Theory of Planned Behavior – Persuasion Theory in Action

Theoretical Foundations: TRA to TPB

The Theory of Reasoned Action (TRA) posits that behavioral intentions are the immediate predictors of behavior, driven by attitudes (personal evaluation) and subjective norms (perception of others' expectations). The Theory of Planned Behavior (TPB) expands this by adding 'perceived behavioral control'—the individual's belief in their ability to perform the action—which influences both intentions and the behavior itself.

Predicting and Strengthening Intentions

The influence of attitudes, norms, and control varies depending on the context. The relationship between intentions and behavior is strengthened by specificity (defining clear action, target, context, and time) and temporal stability. While TPB focuses on rational reasoning, research suggests incorporating emotional factors (such as anticipated regret, guilt, or pride) and the influence of past habitual behaviors to improve predictive accuracy.

Applying TPB in Persuasive Communication

Persuaders can influence intentions by targeting the three core determinants. Attitudes can be changed by modifying the salience or strength of beliefs. Subjective norms are altered by identifying important referents and adjusting an individual's motivation to comply with them. Perceived behavioral control is strengthened by removing obstacles, providing successful models, or offering verbal encouragement.