The roles were initially culturally determined. As a consequence of this ambivalence, they make contradictory demands on, and give double messages to, other members of the patient's family of origin about what is expected of them.
The ambivalence in the parents, in turn, is created by learned and ingrained family rules which became obsolete when the ambient culture changed quickly. In other words, the family rules lag behind changes in the requirements of the ambient culture.
The double messages are believed to reinforce (in the behaviorist sense and on a variable intermittent reinforcement schedule) the patient's intrapsychic conflicts and the resultant dysfunctional behavior. The patient's responsive behavior then simultaneously reinforces ambivalent, dysfunctional behavior in the rest of the family.
The reasons that problematic patterns exist usually involve historical events that have taken place over at least a couple of generations, and sometimes start even further back than that. Important historical events which might explain them better may not be discoverable because there are no longer any relatives alive who are old enough to know about them.
Psychotherapy outcome studies that do not look at the frequency of certain behavior patterns and psychological symptoms two years after treatment has ended are highly misleading.
These counter-moves do not necessarily occur immediately after the patient initially does what we have decided on in therapy sessions, but may occur suddenly at any time - often when least expected.