But if a person continues to develop morally, he or she will reach what Kohlberg labeled the postconventional level. The person at the postconventional level stops defining right and wrong in terms of group loyalties or norms. Instead, the adult at this level develops moral principles that define right and wrong from a universal point of view. The moral principles of the postconventional person are principles that would appeal to any reasonable person because they take everyone's interest into account. If you ask a person at the postconventional level why something is right or wrong, he or she will appeal to what promotes or doesn't promote the universal ideals of justice or human rights or human welfare.
Many factors can stimulate a person's growth through the three levels of moral development.
One of the most crucial factors, Kohlberg found, is education. Kohlberg discovered that when his subjects took courses in ethics and these courses challenged them to look at issues from a universal point of view, they tended to move upward through the levels. This finding, as Rest points out, has been repeatedly supported by other researchers. If you look at the hard evidence psychologists have amassed, the answer is yes.