Theory of Planned Behavior
Overview
The Theory of Planned Behavior (TPB) is a psychological model that predicts deliberate actions by linking attitudes, social influences, and perceived control to behavioral intentions. Developed by Icek Ajzen in 1985, TPB extends the earlier Theory of Reasoned Action by adding perceived behavioral control, making it especially useful for behaviors where people feel only partial power over outcomes.
Key Ideas
- Attitude toward the behavior – personal evaluation of whether the action is good or bad.
- Subjective norm – perceived social pressure from important others.
- Perceived behavioral control – belief in one’s ability to execute the behavior and the extent of external constraints. These three components form a composite behavioral intention, which is the most proximal predictor of actual action.
Applications
TPB has been employed across disciplines: public health, environmental psychology, education, and even literary criticism (understanding character motivations). In practice, interventions often target the three predictors to shift intentions and, ultimately, behavior.
Critiques
Critics argue that TPB overemphasizes conscious deliberation, neglecting spontaneous or habitual actions. The model also assumes linear, additive relationships among components, potentially oversimplifying complex psychological processes. Additionally, measuring subjective constructs accurately remains a methodological challenge. Despite these limitations, TPB remains a foundational tool for linking mental states to observable behavior.