Not for the first time, someone on LW links a West Hunter page that isn't content to make a reasonable point, but has to exaggerate that point and present it with sneering.

Cochran's post is short, but to make it even shorter:

Some people claim that it is really, really difficult for humans to psych themselves up to kill another human. They often cite a claim by S. L. A. Marshall that only a small fraction – less than 25% – of WWII American combat infantrymen fired their weapons in battle.

[...] it’s all bullshit. S.L.A Marshall’s ‘data’ is vapor; there was and is nothing to it. He made shit up, not just on this topic. There’s every to reason to think that the vast majority of infantrymen throughout history did their level best to kill those on the other side [...]

You have to wonder about a universal human instinct that apparently misfired in every battle in recorded history.

It's true that Marshall's claim about WWII soldiers isn't trustworthy. (I haven't spent enough time with the literature to go further and confirm the claim's made-up bullshit vapour. But it wouldn't surprise me.) Unfortunately Cochran has to have his cherry on top; he writes off not only Marshall but the general idea of soldiers, and people in general, finding it hard to kill other people.

Now, I first read about that idea, and about Marshall's dodgy WWII work, in (I'm fairly sure) Randall Collins's Violence: A Micro-Sociological Theory, which quotes Marshall at length and cites him for various (alleged) results, among them the WWII statistic. According to Collins, the famous statistic "has been controversial", though he also writes "Marshall is not presenting a statistical argument, but was summarizing his judgment".

That's not really good enough. But Collins doesn't rely exclusively on Marshall — the chapter where Collins goes on & on about Marshall cites many other sources which contradict Cochran's sarcasm & scepticism. They include five citations to affirm that a nontrivial number of soldiers soil themselves in battle, with one of those five mentioning soldiers trying to hide on the ground or under "blankets or sleeping bags"; Marshall's predecessor Colonel Charles Ardant du Picq, who gave "questionnaires to French army officers in the 1860s, who reported a tendency for soldiers to fire wildly in the air"; John Keegan's Face of Battle, which reveals that "eighteenth- and early nineteenth-century massed firing formations" often included NCOs pressing their swords against soldiers' backs "to force them to hold their position"; Paddy Griffith on a "pervasiveness of fear and firing incompetence" in the US Civil War; Richard Holmes and Dave Grossman on the same "pervasiveness" "for twentieth-century wars"; a conclusion "that the level of non-firing was similar [in WWII] in all armies" from Dyer's 1985 edition of War; Ulysses S. Grant's description of newly equipped troops fleeing in panic on the first day of the Battle of Shiloh; and Martin Gilbert's First World War to show that "[m]utinies in World War I occurred among all the armies that had been long in action, or had taken accumulated casualties [on the order of 100%]".

Collins also tabulates observations from a collection of combat photographs and from Russell W. Glenn's Reading Athena's Dance Card, finding that more US infantry in Vietnam reported firing "Rarely" or "Sometimes" (54% in total) than "Virtually always" (46%) in "life-threatening enemy confrontations", and that most of his photos show no troops firing at all.

I could go on. This is just the first half of chapter 2. Some of the evidence is anecdotal and could be cherry-picked, but the broad drift seems really very clear, and the rest of the book compiles further evidence that people tend to experience "confrontational tension and fear" in the face of potential violence, which leads them to back down or fumble — though competent violence can still occur when people overcome that tension & fear.

Cochran is probably right about Marshall, but probably wrong about the ease with which people kill each other. Perhaps Cochran should be less keen to call others idiots in the future.

Killing them would be introducing valid evidence. Talking about it is just fictional evidence.

That is a really clever mixup of different argumentation modes. That being said, Mr. Cochran strangling one of his opponents would still be only weak evidence that it is not so difficult for humans to psych themselves up to kill another human.

First of all, he hasn't actually done it (I presume).

Secondly, we know it's difficult, not impossible.

Thirdly, we know there are sociopaths and psychopaths who can do this without much thought, as well as perhaps normal people who have become desensitized to killing. Fortunately these are a small percentage of the populace.

There is, in fact, a large amount of research that has gone into studying the minds of people who kill: in wartime, in criminal activity, in law enforcement, and so forth; and there is a strong consensus that for most people intentional killing is hard. For example,

In World War Two, it is a fact that only 15-20 percent of the soldiers fired at the enemy. That is one in five soldiers actually shooting at a Nazi when he sees one. While this rate may have increased in desperate situations, in most combat situations soldiers were reluctant to kill each other. The Civil War was not dramatically different or any previous wars.

In WW2 only one percent of the pilots accounted for thirty to forty percent of enemy fighters shot down in the air. Some pilots didn't shoot down a single enemy plane.

In Korea, the rate of soldiers unwilling to fire on the enemy decreased and fifty five percent of the soldiers fired at the enemy. In Vietnam, this rate increased to about ninety five percent but this doesn't mean they were trying to hit the target. In fact it usually took around fifty-two thousand bullets to score one kill in regular infantry units! It may be interesting to not that when Special Forces kills are recorded and monitored this often includes kills scored by calling in artillery or close air support. In this way SF type units could score very high kill ratios like fifty to a hundred for every SF trooper killed. This is not to say these elite troops didn't score a large number of bullet type kills. It is interesting to note that most kills in war are from artillery or other mass destruction type weapons.

If one studies history and is able to cut through the hype, one will find that man is often unwilling to kill his fellow man and the fighter finds it very traumatic when he has to do so. On the battlefield the stress of being killed and injured is not always the main fear.

-- William S. Frisbee, The Psychology of Killing

If you want a more detailed look at this, including lots of references to the original Defense Department research, there are a number of good books by army officers including On Killing by Lieutenant Colonel Dave Grossman. One of the originals is Men Against Fire by World War I Officer S. L. A Marshall. Bruce Siddle's work, more focused on law enforcement, is also worth a look. E.g. Sharpening the Warrior's Edge.

None of these are perfect or irrefutable evidence. For instance, the research I'm aware focuses primarily on U.S. and British troops and police officers. It's certainly possible that this is culturally conditioned and the results might be different elsewhere. However, I've yet to see any strong critiques of the general consensus about the difficulty of killing in war. The best evidence we have is that killing is in fact difficult for most people, most of the time, even in war.