Perceived opinions of their significant others reflect the person's perceived social support for the target behavior and are weighted by the importance of each significant other to the person. Attitudes are determined by beliefs and reflect the person's affective evaluation of engaging in the target behavior. Subjective norms are determined by the perceived opinions of significant others and reflect an affective evaluation of the overall social support for the target behavior. Intentions are an expressed commitment to engage in the target behavior and are determined by attitudes and subjective norms. The target behavior is determined solely by intentions.
Parallels exist between the theory of reasoned action and the innovation-decision process.
Both of these social-cognitive models have roots in Lewin's field theory, incorporate attitudinal and normative concepts, and incorporate an indication of commitment to act as a determinant of behavior. A central difference between the two models is that disjunctures that can occur within the causal structure of the theory of reasoned action are considered as indeterminacies that require the introduction of stimulus or contingent conditions for their resolution. Programs aimed at planned behavior change based upon the theory of reasoned action focus on changing beliefs and perceived opinions of significant others. The innovation-decision process, on the other hand, explicitly specifies that disjunctures can occur at all stages of the process and that resolving these disjunctures requires intervention by change agents at all stages of the process. The integration of elements from the two theories might enhance the ability of both of them to predict intentions and behavior that are not determined solely by attitudinal or normative conditions.