Ardant du Picq was a French officer in the 19th Century. His work on the behavior of men in combat was published after his death in the Franco-Prussian war in 1870 and has remained relevant to this day.
du Picq studied reports of armies in combat from ancient times to the present and demonstrated several interesting effects that seem contradictory. For example in ancient battles, although the danger lies to the front, it is troops in the rear that break and run first. Lacking the exertion of actually fighting for their lives, they have nothing to do but face the fear.
In modern times, similar rules apply. Troops want to defend themselves by firing back as quickly as possible. The theoretical orderly firing by lines or platoons or by volley basically breaks down at once into each man firing as fast as he can.
The vaunted ‘bayonet charge’ is also found to be impossible to locate. Most degraded back into a firefight, and the remainder had the defender retire before the two sides came into contact at all.
The situation is even more extreme with a cavalry charge. One side or the other breaks off before contact is made.
du Picq did emphasize the offensive as the best way to impose your moral force on the opponent, but those who claim him as an ultimate ancestor to the offensive à outrance theory of World War I are misguided. For one thing, is dismissal of the bayonet charge and recommendation of using skirmishers is contrary to the ‘human wave’ nature of the theory.
And also, as Zuber seems to have demonstrated in The Real German War Plan, both the Schlieffen plan and the French offensive plan that countered it were straw men put up to give post war Generals something to hang the defeats on besides themselves. For one thing, the military manuals describing the new “Offense to the Limit” were not distributed until months before the war. Most troops would have never trained even once using these new theories.
It is a lot easier to say that some dead guy messed up the plan than to say that the troops I trained just weren’t ready for combat – or that you messed up in the action yourself.
du Picq was one of the first men to look at how men react in battle as men, rather than look at alignments, technology or even leadership. His conclusion is that most of the time, those last three matter a lot less than everyone imagines.