Family members are intensely connected emotionally.
 This connectedness can foster reactivity.
 As family members, we react not just to each other's behavior but to what we believe are each other's needs and  expectations. We watch carefully, albeit mostly subconsciously, for changes in each other’s behavior. We do so in order to predict what will happen next, based upon past experience.
The family members watching another’s behavior will react in what they believe will be reciprocal to the action they are predicting is about to occur.  Around it goes, a change in one person's behavior or functioning will lead to a reciprocal change in the functioning of others.
It's impossible not to be impacted by other members of the family system, even if we are separated, especially if we are still parenting, because family members are emotionally interdependent on each other to some degree.
This emotional interdependence is a human characteristic of evolution. In promoting cohesiveness ...
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