Piaget is correct in assuming a culturally universal age development of a sense of justice, involving progressive concern for the needs and feelings of others and elaborated conceptions of reciprocity and equality.

Lawrence Kohlberg's quote refers to Jean Piaget’s theory of cognitive development and its implications for understanding moral reasoning. Kohlberg agrees with Piaget’s assumption that there is a universal age progression in the development of a sense of justice, which involves growing concern for the needs and feelings of others. According to this view, children naturally move from a more egocentric perspective to a broader understanding of reciprocity and equality, meaning they start to appreciate the mutual responsibilities and fairness in relationships with others as they grow.

Kohlberg elaborates on Piaget’s ideas by emphasizing that the development of moral reasoning is not just about understanding rules or punishments but involves more complex concepts like reciprocity—the idea that people should treat others as they themselves would want to be treated—and equality, which involves a fair distribution of resources and opportunities. In Kohlberg’s own theory of moral development, this growing concern for others becomes central to moral judgments, forming the basis for a mature sense of justice.

The origin of this quote can be traced to Kohlberg’s work in the field of moral psychology, where he expanded on Piaget’s initial ideas. Kohlberg is famous for his stages of moral development, which propose that moral reasoning evolves in stages, from a focus on obedience to a growing understanding of human rights, justice, and fairness. His theory, like Piaget's, is grounded in the idea that moral development is universal, occurring in similar patterns across cultures and societies.

Ultimately, Kohlberg’s agreement with Piaget’s perspective reinforces the idea that moral development, specifically in terms of justice, follows a predictable, universal pattern. As individuals mature, they develop increasingly sophisticated and empathetic views on issues of equality and reciprocity, underlining the importance of moral education and understanding in fostering these traits from an early age.