Is there any evidence that military hazing (shouting, abuse, etc) is conducive to better soldiers?

Out of curiosity I did a quick google and found this article: https://www.csmonitor.com/USA/Military/2020/1007/Trust-your-drill-sergeant-Army-takes-new-approach-to-basic-training

I have no clue as to the veracity of its source but it seems to be in line with @CALICO's experiences.

I found this part particularly interesting, as it's something I never would have considered:

The new basic training model builds on a belief that has become increasingly pronounced in the post-Vietnam era, when the thinking was that while draftees had to be coerced, volunteers needed to be persuaded. The stereotypical “Full Metal Jacket” drill sergeants were working with conscripts who were unwilling to be in the military from the beginning, notes General Barno. In the modern Army, “Recruits have gone through a lot of wickets just to show up on the first day of basic training,” he says. “The Army has worked hard to get these folks in there. You want them to succeed.”

I've been in the Military for quite a while, so I can give my perspective, because I'm not familiar with any actual formalized research done here. It may exist, I just haven't looked, and some of it may still be classified even if it does exist.

To my mind, it serves a couple of functions. One, it gets you used to the type of environment the military tends to operate in. Most of the time, at least in my job, 90% of the time it's like a normal office job. Pleasantries are exchanged, people are cordial and respectful, emails are sent, heads up are given, people try to not inconvenience you if they can help it. The other 10% of the times are high stress, real time, rapidly evolving situations. You may think I'm talking about combat, and it's true that combat is all of those things, but a lot of other things we do are as well. Flight operations, aspects of convoys, simulated combat in training, operating heavy, dangerous equipment, working with weapons and explosives, etc. In those kinds of situations all cordialness is dropped, and either rote, robotic professionalism takes over (when things are going mostly to plan) or extremely rude, abrupt, harsh and direct language is used (when things are about to go south and there's a high potential of someone getting hurt or dying). Basic helps people adapt to those situations and not be jarred or surprised by it. It also washes out recruits who absolutely can not deal with that sort of thing, which is definitely something that happens. Some people just cannot deal with high stress, high stakes situations, which is fine, but the military isn't the place for them, and being able to find that out early is so valuable that it could save someone's life.

I'd agree with https://tildes.net/user/CALICO above; you don't learn much about what you're actually going to be doing in basic. Most of that is handled by follow on and on the job training, basic is just that, the absolute basic you need to be able to survive in the military. I think there may be a way to handle these high stress situations without screaming at recruits, but I also think that there's always going to be a need to test people's breaking points, so to speak, before there are actual lives on the line.

Interestingly, you see this sort of thing across all fields where these kinds of high stakes, life or death situations tend to come up. Fishermen, police officers, firefighters, high rise construction workers, steel workers, loggers and so on all have their own "hazing" rituals, some formal, some informal, all sort of getting around to testing someone's mettle in high stakes situations before they're put into one "for real".