The Theory of Reasoned Action, developed by Martin Fishbein and Icek Ajzen, is a psychological model that explains how our attitudes and social influences shape our intentions and, in turn, our behavior. In simple terms, it suggests that people do things because they intend to, and those intentions come from what they personally believe about the behavior and what they think others expect of them. It’s a key theory for understanding decision-making in health, relationships, and everyday life.
Key Takeaways
- Definition: The Theory of Reasoned Action (TRA) explains how people’s intentions lead to their behaviors, emphasizing that actions are guided by rational thought rather than impulse. Developed by Martin Fishbein and Icek Ajzen, it focuses on the link between beliefs, intentions, and actions.
- Components: The theory highlights two main factors that shape behavioral intentions — personal attitudes toward the behavior and perceived social pressures, known as subjective norms. Together, these predict whether someone is likely to act.
- Process: TRA proposes that behavior starts with intention, which is formed through evaluating outcomes and considering others’ expectations. If both attitude and social approval align, the person is more likely to follow through.
- Applications: The model is widely used in health campaigns, marketing, and social psychology to predict actions such as exercising, quitting smoking, or purchasing products. It helps design interventions that change beliefs to shift behavior.
- Limitations: TRA assumes people have full control over their actions, which isn’t always true in real-life situations. This led to the development of the Theory of Planned Behavior, which adds perceived behavioral control as a third factor.
The Theory of Reasoned Action, often considered in tandem with the Theory of Planned Behavior, is a cognitive theory and mathematical model that helps psychologists understand human behavior in specific contexts, such as whether or not people will take up healthy habits.
Theoretical Origins
The TRA, along with its later version, the Theory of Planned Behavior (TPB), belongs to a group of ideas known as social cognition models.
These models suggest that our actions are guided by what we believe about a behavior, how we think others will view it, and the social situations we’re in.
This way of thinking is closely related to social learning theory, developed by psychologists like Albert Bandura, which emphasizes how our thoughts and social environment work together to shape behavior.
Origins and Early Development
The Theory of Reasoned Action was created by Martin Fishbein and Icek Ajzen.
Their early publications appeared in the late 1960s and early 1970s, notably, Fishbein’s work in 1967 and joint papers by Ajzen and Fishbein around 1970.
These studies laid the foundation for modern research into attitudes, intentions, and decision-making.
Commitment to Goals
A key idea behind TRA is that people are more likely to commit to a goal when they believe it is both worthwhile and achievable.
This idea comes from early motivation research, summarized in the simple formula:
Commitment = Value of the goal × Expectation of success
This principle, highlighted by Fishbein and Ajzen in 1974, captures the essence of how motivation and belief combine to influence our intentions and behavior.
How the Model Works
The Theory of Reasoned Action has four main terms: Belief, Attitude, Subjective Norms, and Intention (Fishbein and Ajzen, 1975):
1. Behavioral Intention
Your intention is basically your plan or motivation to do something – it’s the best single predictor of whether you’ll actually do it.
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It shows how much effort you’re willing to put in.
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The stronger your intention, the more likely you’ll act on it.
For example, if you’re determined to start exercising three times a week, that intention is a strong sign you probably will.
However, your intention depends on two things: how you feel about exercising (your attitude) and what others think about it (the subjective norm).
In short:
If people have time to think about their choices, their intentions are usually the best clue to what they’ll actually do.
2. Attitude Toward the Behavior
Your attitude toward a behavior is your personal evaluation of it – whether you think it’s good, bad, enjoyable, or worthwhile.
This attitude is shaped by two things:
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Outcome beliefs – what you think will happen if you do it (e.g., “If I quit smoking, I’ll be healthier” or “If I quit smoking, I might gain weight.”)
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Outcome value – how much those outcomes matter to you (e.g., “Being healthier is really important to me.”)
The theory shows that specific attitudes (e.g., “I plan to use birth control pills in the next two years”) are better predictors of behavior than vague, general ones (e.g., “I support birth control”).
3. Subjective Norms (Social Pressure)
Subjective norms refer to the social pressure you feel about a behavior – what you think the important people in your life believe you should do.
This depends on two parts:
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Beliefs about others’ opinions – what you think people close to you (like parents, friends, or partners) expect of you.
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Motivation to comply – how much you care about meeting those expectations.
For instance, someone might not personally like the idea of dieting, but if their friends and family strongly encourage it – and they value those opinions – they may still form the intention to diet.
Putting It All Together
The TRA suggests that your attitude (how you feel about the behavior) and your subjective norm (social expectations) combine to shape your intention, which in turn predicts your behavior.
Research shows:
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Attitudes and subjective norms are strongly linked to intentions (around 0.67 correlation).
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Intentions and actual behavior are moderately linked (around 0.53–0.62 correlation).
