Theory of Planned Behaviour (Ajzen, 1991)

Ajzen added the concept of self-efficacy (our belief that we can act effectively and exercise some control over events that influence our lives) to the Theory of Reasoned Action. This theory emphasises the role of perceived behavioural control as an influence on behavioural intentions and actual behaviour.

Ajzen claimed that control beliefs are important determinants of the perception of behavioural control, and are extremely important for understanding motivation – a person’s confidence (or lack of it) in their ability to perform the required behaviour may be a critical determinant of whether they choose to undertake the behaviour and are successful in its execution. For example, if you think you cannot quit smoking, then you probably will not try.

The perceived behavioural control of a person who is uncertain of their ability to execute a behaviour may be influenced by their perception of their personal resources, such as their own abilities, self-esteem and confidence, and the time and money that are required to be successful. Perceived control can have a direct effect on behaviour, bypassing behavioural intentions. For example, people may fail to stick to weight loss or exercise programmes possibly because there is a doubt in their mind over their own behavioural control, and their ability to stick to the programme and avoid temptation.

By adding perceived behavioural control, Azjen provided a role for past behaviour. For example, if you have tried to quit smoking several times in the past, then you are less likely to believe you can successfully quit in the future, and are therefore less likely to intend to try.

A study by Mummery and Wankel (1999) found that swimmers who held positive attitudes towards training, believed that significant others wanted them to train hard (subjective norm) and held positive perceptions about their swimming ability (perceived behavioural control), formed stronger intentions to train and actually stuck to the training programme significantly more than those who did not hold these attitudes and perceptions.

Theory of Planned Behaviour
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