I think it's hard to unasshole someone who doesn't want to be unassholed, or who simply doesn't value it. But I think if you really call out every single behavior that's assholey (in private, so they aren't embarrassed and defensive) then eventually people do start to get it and, if they want to change, can.

It could be one of those fake it 'til you make it deals. Someone is an asshole internally still but puts on a veneer of nonassholeishness because they are operating in an environment where it's not tolerated, and over time kind of mellow out. At the time of writing this comment, there's only one comment on my post and it's from someone who says s/he indeed was an asshole and it took this kind of incessant badgering to figure it out.

Someone in authority has to tell them specifically what they're doing wrong and that they have to stop.

I've seen people fired when they didn't listen. The improvement to the rest of the company greatly exceeded the loss from that individual. It is a big factor in psychological safety.

I think both are hard but often doable!

And you can set up processes to limit harm from untrained or malicious people. For some reason this doesn't seem to be widely done when it comes to internal "asshole" behavior.

Lots of companies require code reviews before software gets deployed or require two signatures on a company check. But they'll have freeform meetings where anyone can speak next if they manage to grab the "floor" and won't maintain records to prevent someone from claiming undue credit for an accomplishment.

I dunno, seems easy enough to give a set of rules to follow in the workplace but as someone who's worked as a college tutor, it can be hard to impossible to get some people up to speed technically.

True, you can't train anyone, but whether someone is trainable and eager to learn is usually apparent very quickly. It's not always something that comes across in an interview, but usually.

You can: it's called CBT, but it's costly and the subject has to want to become less of an asshole.