Health Belief Model
Why do people ignore good health advice? The Health Belief Model (HBM) predicts action through four core perceptions:
- Perceived susceptibility: How at-risk you feel.
- Perceived severity: How serious the consequences are.
- Perceived benefits: How much the action helps.
- Perceived barriers: Costs or obstacles involved.
Two more components complete the framework: self-efficacy (confidence in your ability to act) and cues to action (external triggers like a doctor's reminder or a symptom).
Common pitfall: Assuming perceived severity alone drives action. A person can know a disease is fatal, but still do nothing if they feel invulnerable or if perceived barriers (cost, time, discomfort) are too high.
Theory of Planned Behavior
A distinct framework, the Theory of Planned Behavior (TPB) by Icek Ajzen, centers on intention as the direct predictor of behavior. Intention is shaped by three specific forces:
| TPB Factor | Meaning | Example |
|---|---|---|
| Attitude | Is this a good idea? | Exercising feels great |
| Subjective norms | What do others think I should do? | My peers work out |
| Perceived behavioral control | How much control do I have? | I have a gym membership |
Simply telling someone a behavior is beneficial rarely works. Effective interventions must address the specific belief holding someone back: lower barriers, build self-efficacy, or shift subjective norms.