I've actually been wondering about this recently... as recently past events have reared their head within my conscious mind and I have become aware of the fact that as a result of them, I have built a myriad of defense mechanisms. It's evident, now, in my apprehension toward relationships (friendships or otherwise) and the way I conduct myself in social situations.
I wonder if at the core, I could be an extravert. When I was a kid, before all this defense building started, I was excessively outgoing and chatty. When I take the cognitive function tests, they usually come out as ENFP though I test as an INFP.
I think it's possible.