Why we laugh evolutionarily speaking.?

I've asked this question before, and the only answer I got was one saying that not only is it cool that we laugh, but that also, in some tribes that are away from anybody other than people also of that tribe, they laugh too(ruling out that it is developed socially, I assume). But the fact that a lot of people don't laugh at funny things when they are alone shows that it is mostly a form of communication(letting the other person know u enjoyed whatever it was). So a little research about what happens when we laugh in the brain showed me that we use, what was called, "A very ancient part of the brain" when we laugh, and very random parts of the brain too, as opposed to other emotions, like sadness, or happiness. Also, I assume sense animals do not understand the concept of humor, or sarcasm, it was one of the last things developed in the human mind.

My question is- Sense a laugh, to me, seems very close to an Ape call(or tan) and it uses a part of the brain that is really old(instincts?), and a wide range of the brain, is it possible that our brain never learned how to handle "Funny" and so we just go back to instincts? (what do monkeys do for anything? they make a "monkey call" which sounds relatively close to a laugh).

This is just something i came up with after some research, it may already have been said or whatnot, I don't know, I'm just asking if it is possible, or a stupid theory.