View full lesson: ed.ted.com/lessons/how-does-your-brain-respond-to-pain-karen-d-davis Ouch! Everyone experiences pain -- but why do some people react to the same painful stimulus in different ways? And what exactly is pain, anyway? Karen D. Davis walks you through your brain on pain, illuminating why the "pain experience" differs from person to person. Lesson by Karen D. Davis, animation by Brett Underhill.