If I had to teach this in one paragraph, I would start here: the easiest stories to recall are not automatically the most probable ones. Three quick checks before you act: 1. Name the mechanism in plain English: Availability bias pushes recent or vivid information to the front of the mind, even when base rates say it should not dominate the decision. 2. Say why it matters for behavior or portfolio decisions: That matters in investing because headlines are optimized for recall, not for calibration. 3. Set the review question: If you had to teach this without jargon, what would you tell someone to monitor first? In real life: One spectacular blow-up can distort how you size an otherwise ordinary risk if you do not reset back to base-rate thinking. Common slip: The mistake is confusing mental accessibility with true frequency. The point is not to memorize the label. The point is to know what variable is actually doing the work.