Answer:
Erikson's generativity versus stagnation and Levinson's seasons of a man's life.
Step-by-step explanation:
The theories that define adult development in midlife are:
Erik Erikson's theory of Generativity and Stagnation, and Levison's theory of seasons of a man's life.
The theory of Generativity versus Stagnation is divide into eight Psychosocial stages. These stages not only covers infancy and adolescence but the whole lifespan of a person, from infancy till maturity.
The theory of Seasons of a man's life was developed by the psychologist Daniel Levinson. There are six stages in this theory through which Levinson explores the midlife of a person from Early Adult Transition to Late Adulthood.