Theory of planned behaviour
Developed from TRA but includes an additional component of 'perceived behavioural control' which is similar to the idea of self-efficacy which relates to the belief that the individual can successfully carry out a behaviour to achieve a desired outcome. According to TPB, behavioural intentions are the outcome of the following beliefs:
- Attitude: this can be a positive or negative evaluation of the behaviour combined with the beliefs about the outcome ( eg giving up smoking is a challenge and it will improve my health).
- Subjective norm: perception of social norms/pressures to perform the behaviour, and an evaluation of whether the individual is motivated to comply with this pressure ( eg my friends will approve of my attempt to give up smoking and i want their approval).
- Perceived behavioural control: a belief that the individual can carry out a particular behaviour based on a consideration of internal control factors (eg skill, abilities, information) and external control factors (eg obstacles, opportunities). These are weighed up in light of past behaviours.
There three factors interact to form a behavioural intention which then leads to the actual behaviour.