A recent book argues persuasively that we can’t be terribly sure of our perceptions, memory, or self-assessment (The Invisible Gorilla by Christopher Chabris & Daniel Simons). But I think my favorite insight was learning that although confidence is a trait that varies from person to person, it actually has little to do with one’s underlying knowledge or ability.  In other words, the degree to which someone exudes confidence does NOT tell you much about how competent he is. And since we naturally assume that confidence corresponds to competence, we often trust the wrong people. Think about that the next time you consider outside marketing help – or make any personnel decisions!