Theory of Subjective Culture and Interpersonal Relations (e.g., Triandis, 1972);
Transtheoretical Model of Behavior Change (Prochaska and DiClemente, 1983, 1986, 1992; Prochaska, DiClemente, and Norcross, 1992; Prochaska et al., 1994);
Information/Motivation/Behavioral-Skills Model (Fisher and Fisher, 1992);
Health Belief Model (Becker, 1974, 1988; Rosenstock, 1974; Rosenstock, Strecher, and Becker, 1994);
Social Cognitive Theory (Bandura, 1977, 1986, 1991, 1994);
Theory of Reasoned Action (Fishbein and Ajzen, 1975; Ajzen and Fishbein, 1980; Fishbein, Middlestadt, and Hitchcock, 1991).
However, there is a growing academic consensus that only a limited number of variables need to be considered in predicting and understanding any given behavior (see, e.g., Petraitis, Flay, and Miller, 1995; Fishbein, 2000). The variables come primarily from three theories that have been widely used in, and have a major influence on, current behavioral health research: the Health Belief Model, Social Cognitive Theory, and the Theory of Reasoned Action. (See Annex A at the end of this chapter for a brief description of each of these theories.)
One way to predict whether or not a given person will engage in a given health behavior is to ask. People are remarkably accurate predictors of their own behaviors, and appropriate measures of intention (one’s subjective probability that he or she will or will not engage in a given behavior) consistently have been shown to be the best single predictors of the likelihood that one will (or will not) perform the behavior in question (see, e.g., Sheppard, Hartwick, and Warshaw, 1988; Van den Putte, 1991). However, people do not always act on their intentions. One may intend to perform a given health behavior, but discover that he or she does not have the necessary skills and abilities to carry out the behavior. In addition, one may encounter unanticipated environmental con-