Influenced by Piaget's theory that development occurs in stages, in
    the mid-1960s American psychologist Lawrence Kolhberg proposed
    a multistage theory of moral evolution. In the early level of
    development [Pre-conventional level], children strive to maximize pleasure and avoid
    punishment. Children at this level consider the needs of others only
    to the extent that meeting those needs will help the child fulfill his
    or her own needs. During the next period [Conventional level], which is characterized by
    conformity to social rules, the child demonstrates respect for and
    duty to authority. The child also seeks to avoid disapproval from
    that authority. As the child matures [Post-conventional level], his or her moral judgment is
    motivated by respect for legally determined rules and an
    understanding that these rules exist to benefit all. Eventually,
    universal principles are internalized. These principles, such as liberty
    and justice, may even transcend aspects of the existing legal
    system. (From "Criminology" article, Encarta.mns.com, search for "Kohlberg" performed 10/24/01.)