Talking about introversion, I found this 9gag photo while browsing on work. Yes, I do internet browsing while at work.
This is the description to pound for. No more buts or ifs.
Hobbies or activities that will make sound if a person is Introvert:
Playing video games (check)
Playing musical instrument
Or anything that describes an activity that can be done alone.
Photo credit: See watermarks.