different model.
- Intention does not tell you how easy or difficult a person expects a behaviour to be, because it is the readiness to act and is shaped by attitude, subjective norms and perceived behavioural control.
- Moral obligation, a person's sense of duty to act, is not one of the three core influences on intention, because some researchers have added it to the theory.
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