http://www.nd.edu/~rbarger/kohlberg.html
The first level of moral thinking is that generally found at the elementary school level. In the first stage of this level, people behave according to socially acceptable norms because they are told to do so by some authority figure (e.g., parent or teacher). This obedience is compelled by the threat or application of punishment. The second stage of this level is characterized by a view that right behavior means acting in one's own best interests.
The second level of moral thinking is that generally found in society, hence the name "conventional." The first stage of this level (stage 3) is characterized by an attitude which seeks to do what will gain the approval of others. The second stage is one oriented to abiding by the law and responding to the obligations of duty.
The third level of moral thinking is one that Kohlberg felt is not reached by the majority of adults. Its first stage (stage 5) is an understanding of social mutuality and a genuine interest in the welfare of others. The last stage (stage 6) is based on respect for universal principle and the demands of individual conscience. While Kohlberg always believed in the existence of Stage 6 and had some nominees for it, he could never get enough subjects to define it, much less observe their longitudinal movement to it.