Carol Gilligan is a psychologist known for her 1982 book "In a Different Voice" which criticized Lawrence Kohlberg's theory of moral development for only studying males. Gilligan proposed an "ethic of care" model which found females tend to focus on responsibilities to others rather than individual rights. Her work suggested differences in how males and females develop morally. Though some criticized her research methods, Gilligan defended her findings and continued research on gender differences in development.