Introduction
The Theory of Reasoned Action (TRA), developed by Martin Fishbein and Icek Ajzen in 1975, represents one of the most influential models within social psychology applied to the study of human behavior.
Its purpose is to explain how and why people decide to carry out certain behaviors, based on a rational and deliberate framework.
A Rational Decision Model
At the heart of TRA lies the idea that human behavior is, to a large extent, the result of a rationally formed behavioral intention.
This intention — that is, the degree to which a person is willing to perform an action — is the best predictor of actual behavior.
What Determines Intention?
The theory identifies two fundamental components:
1. Attitude Toward the Behavior
This refers to the personal evaluation of the behavior, based on beliefs about its consequences. This attitude results from a weighted assessment of:
Behavioral Beliefs
Perceptions about the expected outcomes of the action.
Evaluations of Those Outcomes
Positive or negative assessments of such consequences.
Practical example: If a person believes that donating blood saves lives (belief) and considers that highly positive (evaluation), they will have a favorable attitude toward that behavior.
2. Subjective Norm
This component refers to the perceived social pressure to perform or not perform the behavior. It is determined by:
Normative Beliefs
Perceptions about what important others (family, friends, authority figures) think one should do.
Motivation to Comply
The desire to meet these external expectations.
Practical example: If a student believes that her parents and teachers value constant studying, and she wants to meet those expectations, her subjective norm will support that behavior.
The Model Formula
Although it is not presented as a strict mathematical equation, the model can be conceptualized as:
Behavioral Intention = (Attitude toward the behavior) + (Subjective norm)
Key principle: The stronger the intention, the higher the probability that the behavior will occur, as long as significant external obstacles are absent.
Limits and Evolution: Toward the Theory of Planned Behavior
Limitations of TRA
One of the main critiques of TRA was its assumption of total control over behavior. That is, if someone wants to do something, they simply do it.
This excludes situations where barriers exist:
External
- Limited resources (money, time)
- Restricted opportunities
- Insufficient skills
Internal
- Anxiety or fears
- Uncontrolled impulsivity
- Deeply ingrained habits
The Evolution: TPB
In response to these limitations, Ajzen proposed in 1985 the Theory of Planned Behavior (TPB), which adds a crucial third component:
Perceived Behavioral Control
Represents the individual’s perception of their ability to perform the behavior, and can influence behavior both directly and indirectly.
Practical Applications
TRA has been successfully applied in multiple contexts:
🏥 Public Health
- Prediction of condom use
- Vaccination campaigns
- Smoking cessation programs
- Promotion of physical exercise
📈 Marketing and Communication
- Understanding consumer decisions
- Development of advertising strategies
- Analysis of brand loyalty
🎓 Education
- Promotion of study habits
- Prevention of risky behaviors in adolescents
- Encouragement of school participation
🏢 Organizational Change
- Leadership processes
- Change management
- Development of corporate culture
Applied Example: Recycling in the Workplace
Suppose an institution wants to promote recycling among its employees. According to TRA, the most effective strategy would involve:
Modifying Behavioral Beliefs
- Highlight benefits: "Recycling reduces environmental impact"
- Show impact: "It improves the institutional image"
Strengthening Positive Evaluations
- Personal incentives: Recognition or benefits
- Positive feedback: Showing results achieved
Increasing Normative Pressure
- Organizational culture: Creating an environment where coworkers and supervisors actively value this practice
- Visible leadership: Leaders setting an example
Final Reflection
The Theory of Reasoned Action highlights the role of rational and socially informed intentionality in human behavior.
It reminds us that, although we are not always perfectly logical, our behaviors are often deeply influenced by:
- Our personal attitudes
- What we believe others expect from us
Practical Value
Understanding these mechanisms not only allows us to analyze behavior more accurately, but also to intervene strategically to facilitate behavioral change, from public policy to individual psychotherapy.
"The prediction of human behavior is possible when we understand the intentions that guide it."
References
Ajzen, I. (1985). From intentions to actions: A theory of planned behavior. In J. Kuhl & J. Beckmann (Eds.), Action-control: From cognition to behavior (pp. 11–39). Springer.
Ajzen, I., & Fishbein, M. (1980). Understanding attitudes and predicting social behavior. Englewood Cliffs, NJ: Prentice-Hall.
Fishbein, M., & Ajzen, I. (1975). Belief, attitude, intention, and behavior: An introduction to theory and research. Reading, MA: Addison-Wesley.
Montaño, D. E., & Kasprzyk, D. (2015). Theory of Reasoned Action, Theory of Planned Behavior, and the Integrated Behavioral Model. In Health Behavior: Theory, Research, and Practice (5th ed., pp. 95–124). Jossey-Bass.