Discussion: Development. Adulthood and aging, including changes in the body, in perception, and in cognition; and social and emotional development across the lifespan Read more» Further Study. These optional resources are provided for students that wish to explore this topic more fully. Jun 12, · Psychologist Daniel Levinson developed a comprehensive theory of adult development, referred to as the Seasons of Life theory, which identified .
Adult development is change, a progression from simple to complex behavior, from a less differentiated state to a more differentiated state (Mirriam. ). Consequently, adult developmental theory often deals with 'stages and phases. Research at Harvard and other academic institutions that began in the ’s has uncovered what are called adult stages of development. That research is now being applied to leadership development to help leaders manage complexity, ambiguity, and transformational change.