Origins of public displays of praise and disdain (clapping, booing, etc.)

Factual Questions
1

Why do (e.g.) people in the US (and elsewhere) repeatedly slap their hands together audibly to indicate they like someone in a public venue, and boo and hiss to indicate they don’t?

And all the other conventions (as I understand, whistling is the equivalent of booing in some parts of Europe).

Etc., etc.

2
  • sweet triple digits! *
3

Yes. It is.
Apart from that, no clue about your question…

4

WAG – Why not? You need some way to indicate your feelings that will be percieved at a distance. How many ways are there?

(BTW, I understand deaf people wave their hands to cheer.)