Extroverts may have more going on socially, but we’ve got more going on upstairs. The ‘more’ in the heads of introverts doesn’t refer to more intelligence or creativity, but to the preference for incubating—rather than quickly acting on—thoughts and impressions. The activity centre for introverts is inside, not outside. When an introvert sees an image or hears a question, ideas get tossed around inside while the surface stays calm; an extrovert is more likely to toss out quick impressions and process them out in the open.
-Laurie Helgoe