This is interesting.
Self-confidence is not the real secret of leadership. The more essential ingredient is confidence in other people. Leadership involves motivating others to their finest efforts and channeling those efforts in a coherent direction. Leaders must believe that they can count on other people to come through—like Elsie Bailey's faith as a high school principal that inner-city children can learn, and that her teachers can teach them. If the people in charge rely only on themselves as heroes who can rescue any situation, while focusing on other people's inadequacies, they undermine confidence and reinforce losing streaks. In contrast, when leaders believe in other people, confidence grows, and winning becomes more attainable.
I've always been a firm believer that most people rise to the expectations placed on them. I think there was a study done with school kids once where the teachers were told different things about the kids, and the kids the teachers expected to do the best actually did the best. Maybe it's an urban myth, but either way I think there is some truth to the idea.