Theory of reasoned action

The theory of reasoned action (TRA), developed by Martin Fishbein and Icek Ajzen (1975, 1980), derived from previous research that started out as the theory of attitude, which led to the study of attitude and behavior. The theory was "born largely out of frustration with traditional attitude–behavior research, much of which found weak correlations between attitude measures and performance of volitional behaviors" (Hale, Householder & Greene, 2003, p. 259). The key application of the theory of reasoned action is prediction of behavioral intention, spanning predictions of attitude and predictions of behavior. The subsequent separation of behavioral intention from behavior allows for explanation of limiting factors on attitudinal influence (Ajzen, 1980).

Contents

Definition and example

Derived from the social psychology setting, the theory of reasoned action (TRA) was proposed by Ajzen and Fishbein (1975 & 1980). The components of TRA are three general constructs: behavioral intention (BI), attitude (A), and subjective norm (SN). TRA suggests that a person's behavioral intention depends on the person's attitude about the behavior and subjective norms (BI = A + SN). If a person intends to do a behavior then it is likely that the person will do it.

Behavioral intention measures a person's relative strength of intention to perform a behavior. Attitude consists of beliefs about the consequences of performing the behavior multiplied by his or her valuation of these consequences. Subjective norm is seen as a combination of perceived expectations from relevant individuals or groups along with intentions to comply with these expectations. In other words, "the person's perception that most people who are important to him or her think he should or should not perform the behavior in question" (Ajzen & Fishbein, 1975).

To put the definition into simple terms: a person's volitional (voluntary) behavior is predicted by his/her attitude toward that behavior and how he/she thinks other people would view them if they performed the behavior. A person's attitude, combined with subjective norms, forms his/her behavioral intention.

Fishbein and Ajzen say, though, that attitudes and norms are not weighted equally in predicting behavior. "Indeed, depending on the individual and the situation, these factors might be very different effects on behavioral intention; thus a weight is associated with each of these factors in the predictive formula of the theory. For example, you might be the kind of person who cares little for what others think. If this is the case, the subjective norms would carry little weight in predicting your behavior" (Miller, 2005, p. 127).

Miller (2005) defines each of the three components of the theory as follows and uses the example of embarking on a new exercise program to illustrate the theory:

Utility

The theory of reasoned action has "received considerable and, for the most part, justifiable attention within the field of consumer behavior ... not only does the model appear to predict consumer intentions and behavior quite well, it also provides a relatively simple basis for identifying where and how to target consumers' behavioral change attempts" (Sheppard, Hartwick & Warshaw, 1988, p. 325).

Hale et al. (2003) say the TRA has been tested in numerous studies across many areas including dieting (Sejwacz, Ajzen & Fishbein, 1980), using condoms (Greene, Hale & Rubin, 1997), consuming genetically engineered foods (Sparks, Shepherd & Frewer, 1995), and limiting sun exposure (Hoffman, 1999).

Formula

In its simplest form, the TRA can be expressed as the following equation:

BI {{=}} (AB)W_1 %2B (SN)W_2\,\!

where:

(Source: Hale, 2003)

Process

As a behavioral process, an expanded TRA flow model can be expressed as follows:

Belief toward an outcome Evaluation of the outcome Attitude Behavior
Attitude
Beliefs of what others think Subjective norm
What experts think
Motivation to comply with others
Source: Ajzen, 1980

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).

Theory revision

The theory has even been revised and extended by Ajzen himself into the theory of planned behavior. "This extension involves the addition of one major predictor, perceived behavioral control, to the model. This addition was made to account for times when people have the intention of carrying out a behavior, but the actual behavior is thwarted because they lack confidence or control over behavior" (Miller, 2005, p. 127).

Ajzen's revised conceptual model, accounting for actual behavioral control, can be expressed as follows:

Behavioral Beliefs Attitude Toward the Behavior Intention Behavior
Normative Beliefs Subjective Norm
Control Beliefs Perceived Behavioral Control
Actual Behavioral Control
(Source: Ajzen, 1991)

See also

References

External links