One way to study a person's personality is to examine how the personality operates in relation to others. Erik Erikson's stages of psychosocial development seeks to explain how individuals move from the initial stages of development into adult maturity. He offers these eight stages: oral-sensory, muscular-anal, locomotor, latency, adolescence, young adulthood, middle adulthood and maturity. In the course of these stages, a person develops particular habits and behaviors that influence his personality.
Sigmund Freud's notoriously sexual psychological theories acknowledge the role that conscious and unconscious sexual urges are a large component of our personal makeup. His ruminations on the libido, which is Latin for "I desire," examined notions of how individuals deal with sexual urges. Freud argued that humans go through five stages: oral, anal, phallic, latency and genital. These five stages represent the origin of desire for humans, and a person's personal preoccupations and desires are shaped by the formative experiences at each stage.
A large part of a person's personality lies in concepts of morality because it affects both a person's attitudes and actions in regard to essentially everything in the world. Lawrence Kohlberg hypothesized three stages of moral development. In the preconventional stage, a person sees things only in terms of obedience and punishment without thinking about moral questions underlying these actions. In the conventional stage, a person embraces concepts of right and wrong or law and order. In the post-conventional stage, a person examines the moral codes of behavior and develops an individual moral conception of things.
Jean Piaget thought that all normative humans undergo four stages of development: sensorimotor, preoperational, concrete and formal operations. Sensorimotor refers to the primal feelings of the five senses, in which children learn to pay attention to details. Preoperational development refers to language and using symbols to represent ideas. Concrete involves abstract thinking and judgment, and formal refers to hypothetical and deductive reasoning. Through these cognitive stages, a person develops specific patterns of thinking that characterize her personality and behavior.