KEY POINTS. Lawrence Kohlberg expanded on the earlier work of cognitive theorist Jean Piaget to explain the moral development of children, which he believed follows a series of stages. Kohlberg defined three levels of moral development: preconventional, conventional, and postconventional.
Evolutionary psychologists have suggested that men are more likely than women to prefer mates with a fertile-looking appearance and less likely than women to prefer mates with wealth and social status.
