Object-directed dehumanization is the tendency to view other individuals or groups as though they do not quite belong to the human race. Such a tendency can be socially dangerous. It leads to the 'rational' conclusion that it is not necessary to treat 'them' as if they were like 'us' or to be concerned with what they might be suffering if they were truly human beings.
Self-directed dehumanization includes diminution of the sense of personal responsibility for one's own actions, as well as feelings of powerlessness and of inability to question or to affect the course of events.
The Nazis' efficient technological and corporate structure was an effective mechanism both for removing individual responsibility and in dehumanizing its victims. Jews in transport trains to the death camps were called "pieces". Train officials processed 15,000 pieces from Hungary, 10,000 pieces from Greece, a million pieces from Poland, etc.