  However, the cognitive theory of moral development formulated by Piaget in The Moral Judgment of the Child (1965) and the somewhat later theory of Lawrence Kohlberg (1981, 1984) are the ones that have had most influence on psychologists, educators, and even philosophers.  Thus, for example, what John Rawls has to say about children in his classic work, A Theory of Justice (1971) rests heavily on the work of Piaget and Kohlberg.