A firing rate of 15 to 20 percent among soldiers is like having a literacy rate of 15 to 20 percent among proofreaders. Once those in authority realized the existence and magnitude of the problem, it was only a matter of time until they solved it.
And thus, since World War II, a new era has quietly dawned in modern warfare: an era of psychological warfare — psychological warfare conducted not upon the enemy, but upon one’s own troops. Propaganda and various other crude forms of psychological enabling have always been present in warfare, but in the second half of this century psychology has had an impact as great as that of technology on the modern battlefield.
Lt. Col. Dave Grossman
From On Killing — The Psychological Cost of Learning to Kill In War and Society