It is a psychological process that can be found in legal disputes about child custody. In practice, one of the two parents uses the child to put the ex-partner in trouble through direct and / or indirect action, aimed at destroy target parent. An example is the alienating parent says to child: “Do you see it? Your father / mother has abandon us”, “We are in economic trouble because he does not pay for the food”, “If you want to stay with him / her ok, but i do not agree”. The child, especially if at an early age, begins to introject the thoughts and emotions of the alienating parent, gradually experiencing a rejection of the other. The refuse is initially psychological, then also physical, with subsequent denial of any kind of contact with the target parent.
Of course, parental alienation corresponds to a psychological process structured by various phases and nuances, so if you intervene immediately you can block it, limiting potential damage.