The theory of reasoned action (TRA or ToRA) aims to explain the relationship between attitudes and behaviors within human action. It is mainly used to predict how individuals will behave based on their pre-existing attitudes and behavioral intentions. An individual's decision to engage in a particular behavior is based on the outcomes the individual expects will come as a result of performing the behavior. Developed by Martin Fishbein and Icek Ajzen in 1967, the theory derived from previous research in social psychology, persuasion models, and attitude theories. Fishbein's theories suggested a relationship between attitude and behaviors (the A–B relationship). However, critics estimated that attitude theories were not proving to be good indicators of human behavior. The TRA was later revised and expanded by the two theorists in the following decades to overcome any discrepancies in the A–B relationship with the theory of planned behavior (TPB) and reasoned action approach (RAA). The theory is also used in communication discourse as a theory of understanding.

The primary purpose of the TRA is to understand an individual's voluntary behavior by examining the underlying basic motivation to perform an action. TRA states that a person's intention to perform a behavior is the main predictor of whether or not they actually perform that behavior. Additionally, the normative component (i.e. social norms surrounding the act) also contributes to whether or not the person will actually perform the behavior. According to the theory, intention to perform a certain behavior precedes the actual behavior. This intention is known as behavioral intention and comes as a result of a belief that performing the behavior will lead to a specific outcome. Behavioral intention is important to the theory because these intentions "are determined by attitudes to behaviors and subjective norms". TRA suggests that stronger intentions lead to increased effort to perform the behavior, which also increases the likelihood for the behavior to be performed.

Key concepts and conditions Behavior A positivistic approach to behavior research, TRA attempts to predict and explain one's intention of performing a certain behavior. The theory requires that behavior be clearly defined in terms of the four following concepts: Action (e.g. to go, get), Target (e.g. a mammogram), Context (e.g. at the breast screening center), and Time (e.g. in the 12 months).Montaño, DE, Kasprzyk, D, and Taplin, S. The Theory of Reasoned Action and the Theory of Planned Behavior. In: Glanz, K, Lewis, FM, and Rimer, BK (Eds). Health Behavior and Health Education (Second Edition). San Francisco, CA: Jossey-Bass Publishers. According to TRA, behavioral intention is the main motivator of behavior, while the two key determinants on behavioral intention are people's attitudes and norms.Fishbein, Martin, and Icek Ajzen. Belief, Attitude, Intention And Behavior. Addison-Wesley, 1975. By examining attitudes and subjective norms, researchers can gain an understanding as to whether or not one will perform the intended action.

Attitudes According to TRA, attitudes are one of the key determinants of behavioral intention and refer to the way people feel towards a particular behavior.Ajzen, I., & Albarracín, D. (2007). Predicting and changing behavior: A reasoned action approach. In I. Ajzen, D. Albarracín, & R. Hornik (Eds.), Prediction and change of health behavior: Applying the reasoned action approach (pp. 3-21). Mahwah, NJ, US: Lawrence Erlbaum Associates Publishers. These attitudes are influenced by two factors: the strength of behavioral beliefs regarding the outcomes of the performed behavior (i.e. whether or not the outcome is probable) and the evaluation of the potential outcomes (i.e. whether or not the outcome is positive). Attitudes regarding a certain behavior can either be positive, negative or neutral.Fishbein, M. (1967). A behavior theory approach to the relations between beliefs about an object and the attitude toward the object. In M. Fishbein (Ed.), Readings in attitude theory and measurement (pp. 389-400). New York: John Wiley & Sons. The theory stipulates that there exists a direct correlation between attitudes and outcomes, such that if one believes that a certain behavior will lead to a desirable or favorable outcome, then one is more likely to have a positive attitude towards the behavior. Alternatively, if one believes that a certain behavior will lead to an undesirable or unfavorable outcome, then one is more likely to have a negative attitude towards the behavior. and influence the decision of innovation adoption.

Behavioral belief Behavioral belief allows us to understand people's motivations for their behavior in terms of the behavior's consequences. This concept stipulates that people tend to associate the performance of a certain behavior with a certain set of outcomes or features. For example, a person believes that if he or she studies for a month for his or her driver's license test, that one will pass the test after failing it the first time without studying at all. Here, the behavioral belief is that studying for a month is equated with success, whereas not studying at all is associated with failure.

