This article reviews some of Carol Gilligan’s ideas on the ethics of care and justice, and describes the development and validation of a care-based moral development instrument, the Ethic of Care Interview (ECI). Following Gilligan’s theory, the ECI measures five hierarchical levels of care reasoning that involve a progressively more sophisticated understanding of human interconnection. A series of studies suggests that the ability to care both for others and oneself is a valuable human quality and an important aspect of positive adaptation across the lifespan. The link between care-based moral thought and identity development is strong, especially for women, as Gilligan suggests. Potential decisive determinants of growth in the care ethic ...