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The theory of reasoned action tries to elaborate and predict the behavioural intentions; it was developed by Martin Fishbein and Icek Ajzan. The research for this theory started as a research about a theory of attitudes later which lead to the theory of attitudes and behaviour. This theory has its roots in psychology.


The components which construct theory of reasoned action are Behavioural Intentions (BI), Attitudes (A), and Subjective Norms (SN). The theory suggests that a person’s behavioural intentions will be depending on his attitudes and Subjective norms. That is BI = A+SN.

Attitudes (A) are a sum of beliefs attributed to some particulars. It varies as per the attributions and beliefs.

Example: Students have their attitudes towards the exams. Their performance in the exams has optimum dependency upon the attitude of them towards the exams. Or the problem solving ability of the people depend on their attitudes towards the problem.

Subjective Norms (SN) are mostly situational, it consists our opinion about the subject behaviour. His opinion can be influenced by several factors like society, economy, politics, demographic factors etc. In per the founder of this theory subjective norm is “the person’s perception that most people who are important to him or her think he should or should not perform the behaviour in question” (Fishbein & Ajzen, 1975)

Example: Jim’s parents don’t like watching TV, they believes that it kills the brain tissues. In Jim’s class everybody watches TV and they talk a lot about the movies and other TV shows. Here Jim’s ‘subjective norms’ towards TV may depend upon the how he is being influenced and who makes a deeper impression in his mind.

Behavioural Intention (BI) means a person’s ability or capability to intend to perform behaviour. It has found to predict the behaviour. It is rather considered as the function of both Attitudes and Behavioural Norms.

Example: Leslie is a kind of talkative person; she tries hard to keep her mouth shut. She talked a lot and never kept a secret so people began to call her BBC network. Once she came to know about her nick name and got so depressed. She didn’t want to be called like that and for that she tried to keep her mouth shut and talked to others only when it is needed. Here Leslie intent to behave in another way which was formed by her attitude and subjective norms.

The founders of this theory invented a simple formula, that is

BI = (AB)W1 + (SN)W2

In which

  • BI = behavioural intention
  • (AB) = one’s attitude toward performing the behaviour
  • W = empirically derived weights
  • SN = one’s subjective norm related to performing the behaviour
{ 2 comments… add one }
  • Ingrid thurmond December 24, 2015, 4:52 am

    I appreciated the formula added to the theory, it aided in explaining the concept in another way.

  • Khaled Alyami January 3, 2020, 4:17 am

    Thank you. Adding more details would have been better.

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