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How we can use the Theory of Planned Behaviour

As enablers of change, we’re always looking for new ways to understand and promote positive change in the behaviour of farmers and other key stakeholders. One theory that has been particularly useful in this regard is the Theory of Planned Behaviour. In this episode, we’ll explore its key concepts and provide examples of how it can be applied to agricultural extension.

The Theory of Planned Behaviour or TPB, was published by Icek Ajzen in 1985 in order to overcome some of the deficiencies identified in the Theory of Reasoned Action, which we discussed in an earlier episode. So, what is the Theory of Planned Behaviour?

At its core, TPB is a framework for understanding how attitudes, beliefs, and social pressures influence behaviour. According to this theory, there are three main factors that influence behaviour: attitudes, subjective norms, and perceived behavioural control. It’s almost the same as the Theory of Reasoned Action, but perceived behavioural control was added to recognise that individuals needed to believe that they were capable of doing the behaviour in question. Let’s just refresh our memories on each of these factors.

  1. Attitudes refer to our overall evaluation of a particular behaviour – whether we view it as positive or negative, useful or useless, etc. For example, if we believe that using a certain farming technique will result in higher yields and profits, we are more likely to adopt that technique. Conversely, if we believe that the technique is time-consuming or costly, we may be less likely to adopt it.
  2. Subjective norms refer to our perception of the social pressure to perform a particular behaviour – in other words, whether we believe that others expect us to perform the behaviour. For farmers, this might mean feeling pressure from other farmers in their community to adopt certain practices or feeling pressure from their families or farm advisors.
  3. Perceived behavioural control refers to our perceived ability to perform a behaviour – whether we believe that we have the resources, knowledge, and skills necessary to carry out the behaviour. For example, if a farmer believes that they lack the knowledge or resources to adopt a new practice, they may be less likely to do so.

Interaction of the elements of the Theory of Planned Behaviour. Source: Ajzen (1991, p. 182).

You may be wondering how we can apply this theory in agricultural extension. Well, for starters, one of the key benefits is that it provides a structured framework for understanding the factors that influence behaviour. This can be particularly useful as enablers of change, where we are often trying to promote the adoption of new farming practices.

To apply this theory in agricultural extension, we first need to identify the key attitudes, subjective norms, and perceived behavioural control factors that are influencing farmers’ behaviour. Once we’ve identified these factors, we can tailor our extension efforts to address them. Some examples of this could be the following. Firstly, regarding attitudes; if farmers have negative attitudes towards a particular practice, we might try to address their concerns by providing them with more information about the benefits of the practice, such as through demonstration plots or field days. We might also try to address any misconceptions or misinformation they have about the practice.

Secondly, considering subjective norms; if farmers feel pressure from other farmers in their community to adopt a particular practice, we might work with opinion leaders in the community to promote the benefits of the practice and encourage more widespread adoption. We might also try to create a sense of community ownership and pride around the practice, such as through group training sessions or recognition programs. In Australia the Landcare movement does this via participating farmers often placing signs near their front gates promoting their involvement in this worthwhile venture. 

Thirdly, regarding perceived behavioural control; if farmers believe that they lack the knowledge or resources to adopt a particular practice, we might provide them with training, technical assistance, or access to resources. We might also work with them to develop customised implementation plans that take into account their specific needs and constraints. Extension naturally sits in this area and does a good job of this!

Another benefit of this theory is that it can help us to identify potential barriers to behaviour change that we may not have considered otherwise. For example, we might assume that a lack of knowledge is the primary barrier to adopting a new practice, but this theory might help us to identify other factors such as a lack of motivation or social pressure. By identifying these barriers, we can develop more targeted and effective extension efforts that address the root causes of resistance to change.

The theory has been used in extension to understand farmers’ intentions to follow a nutrient management plan (Daxini et al., 2019). Hall et al. (2019) used TPB to understand the factors influencing farmers’ decisions to engage in extension activities. We think these are great examples of incorporating a theory like TPB into our work.

Well, you’ve read our thoughts, now we’d like to hear yours! Add a comment below and tell us about your experiences with the Theory of Planned Behaviour, including any tips and further ideas about it. We don’t want this to be just a one-way conversation—join in by sharing your thoughts and ideas with us! 

Thanks folks for joining us on this Enablers of change episode. Remember to subscribe to our newsletter if you’d like to know when new episodes are available. And if you liked what you heard, please tell your friends so they too can join the conversation!


Ajzen, I. (1985). From intentions to actions: A theory of planned behavior, Springer.

Ajzen, I. (1991). The theory of planned behavior, Organizational behavior and human decision processes, vol. 50, no. 2, pp. 179-211.

Daxini, A., Ryan, M., O’Donoghue, C., & Barnes, A. P. (2019). Understanding farmers’ intentions to follow a nutrient management plan using the theory of planned behaviour. Land Use Policy, 85, 428-437. Available online. 

Hall, A., Turner, L., & Kilpatrick, S. (2019). Using the theory of planned behaviour framework to understand Tasmanian dairy farmer engagement with extension activities to inform future delivery. The Journal of Agricultural Education and Extension, 25(3), 195-210. Available online. 

Parminter, T., & Kitto, J. (2020). Facilitating farmer learning about Southern South Island winter management practices. Rural Extension and Innovation Systems Journal, 16(1), 38-41. Available online. 

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1 year ago

I am writing my dissertation on this TPB topic, despite a complex subject, your explanation was simple and effective. Thank you very much.

11 months ago

I’ve read quite a lot about TPB and this is an excellent summary of the theory and its application in agricultural extension, thank you. It does seem to apply for more simple behaviour/practice changes – would you agree?

8 months ago

It is very insightful, keep it up

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