5 Theory of Planned Behavior
Mary J. Ryan & Amber K. Worthington
Persuaders are oftentimes most interested in persuading others to adopt voluntary actions. An individual’s intentions to voluntarily behave in a particular way are most immediately determined by their intentions to do so. For example, getting someone to meditate will, at a bare minimum, require them to intend to meditate. One key issue within persuasion is therefore to determine what influences behavioral intentions. The Theory of Reasoned Action, and its extension the Theory of Planned Behavior, are commonly used theories of persuasion that explain what variables predict behavioral intentions.
The Theory of Reasoned Action (Ajzen & Fishbein, 1980) posits that behavior is directly determined by an individual’s behavioral intentions. In other words, as an individual’s intentions to perform a behavior increase, they are more likely to actually perform the behavior. Behavioral intentions are oftentimes assessed with a questionnaire. An example is shown here:
The Theory of Reasoned Action posits that intentions are directly predicted by (1) an individual’s attitude towards the behavior and (2) subjective norms. An attitude is defined as an individual’s evaluation of a given behavior. Someone might have a positive, negative, or neutral attitude about a given behavior. As an individual’s attitude becomes more positive, their intentions to perform a behavior will increase. Attitudes are oftentimes assessed with a questionnaire. An example is shown here:
Subjective norms are defined as an individual’s beliefs about the importance others place on them performing a given behavior. In other words, it is the degree to which an individual perceives that other people want them to engage in the behavior. As an individual’s subjective norms increase, their intentions to perform a behavior will increase. Subjective norms are oftentimes assessed with a questionnaire. An example is shown here:
The Theory of Reasoned Action is depicted below:
The Theory of Planned Behavior (Ajzen, 1988, 1991) extends the Theory of Reasoned Action by including perceived behavioral control. The Theory of Planned Behavior posits that a behavior is directly determined by an individual’s intentions and perceived behavioral control. Perceived behavioral control, also referred to as self-efficacy, encompasses the extent to which an individual believes they have control over performing that behavior. Intentions, in turn, are directly predicted by (1) an individual’s attitude towards the behavior, (2) subjective norms, and (3) perceived behavioral control. Perceived behavioral control is oftentimes assessed with a questionnaire. An example is shown here:
The Theory of Planned Behavior is depicted below:
How are the predictors weighted in the Theory of Planned Behavior?
Attitudes, subjective norms, and perceived behavioral control do not always contribute equally to predicting intentions. Sometimes, an individual’s intentions ma