I'm not sure about introverted. I am, but when I get excited about a topic, I can be as loud as the next person. As long as I feel I have something to contribute, that is. I can rant for two minutes straight and then suddenly and unexpectedly shut up when I've made my point. People are sometimes surprised and ask why I suddenly stopped talking. I'll answer: "I've made my point."... :3
So my bet is on error avoidance.