This means the theory does a good job explaining what people plan to do, but not always whether they’ll follow through—since other factors (like time, opportunity, or confidence) can still get in the way.
Each of these terms is often treated by behavioral scientists as a factor in an equation intended to predict human behavior. As such, they are all related — factors that ultimately contribute to behavior.
Fishbein and Ajzen (1975), who originated the theory of reasoned action, created a diagram to describe the relationship between the main components of their model.
Attitudes, norms, and perceived control each lead to intentions — the readiness to do a behavior. These intentions can then lead, albeit imperfectly, to behaviors.
After Fishbein and Ajzen’s (1975) original behaviors, other scientists have attempted to better group and explain the background factors that lead to the behavioral, normative, and control beliefs that lead to attitude, subjective norms, and perceived behavioral control, respectively.
These environmental factors could include the following:
- Personal factors: traits, locus of control, emotions, and health concerns.
- Demographic factors: Age, gender, race, ethnicity, education, income, and religion.
- Environmental factors: diagnosis, stress, and media exposure.
Health Applications
Peer Influence and Addiction
Neighbors, Foster, and Fossos (2013) outlined several models of addiction. One of these was based on the Theory of Reasoned Action and its predecessor, the theory of Planned Behavior.
Neighbors, Foster, and Fossos argued that the construct of social norms is similar to the idea of injunctive norms put forth by other social norms.
As the psychologists explain it, if an adolescent believes that the important people in their life would disapprove if they smoked cigarettes, they should be less likely to intend to smoke cigarettes — and, subsequently, less likely to actually smoke cigarettes.
These subjective norms are distinct from the social norms that other theories put forth in two ways.
Firstly, they focus exclusively on the important others in someone’s life as a reference group, and the behavior that is relevant to the theory is that of the perceiver rather than behavior in general.
The question that the theory of reasoned action asks is not about the extent to which someone thinks the others that they care for approve or disapprove of smoking, but rather the extent to which someone thinks others approve or disapprove of their smoking and particular (Neighbors, Foster, and Fossos, 2013).
Although this may seem like a small distinction, there are cases where it is an important one.
For instance, as Neighbors, Foster, and Fossos (2013) note, parents who have moderate or favorable views on the legalization of marijuana may be less approving of marijuana use by their own daughters.
Breakfast Consumption
One of the most popular applications of the theory of reasoned action is to assess the probability that a group of people will follow a particular health behavior.
One study attempts to see if the theory of reasoned action would increase breakfast consumption among students in a secondary school in Iran (Hosseini et al., 2015).
To do so, the researchers implemented an informational program that intended to promote breakfast consumption.
Students then filled out a questionnaire before and after the intervention. The first part of this questionnaire concerned knowledge about breakfast consumption, and the second, components of the Theory of Reasoned Action’s factors.
According to the data, subjective norms — whether or not someone believed others around them were consuming breakfast and whether or not they thought the important others in their life wanted them to consume breakfast — were the best predictors of breakfast consumption (Hosseini et al., 2015).
Fast Food Consumption
Marketers have also used the theory of reasoned action to describe a wide variety of behaviors, such as the consumption of automobiles, banking services, computer software, coupons, detergents, and soft drinks.
The researchers Richard P. Bagozzi, Nancy Wong, Shuzo Abe, and Massimo Bergami sought to understand the theory in the context of different cultures by looking at fast food consumption in the United States, Italy, China, and Japan.
They found that predictions under the theory of reasoned action tended to vary based on the social setting — whether someone is eating alone or with others — and cultural orientation — whether someone lives in an individualistic or collectivist culture.
The researchers found that subjective norms tended to influence decisions when eating with friends, but not alone, regardless of the level of individualism or collectivism in one’s culture.
However, the impact of attitudes, subjective norms, and past behavior on intentions was greater for Americans than for Italians, Chinese, or Japanese people.
In general, there was more explainable variance in behavior for Western than Eastern cultures (Bagozzi, Wong, Abe, & Bergami, 2000)
Limitations
The TRA can be seen as a blueprint for a bridge that connects thoughts to actions.
The main critique is that this blueprint only works perfectly if the bridge is short (a simple, fully controllable action) and built in ideal conditions (perfectly rational deliberation).
When applied to real-world complexity, the structure is found to be incomplete, lacking the necessary components (like Perceived Behavioral Control) and reinforcement materials (like implementation planning) needed to reliably support the traffic of complex human behavior.
1. Limited to Volitional (Controllable) Behavior
The most significant limitation of the original TRA is its inherent restriction to predicting behaviors that are fully volitional—that is, actions that are entirely under the person’s conscious control.
