It’s not only Hollywood detectives who have hunches; most, if not all, experienced clinicians must be familiar with the situation in which they feel sure that a certain course of action is the right one but are unable to explain why. Much as we may strive towards evidence-based medicine clinical intuition can not be ignored. Now research neuropsychologists in Iowa (Antoine Bechara and colleagues, Science 1997;275:1293-5) have given scientific respectability to the concept of valid but …