Theories of reasoned action and planned behavior

Can we change behaviour by changing attitudes towards the behaviour of concern?

Not really, contrary to the popular belief.

The connection between attitude and behaviour is not straightforward. In the 1960s, Fishbein and Ajzen concluded it by reviewing research published to that date. They developed a theory to explain the nature of the relationship between the two: The Theory of Reasoned Action.

Theory of Reasoned Action (TRA)

In summary, this theory says;

  • Our action depends on the intent of either doing it or not doing it.
  • Having an intent depends upon two determinants; not only the presence of a positive attitude towards the behaviour but the presence of subjective norms (social pressure) matters too. 
  • A positive attitude includes two aspects: whether it is believed to be enjoyable or not enjoyable and beneficial or harmful.
  • The social pressure needs to be perceived; it may experience in two ways: telling by your significant other and seeing that they are doing that.
  • Stronger the perceptions, the more likely the stronger the intentions are.
A simplified form of the Theory of Reasoned Action in a diagram

Let us see how it applies in real life. 

Think that someone wants to carry out a self-examination of the breast. She might do that if she has any intention of doing that. It is a fairly simple straightforward explanation.

What is challenging is finding out an explanation of how that intent is developed. According to the Theory of Reasoned Action, the intent depends on the presence of a favourable attitude towards that behaviour and whether they feel any sort of social pressure (perceived social pressure) to engage in this behaviour. Below, you can see its application in a nutshell.

Theory of Reasoned Action in action

Moreover, Wikipedia gives a very good account of the theory including its applications in communication, consumer behaviour, and health behaviour.

Theory of Planned Behavior

With time, Ajzen found the theory’s inadequacy in explaining some behaviours that are not under our control. As a result, he added another variable to the equation: the perceived ability to perform the behaviour as a determinant of the intent and re-named it the “Theory of Planned Behavior”.

This theory is an extension of the theory of reasoned action. Both these are not exactly considered behaviour change theories but theories that help us to understand and predict the desired behaviour. However, these two assist us in framing messages and developing health education materials too.

What it says: 

  • The third variable – perceived control over the performance of the behaviour– was added to the previous theory. That is the only difference.  In the example below, if someone believes she can perform the task, she is more likely to engage in breast self-examination. It also includes the perceived ability to overcome barriers: economic, social, geographic, or even cultural.
  • The stronger the beliefs the stronger the intention of engaging in the behaviours.
  • However, Ajzen in his seminal paper published in 1991, cautions about the possible feedback effects of the behaviour on the antecedent variables. (This is not shown in the diagram).
  • The perceived behaviour control may have a direct influence on the behaviour bypassing the intent of doing the behaviour.
  • Although it is not shown in the diagram, attitudes towards the behaviour, perceived social pressure, and perceived ability to engage in the behaviour can influence each other according to Ajzen’s 1991 paper.
Theory of Planned Behavior with an example

The following video clip explains the theory with an example.

Now, the most important question is this?

How can we use these theories for our benefit?

A review published in 1995 has concluded the efficiency of the theory varies depending on the type of behaviour it was applied to. They have found that two-thirds of the explained variation could be attributed to the intention of engaging in the desired behaviour. This is a very important finding for us; in other words, most of our probability of engaging in a particular behaviour depends on the degree of motivation. However, for addictive and screening behaviours, perceived behavioural control is carried to have more control than the intention of doing the behaviour.

Other behaviour change theories

Author: Prasantha De Silva

A specialist in Community Medicine board-certified in Sri Lanka and a research analyst in Canada

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