Indoctrination is direct instruction under circumstances where disagreement or real assimilation is not allowed—the message has to be taken whole to stay in the group. For children, it is not possible to imagine leaving the family and surviving. Indoctrination is mixing a set of beliefs with biological bonding, whether it is with children or hostages. In this way, the beliefs become much trickier to challenge later.
It is also a built in survival behavior to identify with the most powerful person. Children will inevitably experience the primary aggressor as the most powerful person. The primary aggressor's justification for the abuse becomes indoctrination into the beliefs that support abuse. Beyond this however, children are sometimes deliberately indoctrinated into beliefs of power over and misogyny, often with the insistence that this is preparing them “for the real world” or preparing them “to protect themselves.”