Glossary
Theory of Reasoned Action
What is the Theory of Reasoned Action?
The Theory of Reasoned Action (TRA), developed by Martin Fishbein and Icek Ajzen, relates behavior to intentions. It explains those intentions through attitudes toward the behavior and subjective norms.
Key components
- Attitude toward the behavior is a person's evaluation of performing it, including expected outcomes and how much those outcomes matter.
- Subjective norms concern perceived expectations of important others and the person's motivation to comply with them.
In the model, these contribute to an intention, which is closely related to subsequent action. The strength of the relationships must be studied for the behavior involved.
Background and relation to TPB
TRA addresses why a general attitude alone may not predict a specific action well. It applies most directly when the behavior is under voluntary control. It does not claim that people always reason correctly or consciously calculate every choice.
Incomplete control motivated the addition of perceived behavioral control in Ajzen’s Theory of Planned Behavior (TPB).
Applications
For an exercise or health-communication project, the model can organize questions about expected benefits and social expectations. Those answers may suggest options to investigate. They do not establish that changing a belief or message will change behavior.
A marketing example
Imagine someone considering a reusable bottle. They may expect it to save money and believe their friends approve of reducing disposable packaging. Those evaluations and perceived expectations could support an intention to buy it. Whether they actually buy it is a separate outcome to measure.
Evidence and limitations
Webb and Sheeran's meta-analysis of 47 experimental tests found that interventions changing intentions produced a smaller average change in behavior. Intention matters, but it is not sufficient.
Check whether the measures concern the same action and whether people have the control needed to act. Practical obstacles can persist even when attitudes and intentions are favorable.
Why it matters
Wanting to do something and doing it are different outcomes. TRA helps investigate intentions; successful intervention design also needs to address the conditions for action.