There are many different psychology theories, but most can be categorized as one of four key types:
Developmental TheoriesDevelopmental theories provide a set of guiding principles and concepts that describe and explain human development. Some developmental theories focus on the formation of a specific quality, such as Kohlberg's theory of moral development. Other developmental theories focus on growth that happens throughout the lifespan, such as Erikson's theory of psychosocial development.
Grand theories of development include psychoanalytic theory, learning theory and cognitive theory. These theories seek to explain much of human behavior, but are often considered outdated and incomplete in the face of modern research. Psychologists and researchers often use grand theories as a basis for exploration, but consider smaller theories and recent research as well.
Minitheories describe a small, very specific aspect of development. A minitheory might explain fairly narrow behaviors, such as how self-esteem is formed or early childhood socialization. These theories are often rooted in the ideas established by grand theories, but they do not seek to describe and explain the whole of human behavior and growth.