Thanks for sharing this. Not that I didn't know we introverts are the vast minority, or that we tend to get stimulated more by stuff inside our heads than stuff outside it, but it was interesting to see evidence of a biological basis.

Yeah, it's interesting that there's actually a reason why we're more stimulated by things inside our head, and extroverts are more stimulated by the outside world. And we have more brain activity, too. *snicker*

Well of course we do. =D