ABSTRACT
This paper provides a critical analysis of four theories: Self-Efficacy Theory, Health Belief Model, Theory of Planned Behavior, and Protection Motivation Theory. Health behavior theories endeavor to explain and to predict human behaviors that contribute either to the risk or to the prevention of disease onset. There are considerable individual differences with regard to the adoption and maintenance of health behaviors. These differences have been attributed to a variety of factors, such as vulnerability to illness, perceived threat, or attitude towards a particular behavior. Current theoretical approaches offer different explanations as to which causal mechanism shapes the intention to change risk behaviors or helps to maintain health behaviors. From a social-cognitive perspective, a causal model is proposed, the so-called Health Action Process Approach, which focuses on the role of expectancies and covers self-regulatory processes in the maintenance phase. It is assumed that a complex set of expectancies, one of them being self-efficacy expectancy, results in a behavioral intention.