- Inapplicability to Complex/Non-Volitional Actions: Many behaviors relevant to health psychology and social science are not completely volitional. Examples of behaviors that are not fully controllable include addictive behaviors such as smoking, or complex social interactions such as the negotiation of condom use during sexual encounters.
- Need for Expansion: To overcome this fundamental weakness and improve the model’s ability to address non-volitional behavior, the TRA was extended by Ajzen (1985, 1991) to include the concept of Perceived Behavioral Control (PBC), resulting in the Theory of Planned Behaviour (TPB). This addition allows the expanded framework to account for the ease with which people believe they can perform the behavior, even when facing barriers.
2. The Intention-Behavior Gap
A consistent critique applied to the TRA (and often to its successor, the TPB) is the significant drop in predictive ability when moving from intention to actual behavior.
While the components of the TRA (attitudes and subjective norms) correlate strongly with intention, their correlation with the actual performance of behavior is noticeably weaker.
- Correlation Findings: Meta-analyses confirmed the strong link between attitudes/social norms and intentions, but the correlation between intention and behavior ranged lower, specifically between 0.53 and 0.62.
- Need for “Action” Variables: This gap provides strong evidence for the need to identify further variables that move an individual from intention to action. This recognition has spurred research into additional concepts, such as Implementation Intentions (making specific “when, where, and how” plans), which are thought to help bridge this gap.
3. Oversimplification of Human Decision-Making (The Rational Agent)
The TRA, as a social cognition model, assumes that individuals are generally rational decision makers who deliberately weigh the perceived implications of their actions before making a decision.
This strong assumption about human rationality has been subject to criticism in psychology generally, as well as specific limitations within the model:
- Neglect of Affective Variables: The original model focuses heavily on cognitive factors (beliefs, expectations, norms) but often fails to adequately incorporate non-cognitive influences, such as affective (emotional) variables.
- Bounded Rationality: In the broader psychological literature concerning decision-making, it is recognized that human decisions are characterized by bounded rationality. This framework suggests that while people try to make rational decisions (weighing costs and benefits), cognitive limitations (such as limited usable memory, time constraints, and constraints on intelligence/perception) prevent them from being fully rational.
- Automatic and Non-Conscious Processes: The TRA focuses on deliberative (nonspontaneous) behaviors. However, not all behavior is the result of such careful deliberation. The field of social cognition recognizes that many mental processes are automatic—unintentional, uncontrollable, occurring outside of conscious awareness, and cognitively efficient. By focusing only on reasoned action, TRA overlooks the powerful role of these automatic, non-conscious influences.
4. Methodological and Structural Issues
The way the TRA defines and measures its components also presents limitations:
- Lack of Causal Specificity (Cross-Sectional Studies): Research evidence supporting the link between intention and behavior in TRA has been limited by an over-reliance on cross-sectional studies, which cannot fully disentangle cause-effect relationships or examine changing relationships over time.
- Neglect of Reciprocal Relationships: The TRA, like the TPB, does not explicitly acknowledge the potential transaction or reciprocal relationship between the predictor variables and the measured outcomes. For instance, engaging in a behavior itself may actually shape the person’s subsequent attitudes, rather than the attitude always preceding and causing the behavior.
- Issue of Specificity: While the theory correctly notes that the more specific the attitude toward the behavior in question, the better it predicts the behavior, the measurement of concepts like subjective norms can be problematic, depending on whether individually salient beliefs or generalized modal beliefs are assessed.
Theory of Reasoned Action vs. Theory of Planned Behavior
The theory of reasoned action has some limitations. One of these is a significant risk of confounding between attitudes and norms.
This happens because attitudes can often be reframed as norms and norms as attitudes.
For example, someone who has the attitude that kale is good for them may simply be reflecting a subjective norm of a group of influential friends, family, doctors, and social media influencers who believe that kale is healthy.
The theory of planned behavior attempts to resolve these limitations through the idea of perceived behavior control (LaCaille, 2020).
The Theory of Reasoned Action (TRA) and the Theory of Planned Behavior (TPB) are closely related social cognition models used to explain and predict deliberate human behavior.
The TRA served as the foundational model, and the TPB represents its expansion and improvement to address specific limitations of the original theory.
The primary difference between the TRA and the TPB lies in the inclusion of a third, critical conceptual component in the TPB: Perceived Behavioral Control (PBC).
