Theory of Planned Behavior

The theory of Planned Behavior was created by Icek Ajzen in 1991, and it was improved by the Theory of reasoned action. The central idea of the Theory of Planned Behavior (TPB) is that behavior is influenced, albeit indirectly, by attitudes, norms, and perceived behavioral control (PBC). Behavioral decisions are not made impulsively; rather, they are the outcome of a rational process (do Paço & Reis, 2012).

According to Ajzen (1988), an attitude can be defined as a disposition to respond favorably or unfavorably to an object, person, institution, or event. An attitude is acquired through information and/or experience with an object, is a predisposition to respond in a certain way, and has to reflect a reliable pattern of positive or negative reactions to that object (do Paço & Reis, 2012).

Subjective norm refers to ‘the person’s perception that their close social circle, most people who are important to him or her think she/he should or should not perform the behavior in question (Chu et al., 2016).

Perceived behavioral control is defined by Pelling and White (2009) as the perceived comfort level a person experiences when engaging in a behavior. It has an impact on both behavioral intention and behavior because a person may have the desire to carry out a behavior but lack the capacity to do so (Ajzen, 1991; Sanne & Wiese, 2018). Someone is more likely to carry out an action if they feel they have all the necessary resources, skills, and knowledge - and can do it with ease, in their opinion.

These three factors combined can create a behavioral intention. The best predictor of behavior, as previously mentioned, is behavioral intention (Ajzen, 1991). It is positively correlated with behavior because, according to the author, it indicates how hard people are willing to try, of how much of an effort they are planning to exert, in order to perform the behavior.

I will now describe the advantages and the disadvantages of this theory. The model can fall short in some circumstances. Despite the possibility of a constructive behavioral goal, the model fails to take into account the discrepancy between intention and behavior. To solve this issue, you can expand the model with implementation intentions. Other behavioral elements like emotions are not taken into account by the model. Our perception, beliefs, and propensity to behave can all be influenced by emotions. The approach is excellent for determining how attitudes and behavioral intentions relate to one another. It doesn't discuss how to identify behaviors-changing activities. Now let’s take a look at the advantages. Making predictions using the model is beneficial. More accuracy in behavior prediction is achieved by treating the variables as model inputs, especially when compared to the Theory of Reasoned Action. The methodology can be used to gather data to assist you identify the largest hurdles to altering behavior before you risk investing in change.

Numerous authors have employed the well-researched theory of planned behavior in their works. In the world of advertising, it is really helpful. In a lot of cases they investigate the three factors, and how relevant are they in various topic. Two distinct studies on the subject of social media advertising came to two different conclusions: in one, one of the factors was found to be irrelevant, while in the other, they added another factor.

One of the studies examine Instagram advertising, and found out that the main indicators in intention is attitude and subjective norm, and suggest that PBC is not significant. In this case TPB model is not an appropriate one to use to explain engagement with Instagram advertising if PBC is not a significant variable. The findings show that the Theory of Reasoned Action, which was described earlier, would be a better model because it only takes attitude and subjective norms into account when predicting behavioral intention.

In the other study the author examined advertising on Twitter, and found a really different conclusion, founding a fourth factor. The idea generally holds that an individual's intention to engage in the behavior is positively connected with attitude, subjective norm, and perceived behavioral control. The goal of this study, which is based on the TPB, is to create and empirically evaluate a model that forecasts brand followership intentions on Twitter. This study also tries to incorporate brand attachment to the TPB model, extending it. In addition to the variables related to TPB, brand attachment appeared to have a positive influence on intention to follow brands on Twitter (Chu et al., 2016).


Ajzen, I. (1991). The theory of planned behavior. Organizational behavior and human decision processes, 50(2), 179-211.

Ajzen, I. (1998). Models of human social behavior and their application to health psychology. Psychology and health, 13(4), 735-739.

Chu, S. C., Chen, H. T., & Sung, Y. (2016). Following brands on Twitter: An extension of theory of planned behavior. International Journal of Advertising, 35(3), 421-437.

do Paço, A. M. F., & Reis, R. (2012). Factors Affecting Skepticism toward Green Advertising. Journal of Advertising, 41(4), 147–155.

Pelling, E. L., & White, K. M. (2009). The theory of planned behavior applied to young people's use of social networking web sites. Cyberpsychology & Behavior, 12(6), 755-759.

Sanne, P. N., & Wiese, M. (2018). The theory of planned behaviour and user engagement applied to Facebook advertising. South African Journal of Information Management, 20(1), 1-10.