I think the term is "conditioning". During the American civil war they found that a lot of the guys killed in battle had not fired their shots. There's a story that in one gun they found 15 loads of ammunition. IN other words the poor fellow could not bring himself to killing so he kept reloading. Overall apparently the figure is that about 25% of soldiers were able to actually "kill". In the WW1 and WW2 the figures improved but were only around 50%. By the time they got to Vietnam they were able to lift the figure to 90%. Through the training soldiers are "conditioned" to kill. The problem is re-entering normal society after this process. What they need is "exit" counselling which is the type of therapy that those involved in cults have to go through in order to join mainstream society. Goes to explain a long way why many vietnam vets have struggled to live "normal" lives after the war.
