Theory of planned behaviour[edit]
In 1985, Ajzen expanded upon the theory of reasoned action, formulating the Theory of Planned Behaviour, which also emphasises the role of intention in behaviour performance but is intended to cover cases in which a person is not in control of all factors affecting the actual performance of a behaviour. As a result, the new theory states that the incidence of actual behaviour performance is proportional to the amount of control an individual possesses over the behaviour and the strength of the individual's intention in performing the behaviour. In his article, Further hypothesises that self-efficacy is important in determining the strength of the individual's intention to perform a behaviour. In 2010, Fishbein and Ajzen introduced the Reasoned action approach, the successor of the Theory of Planned Behaviour.