Evaluation The evaluation of the outcome refers to the way people perceive and evaluate the potential outcomes of a performed behavior. Such evaluations are conceived in a binary "good-bad" fashion-like manner. For example, a person may evaluate the outcome of quitting smoking cigarettes as positive if the behavioral belief is improved breathing and clean lungs. Conversely, a person may evaluate the outcome of quitting smoking cigarettes as negative if the behavioral belief is weight gain after smoking cessation.

Subjective norms Subjective norms are also one of the key determinants of behavioral intention and refer to the way perceptions of relevant groups or individuals such as family members, friends, and peers may affect one's performance of the behavior. Ajzen defines subjective norms as the "perceived social pressure to perform or not perform the behavior". According to TRA, people develop certain beliefs or normative beliefs as to whether or not certain behaviors are acceptable. These beliefs shape one's perception of the behavior and determine one's intention to perform or not perform the behavior. For example, if one believes that recreational drug use (the behavior) is acceptable within one's social group, one will more likely be willing to engage in the activity. Alternatively, if one's friends groups perceive that the behavior is bad, one will be less likely to engage in recreational drug use. However, subjective norms also take into account people's motivation to comply with their social circle's views and perceptions, which vary depending on the situation and the individual's motivations.

Normative beliefs Normative beliefs touch on whether or not referent groups approve of the action. There exists a direct correlation between normative beliefs and performance of the behavior. Usually, the more likely the referent groups will approve of the action, the more likely the individual will perform the act. Conversely, the less likely the referent groups will approve of the action, the less likely the individual will perform the act.

Motivation to comply Motivation to comply addresses the fact that individuals may or may not comply with social norms of the referent groups surrounding the act. Depending on the individual's motivations in terms of adhering to social pressures, the individual will either succumb to the social pressures of performing the act if it is deemed acceptable, or alternatively will resist to the social pressures of performing the act if it is deemed unacceptable.

Behavioral intention Behavioral intention is a function of both attitudes and subjective norms toward that behavior (also known as the normative component). Attitudes being how strongly one holds the attitude toward the act and subjective norms being the social norms associated with the act. The stronger the attitude and the more positive the subjective norm, the higher the A–B relationship should be. However, the attitudes and subjective norms are unlikely to be weighted equally in predicting behavior. Depending on the individual and situation, these factors might have different impacts on behavioral intention, thus a weight is associated with each of these factors. A few studies have shown that direct prior experience with a certain activity results in an increased weight on the attitude component of the behavioral intention function.

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

where: BI = behavioral intention (AB) = one's attitude toward performing the behavior W = empirically derived weights SN = one's subjective norm related to performing the behavior

Conditions The TRA theorists note that there are three conditions that can affect the relationship between behavioral intention and behavior. The first condition is that "the measure of intention must correspond with respect to their levels of specificity". This means that to predict a specific behavior, the behavioral intention must be equally specific. The second condition is that there must be "stability of intentions between time of measurement and performance of behavior". The intention must remain the same between the time that it is given and the time that the behavior is performed. The third condition is "the degree to which carrying out the intention is under the volitional control of the individual". The individual always has the control of whether or not to perform the behavior. These conditions have to do with the transition from verbal responses to actual behavior.

Scope and limitations

Scope While Fishbein and Ajzen developed the TRA within the field of health to understand health behaviors, the theorists asserted that TRA could be applied in any given context to understand and even predict any human behavior. According to Sheppard et al., behavioral intention can predict the performance of "any voluntary act, unless intent changes prior to the performance or unless the intention measure does not correspond to the behavioral criterion in terms of action, target, context, time-frame and/or specificity". Their statement asserts that according to TRA, the measure of behavioral intention can predict whether or not an individual will perform a certain act, as long as the behavioral intention remains the same and the behavior is clearly and properly defined. Broadening the scope of TRA, Sheppard conducted a study in which they applied TRA in situations that did not completely comply or conform with Fishbein and Ajzen's framework. Surveying 87 previous empirical studies, they applied the theory in contexts where the individual did not have full volitional control over the behavior and/or where individuals did not have all the information to develop the intention.Pinder, Craig C. Work Motivation In Organizational Behavior. Psychology Press, 2008, pp. 253-266. To their surprise, they found that TRA could successfully be applied in situations that did not fully adhere to the three formal terms and conditions specified by the theory.

Limitations