Marshall's findings have been somewhat controversial. Faced with scholarly concern about a researcher's methodology and conclusions, the scientific method involves replicating the research. In Marshall's case, every available, parallel, scholarly study validates his basic findings. Ardant du Picq's surveys of French officers in the 1860s and his observations on ancient battles, Keegan and Holmes' numerous accounts of ineffectual firing throughout history, Richard Holmes' assessment of Argentine firing rates in the Falklands War, Paddy Griffith's data on the extraordinarily low killing rate among Napoleonic and American Civil War regiments, the British Army's laser reenactments of historical battles, the FBI's studies of nonfiring rates among law enforcement officers in the 1950s and 1960s, and countless other individual and anecdotal observations all confirm Marshall's fundamental conclusion that man is not, by nature, a killer.
I'll just post once, and then won't engage in any argument, because I've seen this argument on the Internet so many times it bores me silly and I know it'll be back again in a few months. But for those genuinely interested in what studeis say..
Findings by Holmes, Grossman and others mentioned indicate a few things:
--firing rates among poorly indoctrinated soldiers from highly civilised societies vary greatly, but are often very low (see Grossman 1998, Holmes 2004)
--firing rates among well-indoctrinated soldiers are very high--over 90% (see Grossman 1998)
--pre-firearm warfare is much more immediate and personal than modern combat, and failing to attempt to kill in pre-firearm combat is both more difficult to conceal from ones comrades and much more immediately dangerous to the shirker
--rates of male mortal violence among many tribal peoples are extraordinarily high (see, for example, Brown 2000) in comparison to even the most violent parts of the civilised world
--similar extreme rates of male violence are observable in the archeological record for pre-historical times (Keeley 1997)
In brief:
Human beings are neither innately programmed killers nor innately programmed Ghandis. Male humans do have a tendency to attempt to acquire prestige and other benefits from killing other males that they have been socialised to regard as 'not fully human,' which is primarily a function of being 'not like me/not of my group/tribe/nation.' Modern society has successfully socialised the vast majority of men to regard
all others as fully human, regardless of where they come from. This engages their natural tendency to resist killing such people. Nonetheless, this tendency can be overcome with appropriate training (like the US marines or the Roman legions), and men so trained (and quite possibly women--not enough studies to say) can be taught to dehumanize their targets and kill reliably.
With adventurers, you need to ask:
How successful is their society in socailising men not to regard any other human beings as 'not fully human and thus legitimate targets of homicide?'
How well indoctrinated are typical adventurers as killers?
Do adventurers likely have experience of up-close-and-personal combat?
The answers won't be the same for everybody's campaign world, but I think if you're going for something vaguely like medieval Europe, professional adventurers will have probably have little compunction against killing, while ordinary folk will probably be reasonably well socialised by the church to regard killing as inherently abhorrent. IMHO, this sets up a very interesting dynamic in terms of the way that adventurers are viewed by normal members of society.
