There are several theories about how leadership develops: the trait theory suggests certain personality traits lead to leadership roles; the great events theory says crises can cause ordinary people to rise to leadership; and the transformational leadership theory is that people can learn leadership skills. Effective leaders listen to others, encourage participation, and avoid quick decisions. Studies of leadership have examined organizational structures and management approaches, moving from scientific to social science to postmodern theories. Principles of leadership focus on serving others, developing trustworthiness, and effective communication. The most effective paradigm views people as spiritual beings seeking meaning in their work.