@TanMath Ah I see! I've rejigged it and added an intro line. I think my answer has the meat, but as you say, it's lacking that punchy answer feel, so thanks for the tip. Your answer is fine, and it was a nice touch referring to Provine. I haven't mentioned him directly, I only link to articles that are based on his research.
I think one thing my answer does better (again, v. biased) is build a case for why laughter is primitive by detailing that it's not unique to humans and has nothing to do with word-based language.