The theory of planned behaviour was developed by Icek Ajzen and describes the connection between one's beliefs and one's behaviours. This theory is an extension to Martin Fishbein's theory of reasoned action. Fishbein's theory asserts that if people believe that a behaviour is positive, and if they believe that it is a normal course of behaviour then they themselves will be more likely to adopt this particular behaviour and vice versa. So, according to Fishbein, an adoption of behaviours depends on people's belief on the attitude of the behaviour and their belief of the norm surrounding this behavior.
Ajzen builds on this by adding the notion of people's belief in their control over their own behavior. This is to account for the criticism that just because people plan to perform a certain behavior does not mean that they will actually act on it. For example, just because the night before you plan on getting up at 7am to go to the gym does not mean that when your alarm rings you actually will. According to the theory of planned behaviour, a higher perceived control over your own behaviour will give rise to a higher intention of performing a certain behaviour. Note that this does not actually translate into action.
The key concepts of the theory of planned behaviour are:
- Behavioural belief: an individual's belief about the consequences of certain behaviours.
- Attitude toward behaviour: positive or negative evaluation of self-performance of the behaviour.
- Normative belief: an individual's perception of social norms about the behaviour.
- Subjective norm: individual's perception of the particular behaviour influenced by the beliefs of significant others (family, friendsn etc,,,)
- Perceived behavioural control: individual's perceived ease or difficulty in performing a certain behaviour.
- Control beliefs: individual's beliefs about the factors that might help or impede performance of the behaviour.
- Behavioural intention: an individual's readiness to perform the particular behaviour.