[Chris2048]

I think the difference is:

- is energised by interacting with people

vs

- is de-energised by interacting with people

But there is a social skills / anxiety aspect to this.

Some people aren't particularly inherently energised by social interaction, so will always be introverted. That doesn't mean some social interaction isn't beneficial though - It might mean that they need a lot less though, like how some people biologically need less sleep than others, or degrade slower when deprived of it.

Incidentally, I wonder whether "coping mechanisms" are the difference - that introverts develop stronger internal dialogues that substitute for normal (external) social interaction(s).