Theory of Reasoned Action - Limitations and Extensions

Limitations and Extensions

Sheppard et al. (1988) disagreed with the theory but made certain exceptions for certain situations when they say "a behavioral intention measure will predict the performance of any voluntary act, unless intent changes prior to performance or unless the intention measure does not correspond to the behavioral criterion in terms of action, target, context, time-frame and/or specificity" (p. 325). So, in reference to the above example, if prior to your exercising you learn you have a medical condition, this may affect your behavioral intention.

Sheppard et al. (1988) say there are three limiting conditions on 1) the use of attitudes and subjective norms to predict intentions and 2) the use of intentions to predict the performance of behavior. They are:

1. Goals Versus Behaviors: distinction between a goal intention (an ultimate accomplishment such as losing 10 pounds) and a behavioral intention (taking a diet pill)
2. The Choice Among Alternatives: the presence of choice may dramatically change the nature of the intention formation process and the role of intentions in the performance of behavior
3. Intentions Versus Estimates: there are clearly times when what one intends to do and what one actually expects to do are quite different

Sheppard et al. (1988) suggest "that more than half of the research to date that has utilized the model has investigated activities for which the model was not originally intended" (p. 338). Their expectation was that the model would not fare well in such situations. However, they found the model "performed extremely well in the prediction of goals and in the prediction of activities involving an explicit choice among alternatives." Thus, Sheppard et al. (1988) concluded that the model "has strong predictive utility, even when utilized to investigate situations and activities that do not fall within the boundary conditions originally specified for the model. That is not to say, however, that further modifications and refinements are unnecessary, especially when the model is extended to goal and choice domains" (p. 338).

Hale et al. (2003) also account for certain exceptions to the theory when they say "The aim of the TRA is to explain volitional behaviors. Its explanatory scope excludes a wide range of behaviors such as those that are spontaneous, impulsive, habitual, the result of cravings, or simply scripted or mindless (Bentler & Speckart, 1979; Langer, 1989). Such behaviors are excluded because their performance might not be voluntary or because engaging in the behaviors might not involve a conscious decision on the part of the actor" (p. 250).