According to the developmental psychologist Robert Kegan,[2] a person's self-concept evolves in a series of stages through their lifetime. Such evolution is driven alternately by two main motivations: that of being autonomous and that of belonging to a group. Human beings are "controlled" by these motivations in the sense that they do not have influence on them but are rather defined by them. Additionally, these motivations are in conflict and their relationship develops over a lifespan.[1]:31
Kegan describes 5 stages of development, of which the latter 4 are progressively attained in adulthood, although only a small proportion of adults reach the fourth stage and beyond:
CDF refers to such stages as "social–emotional" in that they relate to the way a person makes meaning of their experience in the social world. CDF holds that people are rarely precisely at a single stage but more accurately are distributed over a range where they are subject to the conflicting influences of a higher and a lower stage.