Maa, let's knock this out. The main difference between the Theory of Reasoned Action (TRA) and the Theory of Planned Behavior (TPB) lies in the addition of one key construct in the TPB: Perceived Behavioral Control. 1. Theory of Reasoned Action (TRA): The TRA proposes that an individual's behavioral intention* is the most important determinant of their actual behavior. This intention is, in turn, determined by two factors: Attitude Toward the Behavior*: The individual's positive or negative evaluation of performing the behavior. Subjective Norms*: The individual's perception of social pressure to perform or not perform the behavior, based on what important others think. The TRA assumes that individuals have complete volitional control* over their actions. It works well for behaviors that are entirely within a person's control (e.g., choosing to eat an apple instead of a candy bar). 2. Theory of Planned Behavior (TPB): The TPB extends the TRA by adding a third determinant of behavioral intention: Perceived Behavioral Control (PBC)*. PBC refers to an individual's belief about the ease or difficulty of performing the behavior. It reflects their perception of having the necessary resources and opportunities, and their confidence in their ability to execute the behavior. The TPB was developed to address the limitations of the TRA in explaining behaviors that are not entirely under an individual's volitional control* (e.g., quitting smoking, exercising regularly, or adhering to a complex medication regimen). Even if someone has a positive attitude and supportive subjective norms, they might not intend to perform a behavior if they believe they lack the control or ability to do so. In the TPB, behavioral intention is influenced by attitude, subjective norms, AND perceived behavioral control. PBC can also directly influence the behavior* itself, as a person's actual control over a behavior can impact whether they successfully perform it, even if they have a strong intention. In summary, the TPB includes Perceived Behavioral Control to account for behaviors where individuals may face internal or external barriers, making it a more comprehensive model for predicting a wider range of health and social behaviors compared to the TRA. What's next?