Theory of Planned Behavior

An extension of the theory of reasoned action, the theory of planned behavior (TPB) is today one of the most popular models for explaining, predicting, and changing human social behavior. It has been applied to study a number of health behaviors, including exercise, smoking, drug use, and compliance with medical regimens. According to the TPB, human behavior is guided by three kinds of considerations:

• 1.
  Beliefs about the likely outcomes of the behavior and the evaluations of these outcomes (behavioral beliefs); in their aggregate, these beliefs produce a positive or negative attitude toward the behavior.
• 2.
  Beliefs about the normative expectations of important others and motivation to comply with these [Page 1033]expectations (normative beliefs) that result in perceived social pressure or a subjective norm.
• 3.
  Beliefs about the ...