Theory of Planned Behavior

Also known as: TPB

framework · psychology · structured-empirical

Ajzen's model: intention shaped by attitudes, norms, and perceived control.

The Theory of Planned Behavior, developed by Icek Ajzen in 1985 and presented systematically in 'The Theory of Planned Behavior' (1991), extends his earlier Theory of Reasoned Action (with Martin Fishbein, 1975) by adding perceived behavioral control as a third determinant of behavioral intention. The model holds that intention to perform a specific behavior is shaped by three independent constructs: attitude toward the behavior (positive or negative evaluation), subjective norms (perceived social pressure from important others), and perceived behavioral control (perceived ease or difficulty of performing the behavior). Intention then predicts behavior, with perceived behavioral control sometimes also having direct effects when actual control is constrained. Each of the three predictors is theorized to derive from underlying beliefs (behavioral, normative, control beliefs), accessible through elicitation interviews. TPB is among the most empirically applied frameworks in health-behavior research, with extensive application to predicting and changing behaviors including diet, exercise, condom use, smoking, voting, and recycling.

Originators

Icek Ajzen; Martin Fishbein (Theory of Reasoned Action precursor) high

Year / Decade

1975 (Theory of Reasoned Action); 1985 (Theory of Planned Behavior introduction); 1991 (canonical formulation) high

Primary sources

Fishbein, M. & Ajzen, I. (1975). Belief, Attitude, Intention, and Behavior, Ajzen, I. (1991). 'The Theory of Planned Behavior', Organizational Behavior and Human Decision Processes, Sniehotta, F.F., Presseau, J. & Araújo-Soares, V. (2014). 'Time to retire the theory of planned behaviour', Health Psychology Review high

Core components

Three intention predictors: Attitude toward the behavior, Subjective norms, Perceived behavioral control
Intention as proximal predictor of behavior
Behavioral, normative, and control beliefs as underlying foundations
Behavior-specific application
Direct path from PBC to behavior when actual control is constrained
Belief elicitation methodology

Primary use case

Health behavior research and intervention design; public health campaigns; behavior-change program design across domains including pro-environmental behavior, financial behavior, organizational behavior; framework underlying many social marketing and behavioral-science applications; standard reference in Theory of Planned Behavior questionnaire development.

Common criticisms

Sniehotta, Presseau, and Araújo-Soares's 2014 'Time to Retire the Theory of Planned Behavior' argued the framework's predictive value is limited and adds little beyond simpler intention-behavior models
intention-behavior gap is substantial — TPB explains intention well but intention-to-action translation poorly
the three predictors often correlate substantially, raising questions about distinct contributions
doesn't well address habits, automaticity, or unconscious processes (which dual-process and habit-formation literatures emphasize)
cross-cultural validity uneven
predictions for any specific behavior require extensive elicitation work that limits practical scalability
'rational actor' framing limits applicability to impulsive or addictive behaviors.

Lineage

Siblings: Self-Efficacy Theory, Transtheoretical Model, Fogg Behavior Model