In reply to nickinscottishmountains:
> (In reply to trevor simpson) It's just a generalisation, based on a hunch, isn't it? For some situations it might be true, for others it might not.
Historically, it seems to have generally been true according to a lot of people who *weren't* in armchairs issuing platitudes. But there are also other reported instances where killing became more psychologically difficult the more physically easy it became. There are accounts of German machine gunners stopping firing during WW1 because they just couldn't watch any more Allied soldiers collapsing in front of them. But the general thing definitely seems to be that people get used to it, and no longer find it as traumatic or significiant after the first few engagements. That's very extensively recorded in accounts written by soldiers.