Theory of planned behavior
Icek Ajzen (1985) proposed TPB in his chapter "From intentions to actions: A theory of planned behavior.
Along with attitudes and subjective norms (which make up TRA), TPB adds the concept of perceived behavioral control, which grew out of self-efficacy theory (SET).
[9] He defined self-efficacy as the conviction that one can successfully execute the behavior required to produce the outcome in question.
[10] As self-efficacy contributes to explanations of various relationships among beliefs, attitudes, intentions, and behavior, TPB has been widely applied in health-related fields such as helping preadolescents to engage in more physical activity, thereby improving their mental health,[11] and getting adults to exercise more.
More recently, Fishbein and Cappella[19] advanced the view that self-efficacy is equivalent to perceived behavioral control in Ajzen's integrative model.
Perceived behavioral control is usually measured with self-report instruments comprising items that begin with the stem, "I am sure I can ... (e.g., exercise, quit smoking, etc.)."
A positive evaluation refers to a belief regarding the effectiveness of the proposed behavior in reducing the vulnerability to negative outcomes.
By contrast, a negative self-evaluation refers to a belief regarding adverse consequences that can result from the enactment of the behavior.
Individuals' elaborative thoughts on subjective norms are perceptions of whether they are expected by their friends, their family, and society in general to perform a particular behavior.
[25] Finally, given a sufficient degree of actual control over the behavior, the individual is expected to carry out his or her intentions when the opportunity arises.
[26] TPB has improved the predictability of intention with regard to several health-related behaviors, including condom use,[27][28] choice of leisure activities,[29] exercise,[30] and diet.
For example, an individual may be guided by the goal of losing 5 kg of weight in 60 days; a positive attitude and intention towards dieting would be important.
TPB was applied in such a way as to encourage parents to include more fruit, vegetables and whole grains in the lunches they packed for their preschool children.
The researchers observed in the TPB-oriented intervention a significant increase in vegetables and whole grains in the lunches parents prepared for their children.
The study team found that the strongest indicator of dietitians' intentions to promote the consumption of whole grain foods was their normative beliefs about diet.
More recent research based on TPB examined college students' intentions to smoke e-cigarettes.
Studies found that attitudes toward smoking and social norms significantly predicted college students' behavior, as TPB suggests.
With this knowledge, a smoking prevention campaign was started, specifically targeting college students collectively, not just as individuals.
They found that environmental concern, perceived value, and willingness to pay were the top leading factors in their purchasing intentions.
They found that Gen Z used knowledge sharing as a precursor to shape their perception and attitudes towards green tourism services.
Over the years, researchers have applied and expanded upon this theory to gain insights into specific financial behaviors and their determinants.
Similarly, in a study involving mortgage clients, Bansal & Taylor (2002)[45] explored factors affecting customer service switching behavior within the context of the TPB.
The TPB has also been applied to study the financial behaviors of college students concerning cash, credit, and saving management, providing valuable insights into how young adults form their financial behaviors based on their intentions, attitudes, social norms, and perceived control.
In this example, "consuming" is the action, "one serving of whole grains" is the target, "during breakfast each day" is the context, and "in the forthcoming month" is the time.
[48] The following are sample questions that may be used during an elicitation interview:[48] TPB covers people's volitional behavior that cannot be explained by TRA.
[26] TPB has improved the predictability of intention in various health-related areas, including condom use, leisure, exercise, diet, etc.
To illustrate, Sussman et al. (2019)[51] prompted participants to form the intention to support a specific environmental organization, for example, to sign a petition.
[51] These findings imply that the associations among the three key elements—attitudes, social norms, and perceived behavioral control—and intentions may be bi-directional.