Here is a detailed comparison of the differences:
1. Scope of Behavior Explained
The most substantial difference is the type of behavior each theory is designed to explain:
| Feature | Theory of Reasoned Action (TRA) | Theory of Planned Behavior (TPB) |
|---|---|---|
| Behaviors Covered | Volitional Behavior, meaning actions that are entirely under the person’s control. | Non-Volitional Behavior and deliberate behaviors in general. |
| Limitation/Improvement | The TRA was limited because much behavior, such as addictive behaviors (e.g., smoking) or complex social negotiations (e.g., negotiating condom use), is not completely volitional. | The TPB was developed to improve the model’s ability to address non-volitional behavior. |
2. The Core Components (Determinants of Intention)
Both models assert that intention is the best predictor of deliberate behavior, and this intention is determined by predictive factors.
| TRA Component | TPB Component | Difference Explained |
|---|---|---|
| Attitude toward the Specific Behavior | Attitude toward the Specific Behavior | Both models retain this element, which is the person’s specific attitude toward the behavior, not their general attitude. |
| Subjective Norms | Subjective Norms | Both retain this element, which accounts for perceived social pressure—beliefs about how important others view the behavior. |
| (Not Included) | Perceived Behavioral Control (PBC) | The TPB includes PBC, which is defined as a person’s belief that they have control over their own behavior in certain situations, even when facing barriers. |
3. Role of Perceived Behavioral Control (PBC)
The introduction of Perceived Behavioral Control (PBC) is the defining feature of the TPB.
- Definition: PBC is the ease with which people believe they can perform the behavior. It measures a person’s belief that they have control over their behavior. This construct is closely related to the concept of self-efficacy, which is the belief that one has the personal capabilities to master a situation and produce positive outcomes.
- Influence on Intention and Behavior: The TPB proposes that PBC directly influences intention. Furthermore, a direct relationship between PBC and behavior was also considered possible if perceptions of control were accurate.
- Empirical Success: The addition of PBC significantly improved the model, making the TPB generally more successful in predicting behavioral change than its predecessor. PBC was found to have a mean correlation with intention of 0.71.
4. Predictive Power
While both models show strong predictive power for intentions, the TPB offers an incremental improvement in predictive success due to the inclusion of PBC:
- Intention Prediction: In studies confirming the TRA, attitudes and social norms correlated highly with intention (approximately 0.67). The TPB variables (including PBC) are often reported to account for between 40 and 50 per cent of the variance in intention.
- Behavior Prediction: The correlation between TRA intention and behavior was between 0.53 and 0.62. TPB variables accounted for between 19 and 38 per cent of the variance in behavior. The ability of the TPB to predict behavior successfully is generally lower than its prediction of intention. This gap is a known limitation of both models, requiring consideration of other variables, such as Implementation Intention (“when, where and how” plans).
References
Ajzen, I., & Fishbein, M. (1975). A Bayesian analysis of attribution processes. Psychological bulletin, 82 (2), 261.
Bagozzi, R. P., Wong, N., Abe, S., & Bergami, M. (2000). Cultural and situational contingencies and the theory of reasoned action: Application to fast food restaurant consumption. Journal of consumer psychology, 9 (2), 97-106.
Fishbein, M. (1979). A theory of reasoned action: some applications and implications.
Hale, J. L., Householder, B. J., & Greene, K. L. (2002). The theory of reasoned action. The persuasion handbook: Developments in theory and practice, 14 (2002), 259-286.
Hosseini, Z., Gharghani, Z. G., Mansoori, A., Aghamolaei, T., & Nasrabadi, M. M. (2015). Application of the theory of reasoned action to promoting breakfast consumption. Medical journal of the Islamic Republic of Iran, 29, 289.
LaCaille, L. (2020). Theory of reasoned action. Encyclopedia of behavioral medicine, 2231-2234.
Madden, T. J., Ellen, P. S., & Ajzen, I. (1992). A comparison of the theory of planned behavior and the theory of reasoned action. Personality and social psychology Bulletin, 18 (1), 3-9.
Montano, D. E., & Kasprzyk, D. (2015). Theory of reasoned action, theory of planned behavior, and the integrated behavioral model. Health behavior: Theory, research and practice, 70 (4), 231.
Neighbors, C., Foster, D. W., & Fossos, N. (2013). Peer influences on addiction. Principles of addiction: Comprehensive addictive behaviours and disorders, 1, 323-331.
Rossi, A. N., & Armstrong, J. B. (1999). Theory of reasoned action vs. theory of planned behavior: Testing the suitability and sufficiency of a popular behavior model using hunting intentions. Human Dimensions of Wildlife, 4 (3), 40-56.
Sheppard, B. H., Hartwick, J., & Warshaw, P. R. (1988). The theory of reasoned action: A meta-analysis of past research with recommendations for modifications and future research. Journal of consumer research, 15 (3), 325-343.
Vallerand, R. J., Deshaies, P., Cuerrier, J. P., Pelletier, L. G., & Mongeau, C. (1992). Ajzen and Fishbein’s theory of reasoned action as applied to moral behavior: A confirmatory analysis. Journal of personality and social psychology, 62 (1), 98.
