This concept describes the way in which level of self is non-genetically passed from one generation to the next. When the child who is the most caught up in the family projection process leaves home, this adult child will have a lower level of differentiation (less self) than his or her parents or freer siblings. When this person marries, he or she will select someone at the same level of differentiation. When this couple have children and one of their children becomes the object of the projection process more so than his siblings, this adult child will leave home and marry someone at an equally lower level of differentiation. The same process allows a child who is freer from the family emotional process to gain self resulting in a higher level of differentiation.
This process repeated over several generations provides a way to think about the differences that evolve between siblings and between offspring in different generations. Dr. Bowen believed this process, occurring over many generations, contributed to a range of differentiation and symptoms in every family system. This is a naturally occurring process that contributes to the complex variability in functioning that exists in all families over time.